forked from TencentOS/TencentOS-kernel
30 Commits
| Author | SHA1 | Message | Date |
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Vlastimil Babka
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c6f34a8de6 |
mm, compaction: make capture control handling safe wrt interrupts
commit b9e20f0da1f5c9c68689450a8cb436c9486434c8 upstream. Hugh reports: "While stressing compaction, one run oopsed on NULL capc->cc in __free_one_page()'s task_capc(zone): compact_zone_order() had been interrupted, and a page was being freed in the return from interrupt. Though you would not expect it from the source, both gccs I was using (4.8.1 and 7.5.0) had chosen to compile compact_zone_order() with the ".cc = &cc" implemented by mov %rbx,-0xb0(%rbp) immediately before callq compact_zone - long after the "current->capture_control = &capc". An interrupt in between those finds capc->cc NULL (zeroed by an earlier rep stos). This could presumably be fixed by a barrier() before setting current->capture_control in compact_zone_order(); but would also need more care on return from compact_zone(), in order not to risk leaking a page captured by interrupt just before capture_control is reset. Maybe that is the preferable fix, but I felt safer for task_capc() to exclude the rather surprising possibility of capture at interrupt time" I have checked that gcc10 also behaves the same. The advantage of fix in compact_zone_order() is that we don't add another test in the page freeing hot path, and that it might prevent future problems if we stop exposing pointers to uninitialized structures in current task. So this patch implements the suggestion for compact_zone_order() with barrier() (and WRITE_ONCE() to prevent store tearing) for setting current->capture_control, and prevents page leaking with WRITE_ONCE/READ_ONCE in the proper order. Link: http://lkml.kernel.org/r/20200616082649.27173-1-vbabka@suse.cz Fixes: 5e1f0f098b46 ("mm, compaction: capture a page under direct compaction") Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reported-by: Hugh Dickins <hughd@google.com> Suggested-by: Hugh Dickins <hughd@google.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Alex Shi <alex.shi@linux.alibaba.com> Cc: Li Wang <liwang@redhat.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: <stable@vger.kernel.org> [5.1+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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Vlastimil Babka
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73d7474692 |
mm, compaction: fully assume capture is not NULL in compact_zone_order()
commit 6467552ca64c4ddd2b83ed73192107d7145f533b upstream.
Dan reports:
The patch 5e1f0f098b46: "mm, compaction: capture a page under direct
compaction" from Mar 5, 2019, leads to the following Smatch complaint:
mm/compaction.c:2321 compact_zone_order()
error: we previously assumed 'capture' could be null (see line 2313)
mm/compaction.c
2288 static enum compact_result compact_zone_order(struct zone *zone, int order,
2289 gfp_t gfp_mask, enum compact_priority prio,
2290 unsigned int alloc_flags, int classzone_idx,
2291 struct page **capture)
^^^^^^^
2313 if (capture)
^^^^^^^
Check for NULL
2314 current->capture_control = &capc;
2315
2316 ret = compact_zone(&cc, &capc);
2317
2318 VM_BUG_ON(!list_empty(&cc.freepages));
2319 VM_BUG_ON(!list_empty(&cc.migratepages));
2320
2321 *capture = capc.page;
^^^^^^^^
Unchecked dereference.
2322 current->capture_control = NULL;
2323
In practice this is not an issue, as the only caller path passes non-NULL
capture:
__alloc_pages_direct_compact()
struct page *page = NULL;
try_to_compact_pages(capture = &page);
compact_zone_order(capture = capture);
So let's remove the unnecessary check, which should also make Smatch happy.
Fixes: 5e1f0f098b46 ("mm, compaction: capture a page under direct compaction")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Link: http://lkml.kernel.org/r/18b0df3c-0589-d96c-23fa-040798fee187@suse.cz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Qian Cai
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d230e2e75a |
mm/slub: fix stack overruns with SLUB_STATS
[ Upstream commit a68ee0573991e90af2f1785db309206408bad3e5 ]
There is no need to copy SLUB_STATS items from root memcg cache to new
memcg cache copies. Doing so could result in stack overruns because the
store function only accepts 0 to clear the stat and returns an error for
everything else while the show method would print out the whole stat.
Then, the mismatch of the lengths returns from show and store methods
happens in memcg_propagate_slab_attrs():
else if (root_cache->max_attr_size < ARRAY_SIZE(mbuf))
buf = mbuf;
max_attr_size is only 2 from slab_attr_store(), then, it uses mbuf[64]
in show_stat() later where a bounch of sprintf() would overrun the stack
variable. Fix it by always allocating a page of buffer to be used in
show_stat() if SLUB_STATS=y which should only be used for debug purpose.
