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2015-11-06mm: make compound_head() robustKirill A. Shutemov1-7/+0
Hugh has pointed that compound_head() call can be unsafe in some context. There's one example: CPU0 CPU1 isolate_migratepages_block() page_count() compound_head() !!PageTail() == true put_page() tail->first_page = NULL head = tail->first_page alloc_pages(__GFP_COMP) prep_compound_page() tail->first_page = head __SetPageTail(p); !!PageTail() == true <head == NULL dereferencing> The race is pure theoretical. I don't it's possible to trigger it in practice. But who knows. We can fix the race by changing how encode PageTail() and compound_head() within struct page to be able to update them in one shot. The patch introduces page->compound_head into third double word block in front of compound_dtor and compound_order. Bit 0 encodes PageTail() and the rest bits are pointer to head page if bit zero is set. The patch moves page->pmd_huge_pte out of word, just in case if an architecture defines pgtable_t into something what can have the bit 0 set. hugetlb_cgroup uses page->lru.next in the second tail page to store pointer struct hugetlb_cgroup. The patch switch it to use page->private in the second tail page instead. The space is free since ->first_page is removed from the union. The patch also opens possibility to remove HUGETLB_CGROUP_MIN_ORDER limitation, since there's now space in first tail page to store struct hugetlb_cgroup pointer. But that's out of scope of the patch. That means page->compound_head shares storage space with: - page->lru.next; - page->next; - page->rcu_head.next; That's too long list to be absolutely sure, but looks like nobody uses bit 0 of the word. page->rcu_head.next guaranteed[1] to have bit 0 clean as long as we use call_rcu(), call_rcu_bh(), call_rcu_sched(), or call_srcu(). But future call_rcu_lazy() is not allowed as it makes use of the bit and we can get false positive PageTail(). [1] http://lkml.kernel.org/g/20150827163634.GD4029@linux.vnet.ibm.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Christoph Lameter <cl@linux.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-05mm: hwpoison: ratelimit messages from unpoison_memory()Naoya Horiguchi1-9/+25
Currently kernel prints out results of every single unpoison event, which i= s not necessary because unpoison is purely a testing feature and testers can = get little or no information from lots of lines of unpoison log storm. So this patch ratelimits printk in unpoison_memory(). This patch introduces a file local ratelimit_state, which adds 64 bytes to memory-failure.o. If we apply pr_info_ratelimited() for 8 callsite below, 2= 56 bytes is added, so it's a win. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-10hwpoison: use page_cgroup_ino for filtering by memcgVladimir Davydov1-14/+2
Hwpoison allows to filter pages by memory cgroup ino. Currently, it calls try_get_mem_cgroup_from_page to obtain the cgroup from a page and then its ino using cgroup_ino, but now we have a helper method for that, page_cgroup_ino, so use it instead. This patch also loosens the hwpoison memcg filter dependency rules - it makes it depend on CONFIG_MEMCG instead of CONFIG_MEMCG_SWAP, because hwpoison memcg filter does not require anything (nor it used to) from CONFIG_MEMCG_SWAP side. Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Reviewed-by: Andres Lagar-Cavilla <andreslc@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Greg Thelen <gthelen@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-08mm: rename alloc_pages_exact_node() to __alloc_pages_node()Vlastimil Babka1-1/+1
alloc_pages_exact_node() was introduced in commit 6484eb3e2a81 ("page allocator: do not check NUMA node ID when the caller knows the node is valid") as an optimized variant of alloc_pages_node(), that doesn't fallback to current node for nid == NUMA_NO_NODE. Unfortunately the name of the function can easily suggest that the allocation is restricted to the given node and fails otherwise. In truth, the node is only preferred, unless __GFP_THISNODE is passed among the gfp flags. The misleading name has lead to mistakes in the past, see for example commits 5265047ac301 ("mm, thp: really limit transparent hugepage allocation to local node") and b360edb43f8e ("mm, mempolicy: migrate_to_node should only migrate to node"). Another issue with the name is that there's a family of alloc_pages_exact*() functions where 'exact' means exact size (instead of page order), which leads to more confusion. To prevent further mistakes, this patch effectively renames alloc_pages_exact_node() to __alloc_pages_node() to better convey that it's an optimized variant of alloc_pages_node() not intended for general usage. Both functions get described in comments. It has been also considered to really provide a convenience function for allocations restricted to a node, but the major opinion seems to be that __GFP_THISNODE already provides that functionality and we shouldn't duplicate the API needlessly. The number of users would be small anyway. Existing callers of alloc_pages_exact_node() are simply converted to call __alloc_pages_node(), with the exception of sba_alloc_coherent() which open-codes the check for NUMA_NO_NODE, so it is converted to use alloc_pages_node() instead. This means it no longer performs some VM_BUG_ON checks, and since the current check for nid in alloc_pages_node() uses a 'nid < 0' comparison (which includes NUMA_NO_NODE), it may hide wrong values which would be previously exposed. Both differences will be rectified by the next patch. To sum up, this patch makes no functional changes, except temporarily hiding potentially buggy callers. Restricting the checks in alloc_pages_node() is left for the next patch which can in turn expose more existing buggy callers. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Robin Holt <robinmholt@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Christoph Lameter <cl@linux.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Cc: Mel Gorman <mgorman@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Greg Thelen <gthelen@google.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Gleb Natapov <gleb@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Cliff Whickman <cpw@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-08mm/hwpoison: don't try to unpoison containment-failed pagesNaoya Horiguchi1-0/+16
