[syzbot] INFO: task can't die in __lock

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* [syzbot] INFO: task can't die in __lock_sock
@ 2021-08-15 16:47 syzbot
  2021-09-01 17:34 ` syzbot
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: syzbot @ 2021-08-15 16:47 UTC (permalink / raw)
  To: davem, johan.hedberg, kuba, linux-bluetooth, linux-kernel,
	luiz.dentz, marcel, netdev, syzkaller-bugs

Hello,

syzbot found the following issue on:

HEAD commit:    4b358aabb93a Add linux-next specific files for 20210813
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1603f181300000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b99612666fbe2d6a
dashboard link: https://syzkaller.appspot.com/bug?extid=7d51f807c81b190a127d
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7d51f807c81b190a127d@syzkaller.appspotmail.com

INFO: task syz-executor.4:21120 can't die for more than 143 seconds.
task:syz-executor.4  state:D stack:28448 pid:21120 ppid:  6572 flags:0x00004004
Call Trace:
 context_switch kernel/sched/core.c:4711 [inline]
 __schedule+0x93a/0x26f0 kernel/sched/core.c:5966
 schedule+0xd3/0x270 kernel/sched/core.c:6045
 __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]
 bt_sock_wait_state+0x249/0x590 net/bluetooth/af_bluetooth.c:557
 rfcomm_sock_connect+0x3a5/0x460 net/bluetooth/rfcomm/sock.c:416
 __sys_connect_file+0x155/0x1a0 net/socket.c:1890
 __sys_connect+0x161/0x190 net/socket.c:1907
 __do_sys_connect net/socket.c:1917 [inline]
 __se_sys_connect net/socket.c:1914 [inline]
 __x64_sys_connect+0x6f/0xb0 net/socket.c:1914
 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: 0033:0x4665e9
RSP: 002b:00007fa7b02bf188 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665e9
RDX: 0000000000000080 RSI: 0000000020000000 RDI: 0000000000000004
RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80
R13: 00007fffd83567bf R14: 00007fa7b02bf300 R15: 0000000000022000
INFO: task syz-executor.4:21120 blocked for more than 143 seconds.
      Not tainted 5.14.0-rc5-next-20210813-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.4  state:D stack:28448 pid:21120 ppid:  6572 flags:0x00004004
Call Trace:
 context_switch kernel/sched/core.c:4711 [inline]
 __schedule+0x93a/0x26f0 kernel/sched/core.c:5966
 schedule+0xd3/0x270 kernel/sched/core.c:6045
 __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]
 bt_sock_wait_state+0x249/0x590 net/bluetooth/af_bluetooth.c:557
 rfcomm_sock_connect+0x3a5/0x460 net/bluetooth/rfcomm/sock.c:416
 __sys_connect_file+0x155/0x1a0 net/socket.c:1890
 __sys_connect+0x161/0x190 net/socket.c:1907
 __do_sys_connect net/socket.c:1917 [inline]
 __se_sys_connect net/socket.c:1914 [inline]
 __x64_sys_connect+0x6f/0xb0 net/socket.c:1914
 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: 0033:0x4665e9
RSP: 002b:00007fa7b02bf188 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665e9
RDX: 0000000000000080 RSI: 0000000020000000 RDI: 0000000000000004
RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80
R13: 00007fffd83567bf R14: 00007fa7b02bf300 R15: 0000000000022000
INFO: task syz-executor.4:21124 can't die for more than 143 seconds.
task:syz-executor.4  state:D stack:29104 pid:21124 ppid:  6572 flags:0x00000004
Call Trace:
 context_switch kernel/sched/core.c:4711 [inline]
 __schedule+0x93a/0x26f0 kernel/sched/core.c:5966
 schedule+0xd3/0x270 kernel/sched/core.c:6045
 __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
 __sys_shutdown_sock net/socket.c:2242 [inline]
 __sys_shutdown_sock net/socket.c:2236 [inline]
 __sys_shutdown+0xf1/0x1b0 net/socket.c:2254
 __do_sys_shutdown net/socket.c:2262 [inline]
 __se_sys_shutdown net/socket.c:2260 [inline]
 __x64_sys_shutdown+0x50/0x70 net/socket.c:2260
 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: 0033:0x4665e9
RSP: 002b:00007fa7b029e188 EFLAGS: 00000246 ORIG_RAX: 0000000000000030
RAX: ffffffffffffffda RBX: 000000000056c038 RCX: 00000000004665e9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c038
R13: 00007fffd83567bf R14: 00007fa7b029e300 R15: 0000000000022000
INFO: task syz-executor.4:21124 blocked for more than 143 seconds.
