diff options
| author | Andrey Vagin <avagin@openvz.org> | 2011-03-09 15:22:23 -0800 |
|---|---|---|
| committer | AK <andi@firstfloor.org> | 2011-03-31 11:58:36 -0700 |
| commit | 7838ead2b8f913f82d2b1d7f51e12d9ff1d6d936 (patch) | |
| tree | dc9205f435b2d75f1caf4e6c6a4e1c9873e193b2 /arch | |
| parent | e5c30be3fa24a717a89a6ee9d0cd735e6002cdfd (diff) | |
x86/mm: Handle mm_fault_error() in kernel space
commit f86268549f424f83b9eb0963989270e14fbfc3de upstream.
mm_fault_error() should not execute oom-killer, if page fault
occurs in kernel space. E.g. in copy_from_user()/copy_to_user().
This would happen if we find ourselves in OOM on a
copy_to_user(), or a copy_from_user() which faults.
Without this patch, the kernels hangs up in copy_from_user(),
because OOM killer sends SIG_KILL to current process, but it
can't handle a signal while in syscall, then the kernel returns
to copy_from_user(), reexcute current command and provokes
page_fault again.
With this patch the kernel return -EFAULT from copy_from_user().
The code, which checks that page fault occurred in kernel space,
has been copied from do_sigbus().
This situation is handled by the same way on powerpc, xtensa,
tile, ...
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <201103092322.p29NMNPH001682@imap1.linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/mm/fault.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 4c4508e8a204..544ed251a40c 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -831,6 +831,13 @@ mm_fault_error(struct pt_regs *regs, unsigned long error_code, unsigned long address, unsigned int fault) { if (fault & VM_FAULT_OOM) { + /* Kernel mode? Handle exceptions or die: */ + if (!(error_code & PF_USER)) { + up_read(¤t->mm->mmap_sem); + no_context(regs, error_code, address); + return; + } + out_of_memory(regs, error_code, address); } else { if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON)) |