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| author | David S. Miller <davem@davemloft.net> | 2014-09-07 21:41:53 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2014-09-07 21:41:53 -0700 |
| commit | eb84d6b60491a3ca3d90d62ee5346b007770d40d (patch) | |
| tree | 22aadf9ada15e1ae5ba4c400aafab6f2541996e6 /kernel/kprobes.c | |
| parent | 97a13e5289baa96eaddd06e61d277457d837af3a (diff) | |
| parent | d030671f3f261e528dc6e396a13f10859a74ae7c (diff) | |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Diffstat (limited to 'kernel/kprobes.c')
| -rw-r--r-- | kernel/kprobes.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 734e9a7d280..3995f546d0f 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1778,7 +1778,18 @@ static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs) unsigned long hash, flags = 0; struct kretprobe_instance *ri; - /*TODO: consider to only swap the RA after the last pre_handler fired */ + /* + * To avoid deadlocks, prohibit return probing in NMI contexts, + * just skip the probe and increase the (inexact) 'nmissed' + * statistical counter, so that the user is informed that + * something happened: + */ + if (unlikely(in_nmi())) { + rp->nmissed++; + return 0; + } + + /* TODO: consider to only swap the RA after the last pre_handler fired */ hash = hash_ptr(current, KPROBE_HASH_BITS); raw_spin_lock_irqsave(&rp->lock, flags); if (!hlist_empty(&rp->free_instances)) { |