      Not tainted 5.14.0-rc5-next-20210813-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.4  state:D stack:29104 pid:21124 ppid:  6572 flags:0x00000004
Call Trace:
 context_switch kernel/sched/core.c:4711 [inline]
 __schedule+0x93a/0x26f0 kernel/sched/core.c:5966
 schedule+0xd3/0x270 kernel/sched/core.c:6045
 __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
 __sys_shutdown_sock net/socket.c:2242 [inline]
 __sys_shutdown_sock net/socket.c:2236 [inline]
 __sys_shutdown+0xf1/0x1b0 net/socket.c:2254
 __do_sys_shutdown net/socket.c:2262 [inline]
 __se_sys_shutdown net/socket.c:2260 [inline]
 __x64_sys_shutdown+0x50/0x70 net/socket.c:2260
 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: 0033:0x4665e9
RSP: 002b:00007fa7b029e188 EFLAGS: 00000246 ORIG_RAX: 0000000000000030
RAX: ffffffffffffffda RBX: 000000000056c038 RCX: 00000000004665e9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c038
R13: 00007fffd83567bf R14: 00007fa7b029e300 R15: 0000000000022000
INFO: lockdep is turned off.
NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted 5.14.0-rc5-next-20210813-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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 6267 Comm: in:imklog Not tainted 5.14.0-rc5-next-20210813-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__sanitizer_cov_trace_pc+0x37/0x60 kernel/kcov.c:197
Code: 81 e1 00 01 00 00 65 48 8b 14 25 40 f0 01 00 a9 00 01 ff 00 74 0e 85 c9 74 35 8b 82 3c 15 00 00 85 c0 74 2b 8b 82 18 15 00 00 <83> f8 02 75 20 48 8b 8a 20 15 00 00 8b 92 1c 15 00 00 48 8b 01 48
RSP: 0018:ffffc9000c577648 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff8880775b9c80 RSI: ffffffff83f260b5 RDI: 0000000000000003
RBP: 0000000000000000 R08: 000000000000002f R09: 0000000000000000
R10: ffffffff83f26037 R11: 0000000000000000 R12: 0000000000000004
R13: ffffffff898ca243 R14: ffffc9008c577a4f R15: ffffc9000c577a51
FS:  00007f9245542700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9a4b72b008 CR3: 000000006fe68000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 number+0x205/0xae0 lib/vsprintf.c:490
 vsnprintf+0xf09/0x14f0 lib/vsprintf.c:2875
 sprintf+0xc0/0x100 lib/vsprintf.c:3011
 print_syslog kernel/printk/printk.c:1257 [inline]
 info_print_prefix+0x2d5/0x340 kernel/printk/printk.c:1287
 record_print_text+0x14d/0x3e0 kernel/printk/printk.c:1339
 syslog_print+0x48c/0x580 kernel/printk/printk.c:1539
 do_syslog.part.0+0x202/0x640 kernel/printk/printk.c:1658
 do_syslog+0x49/0x60 kernel/printk/printk.c:1643
 kmsg_read+0x90/0xb0 fs/proc/kmsg.c:40
 pde_read fs/proc/inode.c:311 [inline]
 proc_reg_read+0x119/0x300 fs/proc/inode.c:321
 vfs_read+0x1b5/0x600 fs/read_write.c:494
 ksys_read+0x12d/0x250 fs/read_write.c:634
 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: 0033:0x7f9247b8522d
Code: c1 20 00 00 75 10 b8 00 00 00 00 0f 05 48 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 4e fc ff ff 48 89 04 24 b8 00 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 97 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007f9245521580 EFLAGS: 00000293 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f9247b8522d
RDX: 0000000000001fa0 RSI: 00007f9245521da0 RDI: 0000000000000004
RBP: 000055eb855a59d0 R08: 0000000000000000 R09: 0000000004000001
R10: 0000000000000001 R11: 0000000000000293 R12: 00007f9245521da0
R13: 0000000000001fa0 R14: 0000000000001f9f R15: 00007f9245521dd7
----------------
Code disassembly (best guess):
   0:	81 e1 00 01 00 00    	and    $0x100,%ecx
   6:	65 48 8b 14 25 40 f0 	mov    %gs:0x1f040,%rdx
   d:	01 00 
   f:	a9 00 01 ff 00       	test   $0xff0100,%eax
  14:	74 0e                	je     0x24
  16:	85 c9                	test   %ecx,%ecx
  18:	74 35                	je     0x4f
  1a:	8b 82 3c 15 00 00    	mov    0x153c(%rdx),%eax
  20:	85 c0                	test   %eax,%eax
  22:	74 2b                	je     0x4f
  24:	8b 82 18 15 00 00    	mov    0x1518(%rdx),%eax
  2a:	83 f8 02             	cmp    $0x2,%eax <-- trapping instruction
  2d:	75 20                	jne    0x4f
  2f:	48 8b 8a 20 15 00 00 	mov    0x1520(%rdx),%rcx
  36:	8b 92 1c 15 00 00    	mov    0x151c(%rdx),%edx
  3c:	48 8b 01             	mov    (%rcx),%rax
  3f:	48                   	rex.W