# echo 1 > /sys/kernel/slab/fs_cache/shrink
BUG: KASAN: stack-out-of-bounds in number+0x421/0x6e0
Write of size 1 at addr ffffc900256cfde0 by task kworker/76:0/53251
Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019
Workqueue: memcg_kmem_cache memcg_kmem_cache_create_func
Call Trace:
number+0x421/0x6e0
vsnprintf+0x451/0x8e0
sprintf+0x9e/0xd0
show_stat+0x124/0x1d0
alloc_slowpath_show+0x13/0x20
__kmem_cache_create+0x47a/0x6b0
addr ffffc900256cfde0 is located in stack of task kworker/76:0/53251 at offset 0 in frame:
process_one_work+0x0/0xb90
this frame has 1 object:
[32, 72) 'lockdep_map'
Memory state around the buggy address:
ffffc900256cfc80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffffc900256cfd00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc900256cfd80: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
^
ffffc900256cfe00: 00 00 00 00 00 f2 f2 f2 00 00 00 00 00 00 00 00
ffffc900256cfe80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: __kmem_cache_create+0x6ac/0x6b0
Workqueue: memcg_kmem_cache memcg_kmem_cache_create_func
Call Trace:
__kmem_cache_create+0x6ac/0x6b0
Fixes: 107dab5c92d5 ("slub: slub-specific propagation changes")
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Glauber Costa <glauber@scylladb.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Link: http://lkml.kernel.org/r/20200429222356.4322-1-cai@lca.pw
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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Dongli Zhang
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fe0aab06d4 |
mm/slub.c: fix corrupted freechain in deactivate_slab()
[ Upstream commit 52f23478081ae0dcdb95d1650ea1e7d52d586829 ] The slub_debug is able to fix the corrupted slab freelist/page. However, alloc_debug_processing() only checks the validity of current and next freepointer during allocation path. As a result, once some objects have their freepointers corrupted, deactivate_slab() may lead to page fault. Below is from a test kernel module when 'slub_debug=PUF,kmalloc-128 slub_nomerge'. The test kernel corrupts the freepointer of one free object on purpose. Unfortunately, deactivate_slab() does not detect it when iterating the freechain. BUG: unable to handle page fault for address: 00000000123456f8 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] SMP PTI ... ... RIP: 0010:deactivate_slab.isra.92+0xed/0x490 ... ... Call Trace: ___slab_alloc+0x536/0x570 __slab_alloc+0x17/0x30 __kmalloc+0x1d9/0x200 ext4_htree_store_dirent+0x30/0xf0 htree_dirblock_to_tree+0xcb/0x1c0 ext4_htree_fill_tree+0x1bc/0x2d0 ext4_readdir+0x54f/0x920 iterate_dir+0x88/0x190 __x64_sys_getdents+0xa6/0x140 do_syscall_64+0x49/0x170 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Therefore, this patch adds extra consistency check in deactivate_slab(). Once an object's freepointer is corrupted, all following objects starting at this object are isolated. [akpm@linux-foundation.org: fix build with CONFIG_SLAB_DEBUG=n] Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Joe Jin <joe.jin@oracle.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Link: http://lkml.kernel.org/r/20200331031450.12182-1-dongli.zhang@oracle.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> |
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Hugh Dickins
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9cd25b9927 |
mm: fix swap cache node allocation mask
[ Upstream commit 243bce09c91b0145aeaedd5afba799d81841c030 ] Chris Murphy reports that a slightly overcommitted load, testing swap and zram along with i915, splats and keeps on splatting, when it had better fail less noisily: gnome-shell: page allocation failure: order:0, mode:0x400d0(__GFP_IO|__GFP_FS|__GFP_COMP|__GFP_RECLAIMABLE), nodemask=(null),cpuset=/,mems_allowed=0 CPU: 2 PID: 1155 Comm: gnome-shell Not tainted 5.7.0-1.fc33.x86_64 #1 Call Trace: dump_stack+0x64/0x88 warn_alloc.cold+0x75/0xd9 __alloc_pages_slowpath.constprop.0+0xcfa/0xd30 __alloc_pages_nodemask+0x2df/0x320 alloc_slab_page+0x195/0x310 allocate_slab+0x3c5/0x440 ___slab_alloc+0x40c/0x5f0 __slab_alloc+0x1c/0x30 kmem_cache_alloc+0x20e/0x220 xas_nomem+0x28/0x70 add_to_swap_cache+0x321/0x400 __read_swap_cache_async+0x105/0x240 swap_cluster_readahead+0x22c/0x2e0 shmem_swapin+0x8e/0xc0 shmem_swapin_page+0x196/0x740 shmem_getpage_gfp+0x3a2/0xa60 shmem_read_mapping_page_gfp+0x32/0x60 shmem_get_pages+0x155/0x5e0 [i915] __i915_gem_object_get_pages+0x68/0xa0 [i915] i915_vma_pin+0x3fe/0x6c0 [i915] eb_add_vma+0x10b/0x2c0 [i915] i915_gem_do_execbuffer+0x704/0x3430 [i915] i915_gem_execbuffer2_ioctl+0x1ea/0x3e0 [i915] drm_ioctl_kernel+0x86/0xd0 [drm] drm_ioctl+0x206/0x390 [drm] ksys_ioctl+0x82/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x5b/0xf0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported on 5.7, but it goes back really to 3.1: when shmem_read_mapping_page_gfp() was implemented for use by i915, and allowed for __GFP_NORETRY and __GFP_NOWARN flags in most places, but missed swapin's "& GFP_KERNEL" mask for page tree node allocation in __read_swap_cache_async() - that was to mask off HIGHUSER_MOVABLE bits from what page cache uses, but GFP_RECLAIM_MASK is now what's needed. Link: https://bugzilla.kernel.org/show_bug.cgi?id=208085 Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2006151330070.11064@eggly.anvils Fixes: 68da9f055755 ("tmpfs: pass gfp to shmem_getpage_gfp") Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reported-by: Chris Murphy <lists@colorremedies.com> Analyzed-by: Vlastimil Babka <vbabka@suse.cz> Analyzed-by: Matthew Wilcox <willy@infradead.org> Tested-by: Chris Murphy <lists@colorremedies.com> Cc: <stable@vger.kernel.org> [3.1+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> |
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Muchun Song
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6f9ef1b629 |
mm/memcontrol.c: add missed css_put()
commit 3a98990ae2150277ed34d3b248c60e68bf2244b2 upstream. We should put the css reference when memory allocation failed. Link: http://lkml.kernel.org/r/20200614122653.98829-1-songmuchun@bytedance.com Fixes: f0a3a24b532d ("mm: memcg/slab: rework non-root kmem_cache lifecycle management") Signed-off-by: Muchun Song <songmuchun@bytedance.com> Acked-by: Roman Gushchin <guro@fb.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Qian Cai <cai@lca.pw> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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Waiman Long
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89f04d21fd |
mm/slab: use memzero_explicit() in kzfree()
commit 8982ae527fbef170ef298650c15d55a9ccd33973 upstream. The kzfree() function is normally used to clear some sensitive information, like encryption keys, in the buffer before freeing it back to the pool. Memset() is currently used for buffer clearing. However unlikely, there is still a non-zero probability that the compiler may choose to optimize away the memory clearing especially if LTO is being used in the future. To make sure that this optimization will never happen, memzero_explicit(), which is introduced in v3.18, is now used in kzfree() to future-proof it. Link: http://lkml.kernel.org/r/20200616154311.12314-2-longman@redhat.com Fixes: 3ef0e5ba4673 ("slab: introduce kzfree()") Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: David Howells <dhowells@redhat.com> Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Cc: James Morris <jmorris@namei.org> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Joe Perches <joe@perches.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: David Rientjes <rientjes@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: "Jason A . Donenfeld" <Jason@zx2c4.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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Pavel Tatashin