memory_failure() can be called at any page at any time, which means that we can't eliminate the possibility of containment failure. In such case the best option is to leak the page intentionally (and never touch it later.) We have an unpoison function for testing, and it cannot handle such containment-failed pages, which results in kernel panic (visible with various calltraces.) So this patch suggests that we limit the unpoisonable pages to properly contained pages and ignore any other ones. Testers are recommended to keep in mind that there're un-unpoisonable pages when writing test programs. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Tested-by: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-08mm/hwpoison: fix race between soft_offline_page and unpoison_memoryWanpeng Li1-4/+0
Wanpeng Li reported a race between soft_offline_page() and unpoison_memory(), which causes the following kernel panic: BUG: Bad page state in process bash pfn:97000 page:ffffea00025c0000 count:0 mapcount:1 mapping: (null) index:0x7f4fdbe00 flags: 0x1fffff80080048(uptodate|active|swapbacked) page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set bad because of flags: flags: 0x40(active) Modules linked in: snd_hda_codec_hdmi i915 rpcsec_gss_krb5 nfsv4 dns_resolver bnep rfcomm nfsd bluetooth auth_rpcgss nfs_acl nfs rfkill lockd grace sunrpc i2c_algo_bit drm_kms_helper snd_hda_codec_realtek snd_hda_codec_generic drm snd_hda_intel fscache snd_hda_codec x86_pkg_temp_thermal coretemp kvm_intel snd_hda_core snd_hwdep kvm snd_pcm snd_seq_dummy snd_seq_oss crct10dif_pclmul snd_seq_midi crc32_pclmul snd_seq_midi_event ghash_clmulni_intel snd_rawmidi aesni_intel lrw gf128mul snd_seq glue_helper ablk_helper snd_seq_device cryptd fuse snd_timer dcdbas serio_raw mei_me parport_pc snd mei ppdev i2c_core video lp soundcore parport lpc_ich shpchp mfd_core ext4 mbcache jbd2 sd_mod e1000e ahci ptp libahci crc32c_intel libata pps_core CPU: 3 PID: 2211 Comm: bash Not tainted 4.2.0-rc5-mm1+ #45 Hardware name: Dell Inc. OptiPlex 7020/0F5C5X, BIOS A03 01/08/2015 Call Trace: dump_stack+0x48/0x5c bad_page+0xe6/0x140 free_pages_prepare+0x2f9/0x320 ? uncharge_list+0xdd/0x100 free_hot_cold_page+0x40/0x170 __put_single_page+0x20/0x30 put_page+0x25/0x40 unmap_and_move+0x1a6/0x1f0 migrate_pages+0x100/0x1d0 ? kill_procs+0x100/0x100 ? unlock_page+0x6f/0x90 __soft_offline_page+0x127/0x2a0 soft_offline_page+0xa6/0x200 This race is explained like below: CPU0 CPU1 soft_offline_page __soft_offline_page TestSetPageHWPoison unpoison_memory PageHWPoison check (true) TestClearPageHWPoison put_page -> release refcount held by get_hwpoison_page in unpoison_memory put_page -> release refcount held by isolate_lru_page in __soft_offline_page migrate_pages The second put_page() releases refcount held by isolate_lru_page() which will lead to unmap_and_move() releases the last refcount of page and w/ mapcount still 1 since try_to_unmap() is not called if there is only one user map the page. Anyway, the page refcount and mapcount will still mess if the page is mapped by multiple users. This race was introduced by commit 4491f71260 ("mm/memory-failure: set PageHWPoison before migrate_pages()"), which focuses on preventing the reuse of successfully migrated page. Before this commit we prevent the reuse by changing the migratetype to MIGRATE_ISOLATE during soft offlining, which has the following problems, so simply reverting the commit is not a best option: 1) it doesn't eliminate the reuse completely, because set_migratetype_isolate() can fail to set MIGRATE_ISOLATE to the target page if the pageblock of the page contains one or more unmovable pages (i.e. has_unmovable_pages() returns true). 2) the original code changes migratetype to MIGRATE_ISOLATE forcibly, and sets it to MIGRATE_MOVABLE forcibly after soft offline, regardless of the original migratetype state, which could impact other subsystems like memory hotplug or compaction. This patch moves PageSetHWPoison just after put_page() in unmap_and_move(), which closes up the reported race window and minimizes another race window b/w SetPageHWPoison and reallocation (which causes the reuse of soft-offlined page.) The latter race window still exists but it's acceptable, because it's rare and effectively the same as ordinary "containment failure" case even if it happens, so keep the window open is acceptable. Fixes: 4491f71260 ("mm/memory-failure: set PageHWPoison before migrate_pages()") Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reported-by: Wanpeng Li <wanpeng.li@hotmail.com> Tested-by: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-08mm/hwpoison: introduce num_poisoned_pages wrappersNaoya Horiguchi1-16/+14
num_poisoned_pages counter will be changed outside mm/memory-failure.c by a subsequent patch, so this patch prepares wrappers to manipulate it. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Tested-by: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-08mm/hwpoison: replace most of put_page in memory error handling by ↵Wanpeng Li1-17/+15
put_hwpoison_page Replace most instances of put_page() in memory error handling with put_hwpoison_page(). Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-08mm/hwpoison: introduce put_hwpoison_page to put refcount for memory error ↵Wanpeng Li1-0/+21
handling Introduce put_hwpoison_page to put refcount for memory error handling. Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Suggested-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-08mm/hwpoison: fix PageHWPoison test/set raceWanpeng Li1-0/+2
There is a race between madvise_hwpoison path and memory_failure: CPU0 CPU1 madvise_hwpoison get_user_pages_fast PageHWPoison check (false) memory_failure TestSetPageHWPoison soft_offline_page PageHWPoison check (true) return -EBUSY (without put_page) Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Suggested-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-08mm/hwpoison: fix failure to split thp w/ refcount heldWanpeng Li1-0/+2
THP pages will get a refcount in madvise_hwpoison() w/ MF_COUNT_INCREASED flag, however, the refcount is still held when fail to split THP pages. Fix it by reducing the refcount of THP pages when fail to split THP. Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-08memcg: export struct mem_cgroupMichal Hocko1-1/+1
