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| author | Keshavamurthy Anil S <anil.s.keshavamurthy@intel.com> | 2005-09-06 15:19:35 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-09-07 16:58:01 -0700 |
| commit | deac66ae454cacf942c051b86d9232af546fb187 (patch) | |
| tree | 17a72e7a2dcf2d1a93a6afdef661f290b1888f1c /kernel/kprobes.c | |
| parent | bce0649417d6e71f6df8ab7b11103d247913b142 (diff) | |
| download | lwn-deac66ae454cacf942c051b86d9232af546fb187.tar.gz lwn-deac66ae454cacf942c051b86d9232af546fb187.zip | |
[PATCH] kprobes: fix bug when probed on task and isr functions
This patch fixes a race condition where in system used to hang or sometime
crash within minutes when kprobes are inserted on ISR routine and a task
routine.
The fix has been stress tested on i386, ia64, pp64 and on x86_64. To
reproduce the problem insert kprobes on schedule() and do_IRQ() functions
and you should see hang or system crash.
Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Acked-by: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/kprobes.c')
| -rw-r--r-- | kernel/kprobes.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 3b7653f2e7ae..f3ea492ab44d 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -155,14 +155,36 @@ void __kprobes free_insn_slot(kprobe_opcode_t *slot) /* Locks kprobe: irqs must be disabled */ void __kprobes lock_kprobes(void) { + unsigned long flags = 0; + + /* Avoiding local interrupts to happen right after we take the kprobe_lock + * and before we get a chance to update kprobe_cpu, this to prevent + * deadlock when we have a kprobe on ISR routine and a kprobe on task + * routine + */ + local_irq_save(flags); + spin_lock(&kprobe_lock); kprobe_cpu = smp_processor_id(); + + local_irq_restore(flags); } void __kprobes unlock_kprobes(void) { + unsigned long flags = 0; + + /* Avoiding local interrupts to happen right after we update + * kprobe_cpu and before we get a a chance to release kprobe_lock, + * this to prevent deadlock when we have a kprobe on ISR routine and + * a kprobe on task routine + */ + local_irq_save(flags); + kprobe_cpu = NR_CPUS; spin_unlock(&kprobe_lock); + + local_irq_restore(flags); } /* You have to be holding the kprobe_lock */ |