syzbot

INFO: task syz-executor171:5042 blocked for more than 143 seconds.
      Not tainted 6.5.0-next-20230828-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor171 state:D stack:27528 pid:5042  ppid:5039   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0xee1/0x59f0 kernel/sched/core.c:6695
 schedule+0xe7/0x1b0 kernel/sched/core.c:6771
 wb_wait_for_completion+0x1ae/0x270 fs/fs-writeback.c:192
 sync_inodes_sb+0x1b7/0xa50 fs/fs-writeback.c:2736
 sync_filesystem fs/sync.c:64 [inline]
 sync_filesystem+0x16f/0x280 fs/sync.c:30
 generic_shutdown_super+0x7e/0x3c0 fs/super.c:656
 kill_block_super+0x3b/0x70 fs/super.c:1609
 ext4_kill_sb+0x6a/0xb0 fs/ext4/super.c:7305
 deactivate_locked_super+0xa0/0x2d0 fs/super.c:454
 deactivate_super+0xde/0x100 fs/super.c:504
 cleanup_mnt+0x222/0x3d0 fs/namespace.c:1254
 task_work_run+0x14d/0x240 kernel/task_work.c:179
 ptrace_notify+0x10c/0x130 kernel/signal.c:2387
 ptrace_report_syscall include/linux/ptrace.h:411 [inline]
 ptrace_report_syscall_exit include/linux/ptrace.h:473 [inline]
 syscall_exit_work kernel/entry/common.c:251 [inline]
 syscall_exit_to_user_mode_prepare+0x120/0x220 kernel/entry/common.c:278
 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline]
 syscall_exit_to_user_mode+0xd/0x60 kernel/entry/common.c:296
 do_syscall_64+0x44/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f6d3564e587
RSP: 002b:00007ffdfa71f368 EFLAGS: 00000202 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f6d3564e587
RDX: 0000000000000000 RSI: 000000000000000a RDI: 00007ffdfa71f420
RBP: 00007ffdfa71f420 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000202 R12: 00007ffdfa720490
R13: 00005555574346c0 R14: 431bde82d7b634db R15: 00007ffdfa7204b0
 </TASK>
INFO: lockdep is turned off.
NMI backtrace for cpu 1
CPU: 1 PID: 29 Comm: khungtaskd Not tainted 6.5.0-next-20230828-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x277/0x380 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x299/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
 watchdog+0xfac/0x1230 kernel/hung_task.c:379
 kthread+0x33a/0x430 kernel/kthread.c:388
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4483 Comm: klogd Not tainted 6.5.0-next-20230828-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
RIP: 0010:__orc_find+0x2/0x130 arch/x86/kernel/unwind_orc.c:85
Code: e8 03 2e 1b 03 e9 08 fb ff ff 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 53 48 89 fb e8 97 95 4d 00 48 8b 03 5b c3 66 90 41 57 <41> 56 49 89 fe 41 55 41 54 49 89 cc 55 53 89 d3 48 83 ec 18 48 89
RSP: 0018:ffffc9000311f6f8 EFLAGS: 00000202
RAX: 000000000000e136 RBX: ffffc9000311f7e0 RCX: ffffffff813a71b3
RDX: 0000000000000001 RSI: ffffffff8f55471c RDI: ffffffff8edd1ec0
RBP: 0000000000000001 R08: 0000000000000004 R09: 0000000000003a71
R10: 0000000000098000 R11: 0000000000000000 R12: ffffffff813a71b3
R13: ffffffff8f55471c R14: 000000000000e136 R15: ffffc9000311f815
FS:  00007f58e4ab7380(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055b731cb4600 CR3: 0000000029304000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 orc_find arch/x86/kernel/unwind_orc.c:227 [inline]
 unwind_next_frame+0x329/0x2390 arch/x86/kernel/unwind_orc.c:494
 __unwind_start+0x5a4/0x880 arch/x86/kernel/unwind_orc.c:760
 unwind_start arch/x86/include/asm/unwind.h:64 [inline]
 arch_stack_walk+0xaf/0x170 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0x96/0xd0 kernel/stacktrace.c:122
 kasan_save_stack+0x33/0x50 mm/kasan/common.c:45
 kasan_set_track+0x25/0x30 mm/kasan/common.c:52
 kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:522
 ____kasan_slab_free mm/kasan/common.c:236 [inline]
 ____kasan_slab_free+0x15b/0x1b0 mm/kasan/common.c:200
 kasan_slab_free include/linux/kasan.h:164 [inline]
 slab_free_hook mm/slub.c:1800 [inline]
 slab_free_freelist_hook+0x114/0x1e0 mm/slub.c:1826
 slab_free mm/slub.c:3809 [inline]
 __kmem_cache_free+0xb8/0x2f0 mm/slub.c:3822
 syslog_print+0x2bb/0x5d0 kernel/printk/printk.c:1645
 do_syslog+0x2d4/0x580 kernel/printk/printk.c:1732
 __do_sys_syslog kernel/printk/printk.c:1824 [inline]
 __se_sys_syslog kernel/printk/printk.c:1822 [inline]
 __x64_sys_syslog+0x74/0xb0 kernel/printk/printk.c:1822
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f58e4c18fa7
Code: 73 01 c3 48 8b 0d 81 ce 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 67 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 51 ce 0c 00 f7 d8 64 89 01 48
RSP: 002b:00007ffe74d98468 EFLAGS: 00000206 ORIG_RAX: 0000000000000067
RAX: ffffffffffffffda RBX: 00007f58e4db74a0 RCX: 00007f58e4c18fa7
RDX: 00000000000003ff RSI: 00007f58e4db74a0 RDI: 0000000000000002
RBP: 0000000000000000 R08: 0000000000000007 R09: 8779c1a6297cdc12
R10: 0000000000004000 R11: 0000000000000206 R12: 00007f58e4db74a0
R13: 00007f58e4da7212 R14: 00007f58e4db789c R15: 00007f58e4db789c
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 2.280 msecs