[ Upstream commit ca0246bb97 ]
Reclaim and free can race on an object which is basically fine but in
order for reclaim to be able to map "freed" object we need to encode
object length in the handle. handle_to_chunks() is then introduced to
extract object length from a handle and use it during mapping.
Moreover, to avoid racing on a z3fold "headless" page release, we should
not try to free that page in z3fold_free() if the reclaim bit is set.
Also, in the unlikely case of trying to reclaim a page being freed, we
should not proceed with that page.
While at it, fix the page accounting in reclaim function.
This patch supersedes "[PATCH] z3fold: fix reclaim lock-ups".
Link: http://lkml.kernel.org/r/20181105162225.74e8837d03583a9b707cf559@gmail.com
Signed-off-by: Vitaly Wool <vitaly.vul@sony.com>
Signed-off-by: Jongseok Kim <ks77sj@gmail.com>
Reported-by-by: Jongseok Kim <ks77sj@gmail.com>
Reviewed-by: Snild Dolkow <snild@sony.com>
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>
commit 61448479a9 upstream.
Slub does not call kmalloc_slab() for sizes > KMALLOC_MAX_CACHE_SIZE,
instead it falls back to kmalloc_large().
For slab KMALLOC_MAX_CACHE_SIZE == KMALLOC_MAX_SIZE and it calls
kmalloc_slab() for all allocations relying on NULL return value for
over-sized allocations.
This inconsistency leads to unwanted warnings from kmalloc_slab() for
over-sized allocations for slab. Returning NULL for failed allocations is
the expected behavior.
Make slub and slab code consistent by checking size >
KMALLOC_MAX_CACHE_SIZE in slab before calling kmalloc_slab().
While we are here also fix the check in kmalloc_slab(). We should check
against KMALLOC_MAX_CACHE_SIZE rather than KMALLOC_MAX_SIZE. It all kinda
worked because for slab the constants are the same, and slub always checks
the size against KMALLOC_MAX_CACHE_SIZE before kmalloc_slab(). But if we
get there with size > KMALLOC_MAX_CACHE_SIZE anyhow bad things will
happen. For example, in case of a newly introduced bug in slub code.
Also move the check in kmalloc_slab() from function entry to the size >
192 case. This partially compensates for the additional check in slab
code and makes slub code a bit faster (at least theoretically).
Also drop __GFP_NOWARN in the warning check. This warning means a bug in
slab code itself, user-passed flags have nothing to do with it.
Nothing of this affects slob.
Link: http://lkml.kernel.org/r/20180927171502.226522-1-dvyukov@gmail.com
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Reported-by: syzbot+87829a10073277282ad1@syzkaller.appspotmail.com
Reported-by: syzbot+ef4e8fc3a06e9019bb40@syzkaller.appspotmail.com
Reported-by: syzbot+6e438f4036df52cbb863@syzkaller.appspotmail.com
Reported-by: syzbot+8574471d8734457d98aa@syzkaller.appspotmail.com
Reported-by: syzbot+af1504df0807a083dbd9@syzkaller.appspotmail.com
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
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>
commit 5e41540c8a upstream.
This bug has been experienced several times by the Oracle DB team. The
BUG is in remove_inode_hugepages() as follows:
/*
* If page is mapped, it was faulted in after being
* unmapped in caller. Unmap (again) now after taking
* the fault mutex. The mutex will prevent faults
* until we finish removing the page.
*
* This race can only happen in the hole punch case.
* Getting here in a truncate operation is a bug.
*/
if (unlikely(page_mapped(page))) {
BUG_ON(truncate_op);
In this case, the elevated map count is not the result of a race.
Rather it was incorrectly incremented as the result of a bug in the huge
pmd sharing code. Consider the following:
- Process A maps a hugetlbfs file of sufficient size and alignment
(PUD_SIZE) that a pmd page could be shared.
- Process B maps the same hugetlbfs file with the same size and
alignment such that a pmd page is shared.
- Process B then calls mprotect() to change protections for the mapping
with the shared pmd. As a result, the pmd is 'unshared'.
- Process B then calls mprotect() again to chage protections for the
mapping back to their original value. pmd remains unshared.
- Process B then forks and process C is created. During the fork
process, we do dup_mm -> dup_mmap -> copy_page_range to copy page
tables. Copying page tables for hugetlb mappings is done in the
routine copy_hugetlb_page_range.
In copy_hugetlb_page_range(), the destination pte is obtained by:
dst_pte = huge_pte_alloc(dst, addr, sz);
If pmd sharing is possible, the returned pointer will be to a pte in an
existing page table. In the situation above, process C could share with
either process A or process B. Since process A is first in the list,
the returned pte is a pointer to a pte in process A's page table.
However, the check for pmd sharing in copy_hugetlb_page_range is:
/* If the pagetables are shared don't copy or take references */
if (dst_pte == src_pte)
continue;
Since process C is sharing with process A instead of process B, the
above test fails. The code in copy_hugetlb_page_range which follows
assumes dst_pte points to a huge_pte_none pte. It copies the pte entry
from src_pte to dst_pte and increments this map count of the associated
page. This is how we end up with an elevated map count.
To solve, check the dst_pte entry for huge_pte_none. If !none, this
implies PMD sharing so do not copy.
Link: http://lkml.kernel.org/r/20181105212315.14125-1-mike.kravetz@oracle.com
Fixes: c5c99429fa ("fix hugepages leak due to pagetable page sharing")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Prakash Sangappa <prakash.sangappa@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ac5b2c1891 upstream.
THP allocation might be really disruptive when allocated on NUMA system
with the local node full or hard to reclaim. Stefan has posted an
allocation stall report on 4.12 based SLES kernel which suggests the
same issue:
kvm: page allocation stalls for 194572ms, order:9, mode:0x4740ca(__GFP_HIGHMEM|__GFP_IO|__GFP_FS|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL|__GFP_THISNODE|__GFP_MOVABLE|__GFP_DIRECT_RECLAIM), nodemask=(null)
kvm cpuset=/ mems_allowed=0-1
CPU: 10 PID: 84752 Comm: kvm Tainted: G W 4.12.0+98-ph <a href="/view.php?id=1" title="[geschlossen] Integration Ramdisk" class="resolved">0000001</a> SLE15 (unreleased)
Hardware name: Supermicro SYS-1029P-WTRT/X11DDW-NT, BIOS 2.0 12/05/2017
Call Trace:
dump_stack+0x5c/0x84
warn_alloc+0xe0/0x180
__alloc_pages_slowpath+0x820/0xc90
__alloc_pages_nodemask+0x1cc/0x210
alloc_pages_vma+0x1e5/0x280
do_huge_pmd_wp_page+0x83f/0xf00
__handle_mm_fault+0x93d/0x1060
handle_mm_fault+0xc6/0x1b0
__do_page_fault+0x230/0x430
do_page_fault+0x2a/0x70
page_fault+0x7b/0x80
[...]
