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| author | Vegard Nossum <vegard.nossum@oracle.com> | 2016-08-02 14:02:22 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-08-02 17:31:41 -0400 |
| commit | c5f88bd29ab42d5d1e77085b5f69d5c6da20324e (patch) | |
| tree | 8ef00eeae9afaadcc8be5f0704c3b9c520307d6b /mm | |
| parent | ee8f7fcbe638b07e8d1c3dc98e8be35e56306d05 (diff) | |
| download | linux-c5f88bd29ab42d5d1e77085b5f69d5c6da20324e.tar.bz2 | |
mm: fail prefaulting if page table allocation fails
I ran into this:
BUG: sleeping function called from invalid context at mm/page_alloc.c:3784
in_atomic(): 0, irqs_disabled(): 0, pid: 1434, name: trinity-c1
2 locks held by trinity-c1/1434:
#0: (&mm->mmap_sem){......}, at: [<ffffffff810ce31e>] __do_page_fault+0x1ce/0x8f0
#1: (rcu_read_lock){......}, at: [<ffffffff81378f86>] filemap_map_pages+0xd6/0xdd0
CPU: 0 PID: 1434 Comm: trinity-c1 Not tainted 4.7.0+ #58
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
Call Trace:
dump_stack+0x65/0x84
panic+0x185/0x2dd
___might_sleep+0x51c/0x600
__might_sleep+0x90/0x1a0
__alloc_pages_nodemask+0x5b1/0x2160
alloc_pages_current+0xcc/0x370
pte_alloc_one+0x12/0x90
__pte_alloc+0x1d/0x200
alloc_set_pte+0xe3e/0x14a0
filemap_map_pages+0x42b/0xdd0
handle_mm_fault+0x17d5/0x28b0
__do_page_fault+0x310/0x8f0
trace_do_page_fault+0x18d/0x310
do_async_page_fault+0x27/0xa0
async_page_fault+0x28/0x30
The important bits from the above is that filemap_map_pages() is calling
into the page allocator while holding rcu_read_lock (sleeping is not
allowed inside RCU read-side critical sections).
According to Kirill Shutemov, the prefaulting code in do_fault_around()
is supposed to take care of this, but missing error handling means that
the allocation failure can go unnoticed.
We don't need to return VM_FAULT_OOM (or any other error) here, since we
can just let the normal fault path try again.
Fixes: 7267ec008b5c ("mm: postpone page table allocation until we have page to map")
Link: http://lkml.kernel.org/r/1469708107-11868-1-git-send-email-vegard.nossum@oracle.com
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "Hillf Danton" <hillf.zj@alibaba-inc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/memory.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/mm/memory.c b/mm/memory.c index 4425b6059339..04004834e985 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3133,6 +3133,8 @@ static int do_fault_around(struct fault_env *fe, pgoff_t start_pgoff) if (pmd_none(*fe->pmd)) { fe->prealloc_pte = pte_alloc_one(fe->vma->vm_mm, fe->address); + if (!fe->prealloc_pte) + goto out; smp_wmb(); /* See comment in __pte_alloc() */ } |