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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 13:31:09 -0700
commit76e3b8d9764ca43452b272925df0b05625f98898 (patch)
tree6ceca3f45ce69a08f8992a0857bd670e5d2a79bc
parent3aba3fa070fc0f38de2d41252aee9ff17d2de984 (diff)
downloadlinux-2.6.34-ux500-76e3b8d9764ca43452b272925df0b05625f98898.tar.gz
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 f62777940df..4c4508e8a20 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -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))