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2017-05-08mm, vmalloc: use __GFP_HIGHMEM implicitlyMichal Hocko1-1/+1
__vmalloc* allows users to provide gfp flags for the underlying allocation. This API is quite popular $ git grep "=[[:space:]]__vmalloc\|return[[:space:]]*__vmalloc" | wc -l 77 The only problem is that many people are not aware that they really want to give __GFP_HIGHMEM along with other flags because there is really no reason to consume precious lowmemory on CONFIG_HIGHMEM systems for pages which are mapped to the kernel vmalloc space. About half of users don't use this flag, though. This signals that we make the API unnecessarily too complex. This patch simply uses __GFP_HIGHMEM implicitly when allocating pages to be mapped to the vmalloc space. Current users which add __GFP_HIGHMEM are simplified and drop the flag. Link: http://lkml.kernel.org/r/20170307141020.29107-1-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Cristopher Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-03kasan: separate report parts by empty linesAndrey Konovalov1-0/+7
Makes the report easier to read. Link: http://lkml.kernel.org/r/20170302134851.101218-10-andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Acked-by: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-03kasan: improve double-free report formatAndrey Konovalov3-18/+17
Changes double-free report header from BUG: Double free or freeing an invalid pointer Unexpected shadow byte: 0xFB to BUG: KASAN: double-free or invalid-free in kmalloc_oob_left+0xe5/0xef This makes a bug uniquely identifiable by the first report line. To account for removing of the unexpected shadow value, print shadow bytes at the end of the report as in reports for other kinds of bugs. Link: http://lkml.kernel.org/r/20170302134851.101218-9-andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Acked-by: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-03kasan: print page description after stacksAndrey Konovalov1-6/+8
Moves page description after the stacks since it's less important. Link: http://lkml.kernel.org/r/20170302134851.101218-8-andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Acked-by: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-03kasan: improve slab object descriptionAndrey Konovalov1-11/+42
Changes slab object description from: Object at ffff880068388540, in cache kmalloc-128 size: 128 to: The buggy address belongs to the object at ffff880068388540 which belongs to the cache kmalloc-128 of size 128 The buggy address is located 123 bytes inside of 128-byte region [ffff880068388540, ffff8800683885c0) Makes it more explanatory and adds information about relative offset of the accessed address to the start of the object. Link: http://lkml.kernel.org/r/20170302134851.101218-7-andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Acked-by: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-03kasan: change report headerAndrey Konovalov1-4/+4
Change report header format from: BUG: KASAN: use-after-free in unwind_get_return_address+0x28a/0x2c0 at addr ffff880069437950 Read of size 8 by task insmod/3925 to: BUG: KASAN: use-after-free in unwind_get_return_address+0x28a/0x2c0 Read of size 8 at addr ffff880069437950 by task insmod/3925 The exact access address is not usually important, so move it to the second line. This also makes the header look visually balanced. Link: http://lkml.kernel.org/r/20170302134851.101218-6-andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Acked-by: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-03kasan: simplify address description logicAndrey Konovalov1-16/+21
Simplify logic for describing a memory address. Add addr_to_page() helper function. Makes the code easier to follow. Link: http://lkml.kernel.org/r/20170302134851.101218-5-andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Acked-by: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-03kasan: change allocation and freeing stack traces headersAndrey Konovalov1-6/+4
Change stack traces headers from: Allocated: PID = 42 to: Allocated by task 42: Makes the report one line shorter and look better. Link: http://lkml.kernel.org/r/20170302134851.101218-4-andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Acked-by: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-03kasan: unify report headersAndrey Konovalov1-13/+13
Unify KASAN report header format for different kinds of bad memory accesses. Makes the code simpler. Link: http://lkml.kernel.org/r/20170302134851.101218-3-andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Acked-by: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-03kasan: introduce helper functions for determining bug typeAndrey Konovalov1-10/+30
Patch series "kasan: improve error reports", v2. This patchset improves KASAN reports by making them easier to read and a little more detailed. Also improves mm/kasan/report.c readability. Effectively changes a use-after-free report to: ================================================================== BUG: KASAN: use-after-free in kmalloc_uaf+0xaa/0xb6 [test_kasan] Write of size 1 at addr ffff88006aa59da8 by task insmod/3951 CPU: 1 PID: 3951 Comm: insmod Tainted: G B 4.10.0+ #84 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Call Trace: dump_stack+0x292/0x398 print_address_description+0x73/0x280 kasan_report.part.2+0x207/0x2f0 __asan_report_store1_noabort+0x2c/0x30 kmalloc_uaf+0xaa/0xb6 [test_kasan] kmalloc_tests_init+0x4f/0xa48 [test_kasan] do_one_initcall+0xf3/0x390 do_init_module+0x215/0x5d0 load_module+0x54de/0x82b0 SYSC_init_module+0x3be/0x430 SyS_init_module+0x9/0x10 entry_SYSCALL_64_fastpath+0x1f/0xc2 RIP: 0033:0x7f22cfd0b9da RSP: 002b:00007ffe69118a78 EFLAGS: 00000206 ORIG_RAX: 00000000000000af RAX: ffffffffffffffda RBX: 0000555671242090 RCX: 00007f22cfd0b9da RDX: 00007f22cffcaf88 RSI: 000000000004df7e RDI: 00007f22d0399000 RBP: 00007f22cffcaf88 R08: 0000000000000003 R09: 0000000000000000 R10: 00007f22cfd07d0a R11: 0000000000000206 R12: 0000555671243190 R13: 000000000001fe81 R14: 0000000000000000 R15: 0000000000000004 Allocated by task 3951: save_stack_trace+0x16/0x20 save_stack+0x43/0xd0 kasan_kmalloc+0xad/0xe0 kmem_cache_alloc_trace+0x82/0x270 kmalloc_uaf+0x56/0xb6 [test_kasan] kmalloc_tests_init+0x4f/0xa48 [test_kasan] do_one_initcall+0xf3/0x390 do_init_module+0x215/0x5d0 load_module+0x54de/0x82b0 SYSC_init_module+0x3be/0x430 SyS_init_module+0x9/0x10 entry_SYSCALL_64_fastpath+0x1f/0xc2 Freed by task 3951: save_stack_trace+0x16/0x20 save_stack+0x43/0xd0 kasan_slab_free+0x72/0xc0 kfree+0xe8/0x2b0 kmalloc_uaf+0x85/0xb6 [test_kasan] kmalloc_tests_init+0x4f/0xa48 [test_kasan] do_one_initcall+0xf3/0x390 do_init_module+0x215/0x5d0 load_module+0x54de/0x82b0 SYSC_init_module+0x3be/0x430 SyS_init_module+0x9/0x10 entry_SYSCALL_64_fastpath+0x1f/0xc The buggy address belongs to the object at ffff88006aa59da0 which belongs to the cache kmalloc-16 of size 16 The buggy address is located 8 bytes inside of 16-byte region [ffff88006aa59da0, ffff88006aa59db0) The buggy address belongs to the page: page:ffffea0001aa9640 count:1 mapcount:0 mapping: (null) index:0x0 flags: 0x100000000000100(slab) raw: 0100000000000100 0000000000000000 0000000000000000 0000000180800080 raw: ffffea0001abe380 0000000700000007 ffff88006c401b40 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88006aa59c80: 00 00 fc fc 00 00 fc fc 00 00 fc fc 00 00 fc fc ffff88006aa59d00: 00 00 