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2020-04-21mm: shmem: disable interrupt when acquiring info->lock in userfaultfd_copy pathYang Shi1-2/+2
Syzbot reported the below lockdep splat: WARNING: possible irq lock inversion dependency detected 5.6.0-rc7-syzkaller #0 Not tainted -------------------------------------------------------- syz-executor.0/10317 just changed the state of lock: ffff888021d16568 (&(&info->lock)->rlock){+.+.}, at: spin_lock include/linux/spinlock.h:338 [inline] ffff888021d16568 (&(&info->lock)->rlock){+.+.}, at: shmem_mfill_atomic_pte+0x1012/0x21c0 mm/shmem.c:2407 but this lock was taken by another, SOFTIRQ-safe lock in the past: (&(&xa->xa_lock)->rlock#5){..-.} and interrupts could create inverse lock ordering between them. other info that might help us debug this: Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&(&info->lock)->rlock); local_irq_disable(); lock(&(&xa->xa_lock)->rlock#5); lock(&(&info->lock)->rlock); <Interrupt> lock(&(&xa->xa_lock)->rlock#5); *** DEADLOCK *** The full report is quite lengthy, please see: https://lore.kernel.org/linux-mm/alpine.LSU.2.11.2004152007370.13597@eggly.anvils/T/#m813b412c5f78e25ca8c6c7734886ed4de43f241d It is because CPU 0 held info->lock with IRQ enabled in userfaultfd_copy path, then CPU 1 is splitting a THP which held xa_lock and info->lock in IRQ disabled context at the same time. If softirq comes in to acquire xa_lock, the deadlock would be triggered. The fix is to acquire/release info->lock with *_irq version instead of plain spin_{lock,unlock} to make it softirq safe. Fixes: 4c27fe4c4c84 ("userfaultfd: shmem: add shmem_mcopy_atomic_pte for userfaultfd support") Reported-by: syzbot+e27980339d305f2dbfd9@syzkaller.appspotmail.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: syzbot+e27980339d305f2dbfd9@syzkaller.appspotmail.com Acked-by: Hugh Dickins <hughd@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Link: http://lkml.kernel.org/r/1587061357-122619-1-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-21shmem: fix possible deadlocks on shmlock_user_lockHugh Dickins1-2/+5
Recent commit 71725ed10c40 ("mm: huge tmpfs: try to split_huge_page() when punching hole") has allowed syzkaller to probe deeper, uncovering a long-standing lockdep issue between the irq-unsafe shmlock_user_lock, the irq-safe xa_lock on mapping->i_pages, and shmem inode's info->lock which nests inside xa_lock (or tree_lock) since 4.8's shmem_uncharge(). user_shm_lock(), servicing SysV shmctl(SHM_LOCK), wants shmlock_user_lock while its caller shmem_lock() holds info->lock with interrupts disabled; but hugetlbfs_file_setup() calls user_shm_lock() with interrupts enabled, and might be interrupted by a writeback endio wanting xa_lock on i_pages. This may not risk an actual deadlock, since shmem inodes do not take part in writeback accounting, but there are several easy ways to avoid it. Requiring interrupts disabled for shmlock_user_lock would be easy, but it's a high-level global lock for which that seems inappropriate. Instead, recall that the use of info->lock to guard info->flags in shmem_lock() dates from pre-3.1 days, when races with SHMEM_PAGEIN and SHMEM_TRUNCATE could occur: nowadays it serves no purpose, the only flag added or removed is VM_LOCKED itself, and calls to shmem_lock() an inode are already serialized by the caller. Take info->lock out of the chain and the possibility of deadlock or lockdep warning goes away. Fixes: 4595ef88d136 ("shmem: make shmem_inode_info::lock irq-safe") Reported-by: syzbot+c8a8197c8852f566b9d9@syzkaller.appspotmail.com Reported-by: syzbot+40b71e145e73f78f81ad@syzkaller.appspotmail.com Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Yang Shi <yang.shi@linux.alibaba.com> Cc: Yang Shi <yang.shi@linux.alibaba.com> Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2004161707410.16322@eggly.anvils Link: https://lore.kernel.org/lkml/000000000000e5838c05a3152f53@google.com/ Link: https://lore.kernel.org/lkml/0000000000003712b305a331d3b1@google.com/ Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-21vmalloc: fix remap_vmalloc_range() bounds checksJann Horn1-3/+13
remap_vmalloc_range() has had various issues with the bounds checks it promises to perform ("This function checks that addr is a valid vmalloc'ed area, and that it is big enough to cover the vma") over time, e.g.: - not detecting pgoff<<PAGE_SHIFT overflow - not detecting (pgoff<<PAGE_SHIFT)+usize overflow - not checking whether addr and addr+(pgoff<<PAGE_SHIFT) are the same vmalloc allocation - comparing a potentially wildly out-of-bounds pointer with the end of the vmalloc region In particular, since commit fc9702273e2e ("bpf: Add mmap() support for BPF_MAP_TYPE_ARRAY"), unprivileged users can cause kernel null pointer dereferences by calling mmap() on a BPF map with a size that is bigger than the distance from the start of the BPF map to the end of the address space. This could theoretically be used as a kernel ASLR bypass, by using whether mmap() with a given offset oopses or returns an error code to perform a binary search over the possible address range. To allow remap_vmalloc_range_partial() to verify that addr and addr+(pgoff<<PAGE_SHIFT) are in the same vmalloc region, pass the offset to remap_vmalloc_range_partial() instead of adding it to the pointer in remap_vmalloc_range(). In remap_vmalloc_range_partial(), fix the check against get_vm_area_size() by using size comparisons instead of pointer comparisons, and add checks for pgoff. Fixes: 833423143c3a ("[PATCH] mm: introduce remap_vmalloc_range()") Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: stable@vger.kernel.org Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Martin KaFai Lau <kafai@fb.com> Cc: Song Liu <songliubraving@fb.com> Cc: Yonghong Song <yhs@fb.com> Cc: Andrii Nakryiko <andriin@fb.com> Cc: John Fastabend <john.fastabend@gmail.com> Cc: KP Singh <kpsingh@chromium.org> Link: http://lkml.kernel.org/r/20200415222312.236431-1-jannh@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-21mm/shmem: fix build without THPHugh Dickins1-1/+1
Some optimizers don't notice that shmem_punch_compound() is always true (PageTransCompound() being false) without CONFIG_TRANSPARENT_HUGEPAGE==y. Use IS_ENABLED to help them to avoid the BUILD_BUG inside HPAGE_PMD_NR. Fixes: 71725ed10c40 ("mm: huge tmpfs: try to split_huge_page() when punching hole") Reported-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Randy Dunlap <rdunlap@infradead.org> Acked-by: Randy Dunlap <rdunlap@infradead.org> Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2004142339170.10035@eggly.anvils Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-21mm/ksm: fix NULL pointer dereference when KSM zero page is enabledMuchun Song1-2/+10