mem_cgroup structure is defined in mm/memcontrol.c currently which means that the code outside of this file has to use external API even for trivial access stuff. This patch exports mm_struct with its dependencies and makes some of the exported functions inlines. This even helps to reduce the code size a bit (make defconfig + CONFIG_MEMCG=y) text data bss dec hex filename 12355346 1823792 1089536 15268674 e8fb42 vmlinux.before 12354970 1823792 1089536 15268298 e8f9ca vmlinux.after This is not much (370B) but better than nothing. We also save a function call in some hot paths like callers of mem_cgroup_count_vm_event which is used for accounting. The patch doesn't introduce any functional changes. [vdavykov@parallels.com: inline memcg_kmem_is_active] [vdavykov@parallels.com: do not expose type outside of CONFIG_MEMCG] [akpm@linux-foundation.org: memcontrol.h needs eventfd.h for eventfd_ctx] [akpm@linux-foundation.org: export mem_cgroup_from_task() to modules] Signed-off-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Vladimir Davydov <vdavydov@parallels.com> Suggested-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-08-14mm/hwpoison: fix panic due to split huge zero pageWanpeng Li1-2/+5
Bug: ------------[ cut here ]------------ kernel BUG at mm/huge_memory.c:1957! invalid opcode: 0000 [#1] SMP Modules linked in: snd_hda_codec_hdmi i915 rpcsec_gss_krb5 snd_hda_codec_realtek snd_hda_codec_generic nfsv4 dns_re CPU: 2 PID: 2576 Comm: test_huge Not tainted 4.2.0-rc5-mm1+ #27 Hardware name: Dell Inc. OptiPlex 7020/0F5C5X, BIOS A03 01/08/2015 task: ffff880204e3d600 ti: ffff8800db16c000 task.ti: ffff8800db16c000 RIP: split_huge_page_to_list+0xdb/0x120 Call Trace: memory_failure+0x32e/0x7c0 madvise_hwpoison+0x8b/0x160 SyS_madvise+0x40/0x240 ? do_page_fault+0x37/0x90 entry_SYSCALL_64_fastpath+0x12/0x71 Code: ff f0 41 ff 4c 24 30 74 0d 31 c0 48 83 c4 08 5b 41 5c 41 5d c9 c3 4c 89 e7 e8 e2 58 fd ff 48 83 c4 08 31 c0 RIP split_huge_page_to_list+0xdb/0x120 RSP <ffff8800db16fde8> ---[ end trace aee7ce0df8e44076 ]--- Testcase: #define _GNU_SOURCE #include <stdlib.h> #include <stdio.h> #include <sys/mman.h> #include <unistd.h> #include <fcntl.h> #include <sys/types.h> #include <errno.h> #include <string.h> #define MB 1024*1024 int main(void) { char *mem; posix_memalign((void **)&mem, 2 * MB, 200 * MB); madvise(mem, 200 * MB, MADV_HWPOISON); free(mem); return 0; } Huge zero page is allocated if page fault w/o FAULT_FLAG_WRITE flag. The get_user_pages_fast() which called in madvise_hwpoison() will get huge zero page if the page is not allocated before. Huge zero page is a tranparent huge page, however, it is not an anonymous page. memory_failure will split the huge zero page and trigger BUG_ON(is_huge_zero_page(page)); After commit 98ed2b0052e6 ("mm/memory-failure: give up error handling for non-tail-refcounted thp"), memory_failure will not catch non anon thp from madvise_hwpoison path and this bug occur. Fix it by catching non anon thp in memory_failure in order to not split huge zero page in madvise_hwpoison path. After this patch: Injecting memory failure for page 0x202800 at 0x7fd8ae800000 MCE: 0x202800: non anonymous thp [...] [akpm@linux-foundation.org: remove second split, per Wanpeng] Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-08-14mm/hwpoison: fix fail isolate hugetlbfs page w/ refcount heldWanpeng Li1-7/+6
Hugetlbfs pages will get a refcount in get_any_page() or madvise_hwpoison() if soft offlining through madvise. The refcount which is held by the soft offline path should be released if we fail to isolate hugetlbfs pages. Fix it by reducing the refcount for both isolation success and failure. Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: <stable@vger.kernel.org> [3.9+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-08-14mm/hwpoison: fix page refcount of unknown non LRU pageWanpeng Li1-0/+2
After trying to drain pages from pagevec/pageset, we try to get reference count of the page again, however, the reference count of the page is not reduced if the page is still not on LRU list. Fix it by adding the put_page() to drop the page reference which is from __get_any_page(). Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: <stable@vger.kernel.org> [3.9+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-08-07mm/memory-failure: set PageHWPoison before migrate_pages()Naoya Horiguchi1-3/+4
Now page freeing code doesn't consider PageHWPoison as a bad page, so by setting it before completing the page containment, we can prevent the error page from being reused just after successful page migration. I added TTU_IGNORE_HWPOISON for try_to_unmap() to make sure that the page table entry is transformed into migration entry, not to hwpoison entry. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Dean Nelson <dnelson@redhat.com> Cc: Tony Luck <tony.luck@intel.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Hugh Dickins <hughd@google.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-08-07mm/memory-failure: give up error handling for non-tail-refcounted thpNaoya Horiguchi1-9/+12
"non anonymous thp" case is still racy with freeing thp, which causes panic due to put_page() for refcount-0 page. It seems that closing up this race might be hard (and/or not worth doing,) so let's give up the error handling for this case. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Dean Nelson <dnelson@redhat.com> Cc: Tony Luck <tony.luck@intel.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Hugh Dickins <hughd@google.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-08-07mm/memory-failure: fix race in counting num_poisoned_pagesNaoya Horiguchi1-2/+2
When memory_failure() is called on a page which are just freed after page migration from soft offlining, the counter num_poisoned_pages is raised twi= ce. So let's fix it with using TestSetPageHWPoison. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Dean Nelson <dnelson@redhat.com> Cc: Tony Luck <tony.luck@intel.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Hugh Dickins <hughd@google.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-08-07mm/memory-failure: unlock_page before put_pageNaoya Horiguchi1-2/+2
Recently I addressed a few of hwpoison race problems and the patches are merged on v4.2-rc1. It made progress, but unfortunately some problems still remain due to less coverage of my testing. So I'm trying to fix or avoid them in this series. One point I'm expecting to discuss is that patch 4/5 changes the page flag set to be checked on free time. In current behavior, __PG_HWPOISON is not supposed to be set when the page is freed. I think that there is no strong reason for this behavior, and it causes a problem hard to fix only in error handler side (because __PG_HWPOISON could be set at arbitrary timing.) So I suggest to change it. With this patchset, hwpoison stress testing in official mce-test testsuite (which previously failed) passes. This patch (of 5): In "just unpoisoned" path, we do put_page and then unlock_page, which is a wrong order and causes "freeing locked page" bug. So let's fix it. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Dean Nelson <dnelson@redhat.com> Cc: Tony Luck <tony.luck@intel.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Hugh Dickins <hughd@google.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24tracing: add trace event for memory-failureXie XiuQi1-0/+3
