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* mm: fix crash when using XFS on loopbackMikulas Patocka2014-01-151-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 8456a648cf44 ("slab: use struct page for slab management") causes a crash in the LVM2 testsuite on PA-RISC (the crashing test is fsadm.sh). The testsuite doesn't crash on 3.12, crashes on 3.13-rc1 and later. Bad Address (null pointer deref?): Code=15 regs=000000413edd89a0 (Addr=000006202224647d) CPU: 3 PID: 24008 Comm: loop0 Not tainted 3.13.0-rc6 #5 task: 00000001bf3c0048 ti: 000000413edd8000 task.ti: 000000413edd8000 YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI PSW: 00001000000001101111100100001110 Not tainted r00-03 000000ff0806f90e 00000000405c8de0 000000004013e6c0 000000413edd83f0 r04-07 00000000405a95e0 0000000000000200 00000001414735f0 00000001bf349e40 r08-11 0000000010fe3d10 0000000000000001 00000040829c7778 000000413efd9000 r12-15 0000000000000000 000000004060d800 0000000010fe3000 0000000010fe3000 r16-19 000000413edd82a0 00000041078ddbc0 0000000000000010 0000000000000001 r20-23 0008f3d0d83a8000 0000000000000000 00000040829c7778 0000000000000080 r24-27 00000001bf349e40 00000001bf349e40 202d66202224640d 00000000405a95e0 r28-31 202d662022246465 000000413edd88f0 000000413edd89a0 0000000000000001 sr00-03 000000000532c000 0000000000000000 0000000000000000 000000000532c000 sr04-07 0000000000000000 0000000000000000 0000000000000000 0000000000000000 IASQ: 0000000000000000 0000000000000000 IAOQ: 00000000401fe42c 00000000401fe430 IIR: 539c0030 ISR: 00000000202d6000 IOR: 000006202224647d CPU: 3 CR30: 000000413edd8000 CR31: 0000000000000000 ORIG_R28: 00000000405a95e0 IAOQ[0]: vma_interval_tree_iter_first+0x14/0x48 IAOQ[1]: vma_interval_tree_iter_first+0x18/0x48 RP(r2): flush_dcache_page+0x128/0x388 Backtrace: flush_dcache_page+0x128/0x388 lo_splice_actor+0x90/0x148 [loop] splice_from_pipe_feed+0xc0/0x1d0 __splice_from_pipe+0xac/0xc0 lo_direct_splice_actor+0x1c/0x70 [loop] splice_direct_to_actor+0xec/0x228 lo_receive+0xe4/0x298 [loop] loop_thread+0x478/0x640 [loop] kthread+0x134/0x168 end_fault_vector+0x20/0x28 xfs_setsize_buftarg+0x0/0x90 [xfs] Kernel panic - not syncing: Bad Address (null pointer deref?) Commit 8456a648cf44 changes the page structure so that the slab subsystem reuses the page->mapping field. The crash happens in the following way: * XFS allocates some memory from slab and issues a bio to read data into it. * the bio is sent to the loopback device. * lo_receive creates an actor and calls splice_direct_to_actor. * lo_splice_actor copies data to the target page. * lo_splice_actor calls flush_dcache_page because the page may be mapped by userspace. In that case we need to flush the kernel cache. * flush_dcache_page asks for the list of userspace mappings, however that page->mapping field is reused by the slab subsystem for a different purpose. This causes the crash. Note that other architectures without coherent caches (sparc, arm, mips) also call page_mapping from flush_dcache_page, so they may crash in the same way. This patch fixes this bug by testing if the page is a slab page in page_mapping and returning NULL if it is. The patch also fixes VM_BUG_ON(PageSlab(page)) that could happen in earlier kernels in the same scenario on architectures without cache coherence when CONFIG_DEBUG_VM is enabled - so it should be backported to stable kernels. In the old kernels, the function page_mapping is placed in include/linux/mm.h, so you should modify the patch accordingly when backporting it. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Cc: John David Anglin <dave.anglin@bell.net>] Cc: Andi Kleen <ak@linux.intel.com> Cc: Christoph Lameter <cl@linux.com> Acked-by: Pekka Enberg <penberg@kernel.org> Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Helge Deller <deller@gmx.de> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* thp: fix copy_page_rep GPF by testing is_huge_zero_pmd once onlyHugh Dickins2014-01-121-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We see General Protection Fault on RSI in copy_page_rep: that RSI is what you get from a NULL struct page pointer. RIP: 0010:[<ffffffff81154955>] [<ffffffff81154955>] copy_page_rep+0x5/0x10 RSP: 0000:ffff880136e15c00 EFLAGS: 00010286 RAX: ffff880000000000 RBX: ffff880136e14000 RCX: 0000000000000200 RDX: 6db6db6db6db6db7 RSI: db73880000000000 RDI: ffff880dd0c00000 RBP: ffff880136e15c18 R08: 0000000000000200 R09: 000000000005987c R10: 000000000005987c R11: 0000000000000200 R12: 0000000000000001 R13: ffffea00305aa000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f195752f700(0000) GS:ffff880c7fc20000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000093010000 CR3: 00000001458e1000 CR4: 00000000000027e0 Call Trace: copy_user_huge_page+0x93/0xab do_huge_pmd_wp_page+0x710/0x815 handle_mm_fault+0x15d8/0x1d70 __do_page_fault+0x14d/0x840 do_page_fault+0x2f/0x90 page_fault+0x22/0x30 do_huge_pmd_wp_page() tests is_huge_zero_pmd(orig_pmd) four times: but since shrink_huge_zero_page() can free the huge_zero_page, and we have no hold of our own on it here (except where the fourth test holds page_table_lock and has checked pmd_same), it's possible for it to answer yes the first time, but no to the second or third test. Change all those last three to tests for NULL page. (Note: this is not the same issue as trinity's DEBUG_PAGEALLOC BUG in copy_page_rep with RSI: ffff88009c422000, reported by Sasha Levin in https://lkml.org/lkml/2013/3/29/103. I believe that one is due to the source page being split, and a tail page freed, while copy is in progress; and not a problem without DEBUG_PAGEALLOC, since the pmd_same check will prevent a miscopy from being made visible.) Fixes: 97ae17497e99 ("thp: implement refcounting for huge zero page") Signed-off-by: Hugh Dickins <hughd@google.com> Cc: stable@vger.kernel.org # v3.10 v3.11 v3.12 