---
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@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [syzbot] INFO: task can't die in __lock_sock
  2021-08-15 16:47 [syzbot] INFO: task can't die in __lock_sock syzbot
@ 2021-09-01 17:34 ` syzbot
  2021-09-02  1:34 ` syzbot
       [not found] ` <20210902031752.2502-1-hdanton@sina.com>
  2 siblings, 0 replies; 4+ messages in thread
From: syzbot @ 2021-09-01 17:34 UTC (permalink / raw)
  To: davem, desmondcheongzx, johan.hedberg, kuba, linux-bluetooth,
	linux-kernel, luiz.dentz, marcel, netdev, syzkaller-bugs

syzbot has found a reproducer for the following issue on:

HEAD commit:    c1b13fe76e95 Add linux-next specific files for 20210901
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=12c6034d300000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e2afff7bc32736e5
dashboard link: https://syzkaller.appspot.com/bug?extid=7d51f807c81b190a127d
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=14d42469300000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1107d815300000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7d51f807c81b190a127d@syzkaller.appspotmail.com

INFO: task syz-executor157:6562 blocked for more than 143 seconds.
      Not tainted 5.14.0-next-20210901-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor157 state:D stack:26880 pid: 6562 ppid:  6530 flags:0x00004006
Call Trace:
 context_switch kernel/sched/core.c:4955 [inline]
 __schedule+0x940/0x26f0 kernel/sched/core.c:6302
 schedule+0xd3/0x270 kernel/sched/core.c:6381
 __lock_sock+0x13d/0x260 net/core/sock.c:2644
 lock_sock_nested+0xf6/0x120 net/core/sock.c:3185
 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:1314
 __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:2868
 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: 0033:0x445fe9
RSP: 002b:00007fff85049fe8 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: fffffffffffffffc RBX: 0000000000000003 RCX: 0000000000445fe9
RDX: 0000000000000080 RSI: 0000000020000000 RDI: 0000000000000004
RBP: 0000000000000003 R08: 000000ff00000001 R09: 000000ff00000001
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000014112b8
R13: 0000000000000072 R14: 00007fff8504a040 R15: 0000000000000003