fc fc 00 00 fc fc 00 00 fc fc 00 00 fc fc >ffff88006aa59d80: fb fb fc fc fb fb fc fc fb fb fc fc fb fb fc fc ^ ffff88006aa59e00: fb fb fc fc fb fb fc fc fb fb fc fc fb fb fc fc ffff88006aa59e80: fb fb fc fc 00 00 fc fc 00 00 fc fc 00 00 fc fc ================================================================== from: ================================================================== BUG: KASAN: use-after-free in kmalloc_uaf+0xaa/0xb6 [test_kasan] at addr ffff88006c4dcb28 Write of size 1 by task insmod/3984 CPU: 1 PID: 3984 Comm: insmod Tainted: G B 4.10.0+ #83 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Call Trace: dump_stack+0x292/0x398 kasan_object_err+0x1c/0x70 kasan_report.part.1+0x20e/0x4e0 __asan_report_store1_noabort+0x2c/0x30 kmalloc_uaf+0xaa/0xb6 [test_kasan] kmalloc_tests_init+0x4f/0xa48 [test_kasan] do_one_initcall+0xf3/0x390 do_init_module+0x215/0x5d0 load_module+0x54de/0x82b0 SYSC_init_module+0x3be/0x430 SyS_init_module+0x9/0x10 entry_SYSCALL_64_fastpath+0x1f/0xc2 RIP: 0033:0x7feca0f779da RSP: 002b:00007ffdfeae5218 EFLAGS: 00000206 ORIG_RAX: 00000000000000af RAX: ffffffffffffffda RBX: 000055a064c13090 RCX: 00007feca0f779da RDX: 00007feca1236f88 RSI: 000000000004df7e RDI: 00007feca1605000 RBP: 00007feca1236f88 R08: 0000000000000003 R09: 0000000000000000 R10: 00007feca0f73d0a R11: 0000000000000206 R12: 000055a064c14190 R13: 000000000001fe81 R14: 0000000000000000 R15: 0000000000000004 Object at ffff88006c4dcb20, in cache kmalloc-16 size: 16 Allocated: PID = 3984 save_stack_trace+0x16/0x20 save_stack+0x43/0xd0 kasan_kmalloc+0xad/0xe0 kmem_cache_alloc_trace+0x82/0x270 kmalloc_uaf+0x56/0xb6 [test_kasan] kmalloc_tests_init+0x4f/0xa48 [test_kasan] do_one_initcall+0xf3/0x390 do_init_module+0x215/0x5d0 load_module+0x54de/0x82b0 SYSC_init_module+0x3be/0x430 SyS_init_module+0x9/0x10 entry_SYSCALL_64_fastpath+0x1f/0xc2 Freed: PID = 3984 save_stack_trace+0x16/0x20 save_stack+0x43/0xd0 kasan_slab_free+0x73/0xc0 kfree+0xe8/0x2b0 kmalloc_uaf+0x85/0xb6 [test_kasan] kmalloc_tests_init+0x4f/0xa48 [test_kasan] do_one_initcall+0xf3/0x390 do_init_module+0x215/0x5d0 load_module+0x54de/0x82b0 SYSC_init_module+0x3be/0x430 SyS_init_module+0x9/0x10 entry_SYSCALL_64_fastpath+0x1f/0xc2 Memory state around the buggy address: ffff88006c4dca00: fb fb fc fc fb fb fc fc fb fb fc fc fb fb fc fc ffff88006c4dca80: fb fb fc fc fb fb fc fc fb fb fc fc fb fb fc fc >ffff88006c4dcb00: fb fb fc fc fb fb fc fc fb fb fc fc fb fb fc fc ^ ffff88006c4dcb80: fb fb fc fc 00 00 fc fc fb fb fc fc fb fb fc fc ffff88006c4dcc00: fb fb fc fc fb fb fc fc fb fb fc fc fb fb fc fc ================================================================== This patch (of 9): Introduce get_shadow_bug_type() function, which determines bug type based on the shadow value for a particular kernel address. Introduce get_wild_bug_type() function, which determines bug type for addresses which don't have a corresponding shadow value. Link: http://lkml.kernel.org/r/20170302134851.101218-2-andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Acked-by: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-31kasan: report only the first error by defaultMark Rutland2-5/+36
Disable kasan after the first report. There are several reasons for this: - Single bug quite often has multiple invalid memory accesses causing storm in the dmesg. - Write OOB access might corrupt metadata so the next report will print bogus alloc/free stacktraces. - Reports after the first easily could be not bugs by itself but just side effects of the first one. Given that multiple reports usually only do harm, it makes sense to disable kasan after the first one. If user wants to see all the reports, the boot-time parameter kasan_multi_shot must be used. [aryabinin@virtuozzo.com: wrote changelog and doc, added missing include] Link: http://lkml.kernel.org/r/20170323154416.30257-1-aryabinin@virtuozzo.com Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-10Merge branch 'prep-for-5level'Linus Torvalds1-5/+39
Merge 5-level page table prep from Kirill Shutemov: "Here's relatively low-risk part of 5-level paging patchset. Merging it now will make x86 5-level paging enabling in v4.12 easier. The first patch is actually x86-specific: detect 5-level paging support. It boils down to single define. The rest of patchset converts Linux MMU abstraction from 4- to 5-level paging. Enabling of new abstraction in most cases requires adding single line of code in arch-specific code. The rest is taken care by asm-generic/. Changes to mm/ code are mostly mechanical: add support for new page table level -- p4d_t -- where we deal with pud_t now. v2: - fix build on microblaze (Michal); - comment for __ARCH_HAS_5LEVEL_HACK in kasan_populate_zero_shadow(); - acks from Michal" * emailed patches from Kirill A Shutemov <kirill.shutemov@linux.intel.com>: mm: introduce __p4d_alloc() mm: convert generic code to 5-level paging asm-generic: introduce <asm-generic/pgtable-nop4d.h> arch, mm: convert all architectures to use 5level-fixup.h asm-generic: introduce __ARCH_USE_5LEVEL_HACK asm-generic: introduce 5level-fixup.h x86/cpufeature: Add 5-level paging detection
2017-03-09kasan: fix races in quarantine_remove_cache()Dmitry Vyukov1-6/+36
quarantine_remove_cache() frees all pending objects that belong to the cache, before we destroy the cache itself. However there are currently two possibilities how it can fail to do so. First, another thread can hold some of the objects from the cache in temp list in quarantine_put(). quarantine_put() has a windows of enabled interrupts, and on_each_cpu() in quarantine_remove_cache() can finish right in that window. These objects will be later freed into the destroyed cache. Then, quarantine_reduce() has the same problem. It grabs a batch of objects from the global quarantine, then unlocks quarantine_lock and then frees the batch. quarantine_remove_cache() can finish while some objects from the cache are still in the local to_free list in quarantine_reduce(). Fix the race with quarantine_put() by disabling interrupts for the whole duration of quarantine_put(). In combination with on_each_cpu() in quarantine_remove_cache() it ensures that quarantine_remove_cache() either sees the objects in the per-cpu list or in the global list. Fix the race with quarantine_reduce() by protecting quarantine_reduce() with srcu critical section and then doing synchronize_srcu() at the end of quarantine_remove_cache(). I've done some assessment of how good synchronize_srcu() works in this case. And on a 4 CPU VM I see that it blocks waiting for pending read critical sections in about 2-3% of cases. Which looks good to me. I suspect that these races are the root cause of some GPFs that I episodically hit. Previously I did not have any explanation for them. BUG: unable to handle kernel NULL pointer dereference at 00000000000000c8 IP: qlist_free_all+0x2e/0xc0 mm/kasan/quarantine.c:155 PGD 6aeea067 PUD 60ed7067 PMD 0 Oops: 0000 [#1] SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 0 PID: 13667 Comm: syz-executor2 Not tainted 4.10.0+ #60 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 task: ffff88005f948040 task.stack: ffff880069818000 RIP: 0010:qlist_free_all+0x2e/0xc0 mm/kasan/quarantine.c:155 RSP: 0018:ffff88006981f298 EFLAGS: 00010246 RAX: ffffea0000ffff00 RBX: 0000000000000000 RCX: ffffea0000ffff1f RDX: 0000000000000000 RSI: ffff88003fffc3e0 RDI: 0000000000000000 RBP: ffff88006981f2c0 