Mem-Info:
active_anon:126315487 inactive_anon:1612476 isolated_anon:5
active_file:60183 inactive_file:245285 isolated_file:0
unevictable:15657 dirty:286 writeback:1 unstable:0
slab_reclaimable:75543 slab_unreclaimable:2509111
mapped:81814 shmem:31764 pagetables:370616 bounce:0
free:32294031 free_pcp:6233 free_cma:0
Node 0 active_anon:254680388kB inactive_anon:1112760kB active_file:240648kB inactive_file:981168kB unevictable:13368kB isolated(anon):0kB isolated(file):0kB mapped:280240kB dirty:1144kB writeback:0kB shmem:95832kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 81225728kB writeback_tmp:0kB unstable:0kB all_unreclaimable? no
Node 1 active_anon:250583072kB inactive_anon:5337144kB active_file:84kB inactive_file:0kB unevictable:49260kB isolated(anon):20kB isolated(file):0kB mapped:47016kB dirty:0kB writeback:4kB shmem:31224kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 31897600kB writeback_tmp:0kB unstable:0kB all_unreclaimable? no
The defrag mode is "madvise" and from the above report it is clear that
the THP has been allocated for MADV_HUGEPAGA vma.
Andrea has identified that the main source of the problem is
__GFP_THISNODE usage:
: The problem is that direct compaction combined with the NUMA
: __GFP_THISNODE logic in mempolicy.c is telling reclaim to swap very
: hard the local node, instead of failing the allocation if there's no
: THP available in the local node.
:
: Such logic was ok until __GFP_THISNODE was added to the THP allocation
: path even with MPOL_DEFAULT.
:
: The idea behind the __GFP_THISNODE addition, is that it is better to
: provide local memory in PAGE_SIZE units than to use remote NUMA THP
: backed memory. That largely depends on the remote latency though, on
: threadrippers for example the overhead is relatively low in my
: experience.
:
: The combination of __GFP_THISNODE and __GFP_DIRECT_RECLAIM results in
: extremely slow qemu startup with vfio, if the VM is larger than the
: size of one host NUMA node. This is because it will try very hard to
: unsuccessfully swapout get_user_pages pinned pages as result of the
: __GFP_THISNODE being set, instead of falling back to PAGE_SIZE
: allocations and instead of trying to allocate THP on other nodes (it
: would be even worse without vfio type1 GUP pins of course, except it'd
: be swapping heavily instead).
Fix this by removing __GFP_THISNODE for THP requests which are
requesting the direct reclaim. This effectivelly reverts 5265047ac3
on the grounds that the zone/node reclaim was known to be disruptive due
to premature reclaim when there was memory free. While it made sense at
the time for HPC workloads without NUMA awareness on rare machines, it
was ultimately harmful in the majority of cases. The existing behaviour
is similar, if not as widespare as it applies to a corner case but
crucially, it cannot be tuned around like zone_reclaim_mode can. The
default behaviour should always be to cause the least harm for the
common case.
If there are specialised use cases out there that want zone_reclaim_mode
in specific cases, then it can be built on top. Longterm we should
consider a memory policy which allows for the node reclaim like behavior
for the specific memory ranges which would allow a
[1] http://lkml.kernel.org/r/20180820032204.9591-1-aarcange@redhat.com
Mel said:
: Both patches look correct to me but I'm responding to this one because
: it's the fix. The change makes sense and moves further away from the
: severe stalling behaviour we used to see with both THP and zone reclaim
: mode.
:
: I put together a basic experiment with usemem configured to reference a
: buffer multiple times that is 80% the size of main memory on a 2-socket
: box with symmetric node sizes and defrag set to "always". The defrag
: setting is not the default but it would be functionally similar to
: accessing a buffer with madvise(MADV_HUGEPAGE). Usemem is configured to
: reference the buffer multiple times and while it's not an interesting
: workload, it would be expected to complete reasonably quickly as it fits
: within memory. The results were;
:
: usemem
: vanilla noreclaim-v1
: Amean Elapsd-1 42.78 ( 0.00%) 26.87 ( 37.18%)
: Amean Elapsd-3 27.55 ( 0.00%) 7.44 ( 73.00%)
: Amean Elapsd-4 5.72 ( 0.00%) 5.69 ( 0.45%)
:
: This shows the elapsed time in seconds for 1 thread, 3 threads and 4
: threads referencing buffers 80% the size of memory. With the patches
: applied, it's 37.18% faster for the single thread and 73% faster with two
: threads. Note that 4 threads showing little difference does not indicate
: the problem is related to thread counts. It's simply the case that 4
: threads gets spread so their workload mostly fits in one node.
:
: The overall view from /proc/vmstats is more startling
:
: 4.19.0-rc1 4.19.0-rc1
: vanillanoreclaim-v1r1
: Minor Faults 35593425 708164
: Major Faults 484088 36
: Swap Ins 3772837 0
: Swap Outs 3932295 0
:
: Massive amounts of swap in/out without the patch
:
: Direct pages scanned 6013214 0
: Kswapd pages scanned 0 0
: Kswapd pages reclaimed 0 0
: Direct pages reclaimed 4033009 0
:
: Lots of reclaim activity without the patch
:
: Kswapd efficiency 100% 100%
: Kswapd velocity 0.000 0.000
: Direct efficiency 67% 100%
: Direct velocity 11191.956 0.000
:
: Mostly from direct reclaim context as you'd expect without the patch.
:
: Page writes by reclaim 3932314.000 0.000
: Page writes file 19 0
: Page writes anon 3932295 0
: Page reclaim immediate 42336 0
:
: Writes from reclaim context is never good but the patch eliminates it.
:
: We should never have default behaviour to thrash the system for such a
: basic workload. If zone reclaim mode behaviour is ever desired but on a
: single task instead of a global basis then the sensible option is to build
: a mempolicy that enforces that behaviour.