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5af0003729 |
mm: call cond_resched() from deferred_init_memmap()
commit da97f2d56bbd880b4138916a7ef96f9881a551b2 upstream. Now that deferred pages are initialized with interrupts enabled we can replace touch_nmi_watchdog() with cond_resched(), as it was before 3a2d7fa8a3d5. For now, we cannot do the same in deferred_grow_zone() as it is still initializes pages with interrupts disabled. This change fixes RCU problem described in https://lkml.kernel.org/r/20200401104156.11564-2-david@redhat.com [ 60.474005] rcu: INFO: rcu_sched detected stalls on CPUs/tasks: [ 60.475000] rcu: 1-...0: (0 ticks this GP) idle=02a/1/0x4000000000000000 softirq=1/1 fqs=15000 [ 60.475000] rcu: (detected by 0, t=60002 jiffies, g=-1199, q=1) [ 60.475000] Sending NMI from CPU 0 to CPUs 1: [ 1.760091] NMI backtrace for cpu 1 [ 1.760091] CPU: 1 PID: 20 Comm: pgdatinit0 Not tainted 4.18.0-147.9.1.el8_1.x86_64 #1 [ 1.760091] Hardware name: Red Hat KVM, BIOS 1.13.0-1.module+el8.2.0+5520+4e5817f3 04/01/2014 [ 1.760091] RIP: 0010:__init_single_page.isra.65+0x10/0x4f [ 1.760091] Code: 48 83 cf 63 48 89 f8 0f 1f 40 00 48 89 c6 48 89 d7 e8 6b 18 80 ff 66 90 5b c3 31 c0 b9 10 00 00 00 49 89 f8 48 c1 e6 33 f3 ab <b8> 07 00 00 00 48 c1 e2 36 41 c7 40 34 01 00 00 00 48 c1 e0 33 41 [ 1.760091] RSP: 0000:ffffba783123be40 EFLAGS: 00000006 [ 1.760091] RAX: 0000000000000000 RBX: fffffad34405e300 RCX: 0000000000000000 [ 1.760091] RDX: 0000000000000000 RSI: 0010000000000000 RDI: fffffad34405e340 [ 1.760091] RBP: 0000000033f3177e R08: fffffad34405e300 R09: 0000000000000002 [ 1.760091] R10: 000000000000002b R11: ffff98afb691a500 R12: 0000000000000002 [ 1.760091] R13: 0000000000000000 R14: 000000003f03ea00 R15: 000000003e10178c [ 1.760091] FS: 0000000000000000(0000) GS:ffff9c9ebeb00000(0000) knlGS:0000000000000000 [ 1.760091] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1.760091] CR2: 00000000ffffffff CR3: 000000a1cf20a001 CR4: 00000000003606e0 [ 1.760091] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1.760091] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 1.760091] Call Trace: [ 1.760091] deferred_init_pages+0x8f/0xbf [ 1.760091] deferred_init_memmap+0x184/0x29d [ 1.760091] ? deferred_free_pages.isra.97+0xba/0xba [ 1.760091] kthread+0x112/0x130 [ 1.760091] ? kthread_flush_work_fn+0x10/0x10 [ 1.760091] ret_from_fork+0x35/0x40 [ 89.123011] node 0 initialised, 1055935372 pages in 88650ms Fixes: 3a2d7fa8a3d5 ("mm: disable interrupts while initializing deferred pages") Reported-by: Yiqian Wei <yiwei@redhat.com> Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: David Hildenbrand <david@redhat.com> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: James Morris <jmorris@namei.org> Cc: Kirill Tkhai <ktkhai@virtuozzo.com> Cc: Sasha Levin <sashal@kernel.org> Cc: Shile Zhang <shile.zhang@linux.alibaba.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: <stable@vger.kernel.org> [4.17+] Link: http://lkml.kernel.org/r/20200403140952.17177-4-pasha.tatashin@soleen.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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Daniel Jordan
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5429516b59 |
mm/pagealloc.c: call touch_nmi_watchdog() on max order boundaries in deferred init
commit 117003c32771df617acf66e140fbdbdeb0ac71f5 upstream. Patch series "initialize deferred pages with interrupts enabled", v4. Keep interrupts enabled during deferred page initialization in order to make code more modular and allow jiffies to update. Original approach, and discussion can be found here: http://lkml.kernel.org/r/20200311123848.118638-1-shile.zhang@linux.alibaba.com This patch (of 3): deferred_init_memmap() disables interrupts the entire time, so it calls touch_nmi_watchdog() periodically to avoid soft lockup splats. Soon it will run with interrupts enabled, at which point cond_resched() should be used instead. deferred_grow_zone() makes the same watchdog calls through code shared with deferred init but will continue to run with interrupts disabled, so it can't call cond_resched(). Pull the watchdog calls up to these two places to allow the first to be changed later, independently of the second. The frequency reduces from twice per pageblock (init and free) to once per max order block. Fixes: 3a2d7fa8a3d5 ("mm: disable interrupts while initializing deferred pages") Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com> Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Shile Zhang <shile.zhang@linux.alibaba.com> Cc: Kirill Tkhai <ktkhai@virtuozzo.com> Cc: James Morris <jmorris@namei.org> Cc: Sasha Levin <sashal@kernel.org> Cc: Yiqian Wei <yiwei@redhat.com> Cc: <stable@vger.kernel.org> [4.17+] Link: http://lkml.kernel.org/r/20200403140952.17177-2-pasha.tatashin@soleen.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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Pavel Tatashin
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a879380595 |
mm: initialize deferred pages with interrupts enabled
commit 3d060856adfc59afb9d029c233141334cfaba418 upstream. Initializing struct pages is a long task and keeping interrupts disabled for the duration of this operation introduces a number of problems. 1. jiffies are not updated for long period of time, and thus incorrect time is reported. See proposed solution and discussion here: lkml/20200311123848.118638-1-shile.zhang@linux.alibaba.com 2. It prevents farther improving deferred page initialization by allowing intra-node multi-threading. We are keeping interrupts disabled to solve a rather theoretical problem that was never observed in real world (See 3a2d7fa8a3d5). Let's keep interrupts enabled. In case we ever encounter a scenario where an interrupt thread wants to allocate large amount of memory this early in boot we can deal with that by growing zone (see deferred_grow_zone()) by the needed amount before starting deferred_init_memmap() threads. Before: [ 1.232459] node 0 initialised, 12058412 pages in 1ms After: [ 1.632580] node 0 initialised, 12051227 pages in 436ms Fixes: 3a2d7fa8a3d5 ("mm: disable interrupts while initializing deferred pages") Reported-by: Shile Zhang <shile.zhang@linux.alibaba.com> Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Dan Williams <dan.j.williams@intel.com> Cc: James Morris <jmorris@namei.org> Cc: Kirill Tkhai <ktkhai@virtuozzo.com> Cc: Sasha Levin <sashal@kernel.org> Cc: Yiqian Wei <yiwei@redhat.com> Cc: <stable@vger.kernel.org> [4.17+] Link: http://lkml.kernel.org/r/20200403140952.17177-3-pasha.tatashin@soleen.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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Andrea Arcangeli
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2c7404efeb |
mm: thp: make the THP mapcount atomic against __split_huge_pmd_locked()
commit c444eb564fb16645c172d550359cb3d75fe8a040 upstream.