RAS user space tools like rasdaemon which base on trace event, could receive mce error event, but no memory recovery result event. So, I want to add this event to make this scenario complete. This patch add a event at ras group for memory-failure. The output like below: # tracer: nop # # entries-in-buffer/entries-written: 2/2 #P:24 # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / delay # TASK-PID CPU# |||| TIMESTAMP FUNCTION # | | | |||| | | mce-inject-13150 [001] .... 277.019359: memory_failure_event: pfn 0x19869: recovery action for free buddy page: Delayed [xiexiuqi@huawei.com: fix build error] Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Tony Luck <tony.luck@intel.com> Cc: Chen Gong <gong.chen@linux.intel.com> Cc: Jim Davis <jim.epost@gmail.com> Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24memory-failure: change type of action_result's param 3 to enumXie XiuQi1-1/+2
Change type of action_result's param 3 to enum for type consistency, and rename mf_outcome to mf_result for clearly. Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com> Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Chen Gong <gong.chen@linux.intel.com> Cc: Jim Davis <jim.epost@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tony Luck <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24memory-failure: export page_type and action resultXie XiuQi1-101/+67
Export 'outcome' and 'action_page_type' to mm.h, so we could use this emnus outside. This patch is preparation for adding trace events for memory-failure recovery action. Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com> Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Chen Gong <gong.chen@linux.intel.com> Cc: Jim Davis <jim.epost@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tony Luck <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24mm/memory-failure: me_huge_page() does nothing for thpNaoya Horiguchi1-0/+4
memory_failure() is supposed not to handle thp itself, but to split it. But if something were wrong and page_action() were called on thp, me_huge_page() (action routine for hugepages) should be better to take no action, rather than to take wrong action prepared for hugetlb (which triggers BUG_ON().) This change is for potential problems, but makes sense to me because thp is an actively developing feature and this code path can be open in the future. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Tony Luck <tony.luck@intel.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24mm: soft-offline: don't free target page in successful page migrationNaoya Horiguchi1-22/+0
Stress testing showed that soft offline events for a process iterating "mmap-pagefault-munmap" loop can trigger VM_BUG_ON(PAGE_FLAGS_CHECK_AT_PREP) in __free_one_page(): Soft offlining page 0x70fe1 at 0x70100008d000 Soft offlining page 0x705fb at 0x70300008d000 page:ffffea0001c3f840 count:0 mapcount:0 mapping: (null) index:0x2 flags: 0x1fffff80800000(hwpoison) page dumped because: VM_BUG_ON_PAGE(page->flags & ((1 << 25) - 1)) ------------[ cut here ]------------ kernel BUG at /src/linux-dev/mm/page_alloc.c:585! invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC Modules linked in: cfg80211 rfkill crc32c_intel microcode ppdev parport_pc pcspkr serio_raw virtio_balloon parport i2c_piix4 virtio_blk virtio_net ata_generic pata_acpi floppy CPU: 3 PID: 1779 Comm: test_base_madv_ Not tainted 4.0.0-v4.0-150511-1451-00009-g82360a3730e6 #139 RIP: free_pcppages_bulk+0x52a/0x6f0 Call Trace: drain_pages_zone+0x3d/0x50 drain_local_pages+0x1d/0x30 on_each_cpu_mask+0x46/0x80 drain_all_pages+0x14b/0x1e0 soft_offline_page+0x432/0x6e0 SyS_madvise+0x73c/0x780 system_call_fastpath+0x12/0x17 Code: ff 89 45 b4 48 8b 45 c0 48 83 b8 a8 00 00 00 00 0f 85 e3 fb ff ff 0f 1f 00 0f 0b 48 8b 7d 90 48 c7 c6 e8 95 a6 81 e8 e6 32 02 00 <0f> 0b 8b 45 cc 49 89 47 30 41 8b 47 18 83 f8 ff 0f 85 10 ff ff RIP [<ffffffff811a806a>] free_pcppages_bulk+0x52a/0x6f0 RSP <ffff88007a117d28> ---[ end trace 53926436e76d1f35 ]--- When soft offline successfully migrates page, the source page is supposed to be freed. But there is a race condition where a source page looks isolated (i.e. the refcount is 0 and the PageHWPoison is set) but somewhat linked to pcplist. Then another soft offline event calls drain_all_pages() and tries to free such hwpoisoned page, which is forbidden. This odd page state seems to happen due to the race between put_page() in putback_lru_page() and __pagevec_lru_add_fn(). But I don't want to play with tweaking drain code as done in commit 9ab3b598d2df "mm: hwpoison: drop lru_add_drain_all() in __soft_offline_page()", or to change page freeing code for this soft offline's purpose. Instead, let's think about the difference between hard offline and soft offline. There is an interesting difference in how to isolate the in-use page between these, that is, hard offline marks PageHWPoison of the target page at first, and doesn't free it by keeping its refcount 1. OTOH, soft offline tries to free the target page then marks PageHWPoison. This difference might be the source of complexity and result in bugs like the above. So making soft offline isolate with keeping refcount can be a solution for this problem. We can pass to page migration code the "reason" which shows the caller, so let's use this more to avoid calling putback_lru_page() when called from soft offline, which effectively does the isolation for soft offline. With this change, target pages of soft offline never be reused without changing migratetype, so this patch also removes the related code. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Tony Luck <tony.luck@intel.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24mm/memory-failure: introduce get_hwpoison_page() for consistent refcount ↵Naoya Horiguchi1-5/+45
handling memory_failure() can run in 2 different mode (specified by MF_COUNT_INCREASED) in page refcount perspective. When MF_COUNT_INCREASED is set, memory_failure() assumes that the caller takes a refcount of the target page. And if cleared, memory_failure() takes it in it's own. In current code, however, refcounting is done differently in each caller. For example, madvise_hwpoison() uses get_user_pages_fast() and hwpoison_inject() uses get_page_unless_zero(). So this inconsistent refcounting causes refcount failure especially for thp tail pages. Typical user visible effects are like memory leak or VM_BUG_ON_PAGE(!page_count(page)) in isolate_lru_page(). To fix this refcounting issue, this patch introduces get_hwpoison_page() to handle thp tail pages in the same manner for each caller of hwpoison code. memory_failure() might fail to split thp and in such case it returns without completing page isolation. This is not good because PageHWPoison on the thp is still set and there's no easy way to unpoison such thps. So this patch try to roll back any action to the thp in "non anonymous thp" case and "thp split failed" case, expecting an MCE(SRAR) generated by later access afterward will properly free such thps. [akpm@linux-foundation.org: fix CONFIG_HWPOISON_INJECT=m] Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Tony Luck <tony.luck@intel.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24mm/memory-failure: split thp earlier in memory error handlingNaoya Horiguchi1-63/+25
memory_failure() doesn't handle thp itself at this time and need to split it before doing isolation. Currently thp is split in the middle of hwpoison_user_mappings(), but there're corner cases where memory_failure() wrongly tries to handle thp without splitting. 1) "non anonymous" thp, which is not a normal operating mode of thp, but a memory error could hit a thp before anon_vma is initialized. In such case, split_huge_page() fails and me_huge_page() (intended for hugetlb) is called for thp, which triggers BUG_ON in page_hstate(). 2) !PageLRU case, where hwpoison_user_mappings() returns with SWAP_SUCCESS and the result is the same as case 1. memory_failure() can't avoid splitting, so let's split it more earlier, which also reduces code which are prepared for both of normal page and thp. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Tony Luck <tony.luck@intel.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24mm, hwpoison: remove obsolete "Notebook" todo listAndi Kleen1-7/+0
All the items mentioned here have been either addressed, or were not really needed. So just remove the comment. Signed-off-by: Andi Kleen <ak@linux.intel.com> Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24mm, hwpoison: add comment describing when to add new casesAndi Kleen1-0/+8
Here's another comment fix for hwpoison. It describes the "guiding principle" on when to add new memory error recovery code. Signed-off-by: Andi Kleen <ak@linux.intel.com> Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-05-05mm: soft-offline: fix num_poisoned_pages counting on concurrent eventsNaoya Horiguchi1-4/+4
If multiple soft offline events hit one free page/hugepage concurrently, soft_offline_page() can handle the free page/hugepage multiple times, which makes num_poisoned_pages counter increased more than once. This patch fixes this wrong counting by checking TestSetPageHWPoison for normal papes and by checking the return value of dequeue_hwpoisoned_huge_page() for hugepages. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: Dean Nelson <dnelson@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: <stable@vger.kernel.org> [3.14+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-05-05mm/memory-failure: call shake_page() when error hits thp tail pageNaoya Horiguchi1-4/+4
Currently memory_failure() calls shake_page() to sweep pages out from pcplists only when the victim page is 4kB LRU page or thp head page. But we should do this for a thp tail page too. Consider that a memory error hits a thp tail page whose head page is on a pcplist when memory_failure() runs. Then, the current kernel skips shake_pages() part, so hwpoison_user_mappings() returns without calling split_huge_page() nor try_to_unmap() because PageLRU of the thp head is still cleared due to the skip of shake_page(). As a result, me_huge_page() runs for the thp, which is broken behavior. One effect is a leak of the thp. And another is to fail to isolate the memory error, so later access to the error address causes another MCE, which kills the processes which used the thp. This patch fixes this problem by calling shake_page() for thp tail case. Fixes: 385de35722c9 ("thp: allow a hwpoisoned head page to be put back to LRU") Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reviewed-by: Andi Kleen <ak@linux.intel.com> Acked-by: Dean Nelson <dnelson@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Cc: Jin Dongming <jin.dongming@np.css.fujitsu.com> Cc: <stable@vger.kernel.org> [3.4+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15mm: hugetlb: introduce page_huge_activeNaoya Horiguchi1-2/+12
We are not safe from calling isolate_huge_page() on a hugepage concurrently, which can make the victim hugepage in invalid state and results in BUG_ON(). The root problem of this is that we don't have any information on struct page (so easily accessible) about hugepages' activeness. Note that hugepages' activeness means just being linked to hstate->hugepage_activelist, which is not the same as normal pages' activeness represented by PageActive flag. Normal pages are isolated by isolate_lru_page() which prechecks PageLRU before isolation, so let's do similarly for hugetlb with a new paeg_huge_active(). set/clear_page_huge_active() should be called within hugetlb_lock. But hugetlb_cow() and hugetlb_no_page() don't do this, being justified because in these functions set_page_huge_active() is called right after the hugepage is allocated and no other thread tries to isolate it. [akpm@linux-foundation.org: s/PageHugeActive/page_huge_active/, make it return bool] [fengguang.wu@intel.com: set_page_huge_active() can be static] Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Hugh Dickins <hughd@google.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15mm/memory-failure.c: define page types for action_result() in one placeNaoya Horiguchi1-31/+77
This cleanup patch moves all strings passed to action_result() into a singl= e array action_page_type so that a reader can easily find which kind of actio= n results are possible. And this patch also fixes the odd lines to be printed out, like "unknown page state page" or "free buddy, 2nd try page". [akpm@linux-foundation.org: rename messages, per David] [akpm@linux-foundation.org: s/DIRTY_UNEVICTABLE_LRU/CLEAN_UNEVICTABLE_LRU', per Andi] Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reviewed-by: Andi Kleen <ak@linux.intel.com> Cc: Tony Luck <tony.luck@intel.com> Cc: "Xie XiuQi" <xiexiuqi@huawei.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Chen Gong <gong.chen@linux.intel.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-12mm: hwpoison: drop lru_add_drain_all() in __soft_offline_page()Naoya Horiguchi1-2/+0