Showing all locks held in the system:
1 lock held by khungtaskd/26:
 #0: ffffffff8b97fbe0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6446
1 lock held by krfcommd/2876:
 #0: ffffffff8d31ede8 (rfcomm_mutex){+.+.}-{3:3}, at: rfcomm_process_sessions net/bluetooth/rfcomm/core.c:1979 [inline]
 #0: ffffffff8d31ede8 (rfcomm_mutex){+.+.}-{3:3}, at: rfcomm_run+0x2ed/0x4a20 net/bluetooth/rfcomm/core.c:2086
1 lock held by in:imklog/6232:
4 locks held by syz-executor157/6562:
 #0: ffff888145e26210 (&sb->s_type->i_mutex_key#13){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:786 [inline]
 #0: ffff888145e26210 (&sb->s_type->i_mutex_key#13){+.+.}-{3:3}, at: __sock_release+0x86/0x280 net/socket.c:648
 #1: ffff88801d622120 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1612 [inline]
 #1: ffff88801d622120 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: rfcomm_sock_shutdown+0x54/0x210 net/bluetooth/rfcomm/sock.c:928
 #2: ffffffff8d31ede8 (rfcomm_mutex){+.+.}-{3:3}, at: rfcomm_dlc_close+0x34/0x240 net/bluetooth/rfcomm/core.c:507
 #3: ffff88807edd9928 (&d->lock){+.+.}-{3:3}, at: __rfcomm_dlc_close+0x162/0x8a0 net/bluetooth/rfcomm/core.c:487

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 26 Comm: khungtaskd Not tainted 5.14.0-next-20210901-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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 2958 Comm: systemd-journal Not tainted 5.14.0-next-20210901-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+0x7/0x60 kernel/kcov.c:197
Code: fd ff ff b9 ff ff ff ff ba 08 00 00 00 4d 8b 03 48 0f bd ca 49 8b 45 00 48 63 c9 e9 64 ff ff ff 0f 1f 00 65 8b 05 39 e6 8b 7e <89> c1 48 8b 34 24 81 e1 00 01 00 00 65 48 8b 14 25 40 f0 01 00 a9
RSP: 0018:ffffc900014dfde0 EFLAGS: 00000282
RAX: 0000000080000000 RBX: ffffc900014dff58 RCX: 1ffff9200029bfc7
RDX: dffffc0000000000 RSI: 1ffff9200029bfcd RDI: ffffc900014dfe38
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8176c71a
R10: ffffffff81765c97 R11: 0000000000000002 R12: 0000000000000053
R13: 0000000000000002 R14: 0000000000000000 R15: ffffc900014dfe30
FS:  00007f43756768c0(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4372a49000 CR3: 000000001a5d4000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 get_current arch/x86/include/asm/current.h:15 [inline]
 seccomp_run_filters kernel/seccomp.c:402 [inline]
 __seccomp_filter+0x88/0x1040 kernel/seccomp.c:1180
 __secure_computing+0xfc/0x360 kernel/seccomp.c:1311
 syscall_trace_enter.constprop.0+0x94/0x270 kernel/entry/common.c:68
 do_syscall_64+0x16/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f4374931687
Code: 00 b8 ff ff ff ff c3 0f 1f 40 00 48 8b 05 09 d8 2b 00 64 c7 00 5f 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 b8 53 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d e1 d7 2b 00 f7 d8 64 89 01 48
RSP: 002b:00007ffc79978938 EFLAGS: 00000293 ORIG_RAX: 0000000000000053
RAX: ffffffffffffffda RBX: 00007ffc7997b850 RCX: 00007f4374931687
RDX: 00007f43753a2a00 RSI: 00000000000001ed RDI: 00005646c59898a0
RBP: 00007ffc79978970 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000069 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000000 R14: 00007ffc7997b850 R15: 00007ffc79978e60
----------------
Code disassembly (best guess), 3 bytes skipped:
   0:	b9 ff ff ff ff       	mov    $0xffffffff,%ecx
   5:	ba 08 00 00 00       	mov    $0x8,%edx
   a:	4d 8b 03             	mov    (%r11),%r8
   d:	48 0f bd ca          	bsr    %rdx,%rcx
  11:	49 8b 45 00          	mov    0x0(%r13),%rax
  15:	48 63 c9             	movslq %ecx,%rcx
  18:	e9 64 ff ff ff       	jmpq   0xffffff81
  1d:	0f 1f 00             	nopl   (%rax)
  20:	65 8b 05 39 e6 8b 7e 	mov    %gs:0x7e8be639(%rip),%eax        # 0x7e8be660
* 27:	89 c1                	mov    %eax,%ecx <-- trapping instruction
  29:	48 8b 34 24          	mov    (%rsp),%rsi
  2d:	81 e1 00 01 00 00    	and    $0x100,%ecx
  33:	65 48 8b 14 25 40 f0 	mov    %gs:0x1f040,%rdx
  3a:	01 00
  3c:	a9                   	.byte 0xa9


