Re: [syzbot] [wireless?] WARNING in rfkill_unregister
From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Date: 2026-01-02 10:28:45
Also in:
linux-wireless, lkml
On 2026/01/01 21:07, Johannes Berg wrote:
If this email doesn't wake anyone up, I'll do that on the next syzbot rfkill vs. NFC report I get :)
Is the next report https://syzkaller.appspot.com/bug?extid=ef8f802abdb9a32343fc ? Obviously deadlocked (but lockdep cannot report due to dev->mutex being marked as novalidate). INFO: task syz.4.1326:10654 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.1326 state:D stack:27848 pid:10654 tgid:10645 ppid:5823 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x14bc/0x5000 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0x165/0x360 kernel/sched/core.c:6960 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7017 __mutex_lock_common kernel/locking/mutex.c:692 [inline] __mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:776 rfkill_unregister+0xc8/0x220 net/rfkill/core.c:1145 nfc_unregister_device+0x96/0x300 net/nfc/core.c:1167 virtual_ncidev_close+0x56/0x90 drivers/nfc/virtual_ncidev.c:172 __fput+0x44c/0xa70 fs/file_table.c:468 fput_close_sync+0x113/0x220 fs/file_table.c:573 __do_sys_close fs/open.c:1573 [inline] __se_sys_close fs/open.c:1558 [inline] __x64_sys_close+0x7f/0x110 fs/open.c:1558 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f 2 locks held by syz.4.1326/10654: #0: ffff888078c13100 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline] #0: ffff888078c13100 (&dev->mutex){....}-{4:4}, at: nfc_unregister_device+0x63/0x300 net/nfc/core.c:1165 #1: ffffffff8f5fd668 (rfkill_global_mutex){+.+.}-{4:4}, at: rfkill_unregister+0xc8/0x220 net/rfkill/core.c:1145 INFO: task syz.3.1329:10652 blocked for more than 144 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.1329 state:D stack:26824 pid:10652 tgid:10651 ppid:5820 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x14bc/0x5000 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0x165/0x360 kernel/sched/core.c:6960 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7017 __mutex_lock_common kernel/locking/mutex.c:692 [inline] __mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:776 device_lock include/linux/device.h:895 [inline] nfc_dev_down+0x3b/0x290 net/nfc/core.c:143 nfc_rfkill_set_block+0x2d/0x100 net/nfc/core.c:179 rfkill_set_block+0x1d2/0x440 net/rfkill/core.c:346 rfkill_fop_write+0x44b/0x570 net/rfkill/core.c:1301 vfs_write+0x27e/0xb30 fs/read_write.c:684 ksys_write+0x145/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f 2 locks held by syz.3.1329/10652: #0: ffffffff8f5fd668 (rfkill_global_mutex){+.+.}-{4:4}, at: rfkill_fop_write+0x191/0x570 net/rfkill/core.c:1293 #1: ffff888078c13100 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline] #1: ffff888078c13100 (&dev->mutex){....}-{4:4}, at: nfc_dev_down+0x3b/0x290 net/nfc/core.c:143