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authorAndi Kleen <ak@suse.de>2006-07-28 16:44:42 +0400
committerLinus Torvalds <torvalds@g5.osdl.org>2006-07-29 06:28:00 +0400
commitd5a2601734bcc740ee78dc4cb0c56b5687da7bd9 (patch)
tree42146e7eda57909a475ad69cee5cacbf39033cff /arch/i386
parent5d2edfe004f5d0f3d805967bd6b4ada95e6aa419 (diff)
downloadlinux-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.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/i386/kernel/time.c b/arch/i386/kernel/time.c
index 8705c0f05788..edd00f6cee37 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;