path: root/arch/x86
diff options
authorAndrey Vagin <avagin@openvz.org>2011-03-09 15:22:23 -0800
committerIngo Molnar <mingo@elte.hu>2011-03-10 09:41:40 +0100
commitf86268549f424f83b9eb0963989270e14fbfc3de (patch)
tree55fb3f1755a5cb8d81daecfef3aa84bb4ea340e8 /arch/x86
parenta7bd1dafdcc13ec7add4aafc927eb5e3a8d597e6 (diff)
x86/mm: Handle mm_fault_error() in kernel space
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> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: <stable@kernel.org> LKML-Reference: <201103092322.p29NMNPH001682@imap1.linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86')
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 7d90ceb882a..ffc7be104fc 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -828,6 +828,13 @@ 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(&current->mm->mmap_sem);
+ no_context(regs, error_code, address);
+ return;
+ }
out_of_memory(regs, error_code, address);
} else {