Write protect anon page faults require an accurate mapcount to decide
if to break the COW or not. This is implemented in the THP path with
reuse_swap_page() ->
page_trans_huge_map_swapcount()/page_trans_huge_mapcount().
If the COW triggers while the other processes sharing the page are
under a huge pmd split, to do an accurate reading, we must ensure the
mapcount isn't computed while it's being transferred from the head
page to the tail pages.
reuse_swap_cache() already runs serialized by the page lock, so it's
enough to add the page lock around __split_huge_pmd_locked too, in
order to add the missing serialization.
Note: the commit in "Fixes" is just to facilitate the backporting,
because the code before such commit didn't try to do an accurate THP
mapcount calculation and it instead used the page_count() to decide if
to COW or not. Both the page_count and the pin_count are THP-wide
refcounts, so they're inaccurate if used in
reuse_swap_page(). Reverting such commit (besides the unrelated fix to
the local anon_vma assignment) would have also opened the window for
memory corruption side effects to certain workloads as documented in
such commit header.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Suggested-by: Jann Horn <jannh@google.com>
Reported-by: Jann Horn <jannh@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Fixes: 6d0a07edd17c ("mm: thp: calculate the mapcount correctly for THP pages during WP faults")
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Wang Hai
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8c79aa7ddd |
mm/slub: fix a memory leak in sysfs_slab_add()
commit dde3c6b72a16c2db826f54b2d49bdea26c3534a2 upstream.
syzkaller reports for memory leak when kobject_init_and_add() returns an
error in the function sysfs_slab_add() [1]
When this happened, the function kobject_put() is not called for the
corresponding kobject, which potentially leads to memory leak.
This patch fixes the issue by calling kobject_put() even if
kobject_init_and_add() fails.
[1]
BUG: memory leak
unreferenced object 0xffff8880a6d4be88 (size 8):
comm "syz-executor.3", pid 946, jiffies 4295772514 (age 18.396s)
hex dump (first 8 bytes):
70 69 64 5f 33 00 ff ff pid_3...
backtrace:
kstrdup+0x35/0x70 mm/util.c:60
kstrdup_const+0x3d/0x50 mm/util.c:82
kvasprintf_const+0x112/0x170 lib/kasprintf.c:48
kobject_set_name_vargs+0x55/0x130 lib/kobject.c:289
kobject_add_varg lib/kobject.c:384 [inline]
kobject_init_and_add+0xd8/0x170 lib/kobject.c:473
sysfs_slab_add+0x1d8/0x290 mm/slub.c:5811
__kmem_cache_create+0x50a/0x570 mm/slub.c:4384
create_cache+0x113/0x1e0 mm/slab_common.c:407
kmem_cache_create_usercopy+0x1a1/0x260 mm/slab_common.c:505
kmem_cache_create+0xd/0x10 mm/slab_common.c:564
create_pid_cachep kernel/pid_namespace.c:54 [inline]
create_pid_namespace kernel/pid_namespace.c:96 [inline]
copy_pid_ns+0x77c/0x8f0 kernel/pid_namespace.c:148
create_new_namespaces+0x26b/0xa30 kernel/nsproxy.c:95
unshare_nsproxy_namespaces+0xa7/0x1e0 kernel/nsproxy.c:229
ksys_unshare+0x3d2/0x770 kernel/fork.c:2969
__do_sys_unshare kernel/fork.c:3037 [inline]
__se_sys_unshare kernel/fork.c:3035 [inline]
__x64_sys_unshare+0x2d/0x40 kernel/fork.c:3035
do_syscall_64+0xa1/0x530 arch/x86/entry/common.c:295
Fixes: 80da026a8e5d ("mm/slub: fix slab double-free in case of duplicate sysfs filename")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Link: http://lkml.kernel.org/r/20200602115033.1054-1-wanghai38@huawei.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Linus Torvalds
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c3716ee115 |
gup: document and work around "COW can break either way" issue
commit 17839856fd588f4ab6b789f482ed3ffd7c403e1f upstream. Doing a "get_user_pages()" on a copy-on-write page for reading can be ambiguous: the page can be COW'ed at any time afterwards, and the direction of a COW event isn't defined. Yes, whoever writes to it will generally do the COW, but if the thread that did the get_user_pages() unmapped the page before the write (and that could happen due to memory pressure in addition to any outright action), the writer could also just take over the old page instead. End result: the get_user_pages() call might result in a page pointer that is no longer associated with the original VM, and is associated with - and controlled by - another VM having taken it over instead. So when doing a get_user_pages() on a COW mapping, the only really safe thing to do would be to break the COW when getting the page, even when only getting it for reading. At the same time, some users simply don't even care. For example, the perf code wants to look up the page not because it cares about the page, but because the code simply wants to look up the physical address of the access for informational purposes, and doesn't really care about races when a page might be unmapped and remapped elsewhere. This adds logic to force a COW event by setting FOLL_WRITE on any copy-on-write mapping when FOLL_GET (or FOLL_PIN) is used to get a page pointer as a result. The current semantics end up being: - __get_user_pages_fast(): no change. If you don't ask for a write, you won't break COW. You'd better know what you're doing. - get_user_pages_fast(): the fast-case "look it up in the page tables without anything getting mmap_sem" now refuses to follow a read-only page, since it might need COW breaking. Which happens in the slow path - the fast path doesn't know if the memory might be COW or not. - get_user_pages() (including the slow-path fallback for gup_fast()): for a COW mapping, turn on FOLL_WRITE for FOLL_GET/FOLL_PIN, with very similar semantics to FOLL_FORCE. If it turns out that we want finer granularity (ie "only break COW when it might actually matter" - things like the zero page are special and don't need to be broken) we might need to push these semantics deeper into the lookup fault path. So if people care enough, it's possible that we might end up adding a new internal FOLL_BREAK_COW flag to go with the internal FOLL_COW flag we already have for tracking "I had a COW". Alternatively, if it turns out that different callers might want to explicitly control the forced COW break behavior, we might even want to make such a flag visible to the users of get_user_pages() instead of using the above default semantics. But for now, this