syzbot has found a reproducer for the following issue on: HEAD commit: 69e858e0b8b2 Merge tag 'uml-for-linus-6.14-rc1' of git://g.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=132935f8580000 kernel config: https://syzkaller.appspot.com/x/.config?x=98d83cc1742b7377 dashboard link: https://syzkaller.appspot.com/bug?extid=e7c786ece54bad9d1e43 compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10809724580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=132f03df980000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/3d07b0558b0e/disk-69e858e0.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/e5e2250eb3b1/vmlinux-69e858e0.xz kernel image: https://storage.googleapis.com/syzbot-assets/3e676d17effc/bzImage-69e858e0.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+e7c786ece54bad9d1e43@xxxxxxxxxxxxxxxxxxxxxxxxx INFO: task kworker/u8:5:76 blocked for more than 143 seconds. Not tainted 6.13.0-syzkaller-09760-g69e858e0b8b2 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:5 state:D stack:23760 pid:76 tgid:76 ppid:2 task_flags:0x4248060 flags:0x00004000 Workqueue: writeback wb_workfn (flush-8:0) Call Trace: <TASK> context_switch kernel/sched/core.c:5377 [inline] __schedule+0xf43/0x5890 kernel/sched/core.c:6764 __schedule_loop kernel/sched/core.c:6841 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6856 io_schedule+0xbf/0x130 kernel/sched/core.c:7689 bit_wait_io+0x15/0xe0 kernel/sched/wait_bit.c:247 __wait_on_bit+0x62/0x180 kernel/sched/wait_bit.c:49 out_of_line_wait_on_bit+0xda/0x110 kernel/sched/wait_bit.c:64 wait_on_bit_io include/linux/wait_bit.h:105 [inline] do_get_write_access+0x933/0x1270 fs/jbd2/transaction.c:1096 jbd2_journal_get_write_access+0x1d6/0x280 fs/jbd2/transaction.c:1245 __ext4_journal_get_write_access+0x6a/0x340 fs/ext4/ext4_jbd2.c:239 ext4_reserve_inode_write+0x13b/0x270 fs/ext4/inode.c:5831 __ext4_mark_inode_dirty+0x1ab/0x860 fs/ext4/inode.c:6005 __ext4_ext_dirty+0x1a8/0x220 fs/ext4/extents.c:207 ext4_ext_insert_extent+0x12c7/0x3e70 fs/ext4/extents.c:2190 ext4_ext_map_blocks+0x2044/0x5ab0 fs/ext4/extents.c:4400 ext4_map_create_blocks fs/ext4/inode.c:516 [inline] ext4_map_blocks+0x457/0x1370 fs/ext4/inode.c:702 mpage_map_one_extent fs/ext4/inode.c:2219 [inline] mpage_map_and_submit_extent fs/ext4/inode.c:2272 [inline] ext4_do_writepages+0x198d/0x32d0 fs/ext4/inode.c:2735 ext4_writepages+0x303/0x730 fs/ext4/inode.c:2824 do_writepages+0x1b3/0x820 mm/page-writeback.c:2687 __writeback_single_inode+0x166/0xfa0 fs/fs-writeback.c:1680 writeback_sb_inodes+0x606/0xfa0 fs/fs-writeback.c:1976 __writeback_inodes_wb+0xff/0x2e0 fs/fs-writeback.c:2047 wb_writeback+0x803/0xb80 fs/fs-writeback.c:2158 wb_check_old_data_flush fs/fs-writeback.c:2262 [inline] wb_do_writeback fs/fs-writeback.c:2315 [inline] wb_workfn+0x8c0/0xbc0 fs/fs-writeback.c:2343 process_one_work+0x958/0x1b30 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3317 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3398 kthread+0x3af/0x750 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 </TASK> INFO: task jbd2/sda1-8:5171 blocked for more than 144 seconds. Not tainted 6.13.0-syzkaller-09760-g69e858e0b8b2 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:jbd2/sda1-8 state:D stack:26432 pid:5171 tgid:5171 ppid:2 task_flags:0x240040 flags:0x00004000 Call Trace: <TASK> context_switch kernel/sched/core.c:5377 [inline] __schedule+0xf43/0x5890 kernel/sched/core.c:6764 __schedule_loop kernel/sched/core.c:6841 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6856 io_schedule+0xbf/0x130 kernel/sched/core.c:7689 bit_wait_io+0x15/0xe0 kernel/sched/wait_bit.c:247 __wait_on_bit+0x62/0x180 kernel/sched/wait_bit.c:49 out_of_line_wait_on_bit+0xda/0x110 kernel/sched/wait_bit.c:64 wait_on_bit_io include/linux/wait_bit.h:105 [inline] __wait_on_buffer+0x64/0x70 fs/buffer.c:123 wait_on_buffer include/linux/buffer_head.h:414 [inline] jbd2_journal_commit_transaction+0x3823/0x6760 