find_mergeable_vma() can return NULL. In this case, it leads to a crash when we access vm_mm(its offset is 0x40) later in write_protect_page. And this case did happen on our server. The following call trace is captured in kernel 4.19 with the following patch applied and KSM zero page enabled on our server. commit e86c59b1b12d ("mm/ksm: improve deduplication of zero pages with colouring") So add a vma check to fix it. BUG: unable to handle kernel NULL pointer dereference at 0000000000000040 Oops: 0000 [#1] SMP NOPTI CPU: 9 PID: 510 Comm: ksmd Kdump: loaded Tainted: G OE 4.19.36.bsk.9-amd64 #4.19.36.bsk.9 RIP: try_to_merge_one_page+0xc7/0x760 Code: 24 58 65 48 33 34 25 28 00 00 00 89 e8 0f 85 a3 06 00 00 48 83 c4 60 5b 5d 41 5c 41 5d 41 5e 41 5f c3 48 8b 46 08 a8 01 75 b8 <49> 8b 44 24 40 4c 8d 7c 24 20 b9 07 00 00 00 4c 89 e6 4c 89 ff 48 RSP: 0018:ffffadbdd9fffdb0 EFLAGS: 00010246 RAX: ffffda83ffd4be08 RBX: ffffda83ffd4be40 RCX: 0000002c6e800000 RDX: 0000000000000000 RSI: ffffda83ffd4be40 RDI: 0000000000000000 RBP: ffffa11939f02ec0 R08: 0000000094e1a447 R09: 00000000abe76577 R10: 0000000000000962 R11: 0000000000004e6a R12: 0000000000000000 R13: ffffda83b1e06380 R14: ffffa18f31f072c0 R15: ffffda83ffd4be40 FS: 0000000000000000(0000) GS:ffffa0da43b80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000040 CR3: 0000002c77c0a003 CR4: 00000000007626e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: ksm_scan_thread+0x115e/0x1960 kthread+0xf5/0x130 ret_from_fork+0x1f/0x30 [songmuchun@bytedance.com: if the vma is out of date, just exit] Link: http://lkml.kernel.org/r/20200416025034.29780-1-songmuchun@bytedance.com [akpm@linux-foundation.org: add the conventional braces, replace /** with /*] Fixes: e86c59b1b12d ("mm/ksm: improve deduplication of zero pages with colouring") Co-developed-by: Xiongchun Duan <duanxiongchun@bytedance.com> Signed-off-by: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Kirill Tkhai <ktkhai@virtuozzo.com> Cc: Hugh Dickins <hughd@google.com> Cc: Yang Shi <yang.shi@linux.alibaba.com> Cc: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com> Cc: Markus Elfring <Markus.Elfring@web.de> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/20200416025034.29780-1-songmuchun@bytedance.com Link: http://lkml.kernel.org/r/20200414132905.83819-1-songmuchun@bytedance.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-21mm, gup: return EINTR when gup is interrupted by fatal signalsMichal Hocko1-1/+1
EINTR is the usual error code which other killable interfaces return. This is the case for the other fatal_signal_pending break out from the same function. Make the code consistent. ERESTARTSYS is also quite confusing because the signal is fatal and so no restart will happen before returning to the userspace. Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Xu <peterx@redhat.com> Cc: Hillf Danton <hdanton@sina.com> Link: http://lkml.kernel.org/r/20200409071133.31734-1-mhocko@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-21mm/hugetlb: fix a addressing exception caused by huge_pte_offsetLongpeng1-6/+8
Our machine encountered a panic(addressing exception) after run for a long time and the calltrace is: RIP: hugetlb_fault+0x307/0xbe0 RSP: 0018:ffff9567fc27f808 EFLAGS: 00010286 RAX: e800c03ff1258d48 RBX: ffffd3bb003b69c0 RCX: e800c03ff1258d48 RDX: 17ff3fc00eda72b7 RSI: 00003ffffffff000 RDI: e800c03ff1258d48 RBP: ffff9567fc27f8c8 R08: e800c03ff1258d48 R09: 0000000000000080 R10: ffffaba0704c22a8 R11: 0000000000000001 R12: ffff95c87b4b60d8 R13: 00005fff00000000 R14: 0000000000000000 R15: ffff9567face8074 FS: 00007fe2d9ffb700(0000) GS:ffff956900e40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffd3bb003b69c0 CR3: 000000be67374000 CR4: 00000000003627e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: follow_hugetlb_page+0x175/0x540 __get_user_pages+0x2a0/0x7e0 __get_user_pages_unlocked+0x15d/0x210 __gfn_to_pfn_memslot+0x3c5/0x460 [kvm] try_async_pf+0x6e/0x2a0 [kvm] tdp_page_fault+0x151/0x2d0 [kvm] ... kvm_arch_vcpu_ioctl_run+0x330/0x490 [kvm] kvm_vcpu_ioctl+0x309/0x6d0 [kvm] do_vfs_ioctl+0x3f0/0x540 SyS_ioctl+0xa1/0xc0 system_call_fastpath+0x22/0x27 For 1G hugepages, huge_pte_offset() wants to return NULL or pudp, but it may return a wrong 'pmdp' if there is a race. Please look at the following code snippet: ... pud = pud_offset(p4d, addr); if (sz != PUD_SIZE && pud_none(*pud)) return NULL; /* hugepage or swap? */ if (pud_huge(*pud) || !pud_present(*pud)) return (pte_t *)pud; pmd = pmd_offset(pud, addr); if (sz != PMD_SIZE && pmd_none(*pmd)) return NULL; /* hugepage or swap? */ if (pmd_huge(*pmd) || !pmd_present(*pmd)) return (pte_t *)pmd; ... The following sequence would trigger this bug: - CPU0: sz = PUD_SIZE and *pud = 0 , continue - CPU0: "pud_huge(*pud)" is false - CPU1: calling hugetlb_no_page and set *pud to xxxx8e7(PRESENT) - CPU0: "!pud_present(*pud)" is false, continue - CPU0: pmd = pmd_offset(pud, addr) and maybe return a wrong pmdp However, we want CPU0 to return NULL or pudp in this case. We must make sure there is exactly one dereference of pud and pmd. Signed-off-by: Longpeng <longpeng2@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Sean Christopherson <sean.j.christopherson@intel.com> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/20200413010342.771-1-longpeng2@huawei.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-21slub: avoid redzone when choosing freepointer locationKees Cook1-2/+10
Marco Elver reported system crashes when booting with "slub_debug=Z". The freepointer location (s->offset) was not taking into account that the "inuse" size that includes the redzone area should not be used by the freelist pointer. Change the calculation to save the area of the object that an inline freepointer may be written into. Fixes: 3202fa62fb43 ("slub: relocate freelist pointer to middle of object") Reported-by: Marco Elver <elver@google.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Marco Elver <elver@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> Link: http://lkml.kernel.org/r/202004151054.BD695840@keescook Link: https://lore.kernel.org/linux-mm/20200415164726.GA234932@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-19mm: Fix MREMAP_DONTUNMAP accounting on VMA mergeBrian Geffon1-1/+12