A race condition starts to be visible in recent mmotm, where a PG_hwpoison flag is set on a migration source page *before* it's back in buddy page poo= l. This is problematic because no page flag is supposed to be set when freeing (see __free_one_page().) So the user-visible effect of this race is that it could trigger the BUG_ON() when soft-offlining is called. The root cause is that we call lru_add_drain_all() to make sure that the page is in buddy, but that doesn't work because this function just schedule= s a work item and doesn't wait its completion. drain_all_pages() does drainin= g directly, so simply dropping lru_add_drain_all() solves this problem. Fixes: f15bdfa802bf ("mm/memory-failure.c: fix memory leak in successful soft offlining") Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Tony Luck <tony.luck@intel.com> Cc: Chen Gong <gong.chen@linux.intel.com> Cc: <stable@vger.kernel.org> [3.11+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-12vmscan: per memory cgroup slab shrinkersVladimir Davydov1-9/+2
This patch adds SHRINKER_MEMCG_AWARE flag. If a shrinker has this flag set, it will be called per memory cgroup. The memory cgroup to scan objects from is passed in shrink_control->memcg. If the memory cgroup is NULL, a memcg aware shrinker is supposed to scan objects from the global list. Unaware shrinkers are only called on global pressure with memcg=NULL. Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Greg Thelen <gthelen@google.com> Cc: Glauber Costa <glommer@gmail.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> 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: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-13mm: vmscan: invoke slab shrinkers from shrink_zone()Johannes Weiner1-8/+3
The slab shrinkers are currently invoked from the zonelist walkers in kswapd, direct reclaim, and zone reclaim, all of which roughly gauge the eligible LRU pages and assemble a nodemask to pass to NUMA-aware shrinkers, which then again have to walk over the nodemask. This is redundant code, extra runtime work, and fairly inaccurate when it comes to the estimation of actually scannable LRU pages. The code duplication will only get worse when making the shrinkers cgroup-aware and requiring them to have out-of-band cgroup hierarchy walks as well. Instead, invoke the shrinkers from shrink_zone(), which is where all reclaimers end up, to avoid this duplication. Take the count for eligible LRU pages out of get_scan_count(), which considers many more factors than just the availability of swap space, like zone_reclaimable_pages() currently does. Accumulate the number over all visited lruvecs to get the per-zone value. Some nodes have multiple zones due to memory addressing restrictions. To avoid putting too much pressure on the shrinkers, only invoke them once for each such node, using the class zone of the allocation as the pivot zone. For now, this integrates the slab shrinking better into the reclaim logic and gets rid of duplicative invocations from kswapd, direct reclaim, and zone reclaim. It also prepares for cgroup-awareness, allowing memcg-capable shrinkers to be added at the lruvec level without much duplication of both code and runtime work. This changes kswapd behavior, which used to invoke the shrinkers for each zone, but with scan ratios gathered from the entire node, resulting in meaningless pressure quantities on multi-zone nodes. Zone reclaim behavior also changes. It used to shrink slabs until the same amount of pages were shrunk as were reclaimed from the LRUs. Now it merely invokes the shrinkers once with the zone's scan ratio, which makes the shrinkers go easier on caches that implement aging and would prefer feeding back pressure from recently used slab objects to unused LRU pages. [vdavydov@parallels.com: assure class zone is populated] Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Dave Chinner <david@fromorbit.com> Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-13mm/memory-failure: share the i_mmap_rwsemDavidlohr Bueso1-2/+2
No brainer conversion: collect_procs_file() only schedules a process for later kill, share the lock, similarly to the anon vma variant. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Acked-by: "Kirill A. Shutemov" <kirill@shutemov.name> Acked-by: Hugh Dickins <hughd@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-13mm: use new helper functions around the i_mmap_mutexDavidlohr Bueso1-2/+2
Convert all open coded mutex_lock/unlock calls to the i_mmap_[lock/unlock]_write() helpers. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: "Kirill A. Shutemov" <kirill@shutemov.name> Acked-by: Hugh Dickins <hughd@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-10Merge branch 'akpm' (patchbomb from Andrew)Linus Torvalds1-2/+2
Merge first patchbomb from Andrew Morton: - a few minor cifs fixes - dma-debug upadtes - ocfs2 - slab - about half of MM - procfs - kernel/exit.c - panic.c tweaks - printk upates - lib/ updates - checkpatch updates - fs/binfmt updates - the drivers/rtc tree - nilfs - kmod fixes - more kernel/exit.c - various other misc tweaks and fixes * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (190 commits) exit: pidns: fix/update the comments in zap_pid_ns_processes() exit: pidns: alloc_pid() leaks pid_namespace if child_reaper is exiting exit: exit_notify: re-use "dead" list to autoreap current exit: reparent: call forget_original_parent() under tasklist_lock exit: reparent: avoid find_new_reaper() if no children exit: reparent: introduce find_alive_thread() exit: reparent: introduce find_child_reaper() exit: reparent: document the ->has_child_subreaper checks exit: reparent: s/while_each_thread/for_each_thread/ in find_new_reaper() exit: reparent: fix the cross-namespace PR_SET_CHILD_SUBREAPER reparenting exit: reparent: fix the dead-parent PR_SET_CHILD_SUBREAPER reparenting exit: proc: don't try to flush /proc/tgid/task/tgid exit: release_task: fix the comment about group leader accounting exit: wait: drop tasklist_lock before psig->c* accounting exit: wait: don't use zombie->real_parent exit: wait: cleanup the ptrace_reparented() checks usermodehelper: kill the kmod_thread_locker logic usermodehelper: don't use CLONE_VFORK for ____call_usermodehelper() fs/hfs/catalog.c: fix comparison bug in hfs_cat_keycmp nilfs2: fix the nilfs_iget() vs. nilfs_new_inode() races ...
