Hello, syzbot found the following issue on: HEAD commit: 4f9e7fabf864 Merge tag 'trace-v6.5-rc6' of git://git.kerne.. git tree: upstream console+strace: https://syzkaller.appspot.com/x/log.txt?x=14bfc5eba80000 kernel config: https://syzkaller.appspot.com/x/.config?x=1b32f62c755c3a9c dashboard link: https://syzkaller.appspot.com/bug?extid=9157524e62303fd7b21c compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=101aff5ba80000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14d78db0680000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/acffca8b8b8e/disk-4f9e7fab.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/456bbc08eede/vmlinux-4f9e7fab.xz kernel image: https://storage.googleapis.com/syzbot-assets/c6ea47aa41f8/bzImage-4f9e7fab.xz mounted in repro: https://storage.googleapis.com/syzbot-assets/08b2c3496eff/mount_0.gz Bisection is inconclusive: the issue happens on the oldest tested release. bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=17d2b870680000 final oops: https://syzkaller.appspot.com/x/report.txt?x=1432b870680000 console output: https://syzkaller.appspot.com/x/log.txt?x=1032b870680000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+9157524e62303fd7b21c@xxxxxxxxxxxxxxxxxxxxxxxxx INFO: task kworker/u4:3:42 blocked for more than 143 seconds. Not tainted 6.5.0-rc7-syzkaller-00104-g4f9e7fabf864 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u4:3 state:D stack:22416 pid:42 ppid:2 flags:0x00004000 Workqueue: writeback wb_workfn (flush-7:0) Call Trace: <TASK> context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1873/0x48f0 kernel/sched/core.c:6710 schedule+0xc3/0x180 kernel/sched/core.c:6786 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6845 __mutex_lock_common+0xe33/0x2530 kernel/locking/mutex.c:679 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x1b/0x20 kernel/locking/mutex.c:799 jfs_commit_inode+0x246/0x580 fs/jfs/inode.c:102 jfs_write_inode+0x143/0x210 fs/jfs/inode.c:132 write_inode fs/fs-writeback.c:1456 [inline] __writeback_single_inode+0x69b/0xfa0 fs/fs-writeback.c:1668 writeback_sb_inodes+0x8e3/0x11d0 fs/fs-writeback.c:1894 __writeback_inodes_wb+0x11b/0x260 fs/fs-writeback.c:1965 wb_writeback+0x461/0xc60 fs/fs-writeback.c:2072 wb_check_background_flush fs/fs-writeback.c:2142 [inline] wb_do_writeback fs/fs-writeback.c:2230 [inline] wb_workfn+0xc6f/0xff0 fs/fs-writeback.c:2257 process_one_work+0x92c/0x12c0 kernel/workqueue.c:2600 worker_thread+0xa63/0x1210 kernel/workqueue.c:2751 kthread+0x2b8/0x350 kernel/kthread.c:389 ret_from_fork+0x2e/0x60 arch/x86/kernel/process.c:145 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304 </TASK> Showing all locks held in the system: 1 lock held by rcu_tasks_kthre/13: #0: ffffffff8d3295f0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xd20 kernel/rcu/tasks.h:522 1 lock held by rcu_tasks_trace/14: #0: ffffffff8d3299b0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xd20 kernel/rcu/tasks.h:522 1 lock held by khungtaskd/28: #0: ffffffff8d329420 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 4 locks held by kworker/u4:3/42: #0: ffff888019676938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x7e3/0x12c0 kernel/workqueue.c:2572 #1: ffffc90000b37d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x82b/0x12c0 kernel/workqueue.c:2574 #2: ffff8880796080e0 (&type->s_umount_key#43){.+.+}-{3:3}, at: trylock_super+0x1f/0xf0 fs/super.c:413 #3: ffff88807866b008 (&jfs_ip->commit_mutex){+.+.}-{3:3}, at: jfs_commit_inode+0x246/0x580 fs/jfs/inode.c:102 2 locks held by getty/4764: #0: ffff888029ad2098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900015c02f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6b1/0x1dc0 drivers/tty/n_tty.c:2187 4 locks held by syz-executor320/5013: ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 28 Comm: khungtaskd Not tainted 6.5.0-rc7-syzkaller-00104-g4f9e7fabf864 #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+0x1e7/0x2d0 lib/dump_stack.c:106 nmi_cpu_backtrace+0x498/0x4d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x187/0x300 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+0xec2/0xf00 kernel/hung_task.c:379 kthread+0x2b8/0x350 kernel/kthread.c:389 ret_from_fork+0x2e/0x60 arch/x86/kernel/process.c:145 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: 4457 Comm: klogd Not tainted 6.5.0-rc7-syzkaller-00104-g4f9e7fabf864 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023 RIP: 0010:lockdep_hardirqs_on_prepare+0x1a5/0x7a0 kernel/locking/lockdep.c:4363 Code: b1 97 7e 85 c0 0f 85 f4 03 00 00 65 48 8b 05 52 e1 98 7e 48 89 44 24 10 48 8d b8 b8 0a 00 00 48 89 f8 48 c1 e8 03 80 3c 10 00 <74> 0f e8 94 ba 79 00 48 ba 00 00 00 00 00 fc ff df 4c 89 7c 24 18 RSP: 0018:ffffc9000310f720 EFLAGS: 00000046 RAX: 1ffff1100fc4b8c7 RBX: 1ffff92000621eec RCX: ffffffff91fac203 RDX: dffffc0000000000 RSI: ffffffff8b58adc0 RDI: ffff88807e25c638 RBP: ffffc9000310f7d8 R08: ffffffff8e9878ef R09: 1ffffffff1d30f1d R10: dffffc0000000000 R11: fffffbfff1d30f1e R12: dffffc0000000000 R13: 1ffff1101730799b R14: ffffc9000310f760 R15: 1ffff92000621ee8 FS: 00007f4bdb63b380(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055b621ad0780 CR3: 000000002c5b3000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <NMI> </NMI> <TASK> trace_hardirqs_on+0x28/0x40 kernel/trace/trace_preemptirq.c:61 raw_spin_rq_unlock_irq kernel/sched/sched.h:1378 [inline] finish_lock_switch+0x93/0x110 kernel/sched/core.c:5133 finish_task_switch+0x134/0x650 kernel/sched/core.c:5251 context_switch kernel/sched/core.c:5384 [inline] __schedule+0x187b/0x48f0 kernel/sched/core.c:6710 schedule+0xc3/0x180 kernel/sched/core.c:6786 syslog_print+0x2a3/0x9b0 kernel/printk/printk.c:1579 do_syslog+0x505/0x890 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+0x7c/0x90 kernel/printk/printk.c:1822 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f4bdb79cfa7 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:00007ffe34adaec8 EFLAGS: 00000206 ORIG_RAX: 0000000000000067 RAX: ffffffffffffffda RBX: 00007f4bdb93b4a0 RCX: 00007f4bdb79cfa7 RDX: 00000000000003ff RSI: 00007f4bdb93b4a0 RDI: 0000000000000002 RBP: 0000000000000000 R08: 0000000000000002 R09: 27b8e563ad625ccb R10: 0000000000004000 R11: 0000000000000206 R12: 00007f4bdb93b4a0 R13: 00007f4bdb92b212 R14: 00007f4bdb93b503 R15: 00007f4bdb93b503 </TASK> INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.366 msecs --- 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 If the bug is already fixed, let syzbot know by replying with: #syz fix: exact-commit-title If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing. If you want to overwrite bug's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the bug is a duplicate of another bug, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup
