INFO: task krfcommd:2878 blocked for more than 143 seconds. Not tainted 5.14.0-rc7-next-20210826-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:krfcommd state:D stack:29112 pid: 2878 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4756 [inline] __schedule+0x940/0x26f0 kernel/sched/core.c:6029 schedule+0xd3/0x270 kernel/sched/core.c:6108 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6167 __mutex_lock_common kernel/locking/mutex.c:669 [inline] __mutex_lock+0xa34/0x12f0 kernel/locking/mutex.c:729 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-executor410:6580 blocked for more than 143 seconds. Not tainted 5.14.0-rc7-next-20210826-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor410 state:D stack:27528 pid: 6580 ppid: 6548 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:4756 [inline] __schedule+0x940/0x26f0 kernel/sched/core.c:6029 schedule+0xd3/0x270 kernel/sched/core.c:6108 __lock_sock+0x13d/0x260 net/core/sock.c:2645 lock_sock_nested+0xf6/0x120 net/core/sock.c:3186 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+0x288/0x9f0 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+0xbae/0x2a30 kernel/exit.c:825 do_group_exit+0x125/0x310 kernel/exit.c:922 get_signal+0x47f/0x2160 kernel/signal.c:2846 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: 0033:0x445ff9 RSP: 002b:00007ffe6c26c038 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: fffffffffffffffc RBX: 0000000000000003 RCX: 0000000000445ff9 RDX: 0000000000000080 RSI: 0000000020000000 RDI: 0000000000000005 RBP: 0000000000000004 R08: 000000ff00000001 R09: 000000ff00000001 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000018172b8 R13: 0000000000000072 R14: 00007ffe6c26c090 R15: 0000000000000003 Showing all locks held in the system: 1 lock held by khungtaskd/27: #0: ffffffff8b97f800 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6446 1 lock held by krfcommd/2878: #0: ffffffff8d31d688 (rfcomm_mutex){+.+.}-{3:3}, at: rfcomm_process_sessions net/bluetooth/rfcomm/core.c:1979 [inline] #0: ffffffff8d31d688 (rfcomm_mutex){+.+.}-{3:3}, at: rfcomm_run+0x2ed/0x4a20 net/bluetooth/rfcomm/core.c:2086 1 lock held by in:imklog/6446: #0: ffff88806f0354f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:990 4 locks held by syz-executor410/6580: #0: ffff88806c421a10 (&sb->s_type->i_mutex_key#13){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:786 [inline] #0: ffff88806c421a10 (&sb->s_type->i_mutex_key#13){+.+.}-{3:3}, at: __sock_release+0x86/0x280 net/socket.c:648 #1: ffff8881417c3120 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1612 [inline] #1: ffff8881417c3120 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: rfcomm_sock_shutdown+0x54/0x210 net/bluetooth/rfcomm/sock.c:928 #2: ffffffff8d31d688 (rfcomm_mutex){+.+.}-{3:3}, at: rfcomm_dlc_close+0x34/0x240 net/bluetooth/rfcomm/core.c:507 #3: ffff8881478b4128 (&d->lock){+.+.}-{3:3}, at: __rfcomm_dlc_close+0x162/0x8a0 net/bluetooth/rfcomm/core.c:487 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 27 Comm: khungtaskd Not tainted 5.14.0-rc7-next-20210826-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 CPU: 1 PID: 2956 Comm: systemd-journal Not tainted 5.14.0-rc7-next-20210826-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:check_kcov_mode kernel/kcov.c:163 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x1c/0x60 kernel/kcov.c:197 Code: 8b 45 00 48 63 c9 e9 64 ff ff ff 0f 1f 00 65 8b 05 f9 0d 8c 7e 89 c1 48 8b 34 24 81 e1 00 01 00 00 65 48 8b 14 25 40 f0 01 00 00 01 ff 00 74 0e 85 c9 74 35 8b 82 3c 15 00 00 85 c0 74 2b 8b RSP: 0018:ffffc900024efd20 EFLAGS: 00000246 RAX: 0000000080000000 RBX: ffff88801a6d6620 RCX: 0000000000000000 RDX: ffff88807c11b900 RSI: ffffffff81348e26 RDI: ffff88801a6d6620 RBP: 0000000080000000 R08: 0000000000000000 R09: 0000000000000001 R10: ffffffff81c4c90a R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000001 R15: ffffffff8d6e8188 FS: 00007fb5e53908c0(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb5e2767010 CR3: 000000001e2fd000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __phys_addr+0x16/0x140 arch/x86/mm/physaddr.c:17 kmap_to_page include/linux/highmem-internal.h:156 [inline] check_heap_object mm/usercopy.c:236 [inline] __check_object_size mm/usercopy.c:286 [inline] __check_object_size+0x1b5/0x3f0 mm/usercopy.c:256 check_object_size include/linux/thread_info.h:185 [inline] strncpy_from_user+0xaa/0x3e0 lib/strncpy_from_user.c:137 getname_flags.part.0+0x95/0x4f0 fs/namei.c:149 getname_flags+0x9a/0xe0 include/linux/audit.h:319 user_path_at_empty+0x2b/0x90 fs/namei.c:2801 user_path_at include/linux/namei.h:57 [inline] do_faccessat+0x127/0x850 fs/open.c:421 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fb5e464b9c7 Code: 83 c4 08 48 3d 01 f0 ff ff 73 01 c3 48 8b 0d c8 d4 2b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 b8 15 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d a1 d4 2b 00 f7 d8 64 89 01 48 RSP: 002b:00007ffeb6899798 EFLAGS: 00000246 ORIG_RAX: 0000000000000015 RAX: ffffffffffffffda RBX: 00007ffeb689c6b0 RCX: 00007fb5e464b9c7 RDX: 00007fb5e50bca00 RSI: 0000000000000000 RDI: 000055e6475159a3 RBP: 00007ffeb68997d0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000069 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007ffeb689c6b0 R15: 00007ffeb6899cc0 ---------------- Code disassembly (best guess): 0: 8b 45 00 mov 0x0(%rbp),%eax 3: 48 63 c9 movslq %ecx,%rcx 6: e9 64 ff ff ff jmpq 0xffffff6f b: 0f 1f 00 nopl (%rax) e: 65 8b 05 f9 0d 8c 7e mov %gs:0x7e8c0df9(%rip),%eax # 0x7e8c0e0e 15: 89 c1 mov %eax,%ecx 17: 48 8b 34 24 mov (%rsp),%rsi 1b: 81 e1 00 01 00 00 and $0x100,%ecx 21: 65 48 8b 14 25 40 f0 mov %gs:0x1f040,%rdx 28: 01 00 * 2a: a9 00 01 ff 00 test $0xff0100,%eax <-- trapping instruction 2f: 74 0e je 0x3f 31: 85 c9 test %ecx,%ecx 33: 74 35 je 0x6a 35: 8b 82 3c 15 00 00 mov 0x153c(%rdx),%eax 3b: 85 c0 test %eax,%eax 3d: 74 2b je 0x6a 3f: 8b .byte 0x8b