Bluetooth: 6lowpan: fix delay work init in add_peer_chan()
authorMichael Scott <michael.scott@linaro.org>
Wed, 29 Mar 2017 06:10:54 +0000 (23:10 -0700)
committerMarcel Holtmann <marcel@holtmann.org>
Wed, 12 Apr 2017 20:02:39 +0000 (22:02 +0200)
commitd2891c4d071d807f01cc911dc42a68f4568d65cf
tree11fe32602ffc595edfca746689440d392e2b42f2
parentdcb9cfaa5ea9aa0ec08aeb92582ccfe3e4c719a9
Bluetooth: 6lowpan: fix delay work init in add_peer_chan()

When adding 6lowpan devices very rapidly we sometimes see a crash:
[23122.306615] CPU: 2 PID: 0 Comm: swapper/2 Not tainted 4.9.0-43-arm64 #1 Debian 4.9.9.linaro.43-1
[23122.315400] Hardware name: HiKey Development Board (DT)
[23122.320623] task: ffff800075443080 task.stack: ffff800075484000
[23122.326551] PC is at expire_timers+0x70/0x150
[23122.330907] LR is at run_timer_softirq+0xa0/0x1a0
[23122.335616] pc : [<ffff000008142dd8>] lr : [<ffff000008142f58>] pstate: 600001c5

This was due to add_peer_chan() unconditionally initializing the
lowpan_btle_dev->notify_peers delayed work structure, even if the
lowpan_btle_dev passed into add_peer_chan() had previously been
initialized.

Normally, this would go unnoticed as the delayed work timer is set for
100 msec, however when calling add_peer_chan() faster than 100 msec it
clears out a previously queued delay work causing the crash above.

To fix this, let add_peer_chan() know when a new lowpan_btle_dev is passed
in so that it only performs the delay work initialization when needed.

Signed-off-by: Michael Scott <michael.scott@linaro.org>
Acked-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
net/bluetooth/6lowpan.c