When remapping a mapping where a portion of a VMA is remapped into another portion of the VMA it can cause the VMA to become split. During the copy_vma operation the VMA can actually be remerged if it's an anonymous VMA whose pages have not yet been faulted. This isn't normally a problem because at the end of the remap the original portion is unmapped causing it to become split again. However, MREMAP_DONTUNMAP leaves that original portion in place which means that the VMA which was split and then remerged is not actually split at the end of the mremap. This patch fixes a bug where we don't detect that the VMAs got remerged and we end up putting back VM_ACCOUNT on the next mapping which is completely unreleated. When that next mapping is unmapped it results in incorrectly unaccounting for the memory which was never accounted, and eventually we will underflow on the memory comittment. There is also another issue which is similar, we're currently accouting for the number of pages in the new_vma but that's wrong. We need to account for the length of the remap operation as that's all that is being added. If there was a mapping already at that location its comittment would have been adjusted as part of the munmap at the start of the mremap. A really simple repro can be seen in: https://gist.github.com/bgaff/e101ce99da7d9a8c60acc641d07f312c Fixes: e346b3813067 ("mm/mremap: add MREMAP_DONTUNMAP to mremap()") Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Brian Geffon <bgeffon@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-10Merge branch 'akpm' (patches from Andrew)Linus Torvalds11-42/+299
Merge yet more updates from Andrew Morton: - Almost all of the rest of MM (memcg, slab-generic, slab, pagealloc, gup, hugetlb, pagemap, memremap) - Various other things (hfs, ocfs2, kmod, misc, seqfile) * akpm: (34 commits) ipc/util.c: sysvipc_find_ipc() should increase position index kernel/gcov/fs.c: gcov_seq_next() should increase position index fs/seq_file.c: seq_read(): add info message about buggy .next functions drivers/dma/tegra20-apb-dma.c: fix platform_get_irq.cocci warnings change email address for Pali Rohár selftests: kmod: test disabling module autoloading selftests: kmod: fix handling test numbers above 9 docs: admin-guide: document the kernel.modprobe sysctl fs/filesystems.c: downgrade user-reachable WARN_ONCE() to pr_warn_once() kmod: make request_module() return an error when autoloading is disabled mm/memremap: set caching mode for PCI P2PDMA memory to WC mm/memory_hotplug: add pgprot_t to mhp_params powerpc/mm: thread pgprot_t through create_section_mapping() x86/mm: introduce __set_memory_prot() x86/mm: thread pgprot_t through init_memory_mapping() mm/memory_hotplug: rename mhp_restrictions to mhp_params mm/memory_hotplug: drop the flags field from struct mhp_restrictions mm/special: create generic fallbacks for pte_special() and pte_mkspecial() mm/vma: introduce VM_ACCESS_FLAGS mm/vma: define a default value for VM_DATA_DEFAULT_FLAGS ...
2020-04-10mm/memremap: set caching mode for PCI P2PDMA memory to WCLogan Gunthorpe1-0/+3
PCI BAR IO memory should never be mapped as WB, however prior to this the PAT bits were set WB and it was typically overridden by MTRR registers set by the firmware. Set PCI P2PDMA memory to be UC as this is what it currently, typically, ends up being mapped as on x86 after the MTRR registers override the cache setting. Future use-cases may need to generalize this by adding flags to select the caching type, as some P2PDMA cases may not want UC. However, those use-cases are not upstream yet and this can be changed when they arrive. Signed-off-by: Logan Gunthorpe <logang@deltatee.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Andy Lutomirski <luto@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Eric Badger <ebadger@gigaio.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will@kernel.org> Link: http://lkml.kernel.org/r/20200306170846.9333-8-logang@deltatee.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-10mm/memory_hotplug: add pgprot_t to mhp_paramsLogan Gunthorpe2-4/+7
devm_memremap_pages() is currently used by the PCI P2PDMA code to create struct page mappings for IO memory. At present, these mappings are created with PAGE_KERNEL which implies setting the PAT bits to be WB. However, on x86, an mtrr register will typically override this and force the cache type to be UC-. In the case firmware doesn't set this register it is effectively WB and will typically result in a machine check exception when it's accessed. Other arches are not currently likely to function correctly seeing they don't have any MTRR registers to fall back on. To solve this, provide a way to specify the pgprot value explicitly to arch_add_memory(). Of the arches that support MEMORY_HOTPLUG: x86_64, and arm64 need a simple change to pass the pgprot_t down to their respective functions which set up the page tables. For x86_32, set the page tables explicitly using _set_memory_prot() (seeing they are already mapped). For ia64, s390 and sh, reject anything but PAGE_KERNEL settings -- this should be fine, for now, seeing these architectures don't support ZONE_DEVICE. A check in __add_pages() is also added to ensure the pgprot parameter was set for all arches. Signed-off-by: Logan Gunthorpe <logang@deltatee.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Dan Williams <dan.j.williams@intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Eric Badger <ebadger@gigaio.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will@kernel.org> Link: http://lkml.kernel.org/r/20200306170846.9333-7-logang@deltatee.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-10mm/memory_hotplug: rename mhp_restrictions to mhp_paramsLogan Gunthorpe2-8/+8
The mhp_restrictions struct really doesn't specify anything resembling a restriction anymore so rename it to be mhp_params as it is a list of extended parameters. Signed-off-by: Logan Gunthorpe <logang@deltatee.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Eric Badger <ebadger@gigaio.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will@kernel.org> Link: http://lkml.kernel.org/r/20200306170846.9333-3-logang@deltatee.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-10mm/vma: introduce VM_ACCESS_FLAGSAnshuman Khandual2-3/+3
There are many places where all basic VMA access flags (read, write, exec) are initialized or checked against as a group. One such example is during page fault. Existing vma_is_accessible() wrapper already creates the notion of VMA accessibility as a group access permissions. Hence lets just create VM_ACCESS_FLAGS (VM_READ|VM_WRITE|VM_EXEC) which will not only reduce code duplication but also extend the VMA accessibility concept in general. Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Russell King <linux@armlinux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Mark Salter <msalter@redhat.com> Cc: Nick Hu <nickhu@andestech.com> Cc: Ley Foon Tan <ley.foon.tan@intel.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Rob Springer <rspringer@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Link: http://lkml.kernel.org/r/1583391014-8170-3-git-send-email-anshuman.khandual@arm.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-10mm/memory.c: add vm_insert_pages()Arjun Roy1-2/+127