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/memory-failure.c: transfer page count from head page to tail page after ↵Naoya Horiguchi2014-01-021-0/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | split thp Memory failures on thp tail pages cause kernel panic like below: mce: [Hardware Error]: Machine check events logged MCE exception done on CPU 7 BUG: unable to handle kernel NULL pointer dereference at 0000000000000058 IP: [<ffffffff811b7cd1>] dequeue_hwpoisoned_huge_page+0x131/0x1e0 PGD bae42067 PUD ba47d067 PMD 0 Oops: 0000 [#1] SMP ... CPU: 7 PID: 128 Comm: kworker/7:2 Tainted: G M O 3.13.0-rc4-131217-1558-00003-g83b7df08e462 #25 ... Call Trace: me_huge_page+0x3e/0x50 memory_failure+0x4bb/0xc20 mce_process_work+0x3e/0x70 process_one_work+0x171/0x420 worker_thread+0x11b/0x3a0 ? manage_workers.isra.25+0x2b0/0x2b0 kthread+0xe4/0x100 ? kthread_create_on_node+0x190/0x190 ret_from_fork+0x7c/0xb0 ? kthread_create_on_node+0x190/0x190 ... RIP dequeue_hwpoisoned_huge_page+0x131/0x1e0 CR2: 0000000000000058 The reasoning of this problem is shown below: - when we have a memory error on a thp tail page, the memory error handler grabs a refcount of the head page to keep the thp under us. - Before unmapping the error page from processes, we split the thp, where page refcounts of both of head/tail pages don't change. - Then we call try_to_unmap() over the error page (which was a tail page before). We didn't pin the error page to handle the memory error, this error page is freed and removed from LRU list. - We never have the error page on LRU list, so the first page state check returns "unknown page," then we move to the second check with the saved page flag. - The saved page flag have PG_tail set, so the second page state check returns "hugepage." - We call me_huge_page() for freed error page, then we hit the above panic. The root cause is that we didn't move refcount from the head page to the tail page after split thp. So this patch suggests to do this. This panic was introduced by commit 524fca1e73 ("HWPOISON: fix misjudgement of page_action() for errors on mlocked pages"). Note that we did have the same refcount problem before this commit, but it was just ignored because we had only first page state check which returned "unknown page." The commit changed the refcount problem from "doesn't work" to "kernel panic." Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com> Cc: Andi Kleen <andi@firstfloor.org> 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>
* mm: remove bogus warning in copy_huge_pmd()Mel Gorman2014-01-021-3/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Sasha Levin reported the following warning being triggered WARNING: CPU: 28 PID: 35287 at mm/huge_memory.c:887 copy_huge_pmd+0x145/ 0x3a0() Call Trace: copy_huge_pmd+0x145/0x3a0 copy_page_range+0x3f2/0x560 dup_mmap+0x2c9/0x3d0 dup_mm+0xad/0x150 copy_process+0xa68/0x12e0 do_fork+0x96/0x270 SyS_clone+0x16/0x20 stub_clone+0x69/0x90 This warning was introduced by "mm: numa: Avoid unnecessary disruption of NUMA hinting during migration" for paranoia reasons but the warning is bogus. I was thinking of parallel races between NUMA hinting faults and forks but this warning would also be triggered by a parallel reclaim splitting a THP during a fork. Remote the bogus warning. Signed-off-by: Mel Gorman <mgorman@suse.de> Reported-by: Sasha Levin <sasha.levin@oracle.com> Cc: Alex Thorlton <athorlton@sgi.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: fix memcg_size() calculationVladimir Davydov2014-01-021-1/+1
| | | | | | | | | | | | | | The mem_cgroup structure contains nr_node_ids pointers to mem_cgroup_per_node objects, not the objects themselves. Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Glauber Costa <glommer@openvz.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: fix use-after-free in sys_remap_file_pagesRik van Riel2014-01-021-3/+5
| | | | | | | | | | | | | | | | | | remap_file_pages calls mmap_region, which may merge the VMA with other existing VMAs, and free "vma". This can lead to a use-after-free bug. Avoid the bug by remembering vm_flags before calling mmap_region, and not trying to dereference vma later. Signed-off-by: Rik van Riel <riel@redhat.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Cc: PaX Team <pageexec@freemail.hu> Cc: Kees Cook <keescook@chromium.org> Cc: Michel Lespinasse <walken@google.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Hugh Dickins <hughd@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: munlock: fix deadlock in __munlock_pagevec()Vlastimil Babka2014-01-021-5/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 7225522bb429 ("mm: munlock: batch non-THP page isolation and munlock+putback using pagevec" introduced __munlock_pagevec() to speed up munlock by holding lru_lock over multiple isolated pages. Pages that fail to be isolated are put_page()d immediately, also within the lock. This can lead to deadlock when __munlock_pagevec() becomes the holder of the last page pin and put_page() leads to __page_cache_release() which also locks lru_lock. The deadlock has been observed by Sasha Levin using trinity. This patch avoids the deadlock by deferring put_page() operations until lru_lock is released. Another pagevec (which is also used by later phases of the function is reused to gather the pages for put_page() operation. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reported-by: Sasha Levin <sasha.levin@oracle.com> Cc: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Hugh Dickins <hughd@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: munlock: fix a bug where THP tail page is encounteredVlastimil Babka2014-01-021-7/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since commit ff6a6da60b89 ("mm: accelerate munlock() treatment of THP pages") munlock skips tail pages of a munlocked THP page. However, when the head page already has PageMlocked unset, it will not skip the tail pages. Commit 7225522bb429 ("mm: munlock: batch non-THP page isolation and munlock+putback using pagevec") has added a PageTransHuge() check which contains VM_BUG_ON(PageTail(page)). Sasha Levin found this triggered using trinity, on the first tail page of a THP page without PageMlocked flag. This patch fixes the issue by skipping tail pages also in the case when PageMlocked flag is unset. There is still a possibility of race with THP page split between clearing PageMlocked and determining how many pages to skip. The race might result in former tail pages not being skipped, which is however no longer a bug, as during the skip the PageTail flags are cleared. However this race also affects correctness of NR_MLOCK accounting, which is to be fixed in a separate patch. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reported-by: Sasha Levin <sasha.levin@oracle.com> Cc: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Hugh Dickins <hughd@google.com> Cc: Bob Liu <bob.liu@oracle.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* aio/migratepages: make aio migrate pages saneBenjamin LaHaise2013-12-211-6/+7
| | | | | | | | | | | | | | | The arbitrary restriction on page counts offered by the core migrate_page_move_mapping() code results in rather suspicious looking fiddling with page reference counts in the aio_migratepage() operation. To fix this, make migrate_page_move_mapping() take an extra_count parameter that allows aio to tell the code about its own reference count on the page being migrated. While cleaning up aio_migratepage(), make it validate that the old page being passed in is actually what aio_migratepage() expects to prevent misbehaviour in the case of races. Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
* mm: fix build of split ptlock codeOlof Johansson2013-12-211-1/+1
| | | | | | | | | | | | | | | | | | Commit 597d795a2a78 ('mm: do not allocate page->ptl dynamically, if spinlock_t fits to long') restructures some allocators that are compiled even if USE_SPLIT_PTLOCKS arn't used. It results in compilation failure: mm/memory.c:4282:6: error: 'struct page' has no member named 'ptl' mm/memory.c:4288:12: error: 'struct page' has no member named 'ptl' Add in the missing ifdef. Fixes: 597d795a2a78 ('mm: do not allocate page->ptl dynamically, if spinlock_t fits to long') Signed-off-by: Olof Johansson <olof@lixom.net> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: do not allocate page->ptl dynamically, if spinlock_t fits to longKirill A. Shutemov2013-12-201-1/+1
| | | | | | | | | | | | | In struct page we have enough space to fit long-size page->ptl there, but we use dynamically-allocated page->ptl if size(spinlock_t) is larger than sizeof(int). It hurts 64-bit architectures with CONFIG_GENERIC_LOCKBREAK, where sizeof(spinlock_t) == 8, but it easily fits into struct page. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: page_alloc: revert NUMA aspect of fair allocation policyJohannes Weiner2013-12-201-10/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 81c0a2bb515f ("mm: page_alloc: fair zone allocator policy") meant to bring aging fairness among zones in system, but it was overzealous and badly regressed basic workloads on NUMA systems. Due to the way kswapd and page allocator interacts, we still want to make sure that all zones in any given node are used equally for all allocations to maximize memory utilization and prevent thrashing on the highest zone in the node. While the same principle applies to NUMA nodes - memory utilization is obviously improved by spreading allocations throughout all nodes - remote references can be costly and so many workloads prefer locality over memory utilization. The original change assumed that zone_reclaim_mode would be a good enough predictor for that, but it turned out to be as indicative as a coin flip. Revert the NUMA aspect of the fairness until we can find a proper way to make it configurable and agree on a sane default. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: <stable@kernel.org> # 3.12 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Revert "mm: page_alloc: exclude unreclaimable allocations from zone fairness ↵Mel Gorman2013-12-201-2/+1
| | | | | | | | | | | | policy" This reverts commit 73f038b863df. The NUMA behaviour of this patch is less than ideal. An alternative approch is to interleave allocations only within local zones which is implemented in the next patch. Cc: stable@vger.kernel.org Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/hugetlb: check for pte NULL pointer in __page_check_address()Jianguo Wu2013-12-191-0/+4
| | | | | | | | | | | | | | In __page_check_address(), if address's pud is not present, huge_pte_offset() will return NULL, we should check the return value. Signed-off-by: Jianguo Wu <wujianguo@huawei.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Mel Gorman <mgorman@suse.de> Cc: qiuxishi <qiuxishi@huawei.com> Cc: Hanjun Guo <guohanjun@huawei.