This was a severe regression compared to previous kernels that made
important workloads unusable and it starts when __GFP_THISNODE was
added to THP allocations under MADV_HUGEPAGE. It is not a significant
risk to go to the previous behavior before __GFP_THISNODE was added, it
worked like that for years.
This was simply an optimization to some lucky workloads that can fit in
a single node, but it ended up breaking the VM for others that can't
possibly fit in a single node, so going back is safe.
[mhocko@suse.com: rewrote the changelog based on the one from Andrea]
Link: http://lkml.kernel.org/r/20180925120326.24392-2-mhocko@kernel.org
Fixes: 5265047ac3 ("mm, thp: really limit transparent hugepage allocation to local node")
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Stefan Priebe <s.priebe@profihost.ag>
Debugged-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Mel Gorman <mgorman@techsingularity.net>
Tested-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Zi Yan <zi.yan@cs.rutgers.edu>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: <stable@vger.kernel.org> [4.1+]
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>
commit 22146c3ce9 upstream.
Some test systems were experiencing negative huge page reserve counts and
incorrect file block counts. This was traced to /proc/sys/vm/drop_caches
removing clean pages from hugetlbfs file pagecaches. When non-hugetlbfs
explicit code removes the pages, the appropriate accounting is not
performed.
This can be recreated as follows:
fallocate -l 2M /dev/hugepages/foo
echo 1 > /proc/sys/vm/drop_caches
fallocate -l 2M /dev/hugepages/foo
grep -i huge /proc/meminfo
AnonHugePages: 0 kB
ShmemHugePages: 0 kB
HugePages_Total: 2048
HugePages_Free: 2047
HugePages_Rsvd: 18446744073709551615
HugePages_Surp: 0
Hugepagesize: 2048 kB
Hugetlb: 4194304 kB
ls -lsh /dev/hugepages/foo
4.0M -rw-r--r--. 1 root root 2.0M Oct 17 20:05 /dev/hugepages/foo
To address this issue, dirty pages as they are added to pagecache. This
can easily be reproduced with fallocate as shown above. Read faulted
pages will eventually end up being marked dirty. But there is a window
where they are clean and could be impacted by code such as drop_caches.
So, just dirty them all as they are added to the pagecache.
Link: http://lkml.kernel.org/r/b5be45b8-5afe-56cd-9482-28384699a049@oracle.com
Fixes: 6bda666a03 ("hugepages: fold find_or_alloc_pages into huge_no_page()")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Mihcla Hocko <mhocko@suse.com>
Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
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>
commit eb66ae0308 upstream.
Jann Horn points out that our TLB flushing was subtly wrong for the
mremap() case. What makes mremap() special is that we don't follow the
usual "add page to list of pages to be freed, then flush tlb, and then
free pages". No, mremap() obviously just _moves_ the page from one page
table location to another.
That matters, because mremap() thus doesn't directly control the
lifetime of the moved page with a freelist: instead, the lifetime of the
page is controlled by the page table locking, that serializes access to
the entry.
As a result, we need to flush the TLB not just before releasing the lock
for the source location (to avoid any concurrent accesses to the entry),
but also before we release the destination page table lock (to avoid the
TLB being flushed after somebody else has already done something to that
page).
This also makes the whole "need_flush" logic unnecessary, since we now
always end up flushing the TLB for every valid entry.
Reported-and-tested-by: Jann Horn <jannh@google.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Tested-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d79f7aa496 upstream.
Indirectly reclaimable memory can consume a significant part of total
memory and it's actually reclaimable (it will be released under actual
memory pressure).
So, the overcommit logic should treat it as free.
Otherwise, it's possible to cause random system-wide memory allocation
failures by consuming a significant amount of memory by indirectly
reclaimable memory, e.g. dentry external names.
If overcommit policy GUESS is used, it might be used for denial of
service attack under some conditions.
The following program illustrates the approach. It causes the kernel to
allocate an unreclaimable kmalloc-256 chunk for each stat() call, so
that at some point the overcommit logic may start blocking large
allocation system-wide.
int main()
{
char buf[256];
unsigned long i;
struct stat statbuf;
buf[0] = '/';
for (i = 1; i < sizeof(buf); i++)
buf[i] = '_';
for (i = 0; 1; i++) {
sprintf(&buf[248], "%8lu", i);
stat(buf, &statbuf);
}
return 0;
}
This patch in combination with related indirectly reclaimable memory
patches closes this issue.
Link: http://lkml.kernel.org/r/20180313130041.8078-1-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.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>
commit eb59254608 upstream.
Patch series "indirectly reclaimable memory", v2.
This patchset introduces the concept of indirectly reclaimable memory
and applies it to fix the issue of when a big number of dentries with
external names can significantly affect the MemAvailable value.
This patch (of 3):
Introduce a concept of indirectly reclaimable memory and adds the
corresponding memory counter and /proc/vmstat item.
Indirectly reclaimable memory is any sort of memory, used by the kernel
(except of reclaimable slabs), which is actually reclaimable, i.e. will
be released under memory pressure.
The counter is in bytes, as it's not always possible to count such
objects in pages. The name contains BYTES by analogy to
NR_KERNEL_STACK_KB.
Link: http://lkml.kernel.org/r/20180305133743.12746-2-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
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>
commit 6685b35736 upstream.
The commit ca460b3c96 ("percpu: introduce bitmap metadata blocks")
introduced bitmap metadata blocks. These metadata blocks are allocated
whenever a new chunk is created, but they are never freed. Fix it.
Fixes: ca460b3c96 ("percpu: introduce bitmap metadata blocks")
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c7cdff0e86 upstream.
fill_balloon doing memory allocations under balloon_lock
can cause a deadlock when leak_balloon is called from
virtballoon_oom_notify and tries to take same lock.
To fix, split page allocation and enqueue and do allocations outside the lock.
Here's a detailed analysis of the deadlock by Tetsuo Handa:
In leak_balloon(), mutex_lock(&vb->balloon_lock) is called in order to
serialize against fill_balloon(). But in fill_balloon(),
alloc_page(GFP_HIGHUSER[_MOVABLE] | __GFP_NOMEMALLOC | __GFP_NORETRY) is
called with vb->balloon_lock mutex held. Since GFP_HIGHUSER[_MOVABLE]
implies __GFP_DIRECT_RECLAIM | __GFP_IO | __GFP_FS, despite __GFP_NORETRY
is specified, this allocation attempt might indirectly depend on somebody
else's __GFP_DIRECT_RECLAIM memory allocation. And such indirect
__GFP_DIRECT_RECLAIM memory allocation might call leak_balloon() via
virtballoon_oom_notify() via blocking_notifier_call_chain() callback via
out_of_memory() when it reached __alloc_pages_may_oom() and held oom_lock
mutex. Since vb->balloon_lock mutex is already held by fill_balloon(), it
will cause OOM lockup.