R08: ffff88002fed7bd8 R09: 00000001001f000d R10: 00000000001f000d R11: ffff88006981f000 R12: ffff88003fffc3e0 R13: ffff88006981f2d0 R14: ffffffff81877fae R15: 0000000080000000 FS: 00007fb911a2d700(0000) GS:ffff88003ec00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000000000c8 CR3: 0000000060ed6000 CR4: 00000000000006f0 Call Trace: quarantine_reduce+0x10e/0x120 mm/kasan/quarantine.c:239 kasan_kmalloc+0xca/0xe0 mm/kasan/kasan.c:590 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:544 slab_post_alloc_hook mm/slab.h:456 [inline] slab_alloc_node mm/slub.c:2718 [inline] kmem_cache_alloc_node+0x1d3/0x280 mm/slub.c:2754 __alloc_skb+0x10f/0x770 net/core/skbuff.c:219 alloc_skb include/linux/skbuff.h:932 [inline] _sctp_make_chunk+0x3b/0x260 net/sctp/sm_make_chunk.c:1388 sctp_make_data net/sctp/sm_make_chunk.c:1420 [inline] sctp_make_datafrag_empty+0x208/0x360 net/sctp/sm_make_chunk.c:746 sctp_datamsg_from_user+0x7e8/0x11d0 net/sctp/chunk.c:266 sctp_sendmsg+0x2611/0x3970 net/sctp/socket.c:1962 inet_sendmsg+0x164/0x5b0 net/ipv4/af_inet.c:761 sock_sendmsg_nosec net/socket.c:633 [inline] sock_sendmsg+0xca/0x110 net/socket.c:643 SYSC_sendto+0x660/0x810 net/socket.c:1685 SyS_sendto+0x40/0x50 net/socket.c:1653 I am not sure about backporting. The bug is quite hard to trigger, I've seen it few times during our massive continuous testing (however, it could be cause of some other episodic stray crashes as it leads to memory corruption...). If it is triggered, the consequences are very bad -- almost definite bad memory corruption. The fix is non trivial and has chances of introducing new bugs. I am also not sure how actively people use KASAN on older releases. [dvyukov@google.com: - sorted includes[ Link: http://lkml.kernel.org/r/20170309094028.51088-1-dvyukov@google.com Link: http://lkml.kernel.org/r/20170308151532.5070-1-dvyukov@google.com Signed-off-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-09kasan: resched in quarantine_remove_cache()Dmitry Vyukov1-1/+8
We see reported stalls/lockups in quarantine_remove_cache() on machines with large amounts of RAM. quarantine_remove_cache() needs to scan whole quarantine in order to take out all objects belonging to the cache. Quarantine is currently 1/32-th of RAM, e.g. on a machine with 256GB of memory that will be 8GB. Moreover quarantine scanning is a walk over uncached linked list, which is slow. Add cond_resched() after scanning of each non-empty batch of objects. Batches are specifically kept of reasonable size for quarantine_put(). On a machine with 256GB of RAM we should have ~512 non-empty batches, each with 16MB of objects. Link: http://lkml.kernel.org/r/20170308154239.25440-1-dvyukov@google.com Signed-off-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Greg Thelen <gthelen@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-09mm: convert generic code to 5-level pagingKirill A. Shutemov1-5/+39
Convert all non-architecture-specific code to 5-level paging. It's mostly mechanical adding handling one more page table level in places where we deal with pud_t. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-02sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar1-0/+1
<linux/sched/task_stack.h> We are going to split <linux/sched/task_stack.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/task_stack.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02kasan, sched/headers: Uninline kasan_enable/disable_current()Ingo Molnar1-0/+10
<linux/kasan.h> is a low level header that is included early in affected kernel headers. But it includes <linux/sched.h> which complicates the cleanup of sched.h dependencies. But kasan.h has almost no need for sched.h: its only use of scheduler functionality is in two inline functions which are not used very frequently - so uninline kasan_enable_current() and kasan_disable_current(). Also add a <linux/sched.h> dependency to a .c file that depended on kasan.h including it. This paves the way to remove the <linux/sched.h> include from kasan.h. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-02-24kasan: drain quarantine of memcg slab objectsGreg Thelen2-1/+2
Per memcg slab accounting and kasan have a problem with kmem_cache destruction. - kmem_cache_create() allocates a kmem_cache, which is used for allocations from processes running in root (top) memcg. - Processes running in non root memcg and allocating with either __GFP_ACCOUNT or from a SLAB_ACCOUNT cache use a per memcg kmem_cache. - Kasan catches use-after-free by having kfree() and kmem_cache_free() defer freeing of objects. Objects are placed in a quarantine. - kmem_cache_destroy() destroys root and non root kmem_caches. It takes care to drain the quarantine of objects from the root memcg's kmem_cache, but ignores objects associated with non root memcg. This causes leaks because quarantined per memcg objects refer to per memcg kmem cache being destroyed. To see the problem: 1) create a slab cache with kmem_cache_create(,,,SLAB_ACCOUNT,) 2) from non root memcg, allocate and free a few objects from cache 3) dispose of the cache with kmem_cache_destroy() kmem_cache_destroy() will trigger a "Slab cache still has objects" warning indicating that the per memcg kmem_cache structure was leaked. Fix the leak by draining kasan quarantined objects allocated from non root memcg. Racing memcg deletion is tricky, but handled. kmem_cache_destroy() => shutdown_memcg_caches() => __shutdown_memcg_cache() => shutdown_cache() flushes per memcg quarantined objects, even if that memcg has been rmdir'd and gone through memcg_deactivate_kmem_caches(). This leak only affects destroyed SLAB_ACCOUNT kmem caches when kasan is enabled. So I don't think it's worth patching stable kernels. Link: http://lkml.kernel.org/r/1482257462-36948-1-git-send-email-gthelen@google.com Signed-off-by: Greg Thelen <gthelen@google.com> Reviewed-by: Vladimir Davydov <vdavydov.dev@gmail.com> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-22Merge tag 'arm64-upstream' of ↵Linus Torvalds1-7/+8
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux Pull arm64 updates from Will Deacon: - Errata workarounds for Qualcomm's Falkor CPU - Qualcomm L2 Cache PMU driver - Qualcomm SMCCC firmware quirk - Support for DEBUG_VIRTUAL - CPU feature detection for userspace via MRS emulation - Preliminary work for the Statistical Profiling Extension - Misc cleanups and non-critical fixes * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (74 commits) arm64/kprobes: consistently handle MRS/MSR with XZR arm64: cpufeature: correctly handle MRS to XZR arm64: traps: correctly handle MRS/MSR with XZR arm64: ptrace: add XZR-safe regs accessors arm64: include asm/assembler.h in entry-ftrace.S arm64: fix warning about swapper_pg_dir overflow arm64: Work around Falkor erratum 1003 arm64: head.S: Enable EL1 (host) access to SPE when entered at EL2 arm64: arch_timer: document Hisilicon erratum 161010101 arm64: use is_vmalloc_addr arm64: use linux/sizes.h for constants arm64: uaccess: consistently check object sizes perf: add qcom l2 cache perf events driver arm64: remove wrong CONFIG_PROC_SYSCTL ifdef ARM: smccc: Update HVC comment to describe new quirk parameter arm64: do not trace atomic operations ACPI/IORT: Fix the error return code in iort_add_smmu_platform_device() ACPI/IORT: Fix iort_node_get_id() mapping entries indexing arm64: mm: enable CONFIG_HOLES_IN_ZONE for NUMA perf: xgene: Include module.h ...
