syzbot


INFO: task hung in unix_dgram_sendmsg

Status: upstream: reported C repro on 2024/02/16 20:24
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+0fb57e12fba9d61a975d@syzkaller.appspotmail.com
First crash: 121d, last: 103d
Bug presence (2)
Date Name Commit Repro Result
2024/02/17 linux-6.1.y (ToT) 8b4118fabd6e C [report] INFO: task hung in unix_dgram_sendmsg
2024/02/17 upstream (ToT) c1ca10ceffbb C Didn't crash
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: task hung in unix_dgram_sendmsg origin:lts-only C inconclusive 24 103d 109d 0/3 upstream: reported C repro on 2024/02/28 06:17
upstream INFO: task hung in unix_dgram_sendmsg net C done 36 109d 128d 26/27 fixed on 2024/03/25 11:41
Fix bisection attempts (1)
Created Duration User Patch Repo Result
2024/03/11 17:46 1h26m fix candidate upstream job log (0)

Sample crash report:
INFO: task klogd:2990 blocked for more than 143 seconds.
      Not tainted 6.1.80-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:klogd           state:D stack:23880 pid:2990  ppid:1      flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x142d/0x4550 kernel/sched/core.c:6558
 schedule+0xbf/0x180 kernel/sched/core.c:6634
 wait_for_unix_gc+0x14c/0x210 net/unix/garbage.c:201
 unix_dgram_sendmsg+0x113/0x2050 net/unix/af_unix.c:1899
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 __sys_sendto+0x480/0x600 net/socket.c:2148
 __do_sys_sendto net/socket.c:2160 [inline]
 __se_sys_sendto net/socket.c:2156 [inline]
 __x64_sys_sendto+0xda/0xf0 net/socket.c:2156
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f9d3b4519b5
RSP: 002b:00007fff524e78d8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f9d3b4519b5
RDX: 0000000000000058 RSI: 000055741609fbf0 RDI: 0000000000000003
RBP: 000055741609b910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000004000 R11: 0000000000000246 R12: 0000000000000013
R13: 00007f9d3b5df212 R14: 00007fff524e79d8 R15: 0000000000000000
 </TASK>
INFO: task dhcpcd:3214 blocked for more than 143 seconds.
      Not tainted 6.1.80-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:dhcpcd          state:D stack:25008 pid:3214  ppid:1      flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x142d/0x4550 kernel/sched/core.c:6558
 schedule+0xbf/0x180 kernel/sched/core.c:6634
 wait_for_unix_gc+0x14c/0x210 net/unix/garbage.c:201
 unix_dgram_sendmsg+0x113/0x2050 net/unix/af_unix.c:1899
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 sock_write_iter+0x394/0x4e0 net/socket.c:1143
 call_write_iter include/linux/fs.h:2251 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x7ae/0xba0 fs/read_write.c:584
 ksys_write+0x19c/0x2c0 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f6eb6b49bf2
RSP: 002b:00007ffe53429d78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000055fb5428fdf0 RCX: 00007f6eb6b49bf2
RDX: 0000000000000047 RSI: 00007ffe53429d90 RDI: 0000000000000005
RBP: 00007ffe53429d90 R08: 0000000000000008 R09: 0000000000000036
R10: 0000000000000000 R11: 0000000000000246 R12: 000055fb53d8defc
R13: 00007ffe5342a1c0 R14: 000055fb54369bb0 R15: 0000000000000001
 </TASK>
INFO: task syz-executor108:6546 blocked for more than 143 seconds.
      Not tainted 6.1.80-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor108 state:D stack:27208 pid:6546  ppid:3544   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x142d/0x4550 kernel/sched/core.c:6558
 schedule+0xbf/0x180 kernel/sched/core.c:6634
 wait_for_unix_gc+0x14c/0x210 net/unix/garbage.c:201
 unix_stream_sendmsg+0xc3/0x1070 net/unix/af_unix.c:2167
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 ____sys_sendmsg+0x5a5/0x8f0 net/socket.c:2514
 ___sys_sendmsg net/socket.c:2568 [inline]
 __sys_sendmsg+0x2a9/0x390 net/socket.c:2597
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7ff85a718e49
RSP: 002b:00007ffd94703518 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007ff85a718e49
RDX: 0000000000048005 RSI: 0000000020000680 RDI: 0000000000000003
RBP: 00000000000f4240 R08: 0000000055615610 R09: 0000000055615610
R10: 0000000055615610 R11: 0000000000000246 R12: 000000000000faab
R13: 00007ffd94703524 R14: 00007ffd94703540 R15: 00007ffd94703530
 </TASK>
INFO: task udevd:6547 blocked for more than 144 seconds.
      Not tainted 6.1.80-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd           state:D stack:27136 pid:6547  ppid:3001   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x142d/0x4550 kernel/sched/core.c:6558
 schedule+0xbf/0x180 kernel/sched/core.c:6634
 wait_for_unix_gc+0x14c/0x210 net/unix/garbage.c:201
 unix_dgram_sendmsg+0x113/0x2050 net/unix/af_unix.c:1899
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 sock_write_iter+0x394/0x4e0 net/socket.c:1143
 call_write_iter include/linux/fs.h:2251 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x7ae/0xba0 fs/read_write.c:584
 ksys_write+0x19c/0x2c0 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fef8b716bf2
RSP: 002b:00007fffa1746678 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fef8b716bf2
RDX: 0000000000000000 RSI: 00007fffa17466cf RDI: 000000000000000a
RBP: 00007fffa17466cf R08: 0000000000000001 R09: d281d505c9d3a92d
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000000a
R13: 00007fef8bad7ae0 R14: 0000000000000000 R15: 000055bc6e7c1910
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8d12aa90 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:516
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8d12b290 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:516
1 lock held by khungtaskd/28:
 #0: ffffffff8d12a8c0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:319 [inline]
 #0: ffffffff8d12a8c0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:760 [inline]
 #0: ffffffff8d12a8c0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6494
2 locks held by kworker/u4:4/102:
 #0: ffff888012479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267
 #1: ffffc900015c7d20 ((work_completion)(&(&kfence_timer)->work)){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267
1 lock held by dhcpcd/3215:
2 locks held by getty/3304:
 #0: ffff888027f8c098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc900031262f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6a7/0x1db0 drivers/tty/n_tty.c:2188