Add the ability to insert multiple pages at once to a user VM with lower PTE spinlock operations. The intention of this patch-set is to reduce atomic ops for tcp zerocopy receives, which normally hits the same spinlock multiple times consecutively. [akpm@linux-foundation.org: pte_alloc() no longer takes the `addr' argument] [arjunroy@google.com: add missing page_count() check to vm_insert_pages()] Link: http://lkml.kernel.org/r/20200214005929.104481-1-arjunroy.kdev@gmail.com [arjunroy@google.com: vm_insert_pages() checks if pte_index defined] Link: http://lkml.kernel.org/r/20200228054714.204424-2-arjunroy.kdev@gmail.com Signed-off-by: Arjun Roy <arjunroy@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: David Miller <davem@davemloft.net> Cc: Matthew Wilcox <willy@infradead.org> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Link: http://lkml.kernel.org/r/20200128025958.43490-2-arjunroy.kdev@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-10mm/memory.c: refactor insert_page to prepare for batched-lock insertArjun Roy1-15/+24
Add helper methods for vm_insert_page()/insert_page() to prepare for vm_insert_pages(), which batch-inserts pages to reduce spinlock operations when inserting multiple consecutive pages into the user page table. The intention of this patch-set is to reduce atomic ops for tcp zerocopy receives, which normally hits the same spinlock multiple times consecutively. Signed-off-by: Arjun Roy <arjunroy@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: David Miller <davem@davemloft.net> Cc: Matthew Wilcox <willy@infradead.org> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Link: http://lkml.kernel.org/r/20200128025958.43490-1-arjunroy.kdev@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-10mm/mmap.c: initialize align_offset explicitly for vm_unmapped_areaJaewon Kim1-0/+2
On passing requirement to vm_unmapped_area, arch_get_unmapped_area and arch_get_unmapped_area_topdown did not set align_offset. Internally on both unmapped_area and unmapped_area_topdown, if info->align_mask is 0, then info->align_offset was meaningless. But commit df529cabb7a2 ("mm: mmap: add trace point of vm_unmapped_area") always prints info->align_offset even though it is uninitialized. Fix this uninitialized value issue by setting it to 0 explicitly. Before: vm_unmapped_area: addr=0x755b155000 err=0 total_vm=0x15aaf0 flags=0x1 len=0x109000 lo=0x8000 hi=0x75eed48000 mask=0x0 ofs=0x4022 After: vm_unmapped_area: addr=0x74a4ca1000 err=0 total_vm=0x168ab1 flags=0x1 len=0x9000 lo=0x8000 hi=0x753d94b000 mask=0x0 ofs=0x0 Signed-off-by: Jaewon Kim <jaewon31.kim@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michel Lespinasse <walken@google.com> Cc: Borislav Petkov <bp@suse.de> Link: http://lkml.kernel.org/r/20200409094035.19457-1-jaewon31.kim@samsung.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-10mm: hugetlb: optionally allocate gigantic hugepages using cmaRoman Gushchin1-0/+109
Commit 944d9fec8d7a ("hugetlb: add support for gigantic page allocation at runtime") has added the run-time allocation of gigantic pages. However it actually works only at early stages of the system loading, when the majority of memory is free. After some time the memory gets fragmented by non-movable pages, so the chances to find a contiguous 1GB block are getting close to zero. Even dropping caches manually doesn't help a lot. At large scale rebooting servers in order to allocate gigantic hugepages is quite expensive and complex. At the same time keeping some constant percentage of memory in reserved hugepages even if the workload isn't using it is a big waste: not all workloads can benefit from using 1 GB pages. The following solution can solve the problem: 1) On boot time a dedicated cma area* is reserved. The size is passed as a kernel argument. 2) Run-time allocations of gigantic hugepages are performed using the cma allocator and the dedicated cma area In this case gigantic hugepages can be allocated successfully with a high probability, however the memory isn't completely wasted if nobody is using 1GB hugepages: it can be used for pagecache, anon memory, THPs, etc. * On a multi-node machine a per-node cma area is allocated on each node. Following gigantic hugetlb allocation are using the first available numa node if the mask isn't specified by a user. Usage: 1) configure the kernel to allocate a cma area for hugetlb allocations: pass hugetlb_cma=10G as a kernel argument 2) allocate hugetlb pages as usual, e.g. echo 10 > /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages If the option isn't enabled or the allocation of the cma area failed, the current behavior of the system is preserved. x86 and arm-64 are covered by this patch, other architectures can be trivially added later. The patch contains clean-ups and fixes proposed and implemented by Aslan Bakirov and Randy Dunlap. It also contains ideas and suggestions proposed by Rik van Riel, Michal Hocko and Mike Kravetz. Thanks! Signed-off-by: Roman Gushchin <guro@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Andreas Schaufler <andreas.schaufler@gmx.de> Acked-by: Mike Kravetz <mike.kravetz@oracle.com> Acked-by: Michal Hocko <mhocko@kernel.org> Cc: Aslan Bakirov <aslan@fb.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Joonsoo Kim <js1304@gmail.com> Link: http://lkml.kernel.org/r/20200407163840.92263-3-guro@fb.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-10mm: cma: NUMA node interfaceAslan Bakirov2-8/+10
I've noticed that there is no interface exposed by CMA which would let me to declare contigous memory on particular NUMA node. This patchset adds the ability to try to allocate contiguous memory on a specific node. It will fallback to other nodes if the specified one doesn't work. Implement a new method for declaring contigous memory on particular node and keep cma_declare_contiguous() as a wrapper. [akpm@linux-foundation.org: build fix] Signed-off-by: Aslan Bakirov <aslan@fb.com> Signed-off-by: Roman Gushchin <guro@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Michal Hocko <mhocko@kernel.org> Cc: Andreas Schaufler <andreas.schaufler@gmx.de> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Rik van Riel <riel@surriel.com> Cc: Joonsoo Kim <js1304@gmail.com> Link: http://lkml.kernel.org/r/20200407163840.92263-2-guro@fb.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-10mm/page_alloc: make pcpu_drain_mutex and pcpu_drain staticJason Yan1-2/+2