2017-02-03kasan: respect /proc/sys/kernel/traceoff_on_warningPeter Zijlstra1-0/+3
After much waiting I finally reproduced a KASAN issue, only to find my trace-buffer empty of useful information because it got spooled out :/ Make kasan_report honour the /proc/sys/kernel/traceoff_on_warning interface. Link: http://lkml.kernel.org/r/20170125164106.3514-1-aryabinin@virtuozzo.com Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Acked-by: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-01-11mm/kasan: Switch to using __pa_symbol and lm_aliasLaura Abbott1-7/+8
__pa_symbol is the correct API to find the physical address of symbols. Switch to it to allow for debugging APIs to work correctly. Other functions such as p*d_populate may call __pa internally. Ensure that the address passed is in the linear region by calling lm_alias. Reviewed-by: Mark Rutland <mark.rutland@arm.com> Tested-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Laura Abbott <labbott@redhat.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2016-12-13Merge tag 'pm-4.10-rc1' of ↵Linus Torvalds1-1/+8
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull power management updates from Rafael Wysocki: "Again, cpufreq gets more changes than the other parts this time (one new driver, one old driver less, a bunch of enhancements of the existing code, new CPU IDs, fixes, cleanups) There also are some changes in cpuidle (idle injection rework, a couple of new CPU IDs, online/offline rework in intel_idle, fixes and cleanups), in the generic power domains framework (mostly related to supporting power domains containing CPUs), and in the Operating Performance Points (OPP) library (mostly related to supporting devices with multiple voltage regulators) In addition to that, the system sleep state selection interface is modified to make it easier for distributions with unchanged user space to support suspend-to-idle as the default system suspend method, some issues are fixed in the PM core, the latency tolerance PM QoS framework is improved a bit, the Intel RAPL power capping driver is cleaned up and there are some fixes and cleanups in the devfreq subsystem Specifics: - New cpufreq driver for Broadcom STB SoCs and a Device Tree binding for it (Markus Mayer) - Support for ARM Integrator/AP and Integrator/CP in the generic DT cpufreq driver and elimination of the old Integrator cpufreq driver (Linus Walleij) - Support for the zx296718, r8a7743 and r8a7745, Socionext UniPhier, and PXA SoCs in the the generic DT cpufreq driver (Baoyou Xie, Geert Uytterhoeven, Masahiro Yamada, Robert Jarzmik) - cpufreq core fix to eliminate races that may lead to using inactive policy objects and related cleanups (Rafael Wysocki) - cpufreq schedutil governor update to make it use SCHED_FIFO kernel threads (instead of regular workqueues) for doing delayed work (to reduce the response latency in some cases) and related cleanups (Viresh Kumar) - New cpufreq sysfs attribute for resetting statistics (Markus Mayer) - cpufreq governors fixes and cleanups (Chen Yu, Stratos Karafotis, Viresh Kumar) - Support for using generic cpufreq governors in the intel_pstate driver (Rafael Wysocki) - Support for per-logical-CPU P-state limits and the EPP/EPB (Energy Performance Preference/Energy Performance Bias) knobs in the intel_pstate driver (Srinivas Pandruvada) - New CPU ID for Knights Mill in intel_pstate (Piotr Luc) - intel_pstate driver modification to use the P-state selection algorithm based on CPU load on platforms with the system profile in the ACPI tables set to "mobile" (Srinivas Pandruvada) - intel_pstate driver cleanups (Arnd Bergmann, Rafael Wysocki, Srinivas Pandruvada) - cpufreq powernv driver updates including fast switching support (for the schedutil governor), fixes and cleanus (Akshay Adiga, Andrew Donnellan, Denis Kirjanov) - acpi-cpufreq driver rework to switch it over to the new CPU offline/online state machine (Sebastian Andrzej Siewior) - Assorted cleanups in cpufreq drivers (Wei Yongjun, Prashanth Prakash) - Idle injection rework (to make it use the regular idle path instead of a home-grown custom one) and related powerclamp thermal driver updates (Peter Zijlstra, Jacob Pan, Petr Mladek, Sebastian Andrzej Siewior) - New CPU IDs for Atom Z34xx and Knights Mill in intel_idle (Andy Shevchenko, Piotr Luc) - intel_idle driver cleanups and switch over to using the new CPU offline/online state machine (Anna-Maria Gleixner, Sebastian Andrzej Siewior) - cpuidle DT driver update to support suspend-to-idle properly (Sudeep Holla) - cpuidle core cleanups and misc updates (Daniel Lezcano, Pan Bian, Rafael Wysocki) - Preliminary support for power domains including CPUs in the generic power domains (genpd) framework and related DT bindings (Lina Iyer) - Assorted fixes and cleanups in the generic power domains (genpd) framework (Colin Ian King, Dan Carpenter, Geert Uytterhoeven) - Preliminary support for devices with multiple voltage regulators and related fixes and cleanups in the Operating Performance Points (OPP) library (Viresh Kumar, Masahiro Yamada, Stephen Boyd) - System sleep state selection interface rework to make it easier to support suspend-to-idle as the default system suspend method (Rafael Wysocki) - PM core fixes and cleanups, mostly related to the interactions between the system suspend and runtime PM frameworks (Ulf Hansson, Sahitya Tummala, Tony Lindgren) - Latency tolerance PM QoS framework imorovements (Andrew Lutomirski) - New Knights Mill CPU ID for the Intel RAPL power capping driver (Piotr Luc) - Intel RAPL power capping driver fixes, cleanups and switch over to using the new CPU offline/online state machine (Jacob Pan, Thomas Gleixner, Sebastian Andrzej Siewior) - Fixes and cleanups in the exynos-ppmu, exynos-nocp, rk3399_dmc, rockchip-dfi devfreq drivers and the devfreq core (Axel Lin, Chanwoo Choi, Javier Martinez Canillas, MyungJoo Ham, Viresh Kumar) - Fix for false-positive KASAN warnings during resume from ACPI S3 (suspend-to-RAM) on x86 (Josh Poimboeuf) - Memory map verification during resume from hibernation on x86 to ensure a consistent address space layout (Chen Yu) - Wakeup sources debugging enhancement (Xing Wei) - rockchip-io AVS driver cleanup (Shawn Lin)" * tag 'pm-4.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (127 commits) devfreq: rk3399_dmc: Don't use OPP structures outside of RCU locks devfreq: rk3399_dmc: Remove dangling rcu_read_unlock() devfreq: exynos: Don't use OPP structures outside of RCU locks Documentation: intel_pstate: Document HWP energy/performance hints cpufreq: intel_pstate: Support for energy performance hints with HWP cpufreq: intel_pstate: Add locking around HWP requests PM / sleep: Print active wakeup sources when blocking on wakeup_count reads PM / core: Fix bug in the error handling of async suspend PM / wakeirq: Fix dedicated wakeirq for drivers not using autosuspend PM / Domains: Fix compatible for domain idle state PM / OPP: Don't WARN on multiple calls to dev_pm_opp_set_regulators() PM / OPP: Allow platform specific custom set_opp() callbacks PM / OPP: Separate out _generic_set_opp() PM / OPP: Add infrastructure to manage multiple regulators PM / OPP: Pass struct dev_pm_opp_supply to _set_opp_voltage() PM / OPP: Manage supply's voltage/current in a separate structure PM / OPP: Don't use OPP structure outside of rcu protected section PM / OPP: Reword binding supporting multiple regulators per device PM / OPP: Fix incorrect cpu-supply property in binding cpuidle: Add a kerneldoc comment to cpuidle_use_deepest_state() ..
