miaoqing pan <miaoqing@xxxxxxxxxxxxxx> wrote: > The bug was triggered when do suspend/resuming continuously > on Dell XPS L322X/0PJHXN version 9333 (2013) with kernel > 4.12.0-041200rc4-generic. But can't reproduce on DELL > E5440 + AR9300 PCIE chips. > > The warning is caused by accessing invalid pointer sc->rng_task. > sc->rng_task is not be cleared after kthread_stop(sc->rng_task) > be called in ath9k_rng_stop(). Because the kthread is stopped > before ath9k_rng_kthread() be scheduled. > > So set sc->rng_task to null after kthread_stop(sc->rng_task) to > resolve this issue. > > WARNING: CPU: 0 PID: 984 at linux/kernel/kthread.c:71 kthread_stop+0xf1/0x100 > CPU: 0 PID: 984 Comm: NetworkManager Not tainted 4.12.0-041200rc4-generic #201706042031 > Hardware name: Dell Inc. Dell System XPS L322X/0PJHXN, BIOS A09 05/15/2013 > task: ffff950170fdda00 task.stack: ffffa22c01538000 > RIP: 0010:kthread_stop+0xf1/0x100 > RSP: 0018:ffffa22c0153b5b0 EFLAGS: 00010246 > RAX: ffffffffa6257800 RBX: ffff950171b79560 RCX: 0000000000000000 > RDX: 0000000080000000 RSI: 000000007fffffff RDI: ffff9500ac9a9680 > RBP: ffffa22c0153b5c8 R08: 0000000000000000 R09: 0000000000000000 > R10: ffffa22c0153b648 R11: ffff9501768004b8 R12: ffff9500ac9a9680 > R13: ffff950171b79f70 R14: ffff950171b78780 R15: ffff9501749dc018 > FS: 00007f0d6bfd5540(0000) GS:ffff95017f200000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007fc190161a08 CR3: 0000000232906000 CR4: 00000000001406f0 > Call Trace: > ath9k_rng_stop+0x1a/0x20 [ath9k] > ath9k_stop+0x3b/0x1d0 [ath9k] > drv_stop+0x33/0xf0 [mac80211] > ieee80211_stop_device+0x43/0x50 [mac80211] > ieee80211_do_stop+0x4f2/0x810 [mac80211] > > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=196043 > Reported-by: Giulio Genovese <giulio.genovese@xxxxxxxxx> > Tested-by: Giulio Genovese <giulio.genovese@xxxxxxxxx> > Cc: <stable@xxxxxxxxxxxxxxx> > Signed-off-by: Miaoqing Pan <miaoqing@xxxxxxxxxxxxxx> > Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxxxx> 3 patches applied to ath-next branch of ath.git, thanks. 07246c115801 ath9k: fix an invalid pointer dereference in ath9k_rng_stop() 473becac4b31 ath9k: avoid potential freezing during random generator read f23cdfb3fe8f ath9k: Use mutex_lock to avoid potential race in start/stop rng -- https://patchwork.kernel.org/patch/9803211/ https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