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

NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted 6.1.80-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 nmi_cpu_backtrace+0x4e1/0x560 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1b0/0x3f0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
 watchdog+0xf88/0xfd0 kernel/hung_task.c:377
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 3215 Comm: dhcpcd Not tainted 6.1.80-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
RIP: 0010:unix_gc+0x10b2/0x13e0 net/unix/garbage.c:319
Code: 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 74 08 48 89 df e8 8f 44 a0 f8 4c 8b 23 48 81 c3 20 01 00 00 49 89 dd 49 c1 ed 03 <48> b8 00 00 00 00 00 fc ff df 41 80 7c 05 00 00 74 08 48 89 df e8
RSP: 0018:ffffc900034efa60 EFLAGS: 00000a06
RAX: 1ffff11004fc6fca RBX: ffff888027e37f70 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: ffffffff8aebed40 RDI: ffffffff8b3d1140
RBP: ffffc900034efbd0 R08: dffffc0000000000 R09: fffffbfff2092058
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff888027e37e50
R13: 1ffff11004fc6fee R14: 0000000000000000 R15: ffffffff8e391840
FS:  00007f6eb6a7f740(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff85a7900d0 CR3: 0000000026ecf000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 unix_release_sock+0xab8/0xcf0 net/unix/af_unix.c:669
 unix_release+0x88/0xc0 net/unix/af_unix.c:1039
 __sock_release net/socket.c:654 [inline]
 sock_close+0xcd/0x230 net/socket.c:1400
 __fput+0x3b7/0x890 fs/file_table.c:320
 task_work_run+0x246/0x300 kernel/task_work.c:179
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xde/0x100 kernel/entry/common.c:171
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:204
 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline]
 syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:297
 do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f6eb6b4a0a8
Code: 48 8b 05 83 9d 0d 00 64 c7 00 16 00 00 00 83 c8 ff 48 83 c4 20 5b c3 64 8b 04 25 18 00 00 00 85 c0 75 20 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 5b 48 8b 15 51 9d 0d 00 f7 d8 64 89 02 48 83
RSP: 002b:00007ffe5340a0a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 00007f6eb6b4a0a8
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000014
RBP: 00007ffe5342a458 R08: 0000000000000007 R09: 15807b7bc2b8c6e4
R10: 0000000000004000 R11: 0000000000000246 R12: 000055fb542b0e80
R13: 00007ffe5341a298 R14: 0000000000000148 R15: 0000000000000004
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.169 msecs