Thread1 Thread2
fill_balloon()
takes a balloon_lock
balloon_page_enqueue()
alloc_page(GFP_HIGHUSER_MOVABLE)
direct reclaim (__GFP_FS context) takes a fs lock
waits for that fs lock alloc_page(GFP_NOFS)
__alloc_pages_may_oom()
takes the oom_lock
out_of_memory()
blocking_notifier_call_chain()
leak_balloon()
tries to take that balloon_lock and deadlocks
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Wei Wang <wei.w.wang@intel.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e125fe405a upstream.
A transparent huge page is represented by a single entry on an LRU list.
Therefore, we can only make unevictable an entire compound page, not
individual subpages.
If a user tries to mlock() part of a huge page, we want the rest of the
page to be reclaimable.
We handle this by keeping PTE-mapped huge pages on normal LRU lists: the
PMD on border of VM_LOCKED VMA will be split into PTE table.
Introduction of THP migration breaks[1] the rules around mlocking THP
pages. If we had a single PMD mapping of the page in mlocked VMA, the
page will get mlocked, regardless of PTE mappings of the page.
For tmpfs/shmem it's easy to fix by checking PageDoubleMap() in
remove_migration_pmd().
Anon THP pages can only be shared between processes via fork(). Mlocked
page can only be shared if parent mlocked it before forking, otherwise CoW
will be triggered on mlock().
For Anon-THP, we can fix the issue by munlocking the page on removing PTE
migration entry for the page. PTEs for the page will always come after
mlocked PMD: rmap walks VMAs from oldest to newest.
Test-case:
#include <unistd.h>
#include <sys/mman.h>
#include <sys/wait.h>
#include <linux/mempolicy.h>
#include <numaif.h>
int main(void)
{
unsigned long nodemask = 4;
void *addr;
addr = mmap((void *)0x20000000UL, 2UL << 20, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS | MAP_LOCKED, -1, 0);
if (fork()) {
wait(NULL);
return 0;
}
mlock(addr, 4UL << 10);
mbind(addr, 2UL << 20, MPOL_PREFERRED | MPOL_F_RELATIVE_NODES,
&nodemask, 4, MPOL_MF_MOVE);
return 0;
}
[1] https://lkml.kernel.org/r/CAOMGZ=G52R-30rZvhGxEbkTw7rLLwBGadVYeo--iizcD3upL3A@mail.gmail.com
Link: http://lkml.kernel.org/r/20180917133816.43995-1-kirill.shutemov@linux.intel.com
Fixes: 616b837153 ("mm: thp: enable thp migration in generic path")
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Vegard Nossum <vegard.nossum@oracle.com>
Reviewed-by: Zi Yan <zi.yan@cs.rutgers.edu>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org> [4.14+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 017b1660df upstream.
The page migration code employs try_to_unmap() to try and unmap the source
page. This is accomplished by using rmap_walk to find all vmas where the
page is mapped. This search stops when page mapcount is zero. For shared
PMD huge pages, the page map count is always 1 no matter the number of
mappings. Shared mappings are tracked via the reference count of the PMD
page. Therefore, try_to_unmap stops prematurely and does not completely
unmap all mappings of the source page.
This problem can result is data corruption as writes to the original
source page can happen after contents of the page are copied to the target
page. Hence, data is lost.
This problem was originally seen as DB corruption of shared global areas
after a huge page was soft offlined due to ECC memory errors. DB
developers noticed they could reproduce the issue by (hotplug) offlining
memory used to back huge pages. A simple testcase can reproduce the
problem by creating a shared PMD mapping (note that this must be at least
PUD_SIZE in size and PUD_SIZE aligned (1GB on x86)), and using
migrate_pages() to migrate process pages between nodes while continually
writing to the huge pages being migrated.
To fix, have the try_to_unmap_one routine check for huge PMD sharing by
calling huge_pmd_unshare for hugetlbfs huge pages. If it is a shared
mapping it will be 'unshared' which removes the page table entry and drops
the reference on the PMD page. After this, flush caches and TLB.
mmu notifiers are called before locking page tables, but we can not be
sure of PMD sharing until page tables are locked. Therefore, check for
the possibility of PMD sharing before locking so that notifiers can
prepare for the worst possible case.
Link: http://lkml.kernel.org/r/20180823205917.16297-2-mike.kravetz@oracle.com
[mike.kravetz@oracle.com: make _range_in_vma() a static inline]
Link: http://lkml.kernel.org/r/6063f215-a5c8-2f0c-465a-2c515ddc952d@oracle.com
Fixes: 39dde65c99 ("shared page table for hugetlb page")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d41aa52523 upstream.
Reproducer, assuming 2M of hugetlbfs available:
Hugetlbfs mounted, size=2M and option user=testuser
# mount | grep ^hugetlbfs
hugetlbfs on /dev/hugepages type hugetlbfs (rw,pagesize=2M,user=dan)
# sysctl vm.nr_hugepages=1
vm.nr_hugepages = 1
# grep Huge /proc/meminfo
AnonHugePages: 0 kB
ShmemHugePages: 0 kB
HugePages_Total: 1
HugePages_Free: 1
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 2048 kB
Hugetlb: 2048 kB
Code:
#include <sys/mman.h>
#include <stddef.h>
#define SIZE 2*1024*1024
int main()
{
void *ptr;
ptr = mmap(NULL, SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_HUGETLB | MAP_ANONYMOUS, -1, 0);
madvise(ptr, SIZE, MADV_DONTDUMP);
madvise(ptr, SIZE, MADV_DODUMP);
}
Compile and strace:
mmap(NULL, 2097152, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB, -1, 0) = 0x7ff7c9200000
madvise(0x7ff7c9200000, 2097152, MADV_DONTDUMP) = 0
madvise(0x7ff7c9200000, 2097152, MADV_DODUMP) = -1 EINVAL (Invalid argument)
hugetlbfs pages have VM_DONTEXPAND in the VmFlags driver pages based on
author testing with analysis from Florian Weimer[1].