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/mempolicy: fix !vma in new_vma_page()Wanpeng Li2013-12-191-6/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BUG_ON(!vma) assumption is introduced by commit 0bf598d863e3 ("mbind: add BUG_ON(!vma) in new_vma_page()"), however, even if address = __vma_address(page, vma); and vma->start < address < vma->end page_address_in_vma() may still return -EFAULT because of many other conditions in it. As a result the while loop in new_vma_page() may end with vma=NULL. This patch revert the commit and also fix the potential dereference NULL pointer reported by Dan. http://marc.info/?l=linux-mm&m=137689530323257&w=2 kernel BUG at mm/mempolicy.c:1204! invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC CPU: 3 PID: 7056 Comm: trinity-child3 Not tainted 3.13.0-rc3+ #2 task: ffff8801ca5295d0 ti: ffff88005ab20000 task.ti: ffff88005ab20000 RIP: new_vma_page+0x70/0x90 RSP: 0000:ffff88005ab21db0 EFLAGS: 00010246 RAX: fffffffffffffff2 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000008040075 RSI: ffff8801c3d74600 RDI: ffffea00079a8b80 RBP: ffff88005ab21dc8 R08: 0000000000000004 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: fffffffffffffff2 R13: ffffea00079a8b80 R14: 0000000000400000 R15: 0000000000400000 FS: 00007ff49c6f4740(0000) GS:ffff880244e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff49c68f994 CR3: 000000005a205000 CR4: 00000000001407e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffffea00079a8b80 ffffea00079a8bc0 ffffea00079a8ba0 ffff88005ab21e50 ffffffff811adc7a 0000000000000000 ffff8801ca5295d0 0000000464e224f8 0000000000000000 0000000000000002 0000000000000000 ffff88020ce75c00 Call Trace: migrate_pages+0x12a/0x850 SYSC_mbind+0x513/0x6a0 SyS_mbind+0xe/0x10 ia32_do_call+0x13/0x13 Code: 85 c0 75 2f 4c 89 e1 48 89 da 31 f6 bf da 00 02 00 65 44 8b 04 25 08 f7 1c 00 e8 ec fd ff ff 5b 41 5c 41 5d 5d c3 0f 1f 44 00 00 <0f> 0b 66 0f 1f 44 00 00 4c 89 e6 48 89 df ba 01 00 00 00 e8 48 RIP [<ffffffff8119f200>] new_vma_page+0x70/0x90 RSP <ffff88005ab21db0> Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com> Reported-by: Dave Jones <davej@redhat.com> Reported-by: Sasha Levin <sasha.levin@oracle.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reviewed-by: Bob Liu <bob.liu@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/memory-failure.c: recheck PageHuge() after hugetlb page migrate successfullyJianguo Wu2013-12-191-4/+10
| | | | | | | | | | | | | | | | | | | | | After a successful hugetlb page migration by soft offline, the source page will either be freed into hugepage_freelists or buddy(over-commit page). If page is in buddy, page_hstate(page) will be NULL. It will hit a NULL pointer dereference in dequeue_hwpoisoned_huge_page(). BUG: unable to handle kernel NULL pointer dereference at 0000000000000058 IP: [<ffffffff81163761>] dequeue_hwpoisoned_huge_page+0x131/0x1d0 PGD c23762067 PUD c24be2067 PMD 0 Oops: 0000 [#1] SMP So check PageHuge(page) after call migrate_pages() successfully. Signed-off-by: Jianguo Wu <wujianguo@huawei.com> Tested-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/compaction: respect ignore_skip_hint in update_pageblock_skipJoonsoo Kim2013-12-191-0/+4
| | | | | | | | | | | | | | | | | | | | | | | update_pageblock_skip() only fits to compaction which tries to isolate by pageblock unit. If isolate_migratepages_range() is called by CMA, it try to isolate regardless of pageblock unit and it don't reference get_pageblock_skip() by ignore_skip_hint. We should also respect it on update_pageblock_skip() to prevent from setting the wrong information. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com> Cc: Christoph Lameter <cl@linux.com> Cc: Rafael Aquini <aquini@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Cc: <stable@vger.kernel.org> [3.7+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/mempolicy: correct putback method for isolate pages if failedJoonsoo Kim2013-12-191-1/+1
| | | | | | | | | | | | | | | | | | | | | | | queue_pages_range() isolates hugetlbfs pages and putback_lru_pages() can't handle these. We should change it to putback_movable_pages(). Naoya said that it is worth going into stable, because it can break in-use hugepage list. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Rafael Aquini <aquini@redhat.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com> Cc: Christoph Lameter <cl@linux.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Cc: <stable@vger.kernel.org> [3.12.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: add missing dependency in KconfigSima Baymani2013-12-191-1/+1
| | | | | | | | | | | | | Eliminate the following (rand)config warning by adding missing PROC_FS dependency: warning: (HWPOISON_INJECT && MEM_SOFT_DIRTY) selects PROC_PAGE_MONITOR which has unmet direct dependencies (PROC_FS && MMU) Signed-off-by: Sima Baymani <sima.baymani@gmail.com> Suggested-by: David Rientjes <rientjes@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>
* mm: page_alloc: exclude unreclaimable allocations from zone fairness policyJohannes Weiner2013-12-191-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Dave Hansen noted a regression in a microbenchmark that loops around open() and close() on an 8-node NUMA machine and bisected it down to commit 81c0a2bb515f ("mm: page_alloc: fair zone allocator policy"). That change forces the slab allocations of the file descriptor to spread out to all 8 nodes, causing remote references in the page allocator and slab. The round-robin policy is only there to provide fairness among memory allocations that are reclaimed involuntarily based on pressure in each zone. It does not make sense to apply it to unreclaimable kernel allocations that are freed manually, in this case instantly after the allocation, and incur the remote reference costs twice for no reason. Only round-robin allocations that are usually freed through page reclaim or slab shrinking. Bisected by Dave Hansen. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: numa: defer TLB flush for THP migration as long as possibleMel Gorman2013-12-192-7/+3
