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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/trace
parent5cf99a0f3161bc3ae2391269d134d6bf7e26f00e (diff)
downloadlinux-1aed58e67a6ec1e7a18bfabe8ba6ec2d27c15636.tar.gz
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/trace')
0 files changed, 0 insertions, 0 deletions