is mostly commentary on the issue (this commit message being a lot bigger than the patch, and that patch in turn is almost all comments), with that minimal "enable COW breaking early" logic using the existing FOLL_WRITE behavior. [ It might be worth noting that we've always had this ambiguity, and it could arguably be seen as a user-space issue. You only get private COW mappings that could break either way in situations where user space is doing cooperative things (ie fork() before an execve() etc), but it _is_ surprising and very subtle, and fork() is supposed to give you independent address spaces. So let's treat this as a kernel issue and make the semantics of get_user_pages() easier to understand. Note that obviously a true shared mapping will still get a page that can change under us, so this does _not_ mean that get_user_pages() somehow returns any "stable" page ] Reported-by: Jann Horn <jannh@google.com> Tested-by: Christoph Hellwig <hch@lst.de> Acked-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Kirill Shutemov <kirill@shutemov.name> Acked-by: Jan Kara <jack@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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Waiman Long
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7d2aff3c84 |
mm: add kvfree_sensitive() for freeing sensitive data objects
[ Upstream commit d4eaa2837851db2bfed572898bfc17f9a9f9151e ]
For kvmalloc'ed data object that contains sensitive information like
cryptographic keys, we need to make sure that the buffer is always cleared
before freeing it. Using memset() alone for buffer clearing may not
provide certainty as the compiler may compile it away. To be sure, the
special memzero_explicit() has to be used.
This patch introduces a new kvfree_sensitive() for freeing those sensitive
data objects allocated by kvmalloc(). The relevant places where
kvfree_sensitive() can be used are modified to use it.
Fixes: 4f0882491a14 ("KEYS: Avoid false positive ENOMEM error on key read")
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Acked-by: David Howells <dhowells@redhat.com>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Joe Perches <joe@perches.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Uladzislau Rezki <urezki@gmail.com>
Link: http://lkml.kernel.org/r/20200407200318.11711-1-longman@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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Fan Yang
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2265af95d6 |
mm: Fix mremap not considering huge pmd devmap
commit 5bfea2d9b17f1034a68147a8b03b9789af5700f9 upstream.
The original code in mm/mremap.c checks huge pmd by:
if (is_swap_pmd(*old_pmd) || pmd_trans_huge(*old_pmd)) {
However, a DAX mapped nvdimm is mapped as huge page (by default) but it
is not transparent huge page (_PAGE_PSE | PAGE_DEVMAP). This commit
changes the condition to include the case.
This addresses CVE-2020-10757.
Fixes: 5c7fb56e5e3f ("mm, dax: dax-pmd vs thp-pmd vs hugetlbfs-pmd")
Cc: <stable@vger.kernel.org>
Reported-by: Fan Yang <Fan_Yang@sjtu.edu.cn>
Signed-off-by: Fan Yang <Fan_Yang@sjtu.edu.cn>
Tested-by: Fan Yang <Fan_Yang@sjtu.edu.cn>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Hugh Dickins
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d968711433 |
mm,thp: stop leaking unreleased file pages
[ Upstream commit 2f33a706027c94cd4f70fcd3e3f4a17c1ce4ea4b ]
When collapse_file() calls try_to_release_page(), it has already isolated
the page: so if releasing buffers happens to fail (as it sometimes does),
remember to putback_lru_page(): otherwise that page is left unreclaimable
and unfreeable, and the file extent uncollapsible.
Fixes: 99cb0dbd47a1 ("mm,thp: add read-only THP support for (non-shmem) FS")
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: <stable@vger.kernel.org> [5.4+]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2005231837500.1766@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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Marco Elver
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4b81a5e589 |
kasan: disable branch tracing for core runtime
commit 33cd65e73abd693c00c4156cf23677c453b41b3b upstream. During early boot, while KASAN is not yet initialized, it is possible to enter reporting code-path and end up in kasan_report(). While uninitialized, the branch there prevents generating any reports, however, under certain circumstances when branches are being traced (TRACE_BRANCH_PROFILING), we may recurse deep enough to cause kernel reboots without warning. To prevent similar issues in future, we should disable branch tracing for the core runtime. [elver@google.com: remove duplicate DISABLE_BRANCH_PROFILING, per Qian Cai] Link: https://lore.kernel.org/lkml/20200517011732.GE24705@shao2-debian/ Link: http://lkml.kernel.org/r/20200522075207.157349-1-elver@google.com Reported-by: kernel test robot <rong.a.chen@intel.com> Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrey Konovalov <andreyknvl@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Qian Cai <cai@lca.pw> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r//20200517011732.GE24705@shao2-debian/ Link: http://lkml.kernel.org/r/20200519182459.87166-1-elver@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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Hugh Dickins
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a3e5fd1c0e |
shmem: fix possible deadlocks on shmlock_user_lock
[ Upstream commit ea0dfeb4209b4eab954d6e00ed136bc6b48b380d ]
Recent commit 71725ed10c40 ("mm: huge tmpfs: try to split_huge_page()
when punching hole") has allowed syzkaller to probe deeper, uncovering a
long-standing lockdep issue between the irq-unsafe shmlock_user_lock,
the irq-safe xa_lock on mapping->i_pages, and shmem inode's info->lock
which nests inside xa_lock (or tree_lock) since 4.8's shmem_uncharge().
user_shm_lock(), servicing SysV shmctl(SHM_LOCK), wants
shmlock_user_lock while its caller shmem_lock() holds info->lock with
interrupts disabled; but hugetlbfs_file_setup() calls user_shm_lock()
with interrupts enabled, and might be interrupted by a writeback endio
wanting xa_lock on i_pages.
This may not risk an actual deadlock, since shmem inodes do not take
part in writeback accounting, but there are several easy ways to avoid
it.