| | | | | | | | | | | | THP migration can fail for a variety of reasons. Avoid flushing the TLB to deal with THP migration races until the copy is ready to start. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Alex Thorlton <athorlton@sgi.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: fix TLB flush race between migration, and change_protection_rangeRik van Riel2013-12-193-2/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are a few subtle races, between change_protection_range (used by mprotect and change_prot_numa) on one side, and NUMA page migration and compaction on the other side. The basic race is that there is a time window between when the PTE gets made non-present (PROT_NONE or NUMA), and the TLB is flushed. During that time, a CPU may continue writing to the page. This is fine most of the time, however compaction or the NUMA migration code may come in, and migrate the page away. When that happens, the CPU may continue writing, through the cached translation, to what is no longer the current memory location of the process. This only affects x86, which has a somewhat optimistic pte_accessible. All other architectures appear to be safe, and will either always flush, or flush whenever there is a valid mapping, even with no permissions (SPARC). The basic race looks like this: CPU A CPU B CPU C load TLB entry make entry PTE/PMD_NUMA fault on entry read/write old page start migrating page change PTE/PMD to new page read/write old page [*] flush TLB reload TLB from new entry read/write new page lose data [*] the old page may belong to a new user at this point! The obvious fix is to flush remote TLB entries, by making sure that pte_accessible aware of the fact that PROT_NONE and PROT_NUMA memory may still be accessible if there is a TLB flush pending for the mm. This should fix both NUMA migration and compaction. [mgorman@suse.de: fix build] Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Alex Thorlton <athorlton@sgi.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: numa: avoid unnecessary disruption of NUMA hinting during migrationMel Gorman2013-12-192-6/+28
| | | | | | | | | | | | | | do_huge_pmd_numa_page() handles the case where there is parallel THP migration. However, by the time it is checked the NUMA hinting information has already been disrupted. This patch adds an earlier check with some helpers. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Alex Thorlton <athorlton@sgi.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: numa: clear numa hinting information on mprotectMel Gorman2013-12-192-0/+4
| | | | | | | | | | | | | On a protection change it is no longer clear if the page should be still accessible. This patch clears the NUMA hinting fault bits on a protection change. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Alex Thorlton <athorlton@sgi.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: numa: avoid unnecessary work on the failure pathMel Gorman2013-12-191-1/+3
| | | | | | | | | | | | If a PMD changes during a THP migration then migration aborts but the failure path is doing more work than is necessary. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Alex Thorlton <athorlton@sgi.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: numa: ensure anon_vma is locked to prevent parallel THP splitsMel Gorman2013-12-191-0/+7
| | | | | | | | | | | | | | The anon_vma lock prevents parallel THP splits and any associated complexity that arises when handling splits during THP migration. This patch checks if the lock was successfully acquired and bails from THP migration if it failed for any reason. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Alex Thorlton <athorlton@sgi.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: numa: do not clear PTE for pte_numa updateMel Gorman2013-12-191-2/+7
| | | | | | | | | | | | | | | | | | | | | The TLB must be flushed if the PTE is updated but change_pte_range is clearing the PTE while marking PTEs pte_numa without necessarily flushing the TLB if it reinserts the same entry. Without the flush, it's conceivable that two processors have different TLBs for the same virtual address and at the very least it would generate spurious faults. This patch only unmaps the pages in change_pte_range for a full protection change. [riel@redhat.com: write pte_numa pte back to the page tables] Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Rik van Riel <riel@redhat.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Alex Thorlton <athorlton@sgi.com> Cc: Chegu Vinod <chegu_vinod@hp.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: numa: do not clear PMD during PTE update scanMel Gorman2013-12-191-1/+1
| | | | | | | | | | | | | | If the PMD is flushed then a parallel fault in handle_mm_fault() will enter the pmd_none and do_huge_pmd_anonymous_page() path where it'll attempt to insert a huge zero page. This is wasteful so the patch avoids clearing the PMD when setting pmd_numa. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Alex Thorlton <athorlton@sgi.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: clear pmd_numa before invalidatingMel Gorman2013-12-191-0/+3
| | | | | | | | | | | | | | | | | | | | | | | On x86, PMD entries are similar to _PAGE_PROTNONE protection and are handled as NUMA hinting faults. The following two page table protection bits are what defines them _PAGE_NUMA:set _PAGE_PRESENT:clear A PMD is considered present if any of the _PAGE_PRESENT, _PAGE_PROTNONE, _PAGE_PSE or _PAGE_NUMA bits are set. If pmdp_invalidate encounters a pmd_numa, it clears the present bit leaving _PAGE_NUMA which will be considered not present by the CPU but present by pmd_present. The existing caller of pmdp_invalidate should handle it but it's an inconsistent state for a PMD. This patch keeps the state consistent when calling pmdp_invalidate. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Alex Thorlton <athorlton@sgi.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: numa: call MMU notifiers on THP migrationMel Gorman2013-12-191-8/+14
| | | | | | | | | | | | MMU notifiers must be called on THP page migration or secondary MMUs will get very confused. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Alex Thorlton <athorlton@sgi.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: numa: serialise parallel get_user_page against THP migrationMel Gorman2013-12-192-15/+47
