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x86, mm: fault.c, give another attempt at prefetch handing before SIGBUS

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Impact: extend prefetch handling on 64-bit

Currently there's an extra is_prefetch() check done in do_sigbus(),
which we only do on 32 bits.

This is a last-ditch check before we terminate a task, so it's worth
giving prefetch instructions another chance - should none of our
existing quirks have caught a prefetch instruction related spurious
fault.

The only risk is if a prefetch causes a real sigbus, in that case
we'll not OOM but try another fault. But this code has been on
32-bit for a long time, so it should be fine in practice.

So do this on 64-bit too - and thus remove one more #ifdef.

Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ingo Molnar 2009-02-20 23:39:02 +01:00
parent 7c178a26d3
commit cd1b68f08f
1 changed files with 1 additions and 3 deletions
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4
arch/x86/mm/fault.c
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@ -836,11 +836,9 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address)
if (!(error_code & PF_USER))
no_context(regs, error_code, address);
#ifdef CONFIG_X86_32
/* User space => ok to do another page fault: */
/* User-space => ok to do another page fault: */
if (is_prefetch(regs, error_code, address))
return;
#endif
tsk->thread.cr2 = address;
tsk->thread.error_code = error_code;