2014-12-10mm, memory_hotplug/failure: drain single zone pcplistsVlastimil Babka1-2/+2
Memory hotplug and failure mechanisms have several places where pcplists are drained so that pages are returned to the buddy allocator and can be e.g. prepared for offlining. This is always done in the context of a single zone, we can reduce the pcplists drain to the single zone, which is now possible. The change should make memory offlining due to hotremove or failure faster and not disturbing unrelated pcplists anymore. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Cc: Xishi Qiu <qiuxishi@huawei.com> Cc: Vladimir Davydov <vdavydov@parallels.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-10mm: introduce single zone pcplists drainVlastimil Babka1-2/+2
The functions for draining per-cpu pages back to buddy allocators currently always operate on all zones. There are however several cases where the drain is only needed in the context of a single zone, and spilling other pcplists is a waste of time both due to the extra spilling and later refilling. This patch introduces new zone pointer parameter to drain_all_pages() and changes the dummy parameter of drain_local_pages() to be also a zone pointer. When NULL is passed, the functions operate on all zones as usual. Passing a specific zone pointer reduces the work to the single zone. All callers are updated to pass the NULL pointer in this patch. Conversion to single zone (where appropriate) is done in further patches. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Cc: Xishi Qiu <qiuxishi@huawei.com> Cc: Vladimir Davydov <vdavydov@parallels.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-21RAS, HWPOISON: Fix wrong error recovery statusChen, Gong1-1/+1
When Uncorrected error happens, if the poisoned page is referenced by more than one user after error recovery, the recovery is not successful. But currently the display result is wrong. Before this patch: MCE 0x44e336: dirty mlocked LRU page recovery: Recovered MCE 0x44e336: dirty mlocked LRU page still referenced by 1 users mce: Memory error not recovered After this patch: MCE 0x44e336: dirty mlocked LRU page recovery: Failed MCE 0x44e336: dirty mlocked LRU page still referenced by 1 users mce: Memory error not recovered Signed-off-by: Chen, Gong <gong.chen@linux.intel.com> Link: http://lkml.kernel.org/r/1406530260-26078-3-git-send-email-gong.chen@linux.intel.com Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de>
2014-09-19cgroup: remove redundant check in cgroup_ino()Zefan Li1-1/+1
After we implemented default unified hierarchy, cgrp->kn can never be NULL. Signed-off-by: Zefan Li <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2014-08-06hwpoison: fix race with changing page during offliningAndi Kleen1-0/+10
When a hwpoison page is locked it could change state due to parallel modifications. The original compound page can be torn down and then this 4k page becomes part of a differently-size compound page is is a standalone regular page. Check after the lock if the page is still the same compound page. We could go back, grab the new head page and try again but it should be quite rare, so I thought this was safest. A retry loop would be more difficult to test and may have more side effects. The hwpoison code by design only tries to handle cases that are reasonably common in workloads, as visible in page-flags. I'm not really that concerned about handling this (likely rare case), just not crashing on it. Signed-off-by: Andi Kleen <ak@linux.intel.com> Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-07-30hwpoison: call action_result() in failure path of hwpoison_user_mappings()Naoya Horiguchi1-2/+4
hwpoison_user_mappings() could fail for various reasons, so printk()s to print out the reasons should be done in each failure check inside hwpoison_user_mappings(). And currently we don't call action_result() when hwpoison_user_mappings() fails, which is not consistent with other exit points of memory error handler. So this patch fixes these messaging problems. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Chen Yucong <slaoub@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-07-30hwpoison: fix hugetlbfs/thp precheck in hwpoison_user_mappings()Naoya Horiguchi1-1/+7
A recent fix from Chen Yucong, commit 0bc1f8b0682c ("hwpoison: fix the handling path of the victimized page frame that belong to non-LRU") rejects going into unmapping operation for hugetlbfs/thp pages, which results in failing error containing on such pages. This patch fixes it. With this patch, hwpoison functional tests in mce-test testsuite pass. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Chen Yucong <slaoub@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-07-23mm/rmap.c: fix pgoff calculation to handle hugepage correctlyNaoya Horiguchi1-2/+2
I triggered VM_BUG_ON() in vma_address() when I tried to migrate an anonymous hugepage with mbind() in the kernel v3.16-rc3. This is because pgoff's calculation in rmap_walk_anon() fails to consider compound_order() only to have an incorrect value. This patch introduces page_to_pgoff(), which gets the page's offset in PAGE_CACHE_SIZE. Kirill pointed out that page cache tree should natively handle hugepages, and in order to make hugetlbfs fit it, page->index of hugetlbfs page should be in PAGE_CACHE_SIZE. This is beyond this patch, but page_to_pgoff() contains the point to be fixed in a single function. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Hugh Dickins <hughd@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-07-03hwpoison: fix the handling path of the victimized page frame that belong to ↵Chen Yucong1-4/+5