| | | | | | | | | | | | | | | | | | | | | | | | Base pages are unmapped and flushed from cache and TLB during normal page migration and replaced with a migration entry that causes any parallel NUMA hinting fault or gup to block until migration completes. THP does not unmap pages due to a lack of support for migration entries at a PMD level. This allows races with get_user_pages and get_user_pages_fast which commit 3f926ab945b6 ("mm: Close races between THP migration and PMD numa clearing") made worse by introducing a pmd_clear_flush(). This patch forces get_user_page (fast and normal) on a pmd_numa page to go through the slow get_user_page path where it will serialise against THP migration and properly account for the NUMA hinting fault. On the migration side the page table lock is taken for each PTE update. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Alex Thorlton <athorlton@sgi.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: memcg: do not allow task about to OOM kill to bypass the limitJohannes Weiner2013-12-131-1/+1
| | | | | | | | | | | | | | | | | | | | | Commit 4942642080ea ("mm: memcg: handle non-error OOM situations more gracefully") allowed tasks that already entered a memcg OOM condition to bypass the memcg limit on subsequent allocation attempts hoping this would expedite finishing the page fault and executing the kill. David Rientjes is worried that this breaks memcg isolation guarantees and since there is no evidence that the bypass actually speeds up fault processing just change it so that these subsequent charge attempts fail outright. The notable exception being __GFP_NOFAIL charges which are required to bypass the limit regardless. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reported-by: David Rientjes <rientjes@google.com> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-bt: David Rientjes <rientjes@google.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: memcg: fix race condition between memcg teardown and swapinJohannes Weiner2013-12-131-0/+36
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is a race condition between a memcg being torn down and a swapin triggered from a different memcg of a page that was recorded to belong to the exiting memcg on swapout (with CONFIG_MEMCG_SWAP extension). The result is unreclaimable pages pointing to dead memcgs, which can lead to anything from endless loops in later memcg teardown (the page is charged to all hierarchical parents but is not on any LRU list) or crashes from following the dangling memcg pointer. Memcgs with tasks in them can not be torn down and usually charges don't show up in memcgs without tasks. Swapin with the CONFIG_MEMCG_SWAP extension is the notable exception because it charges the cgroup that was recorded as owner during swapout, which may be empty and in the process of being torn down when a task in another memcg triggers the swapin: teardown: swapin: lookup_swap_cgroup_id() rcu_read_lock() mem_cgroup_lookup() css_tryget() rcu_read_unlock() disable css_tryget() call_rcu() offline_css() reparent_charges() res_counter_charge() (hierarchical!) css_put() css_free() pc->mem_cgroup = dead memcg add page to dead lru Add a final reparenting step into css_free() to make sure any such raced charges are moved out of the memcg before it's finally freed. In the longer term it would be cleaner to have the css_tryget() and the res_counter charge under the same RCU lock section so that the charge reparenting is deferred until the last charge whose tryget succeeded is visible. But this will require more invasive changes that will be harder to evaluate and backport into stable, so better defer them to a separate change set. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* thp: move preallocated PTE page table on move_huge_pmd()Kirill A. Shutemov2013-12-131-1/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Andrey Wagin reported crash on VM_BUG_ON() in pgtable_pmd_page_dtor() with fallowing backtrace: free_pgd_range+0x2bf/0x410 free_pgtables+0xce/0x120 unmap_region+0xe0/0x120 do_munmap+0x249/0x360 move_vma+0x144/0x270 SyS_mremap+0x3b9/0x510 system_call_fastpath+0x16/0x1b The crash can be reproduce with this test case: #define _GNU_SOURCE #include <sys/mman.h> #include <stdio.h> #include <unistd.h> #define MB (1024 * 1024UL) #define GB (1024 * MB) int main(int argc, char **argv) { char *p; int i; p = mmap((void *) GB, 10 * MB, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0); for (i = 0; i < 10 * MB; i += 4096) p[i] = 1; mremap(p, 10 * MB, 10 * MB, MREMAP_FIXED | MREMAP_MAYMOVE, 2 * GB); return 0; } Due to split PMD lock, we now store preallocated PTE tables for THP pages per-PMD table. It means we need to move them to other PMD table if huge PMD moved there. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: Andrey Vagin <avagin@openvz.org> Tested-by: Andrey Vagin <avagin@openvz.org> Reviewed-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>
* mm: memcg: do not declare OOM from __GFP_NOFAIL allocationsJohannes Weiner2013-12-131-0/+3
| | | | | | | | | | | | | | | | | | | Commit 84235de394d9 ("fs: buffer: move allocation failure loop into the allocator") started recognizing __GFP_NOFAIL in memory cgroups but forgot to disable the OOM killer. Any task that does not fail allocation will also not enter the OOM completion path. So don't declare an OOM state in this case or it'll be leaked and the task be able to bypass the limit until the next userspace-triggered page fault cleans up the OOM state. Reported-by: William Dauchy <wdauchy@gmail.com> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: <stable@vger.kernel.org> [3.12.