fs/jbd2/commit.c:810 kjournald2+0x1f8/0x760 fs/jbd2/journal.c:201 kthread+0x3af/0x750 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 </TASK> Showing all locks held in the system: 1 lock held by khungtaskd/30: #0: ffffffff8e1bc080 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8e1bc080 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8e1bc080 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x7f/0x390 kernel/locking/lockdep.c:6746 6 locks held by kworker/u8:5/76: #0: ffff88801eac1148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x12cd/0x1b30 kernel/workqueue.c:3211 #1: ffffc9000216fd18 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x8bb/0x1b30 kernel/workqueue.c:3212 #2: ffff88814e6840e0 (&type->s_umount_key#31){++++}-{4:4}, at: super_trylock_shared+0x1e/0xf0 fs/super.c:562 #3: ffff88814e686b98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: do_writepages+0x1b3/0x820 mm/page-writeback.c:2687 #4: ffff88814e690950 (jbd2_handle){.+.+}-{0:0}, at: start_this_handle+0xf6c/0x1430 fs/jbd2/transaction.c:448 #5: ffff888053bfef80 (&ei->i_data_sem){++++}-{4:4}, at: ext4_map_blocks+0x352/0x1370 fs/ext4/inode.c:701 2 locks held by getty/5595: #0: ffff8880351f20a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc90002fde2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0xfba/0x1480 drivers/tty/n_tty.c:2211 2 locks held by syz-executor350/13863: #0: ffff8880b873ed18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:598 #1: ffff8880b8728a88 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x203/0x8e0 kernel/sched/psi.c:975 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.13.0-syzkaller-09760-g69e858e0b8b2 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:236 [inline] watchdog+0xf62/0x12b0 kernel/hung_task.c:399 kthread+0x3af/0x750 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 </TASK> Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 13875 Comm: syz-executor350 Not tainted 6.13.0-syzkaller-09760-g69e858e0b8b2 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 RIP: 0010:file_set_fsnotify_mode+0xe/0x5d0 fs/notify/fsnotify.c:652 Code: 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f 1f 00 41 57 41 56 41 55 41 54 55 53 <48> 89 fb 48 83 ec 10 e8 76 b6 76 ff 48 8d bb 88 00 00 00 48 b8 00 RSP: 0018:ffffc900032e79c8 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff88802fc64c40 RCX: ffffffff822b6e68 RDX: ffff888021b99e00 RSI: ffffffff822b6e76 RDI: ffff88802fc64c40 RBP: ffff888077665038 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: ffff88802fc64c88 R13: ffff88802fc64cc8 R14: 0000000000000000 R15: ffff88802fc64c90 FS: 0000555583826380(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6cf9a1a01d CR3: 000000002a1c8000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <NMI> </NMI> <TASK> do_dentry_open+0x59e/0x1c40 fs/open.c:941 vfs_open+0x82/0x3f0 fs/open.c:1085 do_open fs/namei.c:3830 [inline] path_openat+0x1e88/0x2d80 fs/namei.c:3989 do_filp_open+0x20c/0x470 fs/namei.c:4016 do_sys_openat2+0x17a/0x1e0 fs/open.c:1427 do_sys_open fs/open.c:1442 [inline] __do_sys_openat fs/open.c:1458 [inline] __se_sys_openat fs/open.c:1453 [inline] __x64_sys_openat+0x175/0x210 fs/open.c:1453 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6cf99d0ae1 Code: 75 57 89 f0 25 00 00 41 00 3d 00 00 41 00 74 49 80 3d 8a 85 07 00 00 74 6d 89 da 48 89 ee bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 93 00 00 00 48 8b 54 24 28 64 48 2b 14 25 RSP: 002b:00007ffd1d04c410 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000080001 RCX: 00007f6cf99d0ae1 RDX: 0000000000080001 RSI: 00007f6cf9a1a022 RDI: 00000000ffffff9c RBP: 00007f6cf9a1a022 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00007ffd1d04c4b0 R13: 431bde82d7b634db R14: 0000000000000001 R15: 0000000000000001 </TASK> INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.450 msecs --- 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.