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [syzbot] INFO: task can't die in __lock_sock
  2021-08-15 16:47 [syzbot] INFO: task can't die in __lock_sock syzbot
  2021-09-01 17:34 ` syzbot
@ 2021-09-02  1:34 ` syzbot
       [not found] ` <20210902031752.2502-1-hdanton@sina.com>
  2 siblings, 0 replies; 4+ messages in thread
From: syzbot @ 2021-09-02  1:34 UTC (permalink / raw)
  To: davem, desmondcheongzx, johan.hedberg, kuba, linux-bluetooth,
	linux-kernel, luiz.dentz, luiz.von.dentz, marcel, netdev,
	syzkaller-bugs

syzbot has bisected this issue to:

commit b7ce436a5d798bc59e71797952566608a4b4626b
Author: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
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=16f90ffe300000
start commit:   29ce8f970107 Merge git://git.kernel.org/pub/scm/linux/kern..
git tree:       net-next
final oops:     https://syzkaller.appspot.com/x/report.txt?x=15f90ffe300000
console output: https://syzkaller.appspot.com/x/log.txt?x=11f90ffe300000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d2f9d4c9ff8c5ae7
dashboard link: https://syzkaller.appspot.com/bug?extid=7d51f807c81b190a127d
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1630a66d300000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16d07c6d300000

Reported-by: syzbot+7d51f807c81b190a127d@syzkaller.appspotmail.com
Fixes: b7ce436a5d79 ("Bluetooth: switch to lock_sock in RFCOMM")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

^ permalink raw reply	[flat|nested] 4+ messages in thread

[parent not found: <20210902031752.2502-1-hdanton@sina.com>]

* Re: [syzbot] INFO: task can't die in __lock_sock
       [not found] ` <20210902031752.2502-1-hdanton@sina.com>
@ 2021-09-02 19:54   ` Desmond Cheong Zhi Xi
  0 siblings, 0 replies; 4+ messages in thread
From: Desmond Cheong Zhi Xi @ 2021-09-02 19:54 UTC (permalink / raw)
  To: Hillf Danton, syzbot
  Cc: Eric Dumazet, linux-bluetooth, linux-kernel, luiz.dentz, netdev,
	syzkaller-bugs