Crashes (27):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/03/06 00:02 linux-6.1.y a3eb3a74aa8c f39a7eed .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in unix_dgram_sendmsg
2024/03/03 06:39 linux-6.1.y a3eb3a74aa8c 25905f5d .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in unix_dgram_sendmsg
2024/02/22 12:31 linux-6.1.y 8b4118fabd6e 345111b5 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in unix_dgram_sendmsg
2024/02/17 12:53 linux-6.1.y 8b4118fabd6e 578f7538 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in unix_dgram_sendmsg
2024/02/17 10:34 linux-6.1.y 8b4118fabd6e 578f7538 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in unix_dgram_sendmsg
2024/02/17 09:53 linux-6.1.y 8b4118fabd6e 578f7538 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in unix_dgram_sendmsg
2024/02/17 02:16 linux-6.1.y 8b4118fabd6e 578f7538 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in unix_dgram_sendmsg
2024/03/03 04:24 linux-6.1.y a3eb3a74aa8c 25905f5d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in unix_dgram_sendmsg
2024/02/29 06:46 linux-6.1.y 81e1dc2f7001 352ab904 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in unix_dgram_sendmsg
2024/02/25 17:42 linux-6.1.y 81e1dc2f7001 8d446f15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in unix_dgram_sendmsg
2024/02/23 02:01 linux-6.1.y 8b4118fabd6e 8d446f15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in unix_dgram_sendmsg
2024/02/23 02:00 linux-6.1.y 8b4118fabd6e 8d446f15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in unix_dgram_sendmsg
2024/02/22 22:05 linux-6.1.y 8b4118fabd6e 8d446f15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in unix_dgram_sendmsg
2024/02/22 20:47 linux-6.1.y 8b4118fabd6e 8d446f15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in unix_dgram_sendmsg
2024/02/22 09:43 linux-6.1.y 8b4118fabd6e 345111b5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in unix_dgram_sendmsg
2024/02/22 06:23 linux-6.1.y 8b4118fabd6e 345111b5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in unix_dgram_sendmsg
2024/02/21 23:05 linux-6.1.y 8b4118fabd6e 345111b5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in unix_dgram_sendmsg
2024/02/21 18:02 linux-6.1.y 8b4118fabd6e 345111b5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in unix_dgram_sendmsg
2024/02/21 13:41 linux-6.1.y 8b4118fabd6e 3af7dd65 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in unix_dgram_sendmsg
2024/02/21 12:25 linux-6.1.y 8b4118fabd6e 3af7dd65 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in unix_dgram_sendmsg
2024/02/20 15:54 linux-6.1.y 8b4118fabd6e 3af7dd65 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in unix_dgram_sendmsg
2024/02/19 18:51 linux-6.1.y 8b4118fabd6e 3af7dd65 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in unix_dgram_sendmsg
2024/02/19 16:43 linux-6.1.y 8b4118fabd6e 3af7dd65 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in unix_dgram_sendmsg
2024/02/16 23:37 linux-6.1.y 8b4118fabd6e 578f7538 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in unix_dgram_sendmsg
2024/02/16 20:58 linux-6.1.y 8b4118fabd6e 578f7538 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in unix_dgram_sendmsg
2024/03/03 04:31 linux-6.1.y a3eb3a74aa8c 25905f5d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in unix_dgram_sendmsg
2024/02/16 20:24 linux-6.1.y 8b4118fabd6e 578f7538 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in unix_dgram_sendmsg
* Struck through repros no longer work on HEAD.