The inclusion of VM_DONTEXPAND into the VM_SPECIAL defination was a
consequence of the large useage of VM_DONTEXPAND in device drivers.
A consequence of [2] is that VM_DONTEXPAND marked pages are unable to be
marked DODUMP.
A user could quite legitimately madvise(MADV_DONTDUMP) their hugetlbfs
memory for a while and later request that madvise(MADV_DODUMP) on the same
memory. We correct this omission by allowing madvice(MADV_DODUMP) on
hugetlbfs pages.
[1] https://stackoverflow.com/questions/52548260/madvisedodump-on-the-same-ptr-size-as-a-successful-madvisedontdump-fails-wit
[2] commit 0103bd16fb ("mm: prepare VM_DONTDUMP for using in drivers")
Link: http://lkml.kernel.org/r/20180930054629.29150-1-daniel@linux.ibm.com
Link: https://lists.launchpad.net/maria-discuss/msg05245.html
Fixes: 0103bd16fb ("mm: prepare VM_DONTDUMP for using in drivers")
Reported-by: Kenneth Penza <kpenza@gmail.com>
Signed-off-by: Daniel Black <daniel@linux.ibm.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7a9cdebdcc upstream.
Jann Horn points out that the vmacache_flush_all() function is not only
potentially expensive, it's buggy too. It also happens to be entirely
unnecessary, because the sequence number overflow case can be avoided by
simply making the sequence number be 64-bit. That doesn't even grow the
data structures in question, because the other adjacent fields are
already 64-bit.
So simplify the whole thing by just making the sequence number overflow
case go away entirely, which gets rid of all the complications and makes
the code faster too. Win-win.
[ Oleg Nesterov points out that the VMACACHE_FULL_FLUSHES statistics
also just goes away entirely with this ]
Reported-by: Jann Horn <jannh@google.com>
Suggested-by: Will Deacon <will.deacon@arm.com>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit dc30b96ab6 upstream.
ondemand_readahead() checks bdi->io_pages to cap the maximum pages
that need to be processed. This works until the readit section. If
we would do an async only readahead (async size = sync size) and
target is at beginning of window we expand the pages by another
get_next_ra_size() pages. Btrace for large reads shows that kernel
always issues a doubled size read at the beginning of processing.
Add an additional check for io_pages in the lower part of the func.
The fix helps devices that hard limit bio pages and rely on proper
handling of max_hw_read_sectors (e.g. older FusionIO cards). For
that reason it could qualify for stable.
Fixes: 9491ae4a ("mm: don't cap request size based on read-ahead setting")
Cc: stable@vger.kernel.org
Signed-off-by: Markus Stockhausen stockhausen@collogia.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d86564a2f0 upstream.
Jann reported that x86 was missing required TLB invalidates when he
hit the !*batch slow path in tlb_remove_table().
This is indeed the case; RCU_TABLE_FREE does not provide TLB (cache)
invalidates, the PowerPC-hash where this code originated and the
Sparc-hash where this was subsequently used did not need that. ARM
which later used this put an explicit TLB invalidate in their
__p*_free_tlb() functions, and PowerPC-radix followed that example.
But when we hooked up x86 we failed to consider this. Fix this by
(optionally) hooking tlb_remove_table() into the TLB invalidate code.
NOTE: s390 was also needing something like this and might now
be able to use the generic code again.
[ Modified to be on top of Nick's cleanups, which simplified this patch
now that tlb_flush_mmu_tlbonly() really only flushes the TLB - Linus ]
Fixes: 9e52fc2b50 ("x86/mm: Enable RCU based page table freeing (CONFIG_HAVE_RCU_TABLE_FREE=y)")
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Rik van Riel <riel@surriel.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: David Miller <davem@davemloft.net>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit db7ddef301 upstream.
There is no need to call this from tlb_flush_mmu_tlbonly, it logically
belongs with tlb_flush_mmu_free. This makes future fixes simpler.
[ This was originally done to allow code consolidation for the
mmu_notifier fix, but it also ends up helping simplify the
HAVE_RCU_TABLE_INVALIDATE fix. - Linus ]
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 53406ed1bc ]
Delete the old VM_BUG_ON_VMA() from zap_pmd_range(), which asserted
that mmap_sem must be held when splitting an "anonymous" vma there.
Whether that's still strictly true nowadays is not entirely clear,
but the danger of sometimes crashing on the BUG is now fairly clear.
Even with the new stricter rules for anonymous vma marking, the
condition it checks for can possible trigger. Commit 44960f2a7b
("staging: ashmem: Fix SIGBUS crash when traversing mmaped ashmem
pages") is good, and originally I thought it was safe from that
VM_BUG_ON_VMA(), because the /dev/ashmem fd exposed to the user is
disconnected from the vm_file in the vma, and madvise(,,MADV_REMOVE)
insists on VM_SHARED.
But after I read John's earlier mail, drawing attention to the
vfs_fallocate() in there: I may be wrong, and I don't know if Android
has THP in the config anyway, but it looks to me like an
unmap_mapping_range() from ashmem's vfs_fallocate() could hit precisely
the VM_BUG_ON_VMA(), once it's vma_is_anonymous().
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 16e536ef47 ]
/sys/../zswap/stored_pages keeps rising in a zswap test with
"zswap.max_pool_percent=0" parameter. But it should not compress or
store pages any more since there is no space in the compressed pool.
Reproduce steps:
1. Boot kernel with "zswap.enabled=1"
2. Set the max_pool_percent to 0
# echo 0 > /sys/module/zswap/parameters/max_pool_percent
3. Do memory stress test to see if some pages have been compressed
# stress --vm 1 --vm-bytes $mem_available"M" --timeout 60s
4. Watching the 'stored_pages' number increasing or not
The root cause is:
When zswap_max_pool_percent is set to 0 via kernel parameter,
zswap_is_full() will always return true due to zswap_shrink(). But if
the shinking is able to reclain a page successfully the code then
proceeds to compressing/storing another page, so the value of
stored_pages will keep changing.
To solve the issue, this patch adds a zswap_is_full() check again after
zswap_shrink() to make sure it's now under the max_pool_percent, and to
not compress/store if we reached the limit.