Fix the following sparse warning: mm/page_alloc.c:106:1: warning: symbol 'pcpu_drain_mutex' was not declared. Should it be static? mm/page_alloc.c:107:1: warning: symbol '__pcpu_scope_pcpu_drain' was not declared. Should it be static? Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Jason Yan <yanaijie@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200407023925.46438-1-yanaijie@huawei.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-10mm/page_alloc.c: fix kernel-doc warningRandy Dunlap1-0/+1
Add description of function parameter 'mt' to fix kernel-doc warning: mm/page_alloc.c:3246: warning: Function parameter or member 'mt' not described in '__putback_isolated_page' Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Link: http://lkml.kernel.org/r/02998bd4-0b82-2f15-2570-f86130304d1e@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-10mm, slab_common: fix a typo in comment "eariler"->"earlier"Qiujun Huang1-1/+1
There is a typo in comment, fix it. s/eariler/earlier/ Signed-off-by: Qiujun Huang <hqjagain@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Christoph Lameter <cl@linux.com> Link: http://lkml.kernel.org/r/20200405160544.1246-1-hqjagain@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-10mm, memcg: do not high throttle allocators based on wraparoundJakub Kicinski1-0/+3
If a cgroup violates its memory.high constraints, we may end up unduly penalising it. For example, for the following hierarchy: A: max high, 20 usage A/B: 9 high, 10 usage A/C: max high, 10 usage We would end up doing the following calculation below when calculating high delay for A/B: A/B: 10 - 9 = 1... A: 20 - PAGE_COUNTER_MAX = 21, so set max_overage to 21. This gets worse with higher disparities in usage in the parent. I have no idea how this disappeared from the final version of the patch, but it is certainly Not Good(tm). This wasn't obvious in testing because, for a simple cgroup hierarchy with only one child, the result is usually roughly the same. It's only in more complex hierarchies that things go really awry (although still, the effects are limited to a maximum of 2 seconds in schedule_timeout_killable at a maximum). [chris@chrisdown.name: changelog] Fixes: e26733e0d0ec ("mm, memcg: throttle allocators based on ancestral memory.high") Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Chris Down <chris@chrisdown.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: <stable@vger.kernel.org> [5.4.x] Link: http://lkml.kernel.org/r/20200331152424.GA1019937@chrisdown.name Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-10Merge tag 'block-5.7-2020-04-10' of git://git.kernel.dk/linux-blockLinus Torvalds1-3/+3
Pull block fixes from Jens Axboe: "Here's a set of fixes that should go into this merge window. This contains: - NVMe pull request from Christoph with various fixes - Better discard support for loop (Evan) - Only call ->commit_rqs() if we have queued IO (Keith) - blkcg offlining fixes (Tejun) - fix (and fix the fix) for busy partitions" * tag 'block-5.7-2020-04-10' of git://git.kernel.dk/linux-block: block: fix busy device checking in blk_drop_partitions again block: fix busy device checking in blk_drop_partitions nvmet-rdma: fix double free of rdma queue blk-mq: don't commit_rqs() if none were queued nvme-fc: Revert "add module to ops template to allow module references" nvme: fix deadlock caused by ANA update wrong locking nvmet-rdma: fix bonding failover possible NULL deref loop: Better discard support for block devices loop: Report EOPNOTSUPP properly nvmet: fix NULL dereference when removing a referral nvme: inherit stable pages constraint in the mpath stack device blkcg: don't offline parent blkcg first blkcg: rename blkcg->cgwb_refcnt to ->online_pin and always use it nvme-tcp: fix possible crash in recv error flow nvme-tcp: don't poll a non-live queue nvme-tcp: fix possible crash in write_zeroes processing nvmet-fc: fix typo in comment nvme-rdma: Replace comma with a semicolon nvme-fcloop: fix deallocation of working context nvme: fix compat address handling in several ioctls
2020-04-08Merge tag 'libnvdimm-for-5.7' of ↵Linus Torvalds3-0/+54
git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm Pull libnvdimm and dax updates from Dan Williams: "There were multiple touches outside of drivers/nvdimm/ this round to add cross arch compatibility to the devm_memremap_pages() interface, enhance numa information for persistent memory ranges, and add a zero_page_range() dax operation. This cycle I switched from the patchwork api to Konstantin's b4 script for collecting tags (from x86, PowerPC, filesystem, and device-mapper folks), and everything looks to have gone ok there. This has all appeared in -next with no reported issues. Summary: - Add support for region alignment configuration and enforcement to fix compatibility across architectures and PowerPC page size configurations. - Introduce 'zero_page_range' as a dax operation. This facilitates filesystem-dax operation without a block-device. - Introduce phys_to_target_node() to facilitate drivers that want to know resulting numa node if a given reserved address range was onlined. - Advertise a persistence-domain for of_pmem and papr_scm. The persistence domain indicates where cpu-store cycles need to reach in the platform-memory subsystem before the platform will consider them power-fail protected. - Promote numa_map_to_online_node() to a cross-kernel generic facility. - Save x86 numa information to allow for node-id lookups for reserved memory ranges, deploy that capability for the e820-pmem driver. - Pick up some miscellaneous minor fixes, that missed v5.6-final, including a some smatch reports in the ioctl path and some unit test compilation fixups. - Fixup some flexible-array declarations" * tag 'libnvdimm-for-5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (29 commits) dax: Move mandatory ->zero_page_range() check in alloc_dax() dax,iomap: Add helper dax_iomap_zero() to zero a range dax: Use new dax zero page method for zeroing a page dm,dax: Add dax zero_page_range operation s390,dcssblk,dax: Add dax zero_page_range operation to dcssblk driver dax, pmem: Add a dax operation zero_page_range pmem: Add functions for reading/writing page to/from pmem libnvdimm: Update persistence domain value for of_pmem and papr_scm device tools/test/nvdimm: Fix out of tree build libnvdimm/region: Fix build error libnvdimm/region: Replace zero-length array with flexible-array member libnvdimm/label: Replace zero-length array with flexible-array member ACPI: NFIT: Replace zero-length array with flexible-array member libnvdimm/region: Introduce an 'align' attribute libnvdimm/region: Introduce NDD_LABELING libnvdimm/namespace: Enforce memremap_compat_align() libnvdimm/pfn: Prevent raw mode fallback if pfn-infoblock valid libnvdimm: Out of bounds read in __nd_ioctl() acpi/nfit: improve bounds checking for 'func' mm/memremap_pages: Introduce memremap_compat_align() ...