Requiring interrupts disabled for shmlock_user_lock would be easy, but
it's a high-level global lock for which that seems inappropriate.
Instead, recall that the use of info->lock to guard info->flags in
shmem_lock() dates from pre-3.1 days, when races with SHMEM_PAGEIN and
SHMEM_TRUNCATE could occur: nowadays it serves no purpose, the only flag
added or removed is VM_LOCKED itself, and calls to shmem_lock() an inode
are already serialized by the caller.
Take info->lock out of the chain and the possibility of deadlock or
lockdep warning goes away.
Fixes: 4595ef88d136 ("shmem: make shmem_inode_info::lock irq-safe")
Reported-by: syzbot+c8a8197c8852f566b9d9@syzkaller.appspotmail.com
Reported-by: syzbot+40b71e145e73f78f81ad@syzkaller.appspotmail.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Yang Shi <yang.shi@linux.alibaba.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2004161707410.16322@eggly.anvils
Link: https://lore.kernel.org/lkml/000000000000e5838c05a3152f53@google.com/
Link: https://lore.kernel.org/lkml/0000000000003712b305a331d3b1@google.com/
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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Christoph Hellwig
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675699b41c |
bdi: add a ->dev_name field to struct backing_dev_info
[ Upstream commit 6bd87eec23cbc9ed222bed0f5b5b02bf300e9a8d ]
Cache a copy of the name for the life time of the backing_dev_info
structure so that we can reference it even after unregistering.
Fixes: 68f23b89067f ("memcg: fix a crash in wb_workfn when a device disappears")
Reported-by: Yufen Yu <yuyufen@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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Christoph Hellwig
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6dfbba543a |
bdi: move bdi_dev_name out of line
[ Upstream commit eb7ae5e06bb6e6ac6bb86872d27c43ebab92f6b2 ] bdi_dev_name is not a fast path function, move it out of line. This prepares for using it from modular callers without having to export an implementation detail like bdi_unknown_name. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org> |
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Yafang Shao
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b94c3f871e |
mm, memcg: fix error return value of mem_cgroup_css_alloc()
commit 11d6761218d19ca06ae5387f4e3692c4fa9e7493 upstream.
When I run my memcg testcase which creates lots of memcgs, I found
there're unexpected out of memory logs while there're still enough
available free memory. The error log is
mkdir: cannot create directory 'foo.65533': Cannot allocate memory
The reason is when we try to create more than MEM_CGROUP_ID_MAX memcgs,
an -ENOMEM errno will be set by mem_cgroup_css_alloc(), but the right
errno should be -ENOSPC "No space left on device", which is an
appropriate errno for userspace's failed mkdir.
As the errno really misled me, we should make it right. After this
patch, the error log will be
mkdir: cannot create directory 'foo.65533': No space left on device
[akpm@linux-foundation.org: s/EBUSY/ENOSPC/, per Michal]
[akpm@linux-foundation.org: s/EBUSY/ENOSPC/, per Michal]
Fixes: 73f576c04b94 ("mm: memcontrol: fix cgroup creation failure after many small jobs")
Suggested-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Link: http://lkml.kernel.org/r/20200407063621.GA18914@dhcp22.suse.cz
Link: http://lkml.kernel.org/r/1586192163-20099-1-git-send-email-laoar.shao@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Henry Willard
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84b31950b5 |
mm: limit boost_watermark on small zones
commit 14f69140ff9c92a0928547ceefb153a842e8492c upstream.
Commit 1c30844d2dfe ("mm: reclaim small amounts of memory when an
external fragmentation event occurs") adds a boost_watermark() function
which increases the min watermark in a zone by at least
pageblock_nr_pages or the number of pages in a page block.
On Arm64, with 64K pages and 512M huge pages, this is 8192 pages or
512M. It does this regardless of the number of managed pages managed in
the zone or the likelihood of success.
This can put the zone immediately under water in terms of allocating
pages from the zone, and can cause a small machine to fail immediately
due to OoM. Unlike set_recommended_min_free_kbytes(), which
substantially increases min_free_kbytes and is tied to THP,
boost_watermark() can be called even if THP is not active.
The problem is most likely to appear on architectures such as Arm64
where pageblock_nr_pages is very large.
It is desirable to run the kdump capture kernel in as small a space as
possible to avoid wasting memory. In some architectures, such as Arm64,
there are restrictions on where the capture kernel can run, and
therefore, the space available. A capture kernel running in 768M can
fail due to OoM immediately after boost_watermark() sets the min in zone
DMA32, where most of the memory is, to 512M. It fails even though there
is over 500M of free memory. With boost_watermark() suppressed, the
capture kernel can run successfully in 448M.
This patch limits boost_watermark() to boosting a zone's min watermark
only when there are enough pages that the boost will produce positive
results. In this case that is estimated to be four times as many pages
as pageblock_nr_pages.
Mel said:
: There is no harm in marking it stable. Clearly it does not happen very
: often but it's not impossible. 32-bit x86 is a lot less common now
: which would previously have been vulnerable to triggering this easily.
: ppc64 has a larger base page size but typically only has one zone.
: arm64 is likely the most vulnerable, particularly when CMA is
: configured with a small movable zone.
Fixes: 1c30844d2dfe ("mm: reclaim small amounts of memory when an external fragmentation event occurs")
Signed-off-by: Henry Willard <henry.willard@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/1588294148-6586-1-git-send-email-henry.willard@oracle.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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David Hildenbrand
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bbfa997230 |
mm/page_alloc: fix watchdog soft lockups during set_zone_contiguous()
commit e84fe99b68ce353c37ceeecc95dce9696c976556 upstream. Without CONFIG_PREEMPT, it can happen that we get soft lockups detected, e.g., while booting up. watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [swapper/0:1] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.6.0-next-20200331+ #4 Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014 RIP: __pageblock_pfn_to_page+0x134/0x1c0 Call Trace: set_zone_contiguous+0x56/0x70 page_alloc_init_late+0x166/0x176 kernel_init_freeable+0xfa/0x255 kernel_init+0xa/0x106 ret_from_fork+0x35/0x40 The issue becomes visible when having a lot of memory (e.g., 4TB) assigned to a single NUMA node - a system that can easily be created using QEMU. Inside VMs on a hypervisor with quite some memory overcommit, this is fairly easy to trigger. Signed-off-by: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Reviewed-by: Baoquan He <bhe@redhat.com> Reviewed-by: Shile Zhang <shile.zhang@linux.alibaba.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Kirill Tkhai <ktkhai@virtuozzo.com> Cc: Shile Zhang <shile.zhang@linux.alibaba.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Alexander Duyck <alexander.duyck@gmail.com> Cc: Baoquan He <bhe@redhat.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/20200416073417.5003-1-david@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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Will Deacon
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dbb9c5c9fe |
mm/mremap: Add comment explaining the untagging behaviour of mremap()
commit b2a84de2a2deb76a6a51609845341f508c518c03 upstream.