On 1/9/21 11:17 pm, Hillf Danton wrote:
> On Wed, 01 Sep 2021 10:34:21 -0700
>> syzbot has found a reproducer for the following issue on:
>>
>> HEAD commit:    c1b13fe76e95 Add linux-next specific files for 20210901
>> git tree:       linux-next
>> console output: https://syzkaller.appspot.com/x/log.txt?x=12c6034d300000
>> kernel config:  https://syzkaller.appspot.com/x/.config?x=e2afff7bc32736e5
>> dashboard link: https://syzkaller.appspot.com/bug?extid=7d51f807c81b190a127d
>> 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=14d42469300000
>> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1107d815300000
>>
>> IMPORTANT: if you fix the issue, please add the following tag to the commit:
>> Reported-by: syzbot+7d51f807c81b190a127d@syzkaller.appspotmail.com
>>
>> INFO: task syz-executor157:6562 blocked for more than 143 seconds.
>>        Not tainted 5.14.0-next-20210901-syzkaller #0
>> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
>> task:syz-executor157 state:D stack:26880 pid: 6562 ppid:  6530 flags:0x00004006
>> Call Trace:
>>   context_switch kernel/sched/core.c:4955 [inline]
>>   __schedule+0x940/0x26f0 kernel/sched/core.c:6302
>>   schedule+0xd3/0x270 kernel/sched/core.c:6381
>>   __lock_sock+0x13d/0x260 net/core/sock.c:2644
>>   lock_sock_nested+0xf6/0x120 net/core/sock.c:3185
>>   lock_sock include/net/sock.h:1612 [inline]
> 
> This is due to b7ce436a5d79 ("Bluetooth: switch to lock_sock in RFCOMM").
> 
>>   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:1314
>>   __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:2868
>>   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: 0033:0x445fe9
>> RSP: 002b:00007fff85049fe8 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
>> RAX: fffffffffffffffc RBX: 0000000000000003 RCX: 0000000000445fe9
>> RDX: 0000000000000080 RSI: 0000000020000000 RDI: 0000000000000004
>> RBP: 0000000000000003 R08: 000000ff00000001 R09: 000000ff00000001
>> R10: 0000000000000000 R11: 0000000000000246 R12: 00000000014112b8
>> R13: 0000000000000072 R14: 00007fff8504a040 R15: 0000000000000003
>>
>> Showing all locks held in the system:
>> 1 lock held by khungtaskd/26:
>>   #0: ffffffff8b97fbe0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6446
>> 1 lock held by krfcommd/2876:
>>   #0: ffffffff8d31ede8 (rfcomm_mutex){+.+.}-{3:3}, at: rfcomm_process_sessions net/bluetooth/rfcomm/core.c:1979 [inline]
>>   #0: ffffffff8d31ede8 (rfcomm_mutex){+.+.}-{3:3}, at: rfcomm_run+0x2ed/0x4a20 net/bluetooth/rfcomm/core.c:2086
>> 1 lock held by in:imklog/6232:
>> 4 locks held by syz-executor157/6562:
>>   #0: ffff888145e26210 (&sb->s_type->i_mutex_key#13){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:786 [inline]
>>   #0: ffff888145e26210 (&sb->s_type->i_mutex_key#13){+.+.}-{3:3}, at: __sock_release+0x86/0x280 net/socket.c:648
>>   #1: ffff88801d622120 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1612 [inline]
>>   #1: ffff88801d622120 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: rfcomm_sock_shutdown+0x54/0x210 net/bluetooth/rfcomm/sock.c:928
> 
> But sk is already locked before b7ce436a5d79.
> 
> What is wierd here is lock_sock() fails to complain about recursive locking
> like this one if syzbot turned lockdep on. Any light on this, Eric?
> 
> Thanks
> Hillf
> 

Sorry, this one was my bad. The patch swapped out spin_lock_bh for 
lock_sock, to provide synchronization with other functions that use 
lock_sock.

Problem is that in one of the call traces, we hit the following deadlock:

   rfcomm_sock_close():
     lock_sock();
     __rfcomm_sock_close():
       rfcomm_dlc_close():
         __rfcomm_dlc_close():
           rfcomm_sk_state_change():
             lock_sock();

But we don't always hold onto the socket lock before calling 
rfcomm_sk_state_change.

I'm still working and testing a fix, but I think one possibility is to 
schedule rfcomm_sk_state_change on a workqueue. This seems to fit with 
the rest of the code, since in rfcomm_sock_shutdown we call 
rfcomm_sock_close then wait for the sk state to change to BT_CLOSED.

