- 07 Aug, 2020 40 commits
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Linus Torvalds authored
Merge misc updates from Andrew Morton: - a few MM hotfixes - kthread, tools, scripts, ntfs and ocfs2 - some of MM Subsystems affected by this patch series: kthread, tools, scripts, ntfs, ocfs2 and mm (hofixes, pagealloc, slab-generic, slab, slub, kcsan, debug, pagecache, gup, swap, shmem, memcg, pagemap, mremap, mincore, sparsemem, vmalloc, kasan, pagealloc, hugetlb and vmscan). * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (162 commits) mm: vmscan: consistent update to pgrefill mm/vmscan.c: fix typo khugepaged: khugepaged_test_exit() check mmget_still_valid() khugepaged: retract_page_tables() remember to test exit khugepaged: collapse_pte_mapped_thp() protect the pmd lock khugepaged: collapse_pte_mapped_thp() flush the right range mm/hugetlb: fix calculation of adjust_range_if_pmd_sharing_possible mm: thp: replace HTTP links with HTTPS ones mm/page_alloc: fix memalloc_nocma_{save/restore} APIs mm/page_alloc.c: skip setting nodemask when we are in interrupt mm/page_alloc: fallbacks at most has 3 elements mm/page_alloc: silence a KASAN false positive mm/page_alloc.c: remove unnecessary end_bitidx for [set|get]_pfnblock_flags_mask() mm/page_alloc.c: simplify pageblock bitmap access mm/page_alloc.c: extract the common part in pfn_to_bitidx() mm/page_alloc.c: replace the definition of NR_MIGRATETYPE_BITS with PB_migratetype_bits mm/shuffle: remove dynamic reconfiguration mm/memory_hotplug: document why shuffle_zone() is relevant mm/page_alloc: remove nr_free_pagecache_pages() mm: remove vm_total_pages ... -
Shakeel Butt authored
The vmstat pgrefill is useful together with pgscan and pgsteal stats to measure the reclaim efficiency. However vmstat's pgrefill is not updated consistently at system level. It gets updated for both global and memcg reclaim however pgscan and pgsteal are updated for only global reclaim. So, update pgrefill only for global reclaim. If someone is interested in the stats representing both system level as well as memcg level reclaim, then consult the root memcg's memory.stat instead of /proc/vmstat. Signed-off-by:
Shakeel Butt <shakeelb@google.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Acked-by:
Yafang Shao <laoar.shao@gmail.com> Acked-by:
Roman Gushchin <guro@fb.com> Acked-by:
Chris Down <chris@chrisdown.name> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Link: http://lkml.kernel.org/r/20200711011459.1159929-1-shakeelb@google.comSigned-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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dylan-meiners authored
Change "optizimation" to "optimization". Signed-off-by:
dylan-meiners <spacct.spacct@gmail.com> Signed-off-by:
David Hildenbrand <david@redhat.com> Link: http://lkml.kernel.org/r/20200609185144.10049-1-spacct.spacct@gmail.comSigned-off-by:
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Hugh Dickins authored
Move collapse_huge_page()'s mmget_still_valid() check into khugepaged_test_exit() itself. collapse_huge_page() is used for anon THP only, and earned its mmget_still_valid() check because it inserts a huge pmd entry in place of the page table's pmd entry; whereas collapse_file()'s retract_page_tables() or collapse_pte_mapped_thp() merely clears the page table's pmd entry. But core dumping without mmap lock must have been as open to mistaking a racily cleared pmd entry for a page table at physical page 0, as exit_mmap() was. And we certainly have no interest in mapping as a THP once dumping core. Fixes: 59ea6d06 ("coredump: fix race condition between collapse_huge_page() and core dumping") Signed-off-by:
Hugh Dickins <hughd@google.com> Signed-off-by:
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Hugh Dickins authored
Only once have I seen this scenario (and forgot even to notice what forced the eventual crash): a sequence of "BUG: Bad page map" alerts from vm_normal_page(), from zap_pte_range() servicing exit_mmap(); pmd:00000000, pte values corresponding to data in physical page 0. The pte mappings being zapped in this case were supposed to be from a huge page of ext4 text (but could as well have been shmem): my belief is that it was racing with collapse_file()'s retract_page_tables(), found *pmd pointing to a page table, locked it, but *pmd had become 0 by the time start_pte was decided. In most cases, that possibility is excluded by holding mmap lock; but exit_mmap() proceeds without mmap lock. Most of what's run by khugepaged checks khugepaged_test_exit() after acquiring mmap lock: khugepaged_collapse_pte_mapped_thps() and hugepage_vma_revalidate() do so, for example. But retract_page_tables() did not: fix that. The fix is for retract_page_tables() to check khugepaged_test_exit(), after acquiring mmap lock, before doing anything to the page table. Getting the mmap lock serializes with __mmput(), which briefly takes and drops it in __khugepaged_exit(); then the khugepaged_test_exit() check on mm_users makes sure we don't touch the page table once exit_mmap() might reach it, since exit_mmap() will be proceeding without mmap lock, not expecting anyone to be racing with it. Fixes: f3f0e1d2 ("khugepaged: add support of collapse for tmpfs/shmem pages") Signed-off-by:
Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Song Liu <songliubraving@fb.com> Cc: <stable@vger.kernel.org> [4.8+] Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008021215400.27773@eggly.anvilsSigned-off-by:
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Hugh Dickins authored
When retract_page_tables() removes a page table to make way for a huge pmd, it holds huge page lock, i_mmap_lock_write, mmap_write_trylock and pmd lock; but when collapse_pte_mapped_thp() does the same (to handle the case when the original mmap_write_trylock had failed), only mmap_write_trylock and pmd lock are held. That's not enough. One machine has twice crashed under load, with "BUG: spinlock bad magic" and GPF on 6b6b6b6b6b6b6b6b. Examining the second crash, page_vma_mapped_walk_done()'s spin_unlock of pvmw->ptl (serving page_referenced() on a file THP, that had found a page table at *pmd) discovers that the page table page and its lock have already been freed by the time it comes to unlock. Follow the example of retract_page_tables(), but we only need one of huge page lock or i_mmap_lock_write to secure against this: because it's the narrower lock, and because it simplifies collapse_pte_mapped_thp() to know the hpage earlier, choose to rely on huge page lock here. Fixes: 27e1f827 ("khugepaged: enable collapse pmd for pte-mapped THP") Signed-off-by:
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Hugh Dickins authored
pmdp_collapse_flush() should be given the start address at which the huge page is mapped, haddr: it was given addr, which at that point has been used as a local variable, incremented to the end address of the extent. Found by source inspection while chasing a hugepage locking bug, which I then could not explain by this. At first I thought this was very bad; then saw that all of the page translations that were not flushed would actually still point to the right pages afterwards, so harmless; then realized that I know nothing of how different architectures and models cache intermediate paging structures, so maybe it matters after all - particularly since the page table concerned is immediately freed. Much easier to fix than to think about. Fixes: 27e1f827 ("khugepaged: enable collapse pmd for pte-mapped THP") Signed-off-by:
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Peter Xu authored
This is found by code observation only. Firstly, the worst case scenario should assume the whole range was covered by pmd sharing. The old algorithm might not work as expected for ranges like (1g-2m, 1g+2m), where the adjusted range should be (0, 1g+2m) but the expected range should be (0, 2g). Since at it, remove the loop since it should not be required. With that, the new code should be faster too when the invalidating range is huge. Mike said: : With range (1g-2m, 1g+2m) within a vma (0, 2g) the existing code will only : adjust to (0, 1g+2m) which is incorrect. : : We should cc stable. The original reason for adjusting the range was to : prevent data corruption (getting wrong page). Since the range is not : always adjusted correctly, the potential for corruption still exists. : : However, I am fairly confident that adjust_range_if_pmd_sharing_possible : is only gong to be called in two cases: : : 1) for a single page : 2) for range == entire vma : : In those cases, the current code should produce the correct results. : : To be safe, let's just cc stable. Fixes: 017b1660 ("mm: migration: fix migration of huge PMD shared pages") Signed-off-by:
Peter Xu <peterx@redhat.com> Signed-off-by:
Mike Kravetz <mike.kravetz@oracle.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/20200730201636.74778-1-peterx@redhat.comSigned-off-by:
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Alexander A. Klimov authored
Rationale: Reduces attack surface on kernel devs opening the links for MITM as HTTPS traffic is much harder to manipulate. Deterministic algorithm: For each file: If not .svg: For each line: If doesn't contain `xmlns`: For each link, `http://[^# ]*(?:\w|/)`: If neither `gnu\.org/license`, nor `mozilla\.org/MPL`: If both the HTTP and HTTPS versions return 200 OK and serve the same content: Replace HTTP with HTTPS. [akpm@linux-foundation.org: fix amd.com URL, per Vlastimil] Signed-off-by:Alexander A. Klimov <grandmaster@al2klimov.de> Signed-off-by:
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Joonsoo Kim authored
Currently, memalloc_nocma_{save/restore} API that prevents CMA area in page allocation is implemented by using current_gfp_context(). However, there are two problems of this implementation. First, this doesn't work for allocation fastpath. In the fastpath, original gfp_mask is used since current_gfp_context() is introduced in order to control reclaim and it is on slowpath. So, CMA area can be allocated through the allocation fastpath even if memalloc_nocma_{save/restore} APIs are used. Currently, there is just one user for these APIs and it has a fallback method to prevent actual problem. Second, clearing __GFP_MOVABLE in current_gfp_context() has a side effect to exclude the memory on the ZONE_MOVABLE for allocation target. To fix these problems, this patch changes the implementation to exclude CMA area in page allocation. Main point of this change is using the alloc_flags. alloc_flags is mainly used to control allocation so it fits for excluding CMA area in allocation. Fixes: d7fefcc8 (mm/cma: add PF flag to force non cma alloc) Signed-off-by:Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by:
Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Hellwig <hch@infradead.org> Cc: Roman Gushchin <guro@fb.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Michal Hocko <mhocko@suse.com> Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com> Link: http://lkml.kernel.org/r/1595468942-29687-1-git-send-email-iamjoonsoo.kim@lge.comSigned-off-by:
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Muchun Song authored
When we are in the interrupt context, it is irrelevant to the current task context. If we use current task's mems_allowed, we can be fair to alloc pages in the fast path and fall back to slow path memory allocation when the current node(which is the current task mems_allowed) does not have enough memory to allocate. In this case, it slows down the memory allocation speed of interrupt context. So we can skip setting the nodemask to allow any node to allocate memory, so that fast path allocation can success. Signed-off-by:
Muchun Song <songmuchun@bytedance.com> Signed-off-by:
Pekka Enberg <penberg@kernel.org> Cc: David Hildenbrand <david@redhat.com> Link: http://lkml.kernel.org/r/20200706025921.53683-1-songmuchun@bytedance.comSigned-off-by:
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Wei Yang authored
MIGRAGE_TYPES is used to be the mark of end and there are at most 3 elements for the one dimension array. Reduce to 3 to save little memory. Signed-off-by:
Wei Yang <richard.weiyang@linux.alibaba.com> Signed-off-by:
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Qian Cai authored
kernel_init_free_pages() will use memset() on s390 to clear all pages from kmalloc_order() which will override KASAN redzones because a redzone was setup from the end of the allocation size to the end of the last page. Silence it by not reporting it there. An example of the report is, BUG: KASAN: slab-out-of-bounds in __free_pages_ok Write of size 4096 at addr 000000014beaa000 Call Trace: show_stack+0x152/0x210 dump_stack+0x1f8/0x248 print_address_description.isra.13+0x5e/0x4d0 kasan_report+0x130/0x178 check_memory_region+0x190/0x218 memset+0x34/0x60 __free_pages_ok+0x894/0x12f0 kfree+0x4f2/0x5e0 unpack_to_rootfs+0x60e/0x650 populate_rootfs+0x56/0x358 do_one_initcall+0x1f4/0xa20 kernel_init_freeable+0x758/0x7e8 kernel_init+0x1c/0x170 ret_from_fork+0x24/0x28 Memory state around the buggy address: 000000014bea9f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000000014bea9f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >000000014beaa000: 03 fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe ^ 000000014beaa080: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe 000000014beaa100: fe fe fe fe fe fe fe fe fe fe fe fe fe fe Fixes: 6471384a ("mm: security: introduce init_on_alloc=1 and init_on_free=1 boot options") Signed-off-by:Qian Cai <cai@lca.pw> Signed-off-by:
Vasily Gorbik <gor@linux.ibm.com> Acked-by:
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Wei Yang authored
After previous cleanup, the end_bitidx is not necessary any more. Signed-off-by:
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Wei Yang authored