2020-04-08mm/gup: Let __get_user_pages_locked() return -EINTR for fatal signalHillf Danton1-1/+4
__get_user_pages_locked() will return 0 instead of -EINTR after commit 4426e945df588 ("mm/gup: allow VM_FAULT_RETRY for multiple times") which added extra code to allow gup detect fatal signal faster. Restore the original -EINTR behavior. Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Fixes: 4426e945df58 ("mm/gup: allow VM_FAULT_RETRY for multiple times") Reported-by: syzbot+3be1a33f04dc782e9fd5@syzkaller.appspotmail.com Signed-off-by: Hillf Danton <hdanton@sina.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Peter Xu <peterx@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07mm/gup: Mark lock taken only after a successful retakePeter Xu1-1/+1
It's definitely incorrect to mark the lock as taken even if down_read_killable() failed. This wass overlooked when we switched from down_read() to down_read_killable() because down_read() won't fail while down_read_killable() could. Fixes: 71335f37c5e8 ("mm/gup: allow to react to fatal signals") Reported-by: syzbot+a8c70b7f3579fc0587dc@syzkaller.appspotmail.com Signed-off-by: Peter Xu <peterx@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07mm/mempolicy: Allow lookup_node() to handle fatal signalPeter Xu1-2/+5
lookup_node() uses gup to pin the page and get node information. It checks against ret>=0 assuming the page will be filled in. However it's also possible that gup will return zero, for example, when the thread is quickly killed with a fatal signal. Teach lookup_node() to gracefully return an error -EFAULT if it happens. Meanwhile, initialize "page" to NULL to avoid potential risk of exploiting the pointer. Fixes: 4426e945df58 ("mm/gup: allow VM_FAULT_RETRY for multiple times") Reported-by: syzbot+693dc11fcb53120b5559@syzkaller.appspotmail.com Signed-off-by: Peter Xu <peterx@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07kasan: unset panic_on_warn before calling panic()Kees Cook1-1/+9
As done in the full WARN() handler, panic_on_warn needs to be cleared before calling panic() to avoid recursive panics. Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Dmitry Vyukov <dvyukov@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Elena Petrova <lenaptr@google.com> Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com> Link: http://lkml.kernel.org/r/20200227193516.32566-6-keescook@chromium.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07kasan: stackdepot: move filter_irq_stacks() to stackdepot.cAlexander Potapenko1-23/+0
filter_irq_stacks() can be used by other tools (e.g. KMSAN), so it needs to be moved to a common location. lib/stackdepot.c seems a good place, as filter_irq_stacks() is usually applied to the output of stack_trace_save(). This patch has been previously mailed as part of KMSAN RFC patch series. [glider@google.co: nds32: linker script: add SOFTIRQENTRY_TEXT\ Link: http://lkml.kernel.org/r/20200311121002.241430-1-glider@google.com [glider@google.com: add IRQENTRY_TEXT and SOFTIRQENTRY_TEXT to linker script] Link: http://lkml.kernel.org/r/20200311121124.243352-1-glider@google.com Signed-off-by: Alexander Potapenko <glider@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Marco Elver <elver@google.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Link: http://lkml.kernel.org/r/20200220141916.55455-3-glider@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07proc: faster open/read/close with "permanent" filesAlexey Dobriyan2-0/+2
Now that "struct proc_ops" exist we can start putting there stuff which could not fly with VFS "struct file_operations"... Most of fs/proc/inode.c file is dedicated to make open/read/.../close reliable in the event of disappearing /proc entries which usually happens if module is getting removed. Files like /proc/cpuinfo which never disappear simply do not need such protection. Save 2 atomic ops, 1 allocation, 1 free per open/read/close sequence for such "permanent" files. Enable "permanent" flag for /proc/cpuinfo /proc/kmsg /proc/modules /proc/slabinfo /proc/stat /proc/sysvipc/* /proc/swaps More will come once I figure out foolproof way to prevent out module authors from marking their stuff "permanent" for performance reasons when it is not. This should help with scalability: benchmark is "read /proc/cpuinfo R times by N threads scattered over the system". N R t, s (before) t, s (after) ----------------------------------------------------- 64 4096 1.582458 1.530502 -3.2% 256 4096 6.371926 6.125168 -3.9% 1024 4096 25.64888 24.47528 -4.6% Benchmark source: #include <chrono> #include <iostream> #include <thread> #include <vector> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <unistd.h> const int NR_CPUS = sysconf(_SC_NPROCESSORS_ONLN); int N; const char *filename; int R; int xxx = 0; int glue(int n) { cpu_set_t m; CPU_ZERO(&m); CPU_SET(n, &m); return sched_setaffinity(0, sizeof(cpu_set_t), &m); } void f(int n) { glue(n % NR_CPUS); while (*(volatile int *)&xxx == 0) { } for (int i = 0; i < R; i++) { int fd = open(filename, O_RDONLY); char buf[4096]; ssize_t rv = read(fd, buf, sizeof(buf)); asm volatile ("" :: "g" (rv)); close(fd); } } int main(int argc, char *argv[]) { if (argc < 4) { std::cerr << "usage: " << argv[0] << ' ' << "N /proc/filename R "; return 1; } N = atoi(argv[1]); filename = argv[2]; R = atoi(argv[3]); for (int i = 0; i < NR_CPUS; i++) { if (glue(i) == 0) break; } std::vector<std::thread> T; T.reserve(N); for (int i = 0; i < N; i++) { T.emplace_back(f, i); } auto t0 = std::chrono::system_clock::now(); { *(volatile int *)&xxx = 1; for (auto& t: T) { t.join(); } } auto t1 = std::chrono::system_clock::now(); std::chrono::duration<double> dt = t1 - t0; std::cout << dt.count() << ' '; return 0; } P.S.: Explicit randomization marker is added because adding non-function pointer will silently disable structure layout randomization. [akpm@linux-foundation.org: coding style fixes] Reported-by: kbuild test robot <lkp@intel.com> Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Joe Perches <joe@perches.com> Link: http://lkml.kernel.org/r/20200222201539.GA22576@avx2 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07mm/dmapool.c: micro-optimisation remove unnecessary branchMateusz Nosek1-3/+1
Previously there was a check if 'size' is aligned to 'align' and if not then it was aligned. This check was expensive as both branch and division are expensive instructions in most architectures. 'ALIGN' function on already aligned value will not change it, and as it is cheaper than branch + division it can be executed all the time and branch can be removed. Signed-off-by: Mateusz Nosek <mateusznosek0@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200320173317.26408-1-mateusznosek0@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07mm: use fallthrough;Joe Perches9-16/+11