>>   #2: ffffffff8d31ede8 (rfcomm_mutex){+.+.}-{3:3}, at: rfcomm_dlc_close+0x34/0x240 net/bluetooth/rfcomm/core.c:507
>>   #3: ffff88807edd9928 (&d->lock){+.+.}-{3:3}, at: __rfcomm_dlc_close+0x162/0x8a0 net/bluetooth/rfcomm/core.c:487
>>
>> =============================================
>>
>> NMI backtrace for cpu 1
>> CPU: 1 PID: 26 Comm: khungtaskd Not tainted 5.14.0-next-20210901-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 1 to CPUs 0:
>> NMI backtrace for cpu 0
>> CPU: 0 PID: 2958 Comm: systemd-journal Not tainted 5.14.0-next-20210901-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+0x7/0x60 kernel/kcov.c:197
>> Code: fd ff ff b9 ff ff ff ff ba 08 00 00 00 4d 8b 03 48 0f bd ca 49 8b 45 00 48 63 c9 e9 64 ff ff ff 0f 1f 00 65 8b 05 39 e6 8b 7e <89> c1 48 8b 34 24 81 e1 00 01 00 00 65 48 8b 14 25 40 f0 01 00 a9
>> RSP: 0018:ffffc900014dfde0 EFLAGS: 00000282
>> RAX: 0000000080000000 RBX: ffffc900014dff58 RCX: 1ffff9200029bfc7
>> RDX: dffffc0000000000 RSI: 1ffff9200029bfcd RDI: ffffc900014dfe38
>> RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8176c71a
>> R10: ffffffff81765c97 R11: 0000000000000002 R12: 0000000000000053
>> R13: 0000000000000002 R14: 0000000000000000 R15: ffffc900014dfe30
>> FS:  00007f43756768c0(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
>> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: 00007f4372a49000 CR3: 000000001a5d4000 CR4: 00000000001506f0
>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>> Call Trace:
>>   get_current arch/x86/include/asm/current.h:15 [inline]
>>   seccomp_run_filters kernel/seccomp.c:402 [inline]
>>   __seccomp_filter+0x88/0x1040 kernel/seccomp.c:1180
>>   __secure_computing+0xfc/0x360 kernel/seccomp.c:1311
>>   syscall_trace_enter.constprop.0+0x94/0x270 kernel/entry/common.c:68
>>   do_syscall_64+0x16/0xb0 arch/x86/entry/common.c:76
>>   entry_SYSCALL_64_after_hwframe+0x44/0xae
>> RIP: 0033:0x7f4374931687
>> Code: 00 b8 ff ff ff ff c3 0f 1f 40 00 48 8b 05 09 d8 2b 00 64 c7 00 5f 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 b8 53 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d e1 d7 2b 00 f7 d8 64 89 01 48
>> RSP: 002b:00007ffc79978938 EFLAGS: 00000293 ORIG_RAX: 0000000000000053
>> RAX: ffffffffffffffda RBX: 00007ffc7997b850 RCX: 00007f4374931687
>> RDX: 00007f43753a2a00 RSI: 00000000000001ed RDI: 00005646c59898a0
>> RBP: 00007ffc79978970 R08: 0000000000000000 R09: 0000000000000000
>> R10: 0000000000000069 R11: 0000000000000293 R12: 0000000000000000
>> R13: 0000000000000000 R14: 00007ffc7997b850 R15: 00007ffc79978e60
>> ----------------
>> Code disassembly (best guess), 3 bytes skipped:
>>     0:	b9 ff ff ff ff       	mov    $0xffffffff,%ecx
>>     5:	ba 08 00 00 00       	mov    $0x8,%edx
>>     a:	4d 8b 03             	mov    (%r11),%r8
>>     d:	48 0f bd ca          	bsr    %rdx,%rcx
>>    11:	49 8b 45 00          	mov    0x0(%r13),%rax
>>    15:	48 63 c9             	movslq %ecx,%rcx
>>    18:	e9 64 ff ff ff       	jmpq   0xffffff81
>>    1d:	0f 1f 00             	nopl   (%rax)
>>    20:	65 8b 05 39 e6 8b 7e 	mov    %gs:0x7e8be639(%rip),%eax        # 0x7e8be660
>> * 27:	89 c1                	mov    %eax,%ecx <-- trapping instruction
>>    29:	48 8b 34 24          	mov    (%rsp),%rsi
>>    2d:	81 e1 00 01 00 00    	and    $0x100,%ecx
>>    33:	65 48 8b 14 25 40 f0 	mov    %gs:0x1f040,%rdx
>>    3a:	01 00
>>    3c:	a9                   	.byte 0xa9
>>
>>


^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2021-09-02 19:54 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2021-08-15 16:47 [syzbot] INFO: task can't die in __lock_sock syzbot
2021-09-01 17:34 ` syzbot
2021-09-02  1:34 ` syzbot
     [not found] ` <20210902031752.2502-1-hdanton@sina.com>
2021-09-02 19:54   ` Desmond Cheong Zhi Xi

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