Due to commit e58469ba ("mm: page_alloc: use word-based accesses for get/set pageblock bitmaps"), pageblock bitmap is accessed with word-based access. This operation could be simplified a little. Intuitively, if we want to get a bit range [start_idx, end_idx] in a word, we can do like this: mask = (1 << (end_bitidx - start_bitidx + 1)) - 1; ret = (word >> start_idx) & mask; And also if we want to set a bit range [start_idx, end_idx] with flags, we can do the same by just shift start_bitidx. By doing so we reduce some instructions for these two helper functions: Before Patched set_pfnblock_flags_mask 209 198(-5%) get_pfnblock_flags_mask 101 87(-13%) Since the syntax is changed a little, we need to check the whole 4-bit migrate_type instead of part of it. Signed-off-by:
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Wei Yang authored
The return value calculation is the same both for SPARSEMEM or not. Just take it out. Signed-off-by:
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Wei Yang authored
We already have the definition of PB_migratetype_bits and current NR_MIGRATETYPE_BITS looks like a cyclic definition. Just use PB_migratetype_bits is enough. Signed-off-by:
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David Hildenbrand authored
Commit e900a918 ("mm: shuffle initial free memory to improve memory-side-cache utilization") promised "autodetection of a memory-side-cache (to be added in a follow-on patch)" over a year ago. The original series included patches [1], however, they were dropped during review [2] to be followed-up later. Due to lack of platforms that publish an HMAT, autodetection is currently not implemented. However, manual activation is actively used [3]. Let's simplify for now and re-add when really (ever?) needed. [1] https://lkml.kernel.org/r/154510700291.1941238.817190985966612531.stgit@dwillia2-desk3.amr.corp.intel.com [2] https://lkml.kernel.org/r/154690326478.676627.103843791978176914.stgit@dwillia2-desk3.amr.corp.intel.com [3] https://lkml.kernel.org/r/CAPcyv4irwGUU2x+c6b4L=KbB1dnasNKaaZd6oSpYjL9kfsnROQ@mail.gmail.comSigned-off-by:
Dan Williams <dan.j.williams@intel.com> Acked-by:
Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Huang Ying <ying.huang@intel.com> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Dan Williams <dan.j.williams@intel.com> Link: http://lkml.kernel.org/r/20200624094741.9918-4-david@redhat.comSigned-off-by:
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David Hildenbrand authored
It's not completely obvious why we have to shuffle the complete zone - introduced in commit e900a918 ("mm: shuffle initial free memory to improve memory-side-cache utilization") - because some sort of shuffling is already performed when onlining pages via __free_one_page(), placing MAX_ORDER-1 pages either to the head or the tail of the freelist. Let's document why we have to shuffle the complete zone when exposing larger, contiguous physical memory areas to the buddy. Signed-off-by:
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David Hildenbrand authored
nr_free_pagecache_pages() isn't used outside page_alloc.c anymore - and the name does not really help to understand what's going on. Let's open-code it instead and add a comment. Signed-off-by:
Wei Yang <richard.weiyang@gmail.com> Reviewed-by:
Pankaj Gupta <pankaj.gupta.linux@gmail.com> Reviewed-by:
Mike Rapoport <rppt@linux.ibm.com> Acked-by:
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David Hildenbrand authored
The global variable "vm_total_pages" is a relic from older days. There is only a single user that reads the variable - build_all_zonelists() - and the first thing it does is update it. Use a local variable in build_all_zonelists() instead and remove the global variable. Signed-off-by:
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Charan Teja Reddy authored
When boosting is enabled, it is observed that rate of atomic order-0 allocation failures are high due to the fact that free levels in the system are checked with ->watermark_boost offset. This is not a problem for sleepable allocations but for atomic allocations which looks like regression. This problem is seen frequently on system setup of Android kernel running on Snapdragon hardware with 4GB RAM size. When no extfrag event occurred in the system, ->watermark_boost factor is zero, thus the watermark configurations in the system are: _watermark = ( [WMARK_MIN] = 1272, --> ~5MB [WMARK_LOW] = 9067, --> ~36MB [WMARK_HIGH] = 9385), --> ~38MB watermark_boost = 0 After launching some memory hungry applications in Android which can cause extfrag events in the system to an extent that ->watermark_boost can be set to max i.e. default boost factor makes it to 150% of high watermark. _watermark = ( [WMARK_MIN] = 1272, --> ~5MB [WMARK_LOW] = 9067, --> ~36MB [WMARK_HIGH] = 9385), --> ~38MB watermark_boost = 14077, -->~57MB With default system configuration, for an atomic order-0 allocation to succeed, having free memory of ~2MB will suffice. But boosting makes the min_wmark to ~61MB thus for an atomic order-0 allocation to be successful system