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authorRavi Bangoria <ravi.bangoria@linux.ibm.com>2018-12-05 09:04:23 +0530
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2018-12-05 23:05:13 -0500
commit1aed58e67a6ec1e7a18bfabe8ba6ec2d27c15636 (patch)
treecf082224136d02e3f332934e6ee9cc97f146b600 /kernel/events
parent5cf99a0f3161bc3ae2391269d134d6bf7e26f00e (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>
Diffstat (limited to 'kernel/events')
-rw-r--r--kernel/events/uprobes.c2
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);
}
}