diff options
| author | Ravi Bangoria | 2018-12-05 09:04:23 +0530 |
|---|---|---|
| committer | Steven Rostedt (VMware) | 2018-12-05 23:05:13 -0500 |
| commit | 1aed58e67a6ec1e7a18bfabe8ba6ec2d27c15636 (patch) | |
| tree | cf082224136d02e3f332934e6ee9cc97f146b600 | |
| parent | 5cf99a0f3161bc3ae2391269d134d6bf7e26f00e (diff) | |
Uprobes: Fix kernel oops with delayed_uprobe_remove()
There could be a race between task exit and probe unregister:
exit_mm()
mmput()
__mmput() uprobe_unregister()
uprobe_clear_state() put_uprobe()
delayed_uprobe_remove() delayed_uprobe_remove()
put_uprobe() is calling delayed_uprobe_remove() without taking
delayed_uprobe_lock and thus the race sometimes results in a
kernel crash. Fix this by taking delayed_uprobe_lock before
calling delayed_uprobe_remove() from put_uprobe().
Detailed crash log can be found at:
Link: http://lkml.kernel.org/r/000000000000140c370577db5ece@google.com
Link: http://lkml.kernel.org/r/20181205033423.26242-1-ravi.bangoria@linux.ibm.com
Acked-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Reported-by: syzbot+cb1fb754b771caca0a88@syzkaller.appspotmail.com
Fixes: 1cc33161a83d ("uprobes: Support SDT markers having reference count (semaphore)")
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| -rw-r--r-- | kernel/events/uprobes.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 96d4bee83489..98b9312ce6b2 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -572,7 +572,9 @@ static void put_uprobe(struct uprobe *uprobe) * gets called, we don't get a chance to remove uprobe from * delayed_uprobe_list from remove_breakpoint(). Do it here. */ + mutex_lock(&delayed_uprobe_lock); delayed_uprobe_remove(uprobe, NULL); + mutex_unlock(&delayed_uprobe_lock); kfree(uprobe); } } |