Commit 96054569 authored Aug 13, 2010 by Linus Torvalds

x86: don't send SIGBUS for kernel page faults

It's wrong for several reasons, but the most direct one is that the
fault may be for the stack accesses to set up a previous SIGBUS. When
we have a kernel exception, the kernel exception handler does all the
fixups, not some user-level signal handler.

Even apart from the nested SIGBUS issue, it's also wrong to give out
kernel fault addresses in the signal handler info block, or to send a
SIGBUS when a system call already returns EFAULT.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 5528f913

arch/x86/mm/fault.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -802,8 +802,10 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
		up_read(&mm->mmap_sem);

		/* Kernel mode? Handle exceptions or die: */
		if (!(error_code & PF_USER))
		if (!(error_code & PF_USER)) {
		no_context(regs, error_code, address);
		return;
		}

		/* User-space => ok to do another page fault: */
		if (is_prefetch(regs, error_code, address))

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