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* security: shmem: implement kernel private shmem inodesEric Paris2013-12-021-7/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We have a problem where the big_key key storage implementation uses a shmem backed inode to hold the key contents. Because of this detail of implementation LSM checks are being done between processes trying to read the keys and the tmpfs backed inode. The LSM checks are already being handled on the key interface level and should not be enforced at the inode level (since the inode is an implementation detail, not a part of the security model) This patch implements a new function shmem_kernel_file_setup() which returns the equivalent to shmem_file_setup() only the underlying inode has S_PRIVATE set. This means that all LSM checks for the inode in question are skipped. It should only be used for kernel internal operations where the inode is not exposed to userspace without proper LSM checking. It is possible that some other users of shmem_file_setup() should use the new interface, but this has not been explored. Reproducing this bug is a little bit difficult. The steps I used on Fedora are: (1) Turn off selinux enforcing: setenforce 0 (2) Create a huge key k=`dd if=/dev/zero bs=8192 count=1 | keyctl padd big_key test-key @s` (3) Access the key in another context: runcon system_u:system_r:httpd_t:s0-s0:c0.c1023 keyctl print $k >/dev/null (4) Examine the audit logs: ausearch -m AVC -i --subject httpd_t | audit2allow If the last command's output includes a line that looks like: allow httpd_t user_tmpfs_t:file { open read }; There was an inode check between httpd and the tmpfs filesystem. With this patch no such denial will be seen. (NOTE! you should clear your audit log if you have tested for this previously) (Please return you box to enforcing) Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com> cc: Hugh Dickins <hughd@google.com> cc: linux-mm@kvack.org
* Merge branch 'slab/next' of ↵Linus Torvalds2013-11-222-363/+253
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux Pull SLAB changes from Pekka Enberg: "The patches from Joonsoo Kim switch mm/slab.c to use 'struct page' for slab internals similar to mm/slub.c. This reduces memory usage and improves performance: https://lkml.org/lkml/2013/10/16/155 Rest of the changes are bug fixes from various people" * 'slab/next' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux: (21 commits) mm, slub: fix the typo in mm/slub.c mm, slub: fix the typo in include/linux/slub_def.h slub: Handle NULL parameter in kmem_cache_flags slab: replace non-existing 'struct freelist *' with 'void *' slab: fix to calm down kmemleak warning slub: proper kmemleak tracking if CONFIG_SLUB_DEBUG disabled slab: rename slab_bufctl to slab_freelist slab: remove useless statement for checking pfmemalloc slab: use struct page for slab management slab: replace free and inuse in struct slab with newly introduced active slab: remove SLAB_LIMIT slab: remove kmem_bufctl_t slab: change the management method of free objects of the slab slab: use __GFP_COMP flag for allocating slab pages slab: use well-defined macro, virt_to_slab() slab: overloading the RCU head over the LRU for RCU free slab: remove cachep in struct slab_rcu slab: remove nodeid in struct slab slab: remove colouroff in struct slab slab: change return type of kmem_getpages() to struct page ...
| * mm, slub: fix the typo in mm/slub.cZhi Yong Wu2013-11-111-3/+3
| | | | | | | | | | | | Acked-by: Christoph Lameter <cl@linux.com> Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
| * slub: Handle NULL parameter in kmem_cache_flagsChristoph Lameter2013-11-111-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Andreas Herrmann writes: When I've used slub_debug kernel option (e.g. "slub_debug=,skbuff_fclone_cache" or similar) on a debug session I've seen a panic like: Highbank #setenv bootargs console=ttyAMA0 root=/dev/sda2 kgdboc.kgdboc=ttyAMA0,115200 slub_debug=,kmalloc-4096 earlyprintk=ttyAMA0 ... Unable to handle kernel NULL pointer dereference at virtual address 00000000 pgd = c0004000 [00000000] *pgd=00000000 Internal error: Oops: 5 [#1] SMP ARM Modules linked in: CPU: 0 PID: 0 Comm: swapper Tainted: G W 3.12.0-00048-gbe408cd #314 task: c0898360 ti: c088a000 task.ti: c088a000 PC is at strncmp+0x1c/0x84 LR is at kmem_cache_flags.isra.46.part.47+0x44/0x60 pc : [<c02c6da0>] lr : [<c0110a3c>] psr: 200001d3 sp : c088bea8 ip : c088beb8 fp : c088beb4 r10: 00000000 r9 : 413fc090 r8 : 00000001 r7 : 00000000 r6 : c2984a08 r5 : c0966e78 r4 : 00000000 r3 : 0000006b r2 : 0000000c r1 : 00000000 r0 : c2984a08 Flags: nzCv IRQs off FIQs off Mode SVC_32 ISA ARM Segment kernel Control: 10c5387d Table: 0000404a DAC: 00000015 Process swapper (pid: 0, stack limit = 0xc088a248) Stack: (0xc088bea8 to 0xc088c000) bea0: c088bed4 c088beb8 c0110a3c c02c6d90 c0966e78 00000040 bec0: ef001f00 00000040 c088bf14 c088bed8 c0112070 c0110a04 00000005 c010fac8 bee0: c088bf5c c088bef0 c010fac8 ef001f00 00000040 00000000 00000040 00000001 bf00: 413fc090 00000000 c088bf34 c088bf18 c0839190 c0112040 00000000 ef001f00 bf20: 00000000 00000000 c088bf54 c088bf38 c0839200 c083914c 00000006 c0961c4c bf40: c0961c28 00000000 c088bf7c c088bf58 c08392ac c08391c0 c08a2ed8 c0966e78 bf60: c086b874 c08a3f50 c0961c28 00000001 c088bfb4 c088bf80 c083b258 c0839248 bf80: 2f800000 0f000000 c08935b4 ffffffff c08cd400 ffffffff c08cd400 c0868408 bfa0: c29849c0 00000000 c088bff4 c088bfb8 c0824974 c083b1e4 ffffffff ffffffff bfc0: c08245c0 00000000 00000000 c0868408 00000000 10c5387d c0892bcc c0868404 bfe0: c0899440 0000406a 00000000 c088bff8 00008074 c0824824 00000000 00000000 [<c02c6da0>] (strncmp+0x1c/0x84) from [<c0110a3c>] (kmem_cache_flags.isra.46.part.47+0x44/0x60) [<c0110a3c>] (kmem_cache_flags.isra.46.part.47+0x44/0x60) from [<c0112070>] (__kmem_cache_create+0x3c/0x410) [<c0112070>] (__kmem_cache_create+0x3c/0x410) from [<c0839190>] (create_boot_cache+0x50/0x74) [<c0839190>] (create_boot_cache+0x50/0x74) from [<c0839200>] (create_kmalloc_cache+0x4c/0x88) [<c0839200>] (create_kmalloc_cache+0x4c/0x88) from [<c08392ac>] (create_kmalloc_caches+0x70/0x114) [<c08392ac>] (create_kmalloc_caches+0x70/0x114) from [<c083b258>] (kmem_cache_init+0x80/0xe0) [<c083b258>] (kmem_cache_init+0x80/0xe0) from [<c0824974>] (start_kernel+0x15c/0x318) [<c0824974>] (start_kernel+0x15c/0x318) from [<00008074>] (0x8074) Code: e3520000 01a00002 089da800 e5d03000 (e5d1c000) ---[ end trace 1b75b31a2719ed1d ]--- Kernel panic - not syncing: Fatal exception Problem is that slub_debug option is not parsed before create_boot_cache is called. Solve this by changing slub_debug to early_param. Kernels 3.11, 3.10 are also affected. I am not sure about older kernels. Christoph Lameter explains: kmem_cache_flags may be called with NULL parameter during early boot. Skip the test in that case. Cc: stable@vger.kernel.org # 3.10 and 3.11 Reported-by: Andreas Herrmann <andreas.herrmann@calxeda.com> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