Commit dcde237319e6 ("mm: Avoid creating virtual address aliases in
brk()/mmap()/mremap()") changed mremap() so that only the 'old' address
is untagged, leaving the 'new' address in the form it was passed from
userspace. This prevents the unexpected creation of aliasing virtual
mappings in userspace, but looks a bit odd when you read the code.
Add a comment justifying the untagging behaviour in mremap().
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Yang Shi
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5cb1d7573c |
mm: shmem: disable interrupt when acquiring info->lock in userfaultfd_copy path
commit 94b7cc01da5a3cc4f3da5e0ff492ef008bb555d6 upstream.
Syzbot reported the below lockdep splat:
WARNING: possible irq lock inversion dependency detected
5.6.0-rc7-syzkaller #0 Not tainted
--------------------------------------------------------
syz-executor.0/10317 just changed the state of lock:
ffff888021d16568 (&(&info->lock)->rlock){+.+.}, at: spin_lock include/linux/spinlock.h:338 [inline]
ffff888021d16568 (&(&info->lock)->rlock){+.+.}, at: shmem_mfill_atomic_pte+0x1012/0x21c0 mm/shmem.c:2407
but this lock was taken by another, SOFTIRQ-safe lock in the past:
(&(&xa->xa_lock)->rlock#5){..-.}
and interrupts could create inverse lock ordering between them.
other info that might help us debug this:
Possible interrupt unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&(&info->lock)->rlock);
local_irq_disable();
lock(&(&xa->xa_lock)->rlock#5);
lock(&(&info->lock)->rlock);
<Interrupt>
lock(&(&xa->xa_lock)->rlock#5);
*** DEADLOCK ***
The full report is quite lengthy, please see:
https://lore.kernel.org/linux-mm/alpine.LSU.2.11.2004152007370.13597@eggly.anvils/T/#m813b412c5f78e25ca8c6c7734886ed4de43f241d
It is because CPU 0 held info->lock with IRQ enabled in userfaultfd_copy
path, then CPU 1 is splitting a THP which held xa_lock and info->lock in
IRQ disabled context at the same time. If softirq comes in to acquire
xa_lock, the deadlock would be triggered.
The fix is to acquire/release info->lock with *_irq version instead of
plain spin_{lock,unlock} to make it softirq safe.
Fixes: 4c27fe4c4c84 ("userfaultfd: shmem: add shmem_mcopy_atomic_pte for userfaultfd support")
Reported-by: syzbot+e27980339d305f2dbfd9@syzkaller.appspotmail.com
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: syzbot+e27980339d305f2dbfd9@syzkaller.appspotmail.com
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Link: http://lkml.kernel.org/r/1587061357-122619-1-git-send-email-yang.shi@linux.alibaba.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Muchun Song
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88cecc0a1e |
mm/ksm: fix NULL pointer dereference when KSM zero page is enabled
commit 56df70a63ed5d989c1d36deee94cae14342be6e9 upstream.
find_mergeable_vma() can return NULL. In this case, it leads to a crash
when we access vm_mm(its offset is 0x40) later in write_protect_page.
And this case did happen on our server. The following call trace is
captured in kernel 4.19 with the following patch applied and KSM zero
page enabled on our server.
commit e86c59b1b12d ("mm/ksm: improve deduplication of zero pages with colouring")
So add a vma check to fix it.
BUG: unable to handle kernel NULL pointer dereference at 0000000000000040
Oops: 0000 [#1] SMP NOPTI
CPU: 9 PID: 510 Comm: ksmd Kdump: loaded Tainted: G OE 4.19.36.bsk.9-amd64 #4.19.36.bsk.9
RIP: try_to_merge_one_page+0xc7/0x760
Code: 24 58 65 48 33 34 25 28 00 00 00 89 e8 0f 85 a3 06 00 00 48 83 c4
60 5b 5d 41 5c 41 5d 41 5e 41 5f c3 48 8b 46 08 a8 01 75 b8 <49>
8b 44 24 40 4c 8d 7c 24 20 b9 07 00 00 00 4c 89 e6 4c 89 ff 48
RSP: 0018:ffffadbdd9fffdb0 EFLAGS: 00010246
RAX: ffffda83ffd4be08 RBX: ffffda83ffd4be40 RCX: 0000002c6e800000
RDX: 0000000000000000 RSI: ffffda83ffd4be40 RDI: 0000000000000000
RBP: ffffa11939f02ec0 R08: 0000000094e1a447 R09: 00000000abe76577
R10: 0000000000000962 R11: 0000000000004e6a R12: 0000000000000000
R13: ffffda83b1e06380 R14: ffffa18f31f072c0 R15: ffffda83ffd4be40
FS: 0000000000000000(0000) GS:ffffa0da43b80000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000040 CR3: 0000002c77c0a003 CR4: 00000000007626e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
ksm_scan_thread+0x115e/0x1960
kthread+0xf5/0x130
ret_from_fork+0x1f/0x30
[songmuchun@bytedance.com: if the vma is out of date, just exit]
Link: http://lkml.kernel.org/r/20200416025034.29780-1-songmuchun@bytedance.com
[akpm@linux-foundation.org: add the conventional braces, replace /** with /*]
Fixes: e86c59b1b12d ("mm/ksm: improve deduplication of zero pages with colouring")
Co-developed-by: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Cc: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com>
Cc: Markus Elfring <Markus.Elfring@web.de>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200416025034.29780-1-songmuchun@bytedance.com
Link: http://lkml.kernel.org/r/20200414132905.83819-1-songmuchun@bytedance.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Longpeng
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256a1a578c |
mm/hugetlb: fix a addressing exception caused by huge_pte_offset
commit 3c1d7e6ccb644d517a12f73a7ff200870926f865 upstream.
