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| author | Tejun Heo <tj@kernel.org> | 2014-09-24 19:00:21 +0200 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2014-09-24 19:00:21 +0200 |
| commit | d06efebf0c37d438fcf07057be00dd40fcfce08d (patch) | |
| tree | 31a0786d132aadf4cbb9725f3f444ef6e1052128 /kernel/kprobes.c | |
| parent | Revert "percpu: free percpu allocation info for uniprocessor system" (diff) | |
| parent | blk-mq, percpu_ref: implement a kludge for SCSI blk-mq stall during probe (diff) | |
| download | linux-d06efebf0c37d438fcf07057be00dd40fcfce08d.tar.xz linux-d06efebf0c37d438fcf07057be00dd40fcfce08d.zip | |
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block into for-3.18
This is to receive 0a30288da1ae ("blk-mq, percpu_ref: implement a
kludge for SCSI blk-mq stall during probe") which implements
__percpu_ref_kill_expedited() to work around SCSI blk-mq stall. The
commit reverted and patches to implement proper fix will be added.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>
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 734e9a7d280b..3995f546d0f3 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)) { |