2016-12-12kasan: eliminate long stalls during quarantine reductionDmitry Vyukov1-46/+48
Currently we dedicate 1/32 of RAM for quarantine and then reduce it by 1/4 of total quarantine size. This can be a significant amount of memory. For example, with 4GB of RAM total quarantine size is 128MB and it is reduced by 32MB at a time. With 128GB of RAM total quarantine size is 4GB and it is reduced by 1GB. This leads to several problems: - freeing 1GB can take tens of seconds, causes rcu stall warnings and just introduces unexpected long delays at random places - if kmalloc() is called under a mutex, other threads stall on that mutex while a thread reduces quarantine - threads wait on quarantine_lock while one thread grabs a large batch of objects to evict - we walk the uncached list of object to free twice which makes all of the above worse - when a thread frees objects, they are already not accounted against global_quarantine.bytes; as the result we can have quarantine_size bytes in quarantine + unbounded amount of memory in large batches in threads that are in process of freeing Reduce size of quarantine in smaller batches to reduce the delays. The only reason to reduce it in batches is amortization of overheads, the new batch size of 1MB should be well enough to amortize spinlock lock/unlock and few function calls. Plus organize quarantine as a FIFO array of batches. This allows to not walk the list in quarantine_reduce() under quarantine_lock, which in turn reduces contention and is just faster. This improves performance of heavy load (syzkaller fuzzing) by ~20% with 4 CPUs and 32GB of RAM. Also this eliminates frequent (every 5 sec) drops of CPU consumption from ~400% to ~100% (one thread reduces quarantine while others are waiting on a mutex). Some reference numbers: 1. Machine with 4 CPUs and 4GB of memory. Quarantine size 128MB. Currently we free 32MB at at time. With new code we free 1MB at a time (1024 batches, ~128 are used). 2. Machine with 32 CPUs and 128GB of memory. Quarantine size 4GB. Currently we free 1GB at at time. With new code we free 8MB at a time (1024 batches, ~512 are used). 3. Machine with 4096 CPUs and 1TB of memory. Quarantine size 32GB. Currently we free 8GB at at time. With new code we free 4MB at a time (16K batches, ~8K are used). Link: http://lkml.kernel.org/r/1478756952-18695-1-git-send-email-dvyukov@google.com Signed-off-by: Dmitry Vyukov <dvyukov@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Greg Thelen <gthelen@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-12kasan: support panic_on_warnDmitry Vyukov1-0/+2
If user sets panic_on_warn, he wants kernel to panic if there is anything barely wrong with the kernel. KASAN-detected errors are definitely not less benign than an arbitrary kernel WARNING. Panic after KASAN errors if panic_on_warn is set. We use this for continuous fuzzing where we want kernel to stop and reboot on any error. Link: http://lkml.kernel.org/r/1476694764-31986-1-git-send-email-dvyukov@google.com Signed-off-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-12Merge branches 'pm-sleep' and 'powercap'Rafael J. Wysocki1-1/+8
* pm-sleep: PM / sleep: Print active wakeup sources when blocking on wakeup_count reads x86/suspend: fix false positive KASAN warning on suspend/resume PM / sleep / ACPI: Use the ACPI_FADT_LOW_POWER_S0 flag PM / sleep: System sleep state selection interface rework PM / hibernate: Verify the consistent of e820 memory map by md5 digest * powercap: powercap / RAPL: Add Knights Mill CPUID powercap/intel_rapl: fix and tidy up error handling powercap/intel_rapl: Track active CPUs internally powercap/intel_rapl: Cleanup duplicated init code powercap/intel rapl: Convert to hotplug state machine powercap/intel_rapl: Propagate error code when registration fails powercap/intel_rapl: Add missing domain data update on hotplug
2016-12-06x86/suspend: fix false positive KASAN warning on suspend/resumeJosh Poimboeuf1-1/+8
Resuming from a suspend operation is showing a KASAN false positive warning: BUG: KASAN: stack-out-of-bounds in unwind_get_return_address+0x11d/0x130 at addr ffff8803867d7878 Read of size 8 by task pm-suspend/7774 page:ffffea000e19f5c0 count:0 mapcount:0 mapping: (null) index:0x0 flags: 0x2ffff0000000000() page dumped because: kasan: bad access detected CPU: 0 PID: 7774 Comm: pm-suspend Tainted: G B 4.9.0-rc7+ #8 Hardware name: Gigabyte Technology Co., Ltd. Z170X-UD5/Z170X-UD5-CF, BIOS F5 03/07/2016 Call Trace: dump_stack+0x63/0x82 kasan_report_error+0x4b4/0x4e0 ? acpi_hw_read_port+0xd0/0x1ea ? kfree_const+0x22/0x30 ? acpi_hw_validate_io_request+0x1a6/0x1a6 __asan_report_load8_noabort+0x61/0x70 ? unwind_get_return_address+0x11d/0x130 unwind_get_return_address+0x11d/0x130 ? unwind_next_frame+0x97/0xf0 __save_stack_trace+0x92/0x100 save_stack_trace+0x1b/0x20 save_stack+0x46/0xd0 ? save_stack_trace+0x1b/0x20 ? save_stack+0x46/0xd0 ? kasan_kmalloc+0xad/0xe0 ? kasan_slab_alloc+0x12/0x20 ? acpi_hw_read+0x2b6/0x3aa ? acpi_hw_validate_register+0x20b/0x20b ? acpi_hw_write_port+0x72/0xc7 ? acpi_hw_write+0x11f/0x15f ? acpi_hw_read_multiple+0x19f/0x19f ? memcpy+0x45/0x50 ? acpi_hw_write_port+0x72/0xc7 ? acpi_hw_write+0x11f/0x15f ? acpi_hw_read_multiple+0x19f/0x19f ? kasan_unpoison_shadow+0x36/0x50 kasan_kmalloc+0xad/0xe0 kasan_slab_alloc+0x12/0x20 kmem_cache_alloc_trace+0xbc/0x1e0 ? acpi_get_sleep_type_data+0x9a/0x578 acpi_get_sleep_type_data+0x9a/0x578 acpi_hw_legacy_wake_prep+0x88/0x22c ? acpi_hw_legacy_sleep+0x3c7/0x3c7 ? acpi_write_bit_register+0x28d/0x2d3 ? acpi_read_bit_register+0x19b/0x19b acpi_hw_sleep_dispatch+0xb5/0xba acpi_leave_sleep_state_prep+0x17/0x19 acpi_suspend_enter+0x154/0x1e0 ? trace_suspend_resume+0xe8/0xe8 suspend_devices_and_enter+0xb09/0xdb0 ? printk+0xa8/0xd8 ? arch_suspend_enable_irqs+0x20/0x20 ? try_to_freeze_tasks+0x295/0x600 pm_suspend+0x6c9/0x780 ? finish_wait+0x1f0/0x1f0 ? suspend_devices_and_enter+0xdb0/0xdb0 state_store+0xa2/0x120 ? kobj_attr_show+0x60/0x60 kobj_attr_store+0x36/0x70 sysfs_kf_write+0x131/0x200 kernfs_fop_write+0x295/0x3f0 __vfs_write+0xef/0x760 ? handle_mm_fault+0x1346/0x35e0 ? do_iter_readv_writev+0x660/0x660 ? __pmd_alloc+0x310/0x310 ? do_lock_file_wait+0x1e0/0x1e0 ? apparmor_file_permission+0x18/0x20 ? security_file_permission+0x73/0x1c0 ? rw_verify_area+0xbd/0x2b0 vfs_write+0x149/0x4a0 SyS_write+0xd9/0x1c0 ? SyS_read+0x1c0/0x1c0 entry_SYSCALL_64_fastpath+0x1e/0xad Memory state around the buggy address: ffff8803867d7700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8803867d7780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff8803867d7800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f4 ^ ffff8803867d7880: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 ffff8803867d7900: 00 00 00 f1 f1 f1 f1 04 f4 f4 f4 f3 f3 f3 f3 00 KASAN instrumentation poisons the stack when entering a function and unpoisons it when exiting the function. However, in the suspend path, some functions never return, so their stack never gets unpoisoned, resulting in stale KASAN shadow data which can cause later false positive warnings like the one above. Reported-by: Scott Bauer <scott.bauer@intel.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-11-30kasan: support use-after-scope detectionDmitry Vyukov3-0/+23
Gcc revision 241896 implements use-after-scope detection. Will be available in gcc 7. Support it in KASAN. Gcc emits 2 new callbacks to poison/unpoison large stack objects when they go in/out of scope. Implement the callbacks and add a test. [dvyukov@google.com: v3] Link: http://lkml.kernel.org/r/1479998292-144502-1-git-send-email-dvyukov@google.com Link: http://lkml.kernel.org/r/1479226045-145148-1-git-send-email-dvyukov@google.com Signed-off-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: <stable@vger.kernel.org> [4.0+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-11-30kasan: update kasan_global for gcc 7Dmitry Vyukov1-0/+3
kasan_global struct is part of compiler/runtime ABI. gcc revision 241983 has added a new field to kasan_global struct. Update kernel definition of kasan_global struct to include the new field. Without this patch KASAN is broken with gcc 7. Link: http://lkml.kernel.org/r/1479219743-28682-1-git-send-email-dvyukov@google.com Signed-off-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: <stable@vger.kernel.org> [4.0+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-16kprobes: Unpoison stack in jprobe_return() for KASANDmitry Vyukov1-3/+19
