Hello, syzbot found the following issue on: HEAD commit: 8ca403f3e7a2 Add linux-next specific files for 20210811 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=12b0745e300000 kernel config: https://syzkaller.appspot.com/x/.config?x=d1151ef35b04cc3a dashboard link: https://syzkaller.appspot.com/bug?extid=bd221c9eb2a95e43c20f compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=119f42a1300000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1707e231300000 The issue was bisected to: commit b7ce436a5d798bc59e71797952566608a4b4626b Author: Desmond Cheong Zhi Xi <desmondcheongzx@xxxxxxxxx> Date: Tue Aug 10 04:14:09 2021 +0000 Bluetooth: switch to lock_sock in RFCOMM bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=12e68b26300000 final oops: https://syzkaller.appspot.com/x/report.txt?x=11e68b26300000 console output: https://syzkaller.appspot.com/x/log.txt?x=16e68b26300000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+bd221c9eb2a95e43c20f@xxxxxxxxxxxxxxxxxxxxxxxxx Fixes: b7ce436a5d79 ("Bluetooth: switch to lock_sock in RFCOMM") INFO: task krfcommd:2895 blocked for more than 143 seconds. Not tainted 5.14.0-rc5-next-20210811-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:krfcommd state:D stack:29640 pid: 2895 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4698 [inline] __schedule+0x93a/0x26f0 kernel/sched/core.c:5955 schedule+0xd3/0x270 kernel/sched/core.c:6034 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6093 __mutex_lock_common kernel/locking/mutex.c:1036 [inline] __mutex_lock+0xa46/0x1300 kernel/locking/mutex.c:1096 rfcomm_process_sessions net/bluetooth/rfcomm/core.c:1979 [inline] rfcomm_run+0x2ed/0x4a20 net/bluetooth/rfcomm/core.c:2086 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 INFO: task syz-executor247:6597 blocked for more than 143 seconds. Not tainted 5.14.0-rc5-next-20210811-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor247 state:D stack:27600 pid: 6597 ppid: 6565 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:4698 [inline] __schedule+0x93a/0x26f0 kernel/sched/core.c:5955 schedule+0xd3/0x270 kernel/sched/core.c:6034 __lock_sock+0x13d/0x260 net/core/sock.c:2645 lock_sock_nested+0xf6/0x120 net/core/sock.c:3178 lock_sock include/net/sock.h:1612 [inline] rfcomm_sk_state_change+0xb4/0x390 net/bluetooth/rfcomm/sock.c:73 __rfcomm_dlc_close+0x1b6/0x8a0 net/bluetooth/rfcomm/core.c:489 rfcomm_dlc_close+0x1ea/0x240 net/bluetooth/rfcomm/core.c:520 __rfcomm_sock_close+0xac/0x260 net/bluetooth/rfcomm/sock.c:220 rfcomm_sock_shutdown+0xe9/0x210 net/bluetooth/rfcomm/sock.c:931 rfcomm_sock_release+0x5f/0x140 net/bluetooth/rfcomm/sock.c:951 __sock_release+0xcd/0x280 net/socket.c:649 sock_close+0x18/0x20 net/socket.c:1311 __fput+0x288/0x920 fs/file_table.c:280 task_work_run+0xdd/0x1a0 kernel/task_work.c:164 exit_task_work include/linux/task_work.h:32 [inline] do_exit+0xbd4/0x2a60 kernel/exit.c:825 do_group_exit+0x125/0x310 kernel/exit.c:922 get_signal+0x47f/0x2160 kernel/signal.c:2831 arch_do_signal_or_restart+0x2a9/0x1c40 arch/x86/kernel/signal.c:865 handle_signal_work kernel/entry/common.c:148 [inline] exit_to_user_mode_loop kernel/entry/common.c:172 [inline] exit_to_user_mode_prepare+0x17d/0x290 kernel/entry/common.c:209 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:302 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x446009 RSP: 002b:00007ffda734ed78 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: fffffffffffffffc RBX: 0000000000000003 RCX: 0000000000446009 RDX: 0000000000000080 RSI: 0000000020000000 RDI: 0000000000000004 RBP: 0000000000000003 R08: 000000ff00000001 R09: 000000ff00000001 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000001dee2b8 R13: 0000000000000072 R14: 00007ffda734edd0 R15: 0000000000000003 INFO: lockdep is turned off. NMI backtrace for cpu 0 CPU: 0 PID: 27 Comm: khungtaskd Not tainted 5.14.0-rc5-next-20210811-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1ae/0x220 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:254 [inline] watchdog+0xcb7/0xed0 kernel/hung_task.c:339 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline] NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline] NMI backtrace for cpu 1 skipped: idling at acpi_safe_halt drivers/acpi/processor_idle.c:109 [inline] NMI backtrace for cpu 1 skipped: idling at acpi_idle_do_entry+0x1c6/0x250 drivers/acpi/processor_idle.c:553 --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. For information about bisection process see: https://goo.gl/tpsmEJ#bisection syzbot can test patches for this issue, for details see: https://goo.gl/tpsmEJ#testing-patches
