]> git.baikalelectronics.ru Git - kernel.git/commit
Uprobes: Fix kernel oops with delayed_uprobe_remove()
authorRavi Bangoria <ravi.bangoria@linux.ibm.com>
Wed, 5 Dec 2018 03:34:23 +0000 (09:04 +0530)
committerSteven Rostedt (VMware) <rostedt@goodmis.org>
Thu, 6 Dec 2018 04:05:13 +0000 (23:05 -0500)
commit37a80e22fbe30af85204df3d2a0c77983b1a697d
treecf082224136d02e3f332934e6ee9cc97f146b600
parent7c34107ddb1723f45e7376c12de43eaa6fca502b
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: 75e358dfd9c2 ("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>
kernel/events/uprobes.c