Convert the various /* fallthrough */ comments to the pseudo-keyword fallthrough; Done via script: https://lore.kernel.org/lkml/b56602fcf79f849e733e7b521bb0e17895d390fa.1582230379.git.joe@perches.com/ Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Link: http://lkml.kernel.org/r/f62fea5d10eb0ccfc05d87c242a620c261219b66.camel@perches.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07mm/mm_init.c: clean code. Use BUILD_BUG_ON when comparing compile time constantMateusz Nosek1-1/+1
MAX_ZONELISTS is a compile time constant, so it should be compared using BUILD_BUG_ON not BUG_ON. Signed-off-by: Mateusz Nosek <mateusznosek0@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Wei Yang <richard.weiyang@gmail.com> Link: http://lkml.kernel.org/r/20200228224617.11343-1-mateusznosek0@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07mm: fix ambiguous comments for better code readabilitychenqiwu1-1/+1
The parameter of remap_pfn_range() @pfn passed from the caller is actually a page-frame number converted by corresponding physical address of kernel memory, the original comment is ambiguous that may mislead the users. Meanwhile, there is an ambiguous typo "VMM" in the comment of vm_area_struct. So fixing them will make the code more readable. Signed-off-by: chenqiwu <chenqiwu@xiaomi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/1583026921-15279-1-git-send-email-qiwuchen55@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07mm/zsmalloc: add missing annotation for unpin_tag()Jules Irenge1-1/+1
Sparse reports a warning at unpin_tag()() warning: context imbalance in unpin_tag() - unexpected unlock The root cause is the missing annotation at unpin_tag() Add the missing __releases(bitlock) annotation Signed-off-by: Jules Irenge <jbi.octave@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Minchan Kim <minchan@kernel.org> Link: http://lkml.kernel.org/r/20200214204741.94112-14-jbi.octave@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07mm/zsmalloc: add missing annotation for pin_tag()Jules Irenge1-1/+1
Sparse reports a warning at pin_tag()() warning: context imbalance in pin_tag() - wrong count at exit The root cause is the missing annotation at pin_tag() Add the missing __acquires(bitlock) annotation Signed-off-by: Jules Irenge <jbi.octave@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Minchan Kim <minchan@kernel.org> Link: http://lkml.kernel.org/r/20200214204741.94112-13-jbi.octave@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07mm/zsmalloc: add missing annotation for migrate_read_unlock()Jules Irenge1-1/+1
Sparse reports a warning at migrate_read_unlock()() warning: context imbalance in migrate_read_unlock() - unexpected unlock The root cause is the missing annotation at migrate_read_unlock() Add the missing __releases(&zspage->lock) annotation Signed-off-by: Jules Irenge <jbi.octave@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Minchan Kim <minchan@kernel.org> Link: http://lkml.kernel.org/r/20200214204741.94112-12-jbi.octave@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07mm/zsmalloc: add missing annotation for migrate_read_lock()Jules Irenge1-1/+1
Sparse reports a warning at migrate_read_lock()() warning: context imbalance in migrate_read_lock() - wrong count at exit The root cause is the missing annotation at migrate_read_lock() Add the missing __acquires(&zspage->lock) annotation Signed-off-by: Jules Irenge <jbi.octave@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Minchan Kim <minchan@kernel.org> Link: http://lkml.kernel.org/r/20200214204741.94112-11-jbi.octave@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07mm/slub: add missing annotation for put_map()Jules Irenge1-1/+1
Sparse reports a warning at put_map()() warning: context imbalance in put_map() - unexpected unlock The root cause is the missing annotation at put_map() Add the missing __releases(&object_map_lock) annotation Signed-off-by: Jules Irenge <jbi.octave@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200214204741.94112-10-jbi.octave@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07mm/slub: add missing annotation for get_map()Jules Irenge1-0/+1
Sparse reports a warning at get_map()() warning: context imbalance in get_map() - wrong count at exit The root cause is the missing annotation at get_map() Add the missing __acquires(&object_map_lock) annotation Signed-off-by: Jules Irenge <jbi.octave@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200214204741.94112-9-jbi.octave@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07mm/mempolicy: add missing annotation for queue_pages_pmd()Jules Irenge1-0/+1
Sparse reports a warning at queue_pages_pmd() context imbalance in queue_pages_pmd() - unexpected unlock The root cause is the missing annotation at queue_pages_pmd() Add the missing __releases(ptl) Signed-off-by: Jules Irenge <jbi.octave@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200214204741.94112-8-jbi.octave@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07mm/hugetlb: add missing annotation for gather_surplus_pages()Jules Irenge1-0/+1
Sparse reports a warning at gather_surplus_pages() warning: context imbalance in hugetlb_cow() - unexpected unlock The root cause is the missing annotation at gather_surplus_pages() Add the missing __must_hold(&hugetlb_lock) Signed-off-by: Jules Irenge <jbi.octave@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Link: http://lkml.kernel.org/r/20200214204741.94112-7-jbi.octave@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07mm/compaction: add missing annotation for compact_lock_irqsaveJules Irenge1-0/+1
Sparse reports a warning at compact_lock_irqsave() warning: context imbalance in compact_lock_irqsave() - wrong count at exit The root cause is the missing annotation at compact_lock_irqsave() Add the missing __acquires(lock) annotation. Signed-off-by: Jules Irenge <jbi.octave@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200214204741.94112-6-jbi.octave@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07mm/zswap: allow setting default status, compressor and allocator in KconfigMaciej S. Szmigiero2-13/+129