non-LRU Until now, the kernel has the same policy to handle victimized page frames that belong to kernel-space(reserved/slab-subsystem) or non-LRU(unknown page state). In other word, the result of handling either of these victimized page frames is (IGNORED | FAILED), and the return value of memory_failure() is -EBUSY. This patch is to avoid that memory_failure() returns very soon due to the "true" value of (!PageLRU(p)), and it also ensures that action_result() can report more precise information("reserved kernel", "kernel slab", and "unknown page state") instead of "non LRU", especially for memory errors which are detected by memory-scrubbing. Andi said: : While running the mcelog test suite on 3.14 I hit the following VM_BUG_ON: : : soft_offline: 0x56d4: unknown non LRU page type 3ffff800008000 : page:ffffea000015b400 count:3 mapcount:2097169 mapping: (null) index:0xffff8800056d7000 : page flags: 0x3ffff800004081(locked|slab|head) : ------------[ cut here ]------------ : kernel BUG at mm/rmap.c:1495! : : I think what happened is that a LRU page turned into a slab page in : parallel with offlining. memory_failure initially tests for this case, : but doesn't retest later after the page has been locked. : : ... : : I ran this patch in a loop over night with some stress plus : the mcelog test suite running in a loop. I cannot guarantee it hit it, : but it should have given it a good beating. : : The kernel survived with no messages, although the mcelog test suite : got killed at some point because it couldn't fork anymore. Probably : some unrelated problem. : : So the patch is ok for me for .16. Signed-off-by: Chen Yucong <slaoub@gmail.com> Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reported-by: Andi Kleen <andi@firstfloor.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-04mm/memory-failure.c: support use of a dedicated thread to handle ↵Naoya Horiguchi1-13/+43
SIGBUS(BUS_MCEERR_AO) Currently memory error handler handles action optional errors in the deferred manner by default. And if a recovery aware application wants to handle it immediately, it can do it by setting PF_MCE_EARLY flag. However, such signal can be sent only to the main thread, so it's problematic if the application wants to have a dedicated thread to handler such signals. So this patch adds dedicated thread support to memory error handler. We have PF_MCE_EARLY flags for each thread separately, so with this patch AO signal is sent to the thread with PF_MCE_EARLY flag set, not the main thread. If you want to implement a dedicated thread, you call prctl() to set PF_MCE_EARLY on the thread. Memory error handler collects processes to be killed, so this patch lets it check PF_MCE_EARLY flag on each thread in the collecting routines. No behavioral change for all non-early kill cases. Tony said: : The old behavior was crazy - someone with a multithreaded process might : well expect that if they call prctl(PF_MCE_EARLY) in just one thread, then : that thread would see the SIGBUS with si_code = BUS_MCEERR_A0 - even if : that thread wasn't the main thread for the process. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Cc: Kamil Iskra <iskra@mcs.anl.gov> Cc: Andi Kleen <andi@firstfloor.org> Cc: Borislav Petkov <bp@suse.de> Cc: Chen Gong <gong.chen@linux.jf.intel.com> Cc: <stable@vger.kernel.org> [3.2+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-04mm/memory-failure.c: don't let collect_procs() skip over processes for ↵Tony Luck1-9/+12
MF_ACTION_REQUIRED When Linux sees an "action optional" machine check (where h/w has reported an error that is not in the current execution path) we generally do not want to signal a process, since most processes do not have a SIGBUS handler - we'd just prematurely terminate the process for a problem that they might never actually see. task_early_kill() decides whether to consider a process - and it checks whether this specific process has been marked for early signals with "prctl", or if the system administrator has requested early signals for all processes using /proc/sys/vm/memory_failure_early_kill. But for MF_ACTION_REQUIRED case we must not defer. The error is in the execution path of the current thread so we must send the SIGBUS immediatley. Fix by passing a flag argument through collect_procs*() to task_early_kill() so it knows whether we can defer or must take action. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Borislav Petkov <bp@suse.de> Cc: Chen Gong <gong.chen@linux.jf.intel.com> Cc: <stable@vger.kernel.org> [3.2+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-04mm/memory-failure.c-failure: send right signal code to correct threadTony Luck1-2/+2
When a thread in a multi-threaded application hits a machine check because of an uncorrectable error in memory - we want to send the SIGBUS with si.si_code = BUS_MCEERR_AR to that thread. Currently we fail to do that if the active thread is not the primary thread in the process. collect_procs() just finds primary threads and this test: if ((flags & MF_ACTION_REQUIRED) && t == current) { will see that the thread we found isn't the current thread and so send a si.si_code = BUS_MCEERR_AO to the primary (and nothing to the active thread at this time). We can fix this by checking whether "current" shares the same mm with the process that collect_procs() said owned the page. If so, we send the SIGBUS to current (with code BUS_MCEERR_AR). Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reported-by: Otto Bruggeman <otto.g.bruggeman@intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Borislav Petkov <bp@suse.de> Cc: Chen Gong <gong.chen@linux.jf.intel.com> Cc: <stable@vger.kernel.org> [3.2+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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