Link: http://lkml.kernel.org/r/20180530103936.17812-1-liwang@redhat.com
Signed-off-by: Li Wang <liwang@redhat.com>
Acked-by: Dan Streetman <ddstreet@ieee.org>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Huang Ying <huang.ying.caritas@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 1e8e18f694 ]
There is a special case that the size is "(N << KASAN_SHADOW_SCALE_SHIFT)
Pages plus X", the value of X is [1, KASAN_SHADOW_SCALE_SIZE-1]. The
operation "size >> KASAN_SHADOW_SCALE_SHIFT" will drop X, and the
roundup operation can not retrieve the missed one page. For example:
size=0x28006, PAGE_SIZE=0x1000, KASAN_SHADOW_SCALE_SHIFT=3, we will get
shadow_size=0x5000, but actually we need 6 pages.
shadow_size = round_up(size >> KASAN_SHADOW_SCALE_SHIFT, PAGE_SIZE);
This can lead to a kernel crash when kasan is enabled and the value of
mod->core_layout.size or mod->init_layout.size is like above. Because
the shadow memory of X has not been allocated and mapped.
move_module:
ptr = module_alloc(mod->core_layout.size);
...
memset(ptr, 0, mod->core_layout.size); //crashed
Unable to handle kernel paging request at virtual address ffff0fffff97b000
......
Call trace:
__asan_storeN+0x174/0x1a8
memset+0x24/0x48
layout_and_allocate+0xcd8/0x1800
load_module+0x190/0x23e8
SyS_finit_module+0x148/0x180
Link: http://lkml.kernel.org/r/1529659626-12660-1-git-send-email-thunder.leizhen@huawei.com
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Reviewed-by: Dmitriy Vyukov <dvyukov@google.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Hanjun Guo <guohanjun@huawei.com>
Cc: Libin <huawei.libin@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 377eeaa8e1 upstream
For the L1TF workaround its necessary to limit the swap file size to below
MAX_PA/2, so that the higher bits of the swap offset inverted never point
to valid memory.
Add a mechanism for the architecture to override the swap file size check
in swapfile.c and add a x86 specific max swapfile check function that
enforces that limit.
The check is only enabled if the CPU is vulnerable to L1TF.
In VMs with 42bit MAX_PA the typical limit is 2TB now, on a native system
with 46bit PA it is 32TB. The limit is only per individual swap file, so
it's always possible to exceed these limits with multiple swap files or
partitions.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 42e4089c78 upstream
For L1TF PROT_NONE mappings are protected by inverting the PFN in the page
table entry. This sets the high bits in the CPU's address space, thus
making sure to point to not point an unmapped entry to valid cached memory.
Some server system BIOSes put the MMIO mappings high up in the physical
address space. If such an high mapping was mapped to unprivileged users
they could attack low memory by setting such a mapping to PROT_NONE. This
could happen through a special device driver which is not access
protected. Normal /dev/mem is of course access protected.
To avoid this forbid PROT_NONE mappings or mprotect for high MMIO mappings.
Valid page mappings are allowed because the system is then unsafe anyways.
It's not expected that users commonly use PROT_NONE on MMIO. But to
minimize any impact this is only enforced if the mapping actually refers to
a high MMIO address (defined as the MAX_PA-1 bit being set), and also skip
the check for root.
For mmaps this is straight forward and can be handled in vm_insert_pfn and
in remap_pfn_range().
For mprotect it's a bit trickier. At the point where the actual PTEs are
accessed a lot of state has been changed and it would be difficult to undo
on an error. Since this is a uncommon case use a separate early page talk
walk pass for MMIO PROT_NONE mappings that checks for this condition
early. For non MMIO and non PROT_NONE there are no changes.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9f15bde671 upstream.
It was reported that a kernel crash happened in mem_cgroup_iter(), which
can be triggered if the legacy cgroup-v1 non-hierarchical mode is used.
Unable to handle kernel paging request at virtual address 6b6b6b6b6b6b8f
......
Call trace:
mem_cgroup_iter+0x2e0/0x6d4
shrink_zone+0x8c/0x324
balance_pgdat+0x450/0x640
kswapd+0x130/0x4b8
kthread+0xe8/0xfc
ret_from_fork+0x10/0x20
mem_cgroup_iter():
......
if (css_tryget(css)) <-- crash here
break;
......
The crashing reason is that mem_cgroup_iter() uses the memcg object whose
pointer is stored in iter->position, which has been freed before and
filled with POISON_FREE(0x6b).
And the root cause of the use-after-free issue is that
invalidate_reclaim_iterators() fails to reset the value of iter->position
to NULL when the css of the memcg is released in non- hierarchical mode.
Link: http://lkml.kernel.org/r/1531994807-25639-1-git-send-email-jing.xia@unisoc.com
Fixes: 6df38689e0 ("mm: memcontrol: fix possible memcg leak due to interrupted reclaim")
Signed-off-by: Jing Xia <jing.xia.mail@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: <chunyan.zhang@unisoc.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 3ee7e8697d upstream.
syzbot is reporting NULL pointer dereference at wb_workfn() [1] due to
wb->bdi->dev being NULL. And Dmitry confirmed that wb->state was
WB_shutting_down after wb->bdi->dev became NULL. This indicates that
unregister_bdi() failed to call wb_shutdown() on one of wb objects.
The problem is in cgwb_bdi_unregister() which does cgwb_kill() and thus
drops bdi's reference to wb structures before going through the list of
wbs again and calling wb_shutdown() on each of them. This way the loop
iterating through all wbs can easily miss a wb if that wb has already
passed through cgwb_remove_from_bdi_list() called from wb_shutdown()
from cgwb_release_workfn() and as a result fully shutdown bdi although
wb_workfn() for this wb structure is still running. In fact there are
also other ways cgwb_bdi_unregister() can race with
cgwb_release_workfn() leading e.g. to use-after-free issues:
CPU1 CPU2
cgwb_bdi_unregister()
cgwb_kill(*slot);
cgwb_release()
queue_work(cgwb_release_wq, &wb->release_work);
cgwb_release_workfn()
wb = list_first_entry(&bdi->wb_list, ...)
spin_unlock_irq(&cgwb_lock);
wb_shutdown(wb);
...
kfree_rcu(wb, rcu);
wb_shutdown(wb); -> oops use-after-free
We solve these issues by synchronizing writeback structure shutdown from
cgwb_bdi_unregister() with cgwb_release_workfn() using a new mutex. That
way we also no longer need synchronization using WB_shutting_down as the
mutex provides it for CONFIG_CGROUP_WRITEBACK case and without
CONFIG_CGROUP_WRITEBACK wb_shutdown() can be called only once from
bdi_unregister().
