diff options
| author | Steven Rostedt <rostedt@goodmis.org> | 2007-06-06 23:34:04 -0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-06-07 17:05:03 -0700 |
| commit | e5e3c84b70e58fc605635fd340fb8dba3cc59058 (patch) | |
| tree | 7ebba42dc0a402ef54bcbd4552e1fe47c519de2b | |
| parent | c52ecdab06ff3b4d0f8914951eb74dc8b049f51c (diff) | |
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>
| -rw-r--r-- | arch/i386/mm/fault.c | 5 | ||||
| -rw-r--r-- | arch/x86_64/mm/fault.c | 6 |
2 files changed, 11 insertions, 0 deletions
diff --git a/arch/i386/mm/fault.c b/arch/i386/mm/fault.c index 29d7d61543a..1ecb3e43b52 100644 --- a/arch/i386/mm/fault.c +++ b/arch/i386/mm/fault.c @@ -458,6 +458,11 @@ bad_area: bad_area_nosemaphore: /* User mode accesses just cause a SIGSEGV */ if (error_code & 4) { + /* + * It's possible to have interrupts off here. + */ + local_irq_enable(); + /* * Valid to do another page fault here because this one came * from user space. 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; |