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authorSteven Rostedt <rostedt@goodmis.org>2007-06-06 23:34:04 -0400
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-06-07 17:05:03 -0700
commite5e3c84b70e58fc605635fd340fb8dba3cc59058 (patch)
tree7ebba42dc0a402ef54bcbd4552e1fe47c519de2b /arch/x86_64
parentc52ecdab06ff3b4d0f8914951eb74dc8b049f51c (diff)
downloadlinux-2.6.34-ux500-e5e3c84b70e58fc605635fd340fb8dba3cc59058.tar.gz
enable interrupts in user path of page fault.
This is a minor fix, but what is currently there is essentially wrong. In do_page_fault, if the faulting address from user code happens to be in kernel address space (int *p = (int*)-1; p = 0xbed;) then the do_page_fault handler will jump over the local_irq_enable with the goto bad_area_nosemaphore; But the first line there sees this is user code and goes through the process of sending a signal to send SIGSEGV to the user task. This whole time interrupts are disabled and the task can not be preempted by a higher priority task. This patch always enables interrupts in the user path of the bad_area_nosemaphore. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/x86_64')
-rw-r--r--arch/x86_64/mm/fault.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/x86_64/mm/fault.c b/arch/x86_64/mm/fault.c
index bfb62a13d7e..635e58d443d 100644
--- a/arch/x86_64/mm/fault.c
+++ b/arch/x86_64/mm/fault.c
@@ -476,6 +476,12 @@ bad_area:
bad_area_nosemaphore:
/* User mode accesses just cause a SIGSEGV */
if (error_code & PF_USER) {
+
+ /*
+ * It's possible to have interrupts off here.
+ */
+ local_irq_enable();
+
if (is_prefetch(regs, address, error_code))
return;