Reported-by: syzbot <syzbot+4a7438e774b21ddd8eca@syzkaller.appspotmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit bb177a732c upstream.
syzbot has noticed that a specially crafted library can easily hit
VM_BUG_ON in __mm_populate
kernel BUG at mm/gup.c:1242!
invalid opcode: 0000 [#1] SMP
CPU: 2 PID: 9667 Comm: a.out Not tainted 4.18.0-rc3 #644
Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 05/19/2017
RIP: 0010:__mm_populate+0x1e2/0x1f0
Code: 55 d0 65 48 33 14 25 28 00 00 00 89 d8 75 21 48 83 c4 20 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 75 18 f1 ff 0f 0b e8 6e 18 f1 ff <0f> 0b 31 db eb c9 e8 93 06 e0 ff 0f 1f 00 55 48 89 e5 53 48 89 fb
Call Trace:
vm_brk_flags+0xc3/0x100
vm_brk+0x1f/0x30
load_elf_library+0x281/0x2e0
__ia32_sys_uselib+0x170/0x1e0
do_fast_syscall_32+0xca/0x420
entry_SYSENTER_compat+0x70/0x7f
The reason is that the length of the new brk is not page aligned when we
try to populate the it. There is no reason to bug on that though.
do_brk_flags already aligns the length properly so the mapping is
expanded as it should. All we need is to tell mm_populate about it.
Besides that there is absolutely no reason to to bug_on in the first
place. The worst thing that could happen is that the last page wouldn't
get populated and that is far from putting system into an inconsistent
state.
Fix the issue by moving the length sanitization code from do_brk_flags
up to vm_brk_flags. The only other caller of do_brk_flags is brk
syscall entry and it makes sure to provide the proper length so t here
is no need for sanitation and so we can use do_brk_flags without it.
Also remove the bogus BUG_ONs.
[osalvador@techadventures.net: fix up vm_brk_flags s@request@len@]
Link: http://lkml.kernel.org/r/20180706090217.GI32658@dhcp22.suse.cz
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: syzbot <syzbot+5dcb560fe12aa5091c06@syzkaller.appspotmail.com>
Tested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Zi Yan <zi.yan@cs.rutgers.edu>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Huang, Ying" <ying.huang@intel.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>
commit 28557cc106 upstream.
Revert commit c7f26ccfb2 ("mm/vmstat.c: fix vmstat_update() preemption
BUG"). Steven saw a "using smp_processor_id() in preemptible" message
and added a preempt_disable() section around it to keep it quiet. This
is not the right thing to do it does not fix the real problem.
vmstat_update() is invoked by a kworker on a specific CPU. This worker
it bound to this CPU. The name of the worker was "kworker/1:1" so it
should have been a worker which was bound to CPU1. A worker which can
run on any CPU would have a `u' before the first digit.
smp_processor_id() can be used in a preempt-enabled region as long as
the task is bound to a single CPU which is the case here. If it could
run on an arbitrary CPU then this is the problem we have an should seek
to resolve.
Not only this smp_processor_id() must not be migrated to another CPU but
also refresh_cpu_vm_stats() which might access wrong per-CPU variables.
Not to mention that other code relies on the fact that such a worker
runs on one specific CPU only.
Therefore revert that commit and we should look instead what broke the
affinity mask of the kworker.
Link: http://lkml.kernel.org/r/20180504104451.20278-1-bigeasy@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Steven J. Hill <steven.hill@cavium.com>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
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>
commit d50d82faa0 upstream.
In kernel 4.17 I removed some code from dm-bufio that did slab cache
merging (commit 21bb132767: "dm bufio: remove code that merges slab
caches") - both slab and slub support merging caches with identical
attributes, so dm-bufio now just calls kmem_cache_create and relies on
implicit merging.
This uncovered a bug in the slub subsystem - if we delete a cache and
immediatelly create another cache with the same attributes, it fails
because of duplicate filename in /sys/kernel/slab/. The slub subsystem
offloads freeing the cache to a workqueue - and if we create the new
cache before the workqueue runs, it complains because of duplicate
filename in sysfs.
This patch fixes the bug by moving the call of kobject_del from
sysfs_slab_remove_workfn to shutdown_cache. kobject_del must be called
while we hold slab_mutex - so that the sysfs entry is deleted before a
cache with the same attributes could be created.
Running device-mapper-test-suite with:
dmtest run --suite thin-provisioning -n /commit_failure_causes_fallback/
triggered:
Buffer I/O error on dev dm-0, logical block 1572848, async page read
device-mapper: thin: 253:1: metadata operation 'dm_pool_alloc_data_block' failed: error = -5
device-mapper: thin: 253:1: aborting current metadata transaction
sysfs: cannot create duplicate filename '/kernel/slab/:a-0000144'
CPU: 2 PID: 1037 Comm: kworker/u48:1 Not tainted 4.17.0.snitm+ #25
Hardware name: Supermicro SYS-1029P-WTR/X11DDW-L, BIOS 2.0a 12/06/2017
Workqueue: dm-thin do_worker [dm_thin_pool]
Call Trace:
dump_stack+0x5a/0x73
sysfs_warn_dup+0x58/0x70
sysfs_create_dir_ns+0x77/0x80
kobject_add_internal+0xba/0x2e0
kobject_init_and_add+0x70/0xb0
sysfs_slab_add+0xb1/0x250
__kmem_cache_create+0x116/0x150
create_cache+0xd9/0x1f0
kmem_cache_create_usercopy+0x1c1/0x250
kmem_cache_create+0x18/0x20
dm_bufio_client_create+0x1ae/0x410 [dm_bufio]
dm_block_manager_create+0x5e/0x90 [dm_persistent_data]
__create_persistent_data_objects+0x38/0x940 [dm_thin_pool]
dm_pool_abort_metadata+0x64/0x90 [dm_thin_pool]
metadata_operation_failed+0x59/0x100 [dm_thin_pool]
alloc_data_block.isra.53+0x86/0x180 [dm_thin_pool]
process_cell+0x2a3/0x550 [dm_thin_pool]
do_worker+0x28d/0x8f0 [dm_thin_pool]
process_one_work+0x171/0x370
worker_thread+0x49/0x3f0
kthread+0xf8/0x130
ret_from_fork+0x35/0x40
kobject_add_internal failed for :a-0000144 with -EEXIST, don't try to register things with the same name in the same directory.
kmem_cache_create(dm_bufio_buffer-16) failed with error -17
Link: http://lkml.kernel.org/r/alpine.LRH.2.02.1806151817130.6333@file01.intranet.prod.int.rdu2.redhat.com
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reported-by: Mike Snitzer <snitzer@redhat.com>
Tested-by: Mike Snitzer <snitzer@redhat.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>
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>
commit 1105a2fc02 upstream.