should have minimum of ~23MB of free memory(from calculations of zone_watermark_ok(), min = 3/4(min/2)). But failures are observed despite system is having ~20MB of free memory. In the testing, this is reproducible as early as first 300secs since boot and with furtherlowram configurations(<2GB) it is observed as early as first 150secs since boot. These failures can be avoided by excluding the ->watermark_boost in watermark caluculations for atomic order-0 allocations. [akpm@linux-foundation.org: fix comment grammar, reflow comment] [charante@codeaurora.org: fix suggested by Mel Gorman] Link: http://lkml.kernel.org/r/31556793-57b1-1c21-1a9d-22674d9bd938@codeaurora.orgSigned-off-by:Charan Teja Reddy <charante@codeaurora.org> Signed-off-by:
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Jaewon Kim authored
zone_watermark_fast was introduced by commit 48ee5f36 ("mm, page_alloc: shortcut watermark checks for order-0 pages"). The commit simply checks if free pages is bigger than watermark without additional calculation such like reducing watermark. It considered free cma pages but it did not consider highatomic reserved. This may incur exhaustion of free pages except high order atomic free pages. Assume that reserved_highatomic pageblock is bigger than watermark min, and there are only few free pages except high order atomic free. Because zone_watermark_fast passes the allocation without considering high order atomic free, normal reclaimable allocation like GFP_HIGHUSER will consume all the free pages. Then finally order-0 atomic allocation may fail on allocation. This means watermark min is not protected against non-atomic allocation. The order-0 atomic allocation with ALLOC_HARDER unwantedly can be failed. Additionally the __GFP_MEMALLOC allocation with ALLOC_NO_WATERMARKS also can be failed. To avoid the problem, zone_watermark_fast should consider highatomic reserve. If the actual size of high atomic free is counted accurately like cma free, we may use it. On this patch just use nr_reserved_highatomic. Additionally introduce __zone_watermark_unusable_free to factor out common parts between zone_watermark_fast and __zone_watermark_ok. This is an example of ALLOC_HARDER allocation failure using v4.19 based kernel. Binder:9343_3: page allocation failure: order:0, mode:0x480020(GFP_ATOMIC), nodemask=(null) Call trace: [<ffffff8008f40f8c>] dump_stack+0xb8/0xf0 [<ffffff8008223320>] warn_alloc+0xd8/0x12c [<ffffff80082245e4>] __alloc_pages_nodemask+0x120c/0x1250 [<ffffff800827f6e8>] new_slab+0x128/0x604 [<ffffff800827b0cc>] ___slab_alloc+0x508/0x670 [<ffffff800827ba00>] __kmalloc+0x2f8/0x310 [<ffffff80084ac3e0>] context_struct_to_string+0x104/0x1cc [<ffffff80084ad8fc>] security_sid_to_context_core+0x74/0x144 [<ffffff80084ad880>] security_sid_to_context+0x10/0x18 [<ffffff800849bd80>] selinux_secid_to_secctx+0x20/0x28 [<ffffff800849109c>] security_secid_to_secctx+0x3c/0x70 [<ffffff8008bfe118>] binder_transaction+0xe68/0x454c Mem-Info: active_anon:102061 inactive_anon:81551 isolated_anon:0 active_file:59102 inactive_file:68924 isolated_file:64 unevictable:611 dirty:63 writeback:0 unstable:0 slab_reclaimable:13324 slab_unreclaimable:44354 mapped:83015 shmem:4858 pagetables:26316 bounce:0 free:2727 free_pcp:1035 free_cma:178 Node 0 active_anon:408244kB inactive_anon:326204kB active_file:236408kB inactive_file:275696kB unevictable:2444kB isolated(anon):0kB isolated(file):256kB mapped:332060kB dirty:252kB writeback:0kB shmem:19432kB writeback_tmp:0kB unstable:0kB all_unreclaimable? no Normal free:10908kB min:6192kB low:44388kB high:47060kB active_anon:409160kB inactive_anon:325924kB active_file:235820kB inactive_file:276628kB unevictable:2444kB writepending:252kB present:3076096kB managed:2673676kB mlocked:2444kB kernel_stack:62512kB pagetables:105264kB bounce:0kB free_pcp:4140kB local_pcp:40kB free_cma:712kB lowmem_reserve[]: 0 0 Normal: 505*4kB (H) 357*8kB (H) 201*16kB (H) 65*32kB (H) 1*64kB (H) 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 10236kB 138826 total pagecache pages 5460 pages in swap cache Swap cache stats: add 8273090, delete 8267506, find 1004381/4060142 This is an example of ALLOC_NO_WATERMARKS allocation failure using v4.14 based kernel. kswapd0: page allocation failure: order:0, mode:0x140000a(GFP_NOIO|__GFP_HIGHMEM|__GFP_MOVABLE), nodemask=(null) kswapd0 cpuset=/ mems_allowed=0 CPU: 4 PID: 1221 Comm: kswapd0 Not tainted 4.14.113-18770262-userdebug #1 Call trace: [<0000000000000000>] dump_backtrace+0x0/0x248 [<0000000000000000>] show_stack+0x18/0x20 [<0000000000000000>] __dump_stack+0x20/0x28 [<0000000000000000>] dump_stack+0x68/0x90 [<0000000000000000>] warn_alloc+0x104/0x198 [<0000000000000000>] __alloc_pages_nodemask+0xdc0/0xdf0 [<0000000000000000>] zs_malloc+0x148/0x3d0 [<0000000000000000>] zram_bvec_rw+0x410/0x798 [<0000000000000000>] zram_rw_page+0x88/0xdc [<0000000000000000>] bdev_write_page+0x70/0xbc [<0000000000000000>] __swap_writepage+0x58/0x37c [<0000000000000000>] swap_writepage+0x40/0x4c [<0000000000000000>] shrink_page_list+0xc30/0xf48 [<0000000000000000>] shrink_inactive_list+0x2b0/0x61c [<0000000000000000>] shrink_node_memcg+0x23c/0x618 [<0000000000000000>] shrink_node+0x1c8/0x304 [<0000000000000000>] kswapd+0x680/0x7c4 [<0000000000000000>] kthread+0x110/0x120 [<0000000000000000>] ret_from_fork+0x10/0x18 Mem-Info: active_anon:111826 inactive_anon:65557 isolated_anon:0\x0a active_file:44260 inactive_file:83422 isolated_file:0\x0a unevictable:4158 dirty:117 writeback:0 unstable:0\x0a slab_reclaimable:13943 slab_unreclaimable:43315\x0a mapped:102511 shmem:3299 pagetables:19566 bounce:0\x0a free:3510 free_pcp:553 free_cma:0 Node 0 active_anon:447304kB inactive_anon:262228kB active_file:177040kB inactive_file:333688kB unevictable:16632kB isolated(anon):0kB isolated(file):0kB mapped:410044kB d irty:468kB writeback:0kB shmem:13196kB writeback_tmp:0kB unstable:0kB all_unreclaimable? no Normal free:14040kB min:7440kB low:94500kB high:98136kB reserved_highatomic:32768KB active_anon:447336kB inactive_anon:261668kB active_file:177572kB inactive_file:333768k B unevictable:16632kB writepending:480kB present:4081664kB managed:3637088kB mlocked:16632kB kernel_stack:47072kB pagetables:78264kB bounce:0kB free_pcp:2280kB local_pcp:720kB free_cma:0kB [ 4738.329607] lowmem_reserve[]: 0 0 Normal: 860*4kB (H) 453*8kB (H) 180*16kB (H) 26*32kB (H) 34*64kB (H) 6*128kB (H) 2*256kB (H) 0*512kB 0*1024kB 0*2048kB 0*4096kB = 14232kB This is trace log which shows GFP_HIGHUSER consumes free pages right before ALLOC_NO_WATERMARKS. <...>-22275 [006] .... 889.213383: mm_page_alloc: page=00000000d2be5665 pfn=970744 order=0 migratetype=0 nr_free=3650 gfp_flags=GFP_HIGHUSER|__GFP_ZERO <...>-22275 [006] .... 889.213385: mm_page_alloc: page=000000004b2335c2 pfn=970745 order=0 migratetype=0 nr_free=3650 gfp_flags=GFP_HIGHUSER|__GFP_ZERO <...>-22275 [006] .... 889.213387: mm_page_alloc: page=00000000017272e1 pfn=970278 order=0 migratetype=0 nr_free=3650 gfp_flags=GFP_HIGHUSER|__GFP_ZERO <...>-22275 [006] .... 889.213389: mm_page_alloc: page=00000000c4be79fb pfn=970279 order=0 migratetype=0 nr_free=3650 gfp_flags=GFP_HIGHUSER|__GFP_ZERO <...>-22275 [006] .... 889.213391: mm_page_alloc: page=00000000f8a51d4f pfn=970260 order=0 migratetype=0 nr_free=3650 gfp_flags=GFP_HIGHUSER|__GFP_ZERO <...>-22275 [006] .... 889.213393: mm_page_alloc: page=000000006ba8f5ac pfn=970261 order=0 migratetype=0 nr_free=3650 gfp_flags=GFP_HIGHUSER|__GFP_ZERO <...>-22275 [006] .... 889.213395: mm_page_alloc: page=00000000819f1cd3 pfn=970196 order=0 migratetype=0 nr_free=3650 gfp_flags=GFP_HIGHUSER|__GFP_ZERO <...>-22275 [006] .... 889.213396: mm_page_alloc: page=00000000f6b72a64 pfn=970197 order=0 migratetype=0 nr_free=3650 gfp_flags=GFP_HIGHUSER|__GFP_ZERO kswapd0-1207 [005] ...1 889.213398: mm_page_alloc: page= (null) pfn=0 order=0 migratetype=1 nr_free=3650 gfp_flags=GFP_NOWAIT|__GFP_HIGHMEM|__GFP_NOWARN|__GFP_MOVABLE [jaewon31.kim@samsung.com: remove redundant code for high-order] Link: http://lkml.kernel.org/r/20200623035242.27232-1-jaewon31.kim@samsung.comReported-by:
Yong-Taek Lee <ytk.lee@samsung.com> Suggested-by:
Minchan Kim <minchan@kernel.org> Signed-off-by:
Jaewon Kim <jaewon31.kim@samsung.com> Signed-off-by:
Baoquan He <bhe@redhat.com> Acked-by:
Mel Gorman <mgorman@techsingularity.net> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Yong-Taek Lee <ytk.lee@samsung.com> Cc: Michal Hocko <mhocko@kernel.org> Link: http://lkml.kernel.org/r/20200619235958.11283-1-jaewon31.kim@samsung.comSigned-off-by:
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Vlastimil Babka authored
Hugh noted that task_capc() could use unlikely(), as most of the time there is no capture in progress and we are in page freeing hot path. Indeed adding unlikely() produces assembly that better matches the assumption and moves all the tests away from the hot path. I have also noticed that we don't need to test for cc->direct_compaction as the only place we set current->task_capture is compact_zone_order() which also always sets cc->direct_compaction true. Suggested-by:
Hugh Dickins <hughd@googlecom> Acked-by:
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Andrey Konovalov authored
Use OOB_TAG_OFF as access offset to land the access into the next granule. Suggested-by:
Walter Wu <walter-zh.wu@mediatek.com> Signed-off-by:
Andrey Konovalov <andreyknvl@google.com> Signed-off-by:
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Andrey Konovalov authored