I observed false KSAN positives in the sctp code, when sctp uses jprobe_return() in jsctp_sf_eat_sack(). The stray 0xf4 in shadow memory are stack redzones: [ ] ================================================================== [ ] BUG: KASAN: stack-out-of-bounds in memcmp+0xe9/0x150 at addr ffff88005e48f480 [ ] Read of size 1 by task syz-executor/18535 [ ] page:ffffea00017923c0 count:0 mapcount:0 mapping: (null) index:0x0 [ ] flags: 0x1fffc0000000000() [ ] page dumped because: kasan: bad access detected [ ] CPU: 1 PID: 18535 Comm: syz-executor Not tainted 4.8.0+ #28 [ ] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ ] ffff88005e48f2d0 ffffffff82d2b849 ffffffff0bc91e90 fffffbfff10971e8 [ ] ffffed000bc91e90 ffffed000bc91e90 0000000000000001 0000000000000000 [ ] ffff88005e48f480 ffff88005e48f350 ffffffff817d3169 ffff88005e48f370 [ ] Call Trace: [ ] [<ffffffff82d2b849>] dump_stack+0x12e/0x185 [ ] [<ffffffff817d3169>] kasan_report+0x489/0x4b0 [ ] [<ffffffff817d31a9>] __asan_report_load1_noabort+0x19/0x20 [ ] [<ffffffff82d49529>] memcmp+0xe9/0x150 [ ] [<ffffffff82df7486>] depot_save_stack+0x176/0x5c0 [ ] [<ffffffff817d2031>] save_stack+0xb1/0xd0 [ ] [<ffffffff817d27f2>] kasan_slab_free+0x72/0xc0 [ ] [<ffffffff817d05b8>] kfree+0xc8/0x2a0 [ ] [<ffffffff85b03f19>] skb_free_head+0x79/0xb0 [ ] [<ffffffff85b0900a>] skb_release_data+0x37a/0x420 [ ] [<ffffffff85b090ff>] skb_release_all+0x4f/0x60 [ ] [<ffffffff85b11348>] consume_skb+0x138/0x370 [ ] [<ffffffff8676ad7b>] sctp_chunk_put+0xcb/0x180 [ ] [<ffffffff8676ae88>] sctp_chunk_free+0x58/0x70 [ ] [<ffffffff8677fa5f>] sctp_inq_pop+0x68f/0xef0 [ ] [<ffffffff8675ee36>] sctp_assoc_bh_rcv+0xd6/0x4b0 [ ] [<ffffffff8677f2c1>] sctp_inq_push+0x131/0x190 [ ] [<ffffffff867bad69>] sctp_backlog_rcv+0xe9/0xa20 [ ... ] [ ] Memory state around the buggy address: [ ] ffff88005e48f380: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ ] ffff88005e48f400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ ] >ffff88005e48f480: f4 f4 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ ] ^ [ ] ffff88005e48f500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ ] ffff88005e48f580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ ] ================================================================== KASAN stack instrumentation poisons stack redzones on function entry and unpoisons them on function exit. If a function exits abnormally (e.g. with a longjmp like jprobe_return()), stack redzones are left poisoned. Later this leads to random KASAN false reports. Unpoison stack redzones in the frames we are going to jump over before doing actual longjmp in jprobe_return(). Signed-off-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: Alexander Potapenko <glider@google.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: kasan-dev@googlegroups.com Cc: surovegin@google.com Cc: rostedt@goodmis.org Link: http://lkml.kernel.org/r/1476454043-101898-1-git-send-email-dvyukov@google.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-11kasan: remove the unnecessary WARN_ONCE from quarantine.cAlexander Potapenko1-5/+2
It's quite unlikely that the user will so little memory that the per-CPU quarantines won't fit into the given fraction of the available memory. Even in that case he won't be able to do anything with the information given in the warning. Link: http://lkml.kernel.org/r/1470929182-101413-1-git-send-email-glider@google.com Signed-off-by: Alexander Potapenko <glider@google.com> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Konovalov <adech.fo@gmail.com> Cc: Christoph Lameter <cl@linux.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kuthonuzo Luruo <kuthonuzo.luruo@hpe.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02kasan: avoid overflowing quarantine size on low memory systemsAlexander Potapenko1-2/+7
If the total amount of memory assigned to quarantine is less than the amount of memory assigned to per-cpu quarantines, |new_quarantine_size| may overflow. Instead, set it to zero. [akpm@linux-foundation.org: cleanup: use WARN_ONCE return value] Link: http://lkml.kernel.org/r/1470063563-96266-1-git-send-email-glider@google.com Fixes: 55834c59098d ("mm: kasan: initial memory quarantine implementation") Signed-off-by: Alexander Potapenko <glider@google.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02kasan: improve double-free reportsAndrey Ryabinin3-18/+41
Currently we just dump stack in case of double free bug. Let's dump all info about the object that we have. [aryabinin@virtuozzo.com: change double free message per Alexander] Link: http://lkml.kernel.org/r/1470153654-30160-1-git-send-email-aryabinin@virtuozzo.com Link: http://lkml.kernel.org/r/1470062715-14077-6-git-send-email-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02mm/kasan: get rid of ->state in struct kasan_alloc_metaAndrey Ryabinin4-63/+35
The state of object currently tracked in two places - shadow memory, and the ->state field in struct kasan_alloc_meta. We can get rid of the latter. The will save us a little bit of memory. Also, this allow us to move free stack into struct kasan_alloc_meta, without increasing memory consumption. So now we should always know when the last time the object was freed. This may be useful for long delayed use-after-free bugs. As a side effect this fixes following UBSAN warning: UBSAN: Undefined behaviour in mm/kasan/quarantine.c:102:13 member access within misaligned address ffff88000d1efebc for type 'struct qlist_node' which requires 8 byte alignment Link: http://lkml.kernel.org/r/1470062715-14077-5-git-send-email-aryabinin@virtuozzo.com Reported-by: kernel test robot <xiaolong.ye@intel.com> Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02mm/kasan: get rid of ->alloc_size in struct kasan_alloc_metaAndrey Ryabinin3-8/+4
Size of slab object already stored in cache->object_size. Note, that kmalloc() internally rounds up size of allocation, so object_size may be not equal to alloc_size, but, usually we don't need to know the exact size of allocated object. In case if we need that information, we still can figure it out from the report. The dump of shadow memory allows to identify the end of allocated memory, and thereby the exact allocation size. Link: http://lkml.kernel.org/r/1470062715-14077-4-git-send-email-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02mm/kasan, slub: don't disable interrupts when object leaves quarantineAndrey Ryabinin1-2/+6
SLUB doesn't require disabled interrupts to call ___cache_free(). Link: http://lkml.kernel.org/r/1470062715-14077-3-git-send-email-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Acked-by: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02mm/kasan: don't reduce quarantine in atomic contextsAndrey Ryabinin1-2/+2
Currently we call quarantine_reduce() for ___GFP_KSWAPD_RECLAIM (implied by __GFP_RECLAIM) allocation. So, basically we call it on almost every allocation. quarantine_reduce() sometimes is heavy operation, and calling it with disabled interrupts may trigger hard LOCKUP: NMI watchdog: Watchdog detected hard LOCKUP on cpu 2irq event stamp: 1411258 Call Trace: <NMI> dump_stack+0x68/0x96 watchdog_overflow_callback+0x15b/0x190 __perf_event_overflow+0x1b1/0x540 perf_event_overflow+0x14/0x20 intel_pmu_handle_irq+0x36a/0xad0 perf_event_nmi_handler+0x2c/0x50 nmi_handle+0x128/0x480 default_do_nmi+0xb2/0x210 do_nmi+0x1aa/0x220 end_repeat_nmi+0x1a/0x1e <<EOE>> __kernel_text_address+0x86/0xb0 print_context_stack+0x7b/0x100 dump_trace+0x12b/0x350 save_stack_trace+0x2b/0x50 set_track+0x83/0x140 free_debug_processing+0x1aa/0x420 __slab_free+0x1d6/0x2e0 ___cache_free+0xb6/0xd0 qlist_free_all+0x83/0x100 quarantine_reduce+0x177/0x1b0 kasan_kmalloc+0xf3/0x100 Reduce the quarantine_reduce iff direct reclaim is allowed. Fixes: 55834c59098d("mm: kasan: initial memory quarantine implementation") Link: http://lkml.kernel.org/r/1470062715-14077-2-git-send-email-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Reported-by: Dave Jones <davej@codemonkey.org.uk> Acked-by: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02mm/kasan: fix corruptions and false positive reportsAndrey Ryabinin1-1/+1
