diff options
| author | Andi Kleen <ak@suse.de> | 2006-07-28 12:44:42 (GMT) |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-07-29 02:28:00 (GMT) |
| commit | d5a2601734bcc740ee78dc4cb0c56b5687da7bd9 (patch) | |
| tree | 42146e7eda57909a475ad69cee5cacbf39033cff /arch/i386 | |
| parent | 5d2edfe004f5d0f3d805967bd6b4ada95e6aa419 (diff) | |
| download | linux-d5a2601734bcc740ee78dc4cb0c56b5687da7bd9.tar.xz | |
[PATCH] i386/x86-64: Add user_mode checks to profile_pc for oprofile
Fixes a obscure user space triggerable crash during oprofiling.
Oprofile calls profile_pc from NMIs even when user_mode(regs) is not true and
the program counter is inside the kernel lock section. This opens
a race - when a user program jumps to a kernel lock address and
a NMI happens before the illegal page fault exception is raised
and the program has a unmapped esp or ebp then the kernel could
oops. NMIs have a higher priority than exceptions so that could
happen.
Add user_mode checks to i386/x86-64 profile_pc to prevent that.
Cc: John Levon <levon@movementarian.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/i386')
| -rw-r--r-- | arch/i386/kernel/time.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/i386/kernel/time.c b/arch/i386/kernel/time.c index 8705c0f..edd00f6 100644 --- a/arch/i386/kernel/time.c +++ b/arch/i386/kernel/time.c @@ -135,7 +135,7 @@ unsigned long profile_pc(struct pt_regs *regs) { unsigned long pc = instruction_pointer(regs); - if (in_lock_functions(pc)) + if (!user_mode_vm(regs) && in_lock_functions(pc)) return *(unsigned long *)(regs->ebp + 4); return pc; |