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authorLinus Torvalds <torvalds@linux-foundation.org>2010-08-13 09:49:20 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2010-08-13 13:20:28 -0700
commit495b59364c67bc1f970a6229895ae15d1684d694 (patch)
tree81af921fede7cedf70f7d70a50ec98d77726fb85
parentab832422673d1774c4ce3941f2ac87743d73bded (diff)
x86: don't send SIGBUS for kernel page faults
commit 96054569190bdec375fe824e48ca1f4e3b53dd36 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--arch/x86/mm/fault.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index f4cee9028cf..1739358b444 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -801,8 +801,10 @@ 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))