• Miaoqing Pan's avatar
    ath9k: fix an invalid pointer dereference in ath9k_rng_stop() · 48879676
    Miaoqing Pan authored
    commit 07246c11 upstream.
    
    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=196043Reported-by: default avatarGiulio Genovese <giulio.genovese@gmail.com>
    Tested-by: default avatarGiulio Genovese <giulio.genovese@gmail.com>
    Signed-off-by: default avatarMiaoqing Pan <miaoqing@codeaurora.org>
    Signed-off-by: default avatarKalle Valo <kvalo@qca.qualcomm.com>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    48879676
rng.c 2.99 KB