Once an object is put into quarantine, we no longer own it, i.e. object could leave the quarantine and be reallocated. So having set_track() call after the quarantine_put() may corrupt slab objects. BUG kmalloc-4096 (Not tainted): Poison overwritten ----------------------------------------------------------------------------- Disabling lock debugging due to kernel taint INFO: 0xffff8804540de850-0xffff8804540de857. First byte 0xb5 instead of 0x6b ... INFO: Freed in qlist_free_all+0x42/0x100 age=75 cpu=3 pid=24492 __slab_free+0x1d6/0x2e0 ___cache_free+0xb6/0xd0 qlist_free_all+0x83/0x100 quarantine_reduce+0x177/0x1b0 kasan_kmalloc+0xf3/0x100 kasan_slab_alloc+0x12/0x20 kmem_cache_alloc+0x109/0x3e0 mmap_region+0x53e/0xe40 do_mmap+0x70f/0xa50 vm_mmap_pgoff+0x147/0x1b0 SyS_mmap_pgoff+0x2c7/0x5b0 SyS_mmap+0x1b/0x30 do_syscall_64+0x1a0/0x4e0 return_from_SYSCALL_64+0x0/0x7a INFO: Slab 0xffffea0011503600 objects=7 used=7 fp=0x (null) flags=0x8000000000004080 INFO: Object 0xffff8804540de848 @offset=26696 fp=0xffff8804540dc588 Redzone ffff8804540de840: bb bb bb bb bb bb bb bb ........ Object ffff8804540de848: 6b 6b 6b 6b 6b 6b 6b 6b b5 52 00 00 f2 01 60 cc kkkkkkkk.R....`. Similarly, poisoning after the quarantine_put() leads to false positive use-after-free reports: BUG: KASAN: use-after-free in anon_vma_interval_tree_insert+0x304/0x430 at addr ffff880405c540a0 Read of size 8 by task trinity-c0/3036 CPU: 0 PID: 3036 Comm: trinity-c0 Not tainted 4.7.0-think+ #9 Call Trace: dump_stack+0x68/0x96 kasan_report_error+0x222/0x600 __asan_report_load8_noabort+0x61/0x70 anon_vma_interval_tree_insert+0x304/0x430 anon_vma_chain_link+0x91/0xd0 anon_vma_clone+0x136/0x3f0 anon_vma_fork+0x81/0x4c0 copy_process.part.47+0x2c43/0x5b20 _do_fork+0x16d/0xbd0 SyS_clone+0x19/0x20 do_syscall_64+0x1a0/0x4e0 entry_SYSCALL64_slow_path+0x25/0x25 Fix this by putting an object in the quarantine after all other operations. Fixes: 80a9201a5965 ("mm, kasan: switch SLUB to stackdepot, enable memory quarantine for SLUB") Link: http://lkml.kernel.org/r/1470062715-14077-1-git-send-email-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Reported-by: Dave Jones <davej@codemonkey.org.uk> Reported-by: Vegard Nossum <vegard.nossum@oracle.com> Reported-by: Sasha Levin <alexander.levin@verizon.com> Acked-by: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-28mm, kasan: switch SLUB to stackdepot, enable memory quarantine for SLUBAlexander Potapenko4-40/+37
For KASAN builds: - switch SLUB allocator to using stackdepot instead of storing the allocation/deallocation stacks in the objects; - change the freelist hook so that parts of the freelist can be put into the quarantine. [aryabinin@virtuozzo.com: fixes] Link: http://lkml.kernel.org/r/1468601423-28676-1-git-send-email-aryabinin@virtuozzo.com Link: http://lkml.kernel.org/r/1468347165-41906-3-git-send-email-glider@google.com Signed-off-by: Alexander Potapenko <glider@google.com> Cc: Andrey Konovalov <adech.fo@gmail.com> Cc: Christoph Lameter <cl@linux.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Steven Rostedt (Red Hat) <rostedt@goodmis.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kostya Serebryany <kcc@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Kuthonuzo Luruo <kuthonuzo.luruo@hpe.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-15kasan/quarantine: fix bugs on qlist_move_cache()Joonsoo Kim1-18/+11
There are two bugs on qlist_move_cache(). One is that qlist's tail isn't set properly. curr->next can be NULL since it is singly linked list and NULL value on tail is invalid if there is one item on qlist. Another one is that if cache is matched, qlist_put() is called and it will set curr->next to NULL. It would cause to stop the loop prematurely. These problems come from complicated implementation so I'd like to re-implement it completely. Implementation in this patch is really simple. Iterate all qlist_nodes and put them to appropriate list. Unfortunately, I got this bug sometime ago and lose oops message. But, the bug looks trivial and no need to attach oops. Fixes: 55834c59098d ("mm: kasan: initial memory quarantine implementation") Link: http://lkml.kernel.org/r/1467766348-22419-1-git-send-email-iamjoonsoo.kim@lge.com Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Acked-by: Alexander Potapenko <glider@google.com> Cc: Kuthonuzo Luruo <poll.stdin@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-06-24mm: mempool: kasan: don't poot mempool objects in quarantineAndrey Ryabinin1-3/+3
Currently we may put reserved by mempool elements into quarantine via kasan_kfree(). This is totally wrong since quarantine may really free these objects. So when mempool will try to use such element, use-after-free will happen. Or mempool may decide that it no longer need that element and double-free it. So don't put object into quarantine in kasan_kfree(), just poison it. Rename kasan_kfree() to kasan_poison_kfree() to respect that. Also, we shouldn't use kasan_slab_alloc()/kasan_krealloc() in kasan_unpoison_element() because those functions may update allocation stacktrace. This would be wrong for the most of the remove_element call sites. (The only call site where we may want to update alloc stacktrace is in mempool_alloc(). Kmemleak solves this by calling kmemleak_update_trace(), so we could make something like that too. But this is out of scope of this patch). Fixes: 55834c59098d ("mm: kasan: initial memory quarantine implementation") Link: http://lkml.kernel.org/r/575977C3.1010905@virtuozzo.com Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Reported-by: Kuthonuzo Luruo <kuthonuzo.luruo@hpe.com> Acked-by: Alexander Potapenko <glider@google.com> Cc: Dmitriy Vyukov <dvyukov@google.com> Cc: Kostya Serebryany <kcc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-06-09kasan: change memory hot-add error messages to info messagesShuah Khan1-2/+2
Change the following memory hot-add error messages to info messages. There is no need for these to be errors. kasan: WARNING: KASAN doesn't support memory hot-add kasan: Memory hot-add will be disabled Link: http://lkml.kernel.org/r/1464794430-5486-1-git-send-email-shuahkh@osg.samsung.com Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-26mm: kasan: remove unused 'reserved' field from struct kasan_alloc_metaAndrey Ryabinin1-1/+0
Commit cd11016e5f52 ("mm, kasan: stackdepot implementation. Enable stackdepot for SLAB") added 'reserved' field, but never used it. Link: http://lkml.kernel.org/r/1464021054-2307-1-git-send-email-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-20mm/kasan: add API to check memory regionsAndrey Ryabinin1-0/+12
Memory access coded in an assembly won't be seen by KASAN as a compiler can instrument only C code. Add kasan_check_[read,write]() API which is going to be used to check a certain memory range. Link: http://lkml.kernel.org/r/1462538722-1574-3-git-send-email-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Acked-by: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-20mm/kasan: print name of mem[set,cpy,move]() caller in reportAndrey Ryabinin1-30/+34
When bogus memory access happens in mem[set,cpy,move]() it's usually caller's fault. So don't blame mem[set,cpy,move]() in bug report, blame the caller instead. Before: BUG: KASAN: out-of-bounds access in memset+0x23/0x40 at <address> After: BUG: KASAN: out-of-bounds access in <memset_caller> at <address> Link: http://lkml.kernel.org/r/1462538722-1574-2-git-send-email-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Acked-by: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-20mm: kasan: initial memory quarantine implementationAlexander Potapenko5-10/+361