Our machine encountered a panic(addressing exception) after run for a
long time and the calltrace is:
RIP: hugetlb_fault+0x307/0xbe0
RSP: 0018:ffff9567fc27f808 EFLAGS: 00010286
RAX: e800c03ff1258d48 RBX: ffffd3bb003b69c0 RCX: e800c03ff1258d48
RDX: 17ff3fc00eda72b7 RSI: 00003ffffffff000 RDI: e800c03ff1258d48
RBP: ffff9567fc27f8c8 R08: e800c03ff1258d48 R09: 0000000000000080
R10: ffffaba0704c22a8 R11: 0000000000000001 R12: ffff95c87b4b60d8
R13: 00005fff00000000 R14: 0000000000000000 R15: ffff9567face8074
FS: 00007fe2d9ffb700(0000) GS:ffff956900e40000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffd3bb003b69c0 CR3: 000000be67374000 CR4: 00000000003627e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
follow_hugetlb_page+0x175/0x540
__get_user_pages+0x2a0/0x7e0
__get_user_pages_unlocked+0x15d/0x210
__gfn_to_pfn_memslot+0x3c5/0x460 [kvm]
try_async_pf+0x6e/0x2a0 [kvm]
tdp_page_fault+0x151/0x2d0 [kvm]
...
kvm_arch_vcpu_ioctl_run+0x330/0x490 [kvm]
kvm_vcpu_ioctl+0x309/0x6d0 [kvm]
do_vfs_ioctl+0x3f0/0x540
SyS_ioctl+0xa1/0xc0
system_call_fastpath+0x22/0x27
For 1G hugepages, huge_pte_offset() wants to return NULL or pudp, but it
may return a wrong 'pmdp' if there is a race. Please look at the
following code snippet:
...
pud = pud_offset(p4d, addr);
if (sz != PUD_SIZE && pud_none(*pud))
return NULL;
/* hugepage or swap? */
if (pud_huge(*pud) || !pud_present(*pud))
return (pte_t *)pud;
pmd = pmd_offset(pud, addr);
if (sz != PMD_SIZE && pmd_none(*pmd))
return NULL;
/* hugepage or swap? */
if (pmd_huge(*pmd) || !pmd_present(*pmd))
return (pte_t *)pmd;
...
The following sequence would trigger this bug:
- CPU0: sz = PUD_SIZE and *pud = 0 , continue
- CPU0: "pud_huge(*pud)" is false
- CPU1: calling hugetlb_no_page and set *pud to xxxx8e7(PRESENT)
- CPU0: "!pud_present(*pud)" is false, continue
- CPU0: pmd = pmd_offset(pud, addr) and maybe return a wrong pmdp
However, we want CPU0 to return NULL or pudp in this case.
We must make sure there is exactly one dereference of pud and pmd.
Signed-off-by: Longpeng <longpeng2@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200413010342.771-1-longpeng2@huawei.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Jann Horn
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1fc21228dc |
vmalloc: fix remap_vmalloc_range() bounds checks
commit bdebd6a2831b6fab69eb85cee74a8ba77f1a1cc2 upstream.
remap_vmalloc_range() has had various issues with the bounds checks it
promises to perform ("This function checks that addr is a valid
vmalloc'ed area, and that it is big enough to cover the vma") over time,
e.g.:
- not detecting pgoff<<PAGE_SHIFT overflow
- not detecting (pgoff<<PAGE_SHIFT)+usize overflow
- not checking whether addr and addr+(pgoff<<PAGE_SHIFT) are the same
vmalloc allocation
- comparing a potentially wildly out-of-bounds pointer with the end of
the vmalloc region
In particular, since commit fc9702273e2e ("bpf: Add mmap() support for
BPF_MAP_TYPE_ARRAY"), unprivileged users can cause kernel null pointer
dereferences by calling mmap() on a BPF map with a size that is bigger
than the distance from the start of the BPF map to the end of the
address space.
This could theoretically be used as a kernel ASLR bypass, by using
whether mmap() with a given offset oopses or returns an error code to
perform a binary search over the possible address range.
To allow remap_vmalloc_range_partial() to verify that addr and
addr+(pgoff<<PAGE_SHIFT) are in the same vmalloc region, pass the offset
to remap_vmalloc_range_partial() instead of adding it to the pointer in
remap_vmalloc_range().
In remap_vmalloc_range_partial(), fix the check against
get_vm_area_size() by using size comparisons instead of pointer
comparisons, and add checks for pgoff.
Fixes: 833423143c3a ("[PATCH] mm: introduce remap_vmalloc_range()")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@vger.kernel.org
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: Andrii Nakryiko <andriin@fb.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: KP Singh <kpsingh@chromium.org>
Link: http://lkml.kernel.org/r/20200415222312.236431-1-jannh@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Jakub Kicinski
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0ff473e602 |
mm, memcg: do not high throttle allocators based on wraparound
commit 9b8b17541f13809d06f6f873325305ddbb760e3e upstream.
If a cgroup violates its memory.high constraints, we may end up unduly
penalising it. For example, for the following hierarchy:
A: max high, 20 usage
A/B: 9 high, 10 usage
A/C: max high, 10 usage
We would end up doing the following calculation below when calculating
high delay for A/B:
A/B: 10 - 9 = 1...
A: 20 - PAGE_COUNTER_MAX = 21, so set max_overage to 21.
This gets worse with higher disparities in usage in the parent.
I have no idea how this disappeared from the final version of the patch,
but it is certainly Not Good(tm). This wasn't obvious in testing because,
for a simple cgroup hierarchy with only one child, the result is usually
roughly the same. It's only in more complex hierarchies that things go
really awry (although still, the effects are limited to a maximum of 2
seconds in schedule_timeout_killable at a maximum).
[chris@chrisdown.name: changelog]
Fixes: e26733e0d0ec ("mm, memcg: throttle allocators based on ancestral memory.high")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Chris Down <chris@chrisdown.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: <stable@vger.kernel.org> [5.4.x]
Link: http://lkml.kernel.org/r/20200331152424.GA1019937@chrisdown.name
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Kaixu Xia
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590eaf1fec |
Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces.
Signed-off-by: Kaixu Xia <kaixuxia@tencent.com> |