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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 13:27:39 -0700
commite320cef8cace354a6d26c97828caaa74ec085cca (patch)
tree8374a0375273428a09345d67789d2f36bfe880a7
parent5eafdadb782787f9ae13bd0b1e5e372c5a6c28f2 (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 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))