Quarantine isolates freed objects in a separate queue. The objects are returned to the allocator later, which helps to detect use-after-free errors. When the object is freed, its state changes from KASAN_STATE_ALLOC to KASAN_STATE_QUARANTINE. The object is poisoned and put into quarantine instead of being returned to the allocator, therefore every subsequent access to that object triggers a KASAN error, and the error handler is able to say where the object has been allocated and deallocated. When it's time for the object to leave quarantine, its state becomes KASAN_STATE_FREE and it's returned to the allocator. From now on the allocator may reuse it for another allocation. Before that happens, it's still possible to detect a use-after free on that object (it retains the allocation/deallocation stacks). When the allocator reuses this object, the shadow is unpoisoned and old allocation/deallocation stacks are wiped. Therefore a use of this object, even an incorrect one, won't trigger ASan warning. Without the quarantine, it's not guaranteed that the objects aren't reused immediately, that's why the probability of catching a use-after-free is lower than with quarantine in place. Quarantine isolates freed objects in a separate queue. The objects are returned to the allocator later, which helps to detect use-after-free errors. Freed objects are first added to per-cpu quarantine queues. When a cache is destroyed or memory shrinking is requested, the objects are moved into the global quarantine queue. Whenever a kmalloc call allows memory reclaiming, the oldest objects are popped out of the global queue until the total size of objects in quarantine is less than 3/4 of the maximum quarantine size (which is a fraction of installed physical memory). As long as an object remains in the quarantine, KASAN is able to report accesses to it, so the chance of reporting a use-after-free is increased. Once the object leaves quarantine, the allocator may reuse it, in which case the object is unpoisoned and KASAN can't detect incorrect accesses to it. Right now quarantine support is only enabled in SLAB allocator. Unification of KASAN features in SLAB and SLUB will be done later. This patch is based on the "mm: kasan: quarantine" patch originally prepared by Dmitry Chernenkov. A number of improvements have been suggested by Andrey Ryabinin. [glider@google.com: v9] Link: http://lkml.kernel.org/r/1462987130-144092-1-git-send-email-glider@google.com Signed-off-by: Alexander Potapenko <glider@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Andrey Konovalov <adech.fo@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Konstantin Serebryany <kcc@google.com> Cc: Dmitry Chernenkov <dmitryc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01mm, kasan: fix compilation for CONFIG_SLABAlexander Potapenko1-1/+1
Add the missing argument to set_track(). Fixes: cd11016e5f52 ("mm, kasan: stackdepot implementation. Enable stackdepot for SLAB") Signed-off-by: Alexander Potapenko <glider@google.com> Cc: Andrey Konovalov <adech.fo@gmail.com> Cc: Christoph Lameter <cl@linux.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Konstantin Serebryany <kcc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-25mm, kasan: stackdepot implementation. Enable stackdepot for SLABAlexander Potapenko3-12/+66
Implement the stack depot and provide CONFIG_STACKDEPOT. Stack depot will allow KASAN store allocation/deallocation stack traces for memory chunks. The stack traces are stored in a hash table and referenced by handles which reside in the kasan_alloc_meta and kasan_free_meta structures in the allocated memory chunks. IRQ stack traces are cut below the IRQ entry point to avoid unnecessary duplication. Right now stackdepot support is only enabled in SLAB allocator. Once KASAN features in SLAB are on par with those in SLUB we can switch SLUB to stackdepot as well, thus removing the dependency on SLUB stack bookkeeping, which wastes a lot of memory. This patch is based on the "mm: kasan: stack depots" patch originally prepared by Dmitry Chernenkov. Joonsoo has said that he plans to reuse the stackdepot code for the mm/page_owner.c debugging facility. [akpm@linux-foundation.org: s/depot_stack_handle/depot_stack_handle_t] [aryabinin@virtuozzo.com: comment style fixes] Signed-off-by: Alexander Potapenko <glider@google.com> Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Andrey Konovalov <adech.fo@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Konstantin Serebryany <kcc@google.com> Cc: Dmitry Chernenkov <dmitryc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-25mm, kasan: add GFP flags to KASAN APIAlexander Potapenko1-7/+8
Add GFP flags to KASAN hooks for future patches to use. This patch is based on the "mm: kasan: unified support for SLUB and SLAB allocators" patch originally prepared by Dmitry Chernenkov. Signed-off-by: Alexander Potapenko <glider@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Andrey Konovalov <adech.fo@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Konstantin Serebryany <kcc@google.com> Cc: Dmitry Chernenkov <dmitryc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-25mm, kasan: SLAB supportAlexander Potapenko3-11/+179
Add KASAN hooks to SLAB allocator. This patch is based on the "mm: kasan: unified support for SLUB and SLAB allocators" patch originally prepared by Dmitry Chernenkov. Signed-off-by: Alexander Potapenko <glider@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Andrey Konovalov <adech.fo@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Konstantin Serebryany <kcc@google.com> Cc: Dmitry Chernenkov <dmitryc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-22kernel: add kcov code coverageDmitry Vyukov1-0/+1
kcov provides code coverage collection for coverage-guided fuzzing (randomized testing). Coverage-guided fuzzing is a testing technique that uses coverage feedback to determine new interesting inputs to a system. A notable user-space example is AFL (http://lcamtuf.coredump.cx/afl/). However, this technique is not widely used for kernel testing due to missing compiler and kernel support. kcov does not aim to collect as much coverage as possible. It aims to collect more or less stable coverage that is function of syscall inputs. To achieve this goal it does not collect coverage in soft/hard interrupts and instrumentation of some inherently non-deterministic or non-interesting parts of kernel is disbled (e.g. scheduler, locking). Currently there is a single coverage collection mode (tracing), but the API anticipates additional collection modes. Initially I also implemented a second mode which exposes coverage in a fixed-size hash table of counters (what Quentin used in his original patch). I've dropped the second mode for simplicity. This patch adds the necessary support on kernel side. The complimentary compiler support was added in gcc revision 231296. We've used this support to build syzkaller system call fuzzer, which has found 90 kernel bugs in just 2 months: https://github.com/google/syzkaller/wiki/Found-Bugs We've also found 30+ bugs in our internal systems with syzkaller. Another (yet unexplored) direction where kcov coverage would greatly help is more traditional "blob mutation". For example, mounting a random blob as a filesystem, or receiving a random blob over wire. Why not gcov. Typical fuzzing loop looks as follows: (1) reset coverage, (2) execute a bit of code, (3) collect coverage, repeat. A typical coverage can be just a dozen of basic blocks (e.g. an invalid input). In such context gcov becomes prohibitively expensive as reset/collect coverage steps depend on total number of basic blocks/edges in program (in case of kernel it is about 2M). Cost of kcov depends only on number of executed basic blocks/edges. On top of that, kernel requires per-thread coverage because there are always background threads and unrelated processes that also produce coverage. With inlined gcov instrumentation per-thread coverage is not possible. kcov exposes kernel PCs and control flow to user-space which is insecure. But debugfs should not be mapped as user accessible. Based on a patch by Quentin Casasnovas. [akpm@linux-foundation.org: make task_struct.kcov_mode have type `enum kcov_mode'] [akpm@linux-foundation.org: unbreak allmodconfig] [akpm@linux-foundation.org: follow x86 Makefile layout standards] Signed-off-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: syzkaller <syzkaller@googlegroups.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Tavis Ormandy <taviso@google.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Kostya Serebryany <kcc@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Kees Cook <keescook@google.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: David Drysdale <drysdale@google.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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