| * Merge branch 'slab/struct-page' into slab/nextPekka Enberg2013-11-111-354/+217
| |\
| | * slab: replace non-existing 'struct freelist *' with 'void *'Joonsoo Kim2013-10-301-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | There is no 'strcut freelist', but codes use pointer to 'struct freelist'. Although compiler doesn't complain anything about this wrong usage and codes work fine, but fixing it is better. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Pekka Enberg <penberg@iki.fi>
| | * slab: fix to calm down kmemleak warningJoonsoo Kim2013-10-301-8/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After using struct page as slab management, we should not call kmemleak_scan_area(), since struct page isn't the tracking object of kmemleak. Without this patch and if CONFIG_DEBUG_KMEMLEAK is enabled, so many kmemleak warnings are printed. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Pekka Enberg <penberg@iki.fi>
| | * slab: rename slab_bufctl to slab_freelistJoonsoo Kim2013-10-241-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | Now, bufctl is not proper name to this array. So change it. Acked-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Pekka Enberg <penberg@iki.fi>
| | * slab: remove useless statement for checking pfmemallocJoonsoo Kim2013-10-241-6/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now, virt_to_page(page->s_mem) is same as the page, because slab use this structure for management. So remove useless statement. Acked-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Pekka Enberg <penberg@iki.fi>
| | * slab: use struct page for slab managementJoonsoo Kim2013-10-241-163/+143
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now, there are a few field in struct slab, so we can overload these over struct page. This will save some memory and reduce cache footprint. After this change, slabp_cache and slab_size no longer related to a struct slab, so rename them as freelist_cache and freelist_size. These changes are just mechanical ones and there is no functional change. Acked-by: Andi Kleen <ak@linux.intel.com> Acked-by: Christoph Lameter <cl@linux.com> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Pekka Enberg <penberg@iki.fi>
| | * slab: replace free and inuse in struct slab with newly introduced activeJoonsoo Kim2013-10-241-29/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | Now, free in struct slab is same meaning as inuse. So, remove both and replace them with active. Acked-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Pekka Enberg <penberg@iki.fi>
| | * slab: remove SLAB_LIMITJoonsoo Kim2013-10-241-7/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | It's useless now, so remove it. Acked-by: Andi Kleen <ak@linux.intel.com> Acked-by: Christoph Lameter <cl@linux.com> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Pekka Enberg <penberg@iki.fi>
| | * slab: remove kmem_bufctl_tJoonsoo Kim2013-10-241-31/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now, we changed the management method of free objects of the slab and there is no need to use special value, BUFCTL_END, BUFCTL_FREE and BUFCTL_ACTIVE. So remove them. Acked-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Pekka Enberg <penberg@iki.fi>
| | * slab: change the management method of free objects of the slabJoonsoo Kim2013-10-241-64/+30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Current free objects management method of the slab is weird, because it touch random position of the array of kmem_bufctl_t when we try to get free object. See following example. struct slab's free = 6 kmem_bufctl_t array: 1 END 5 7 0 4 3 2 To get free objects, we access this array with following pattern. 6 -> 3 -> 7 -> 2 -> 5 -> 4 -> 0 -> 1 -> END If we have many objects, this array would be larger and be not in the same cache line. It is not good for performance. We can do same thing through more easy way, like as the stack. Only thing we have to do is to maintain stack top to free object. I use free field of struct slab for this purpose. After that, if we need to get an object, we can get it at stack top and manipulate top pointer. That's all. This method already used in array_cache management. Following is an access pattern when we use this method. struct slab's free = 0 kmem_bufctl_t array: 6 3 7 2 5 4 0 1 To get free objects, we access this array with following pattern. 0 -> 1 -> 2 -> 3 -> 4 -> 5 -> 6 -> 7 This may help cache line footprint if slab has many objects, and, in addition, this makes code much much simpler. Acked-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Pekka Enberg <penberg@iki.fi>
| | * slab: use __GFP_COMP flag for allocating slab pagesJoonsoo Kim2013-10-241-34/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If we use 'struct page' of first page as 'struct slab', there is no advantage not to use __GFP_COMP. So use __GFP_COMP flag for all the cases. Acked-by: Andi Kleen <ak@linux.intel.com> Acked-by: Christoph Lameter <cl@linux.com> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Pekka Enberg <penberg@iki.fi>
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