Use CONFIG_KASAN_STACK to enable stack tagging. Note, that HWASAN short granules [1] are disabled. Supporting those will require more kernel changes. [1] https://clang.llvm.org/docs/HardwareAssistedAddressSanitizerDesign.htmlSigned-off-by:
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Andrey Konovalov authored
This patch prepares Software Tag-Based KASAN for stack tagging support. With stack tagging enabled, KASAN tags stack variable in each function in its prologue. In start_kernel() stack variables get tagged before KASAN is enabled via setup_arch()->kasan_init(). As the result the tags for start_kernel()'s stack variables end up in the temporary shadow memory. Later when KASAN gets enabled, switched to normal shadow, and starts checking tags, this leads to false-positive reports, as proper tags are missing in normal shadow. Disable KASAN instrumentation for start_kernel(). Also disable it for arm64's setup_arch() as a precaution (it doesn't have any stack variables right now). [andreyknvl@google.com: reorder attributes for start_kernel()] Link: http://lkml.kernel.org/r/26fb6165a17abcf61222eda5184c030fb6b133d1.1596544734.git.andreyknvl@google.comSigned-off-by:
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Andrey Konovalov authored
When CONFIG_EFI is not enabled, we might get an undefined reference to efi_enter_virtual_mode() error, if this efi_enabled() call isn't inlined into start_kernel(). This happens in particular, if start_kernel() is annodated with __no_sanitize_address. Reported-by:
kernel test robot <lkp@intel.com> Signed-off-by:
Ard Biesheuvel <ardb@kernel.org> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Elena Petrova <lenaptr@google.com> Cc: Marco Elver <elver@google.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Walter Wu <walter-zh.wu@mediatek.com> Link: http://lkml.kernel.org/r/6514652d3a32d3ed33d6eb5c91d0af63bf0d1a0c.1596544734.git.andreyknvl@google.comSigned-off-by:
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Andrey Konovalov authored
Patch series "kasan: support stack instrumentation for tag-based mode", v2. This patch (of 5): Prepare Software Tag-Based KASAN for stack tagging support. With Tag-Based KASAN when kernel stacks are allocated via pagealloc (which happens when CONFIG_VMAP_STACK is not enabled), they get tagged. KASAN instrumentation doesn't expect the sp register to be tagged, and this leads to false-positive reports. Fix by resetting the tag of kernel stack pointers after allocation. Signed-off-by:
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Walter Wu authored
We use tag-based KASAN, then KASAN unit tests don't detect out-of-bounds memory access. They need to be fixed. With tag-based KASAN, the state of each 16 aligned bytes of memory is encoded in one shadow byte and the shadow value is tag of pointer, so we need to read next shadow byte, the shadow value is not equal to tag value of pointer, so that tag-based KASAN will detect out-of-bounds memory access. [walter-zh.wu@mediatek.com: use KASAN_SHADOW_SCALE_SIZE instead of 13] Link: http://lkml.kernel.org/r/20200708132524.11688-1-walter-zh.wu@mediatek.comSuggested-by:
Dmitry Vyukov <dvyukov@google.com> Signed-off-by:
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Vincenzo Frascino authored
kasan_unpoison_stack_above_sp_to() is defined in kasan code but never used. The function was introduced as part of the commit: commit 9f7d416c ("kprobes: Unpoison stack in jprobe_return() for KASAN") ... where it was necessary because x86's jprobe_return() would leave stale shadow on the stack, and was an oddity in that regard. Since then, jprobes were removed entirely, and as of commit: commit 80006dbe ("kprobes/x86: Remove jprobe implementation") ... there have been no callers of this function. Remove the declaration and the implementation. Signed-off-by:
Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by:
Mark Rutland <mark.rutland@arm.com> Reviewed-by:
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Walter Wu authored
Generic KASAN will support to record the last two call_rcu() call stacks and print them in KASAN report. So that need to update documentation. Signed-off-by:
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Walter Wu authored
Test call_rcu() call stack recording and verify whether it correctly is printed in KASAN report. Signed-off-by:
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Walter Wu authored