The compressed cache for swap pages (zswap) currently needs from 1 to 3 extra kernel command line parameters in order to make it work: it has to be enabled by adding a "zswap.enabled=1" command line parameter and if one wants a different compressor or pool allocator than the default lzo / zbud combination then these choices also need to be specified on the kernel command line in additional parameters. Using a different compressor and allocator for zswap is actually pretty common as guides often recommend using the lz4 / z3fold pair instead of the default one. In such case it is also necessary to remember to enable the appropriate compression algorithm and pool allocator in the kernel config manually. Let's avoid the need for adding these kernel command line parameters and automatically pull in the dependencies for the selected compressor algorithm and pool allocator by adding an appropriate default switches to Kconfig. The default values for these options match what the code was using previously as its defaults. Signed-off-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vitaly Wool <vitaly.wool@konsulko.com> Link: http://lkml.kernel.org/r/20200202000112.456103-1-mail@maciej.szmigiero.name Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07mm: prevent a warning when casting void* -> enumPalmer Dabbelt1-1/+1
I recently build the RISC-V port with LLVM trunk, which has introduced a new warning when casting from a pointer to an enum of a smaller size. This patch simply casts to a long in the middle to stop the warning. I'd be surprised this is the only one in the kernel, but it's the only one I saw. Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200227211741.83165-1-palmer@dabbelt.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07mm: huge tmpfs: try to split_huge_page() when punching holeHugh Dickins3-56/+60
Yang Shi writes: Currently, when truncating a shmem file, if the range is partly in a THP (start or end is in the middle of THP), the pages actually will just get cleared rather than being freed, unless the range covers the whole THP. Even though all the subpages are truncated (randomly or sequentially), the THP may still be kept in page cache. This might be fine for some usecases which prefer preserving THP, but balloon inflation is handled in base page size. So when using shmem THP as memory backend, QEMU inflation actually doesn't work as expected since it doesn't free memory. But the inflation usecase really needs to get the memory freed. (Anonymous THP will also not get freed right away, but will be freed eventually when all subpages are unmapped: whereas shmem THP still stays in page cache.) Split THP right away when doing partial hole punch, and if split fails just clear the page so that read of the punched area will return zeroes. Hugh Dickins adds: Our earlier "team of pages" huge tmpfs implementation worked in the way that Yang Shi proposes; and we have been using this patch to continue to split the huge page when hole-punched or truncated, since converting over to the compound page implementation. Although huge tmpfs gives out huge pages when available, if the user specifically asks to truncate or punch a hole (perhaps to free memory, perhaps to reduce the memcg charge), then the filesystem should do so as best it can, splitting the huge page. That is not always possible: any additional reference to the huge page prevents split_huge_page() from succeeding, so the result can be flaky. But in practice it works successfully enough that we've not seen any problem from that. Add shmem_punch_compound() to encapsulate the decision of when a split is needed, and doing the split if so. Using this simplifies the flow in shmem_undo_range(); and the first (trylock) pass does not need to do any page clearing on failure, because the second pass will either succeed or do that clearing. Following the example of zero_user_segment() when clearing a partial page, add flush_dcache_page() and set_page_dirty() when clearing a hole - though I'm not certain that either is needed. But: split_huge_page() would be sure to fail if shmem_undo_range()'s pagevec holds further references to the huge page. The easiest way to fix that is for find_get_entries() to return early, as soon as it has put one compound head or tail into the pagevec. At first this felt like a hack; but on examination, this convention better suits all its callers - or will do, if the slight one-page-per-pagevec slowdown in shmem_unlock_mapping() and shmem_seek_hole_data() is transformed into a 512-page-per-pagevec speedup by checking for compound pages there. Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Yang Shi <yang.shi@linux.alibaba.com> Cc: Alexander Duyck <alexander.duyck@gmail.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: David Hildenbrand <david@redhat.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2002261959020.10801@eggly.anvils Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07mm/shmem.c: clean code by removing unnecessary assignmentMateusz Nosek1-6/+3
Previously 0 was assigned to variable 'error' but the variable was never read before reassignemnt later. So the assignment can be removed. Signed-off-by: Mateusz Nosek <mateusznosek0@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Hugh Dickins <hughd@google.com> Link: http://lkml.kernel.org/r/20200301152832.24595-1-mateusznosek0@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07mm/shmem.c: distribute switch variables for initializationKees Cook1-4/+7
Variables declared in a switch statement before any case statements cannot be automatically initialized with compiler instrumentation (as they are not part of any execution flow). With GCC's proposed automatic stack variable initialization feature, this triggers a warning (and they don't get initialized). Clang's automatic stack variable initialization (via CONFIG_INIT_STACK_ALL=y) doesn't throw a warning, but it also doesn't initialize such variables[1]. Note that these warnings (or silent skipping) happen before the dead-store elimination optimization phase, so even when the automatic initializations are later elided in favor of direct initializations, the warnings remain. To avoid these problems, move such variables into the "case" where they're used or lift them up into the main function body. mm/shmem.c: In function `shmem_getpage_gfp': mm/shmem.c:1816:10: warning: statement will never be executed [-Wswitch-unreachable] 1816 | loff_t i_size; | ^~~~~~ [1] https://bugs.llvm.org/show_bug.cgi?id=44916 Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Hugh Dickins <hughd@google.com> Cc: Alexander Potapenko <glider@google.com> Link: http://lkml.kernel.org/r/20200220062312.69165-1-keescook@chromium.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07mm/memory_hotplug.c: use __pfn_to_section() instead of open-codingchenqiwu1-1/+1
Use __pfn_to_section() API instead of open-coding for better code readability. Signed-off-by: chenqiwu <chenqiwu@xiaomi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: David Hildenbrand <david@redhat.com> Link: http://lkml.kernel.org/r/1584345134-16671-1-git-send-email-qiwuchen55@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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