In our armv8a server(QDF2400), I noticed lots of WARN_ON caused by
PAGE_SIZE unaligned for rmap_item->address under memory pressure
tests(start 20 guests and run memhog in the host).
WARNING: CPU: 4 PID: 4641 at virt/kvm/arm/mmu.c:1826 kvm_age_hva_handler+0xc0/0xc8
CPU: 4 PID: 4641 Comm: memhog Tainted: G W 4.17.0-rc3+ #8
Call trace:
kvm_age_hva_handler+0xc0/0xc8
handle_hva_to_gpa+0xa8/0xe0
kvm_age_hva+0x4c/0xe8
kvm_mmu_notifier_clear_flush_young+0x54/0x98
__mmu_notifier_clear_flush_young+0x6c/0xa0
page_referenced_one+0x154/0x1d8
rmap_walk_ksm+0x12c/0x1d0
rmap_walk+0x94/0xa0
page_referenced+0x194/0x1b0
shrink_page_list+0x674/0xc28
shrink_inactive_list+0x26c/0x5b8
shrink_node_memcg+0x35c/0x620
shrink_node+0x100/0x430
do_try_to_free_pages+0xe0/0x3a8
try_to_free_pages+0xe4/0x230
__alloc_pages_nodemask+0x564/0xdc0
alloc_pages_vma+0x90/0x228
do_anonymous_page+0xc8/0x4d0
__handle_mm_fault+0x4a0/0x508
handle_mm_fault+0xf8/0x1b0
do_page_fault+0x218/0x4b8
do_translation_fault+0x90/0xa0
do_mem_abort+0x68/0xf0
el0_da+0x24/0x28
In rmap_walk_ksm, the rmap_item->address might still have the
STABLE_FLAG, then the start and end in handle_hva_to_gpa might not be
PAGE_SIZE aligned. Thus it will cause exceptions in handle_hva_to_gpa
on arm64.
This patch fixes it by ignoring (not removing) the low bits of address
when doing rmap_walk_ksm.
IMO, it should be backported to stable tree. the storm of WARN_ONs is
very easy for me to reproduce. More than that, I watched a panic (not
reproducible) as follows:
page:ffff7fe003742d80 count:-4871 mapcount:-2126053375 mapping: (null) index:0x0
flags: 0x1fffc00000000000()
raw: 1fffc00000000000 0000000000000000 0000000000000000 ffffecf981470000
raw: dead000000000100 dead000000000200 ffff8017c001c000 0000000000000000
page dumped because: nonzero _refcount
CPU: 29 PID: 18323 Comm: qemu-kvm Tainted: G W 4.14.15-5.hxt.aarch64 #1
Hardware name: <snip for confidential issues>
Call trace:
dump_backtrace+0x0/0x22c
show_stack+0x24/0x2c
dump_stack+0x8c/0xb0
bad_page+0xf4/0x154
free_pages_check_bad+0x90/0x9c
free_pcppages_bulk+0x464/0x518
free_hot_cold_page+0x22c/0x300
__put_page+0x54/0x60
unmap_stage2_range+0x170/0x2b4
kvm_unmap_hva_handler+0x30/0x40
handle_hva_to_gpa+0xb0/0xec
kvm_unmap_hva_range+0x5c/0xd0
I even injected a fault on purpose in kvm_unmap_hva_range by seting
size=size-0x200, the call trace is similar as above. So I thought the
panic is similarly caused by the root cause of WARN_ON.
Andrea said:
: It looks a straightforward safe fix, on x86 hva_to_gfn_memslot would
: zap those bits and hide the misalignment caused by the low metadata
: bits being erroneously left set in the address, but the arm code
: notices when that's the last page in the memslot and the hva_end is
: getting aligned and the size is below one page.
:
: I think the problem triggers in the addr += PAGE_SIZE of
: unmap_stage2_ptes that never matches end because end is aligned but
: addr is not.
:
: } while (pte++, addr += PAGE_SIZE, addr != end);
:
: x86 again only works on hva_start/hva_end after converting it to
: gfn_start/end and that being in pfn units the bits are zapped before
: they risk to cause trouble.
Jia He said:
: I've tested by myself in arm64 server (QDF2400,46 cpus,96G mem) Without
: this patch, the WARN_ON is very easy for reproducing. After this patch, I
: have run the same benchmarch for a whole day without any WARN_ONs
Link: http://lkml.kernel.org/r/1525403506-6750-1-git-send-email-hejianet@gmail.com
Signed-off-by: Jia He <jia.he@hxt-semitech.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Tested-by: Jia He <hejianet@gmail.com>
Cc: Suzuki K Poulose <Suzuki.Poulose@arm.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com>
Cc: Arvind Yadav <arvind.yadav.cs@gmail.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.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>
commit a9b6de77b1 upstream.
get_user_pages_fast() for device pages is missing the typical validation
that all page references have been taken while the mapping was valid.
Without this validation truncate operations can not reliably coordinate
against new page reference events like O_DIRECT.
Cc: <stable@vger.kernel.org>
Fixes: 3565fce3a6 ("mm, x86: get_user_pages() for dax mappings")
Reported-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Yufen Yu
Vitaly Wool
Aneesh Kumar K.V
Dmitry Vyukov
Vasily Averin
Mike Kravetz
Andrea Arcangeli
Ralph Campbell
Linus Torvalds
Roman Gushchin
Jérôme Glisse
Mike Rapoport
Jann Horn
Michael S. Tsirkin
Kirill A. Shutemov
Daniel Black
Alexey Dobriyan
Joel Fernandes (Google)
Andrey Ryabinin
Peter Zijlstra
Markus Stockhausen
Nicholas Piggin
jie@chenjie6@huwei.com
Kirill Tkhai
Hugh Dickins
Li Wang
Zhen Lei
Andi Kleen
Mathieu Malaterre
Chintan Pandya
Jing Xia
Jan Kara
Michal Hocko
Christian Borntraeger
Sebastian Andrzej Siewior
Naoya Horiguchi
Cannon Matthews
Mikulas Patocka
Jia He
Dan Williams