Move free track from kasan_alloc_meta to kasan_free_meta in order to make struct kasan_alloc_meta and kasan_free_meta size are both 16 bytes. It is a good size because it is the minimal redzone size and a good number of alignment. For free track, we make some modifications as shown below: 1) Remove the free_track from struct kasan_alloc_meta. 2) Add the free_track into struct kasan_free_meta. 3) Add a macro KASAN_KMALLOC_FREETRACK in order to check whether it can print free stack in KASAN report. [1]https://bugzilla.kernel.org/show_bug.cgi?id=198437 [walter-zh.wu@mediatek.com: build fix] Link: http://lkml.kernel.org/r/20200710162440.23887-1-walter-zh.wu@mediatek.comSuggested-by:
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Walter Wu authored
Patch series "kasan: memorize and print call_rcu stack", v8. This patchset improves KASAN reports by making them to have call_rcu() call stack information. It is useful for programmers to solve use-after-free or double-free memory issue. The KASAN report was as follows(cleaned up slightly): BUG: KASAN: use-after-free in kasan_rcu_reclaim+0x58/0x60 Freed by task 0: kasan_save_stack+0x24/0x50 kasan_set_track+0x24/0x38 kasan_set_free_info+0x18/0x20 __kasan_slab_free+0x10c/0x170 kasan_slab_free+0x10/0x18 kfree+0x98/0x270 kasan_rcu_reclaim+0x1c/0x60 Last call_rcu(): kasan_save_stack+0x24/0x50 kasan_record_aux_stack+0xbc/0xd0 call_rcu+0x8c/0x580 kasan_rcu_uaf+0xf4/0xf8 Generic KASAN will record the last two call_rcu() call stacks and print up to 2 call_rcu() call stacks in KASAN report. it is only suitable for generic KASAN. This feature considers the size of struct kasan_alloc_meta and kasan_free_meta, we try to optimize the structure layout and size, lets it get better memory consumption. [1]https://bugzilla.kernel.org/show_bug.cgi?id=198437 [2]https://groups.google.com/forum/#!searchin/kasan-dev/better$20stack$20traces$20for$20rcu%7Csort:date/kasan-dev/KQsjT_88hDE/7rNUZprRBgAJ This patch (of 4): This feature will record the last two call_rcu() call stacks and prints up to 2 call_rcu() call stacks in KASAN report. When call_rcu() is called, we store the call_rcu() call stack into slub alloc meta-data, so that the KASAN report can print rcu stack. [1]https://bugzilla.kernel.org/show_bug.cgi?id=198437 [2]https://groups.google.com/forum/#!searchin/kasan-dev/better$20stack$20traces$20for$20rcu%7Csort:date/kasan-dev/KQsjT_88hDE/7rNUZprRBgAJ [walter-zh.wu@mediatek.com: build fix] Link: http://lkml.kernel.org/r/20200710162401.23816-1-walter-zh.wu@mediatek.comSuggested-by:
Paul E. McKenney <paulmck@kernel.org> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matthias Brugger <matthias.bgg@gmail.com> Link: http://lkml.kernel.org/r/20200710162123.23713-1-walter-zh.wu@mediatek.com Link: http://lkml.kernel.org/r/20200601050847.1096-1-walter-zh.wu@mediatek.com Link: http://lkml.kernel.org/r/20200601050927.1153-1-walter-zh.wu@mediatek.comSigned-off-by:
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Marco Elver authored
Updates the recently changed compiler requirements for KASAN. In particular, we require GCC >= 8.3.0, and add a note that Clang 11 supports OOB detection of globals. Fixes: 7b861a53 ("kasan: Bump required compiler version") Fixes: acf7b0bf ("kasan: Fix required compiler version") Signed-off-by:
Marco Elver <elver@google.com> Signed-off-by:
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Marco Elver authored
Turn 'KASAN' into a menuconfig, to avoid cluttering its parent menu with the suboptions if enabled. Use 'if KASAN ... endif' instead of having to 'depend on KASAN' for each entry. Signed-off-by:
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Uladzislau Rezki (Sony) authored
Get rid of BUG() macro, that should be used only when a critical situation happens and a system is not able to function anymore. Replace it with WARN() macro instead, dump some extra information about start/end addresses of both VAs which overlap. Such overlap data can help to figure out what happened making further analysis easier. For example if both areas are identical it could mean a double free. A recovery process consists of declining all further steps regarding inserting of conflicting overlap range. In that sense find_va_links() now can return NULL, so its return value has to be checked by callers. Side effect of such process is it can leak memory, but it is better than just killing a machine for no good reason. Apart of that a debugging process can be done on alive system. Signed-off-by:
Uladzislau Rezki (Sony) <urezki@gmail.com> Signed-off-by:
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Mike Rapoport authored
'addr' is set to 'start' and then a few lines afterwards 'start' is set to 'addr'. Remove the second asignment. Fixes: 2ba3e694 ("mm/vmalloc: track which page-table levels were modified") Signed-off-by:
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Uladzislau Rezki (Sony) authored
Reflect information about the author, date and year when the KVA rework was done. Signed-off-by:
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