INFO: task syz.0.17:6669 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.17 state:D stack:28744 pid:6669 tgid:6664 ppid:6511 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5260 [inline] __schedule+0x1472/0x4fe0 kernel/sched/core.c:6867 __schedule_loop kernel/sched/core.c:6949 [inline] rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7245 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked+0x1f8f/0x25c0 kernel/locking/rtmutex.c:1760 __rwbase_read_lock+0xc3/0x180 kernel/locking/rwbase_rt.c:114 rwbase_read_lock kernel/locking/rwbase_rt.c:147 [inline] __down_read kernel/locking/rwsem.c:1466 [inline] down_read+0x132/0x200 kernel/locking/rwsem.c:1539 inode_lock_shared include/linux/fs.h:1042 [inline] f2fs_seek_block fs/f2fs/file.c:464 [inline] f2fs_llseek+0x1f7/0x1890 fs/f2fs/file.c:551 vfs_llseek fs/read_write.c:389 [inline] ksys_lseek fs/read_write.c:402 [inline] __do_sys_lseek fs/read_write.c:412 [inline] __se_sys_lseek fs/read_write.c:410 [inline] __x64_sys_lseek+0x155/0x1f0 fs/read_write.c:410 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fae25faa379 RSP: 002b:00007fae255ed028 EFLAGS: 00000246 ORIG_RAX: 0000000000000008 RAX: ffffffffffffffda RBX: 00007fae261e6090 RCX: 00007fae25faa379 RDX: 0000000000000004 RSI: 0000000000000008 RDI: 0000000000000004 RBP: 00007fae2603dd68 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fae261e6128 R14: 00007fae261e6090 R15: 00007ffc3b46dda8 Showing all locks held in the system: 1 lock held by khungtaskd/38: #0: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 4 locks held by kworker/u8:3/58: #0: ffff888140463138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff888140463138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0 kernel/workqueue.c:3340 #1: ffffc9000124fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc9000124fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0 kernel/workqueue.c:3340 #2: ffff88803db580d0 (&type->s_umount_key#55){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563 #3: ffff888036a81a80 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write fs/f2fs/f2fs.h:2313 [inline] #3: ffff888036a81a80 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_balance_fs+0x5d8/0x800 fs/f2fs/segment.c:464 4 locks held by kworker/u8:7/1345: #0: ffff888140463138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff888140463138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0 kernel/workqueue.c:3340 #1: ffffc90004fefbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc90004fefbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0 kernel/workqueue.c:3340 #2: ffff888020bf60d0 (&type->s_umount_key#55){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563 #3: ffff88803df5da80 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write fs/f2fs/f2fs.h:2313 [inline] #3: ffff88803df5da80 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_balance_fs+0x5d8/0x800 fs/f2fs/segment.c:464 2 locks held by getty/5558: #0: ffff888035fb80a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000418b2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13c0 drivers/tty/n_tty.c:2211 6 locks held by syz.0.17/6665: 2 locks held by syz.0.17/6669: #0: ffff8880325a8928 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1255 #1: ffff88805ad89e10 (&sb->s_type->i_mutex_key#23){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1042 [inline] #1: ffff88805ad89e10 (&sb->s_type->i_mutex_key#23){++++}-{4:4}, at: f2fs_seek_block fs/f2fs/file.c:464 [inline] #1: ffff88805ad89e10 (&sb->s_type->i_mutex_key#23){++++}-{4:4}, at: f2fs_llseek+0x1f7/0x1890 fs/f2fs/file.c:551 6 locks held by syz.1.56/6971: 2 locks held by syz.1.56/6975: #0: ffff888032a71d28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1255 #1: ffff88805ae9f3d8 (&sb->s_type->i_mutex_key#23){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1042 [inline] #1: ffff88805ae9f3d8 (&sb->s_type->i_mutex_key#23){++++}-{4:4}, at: f2fs_seek_block fs/f2fs/file.c:464 [inline] #1: ffff88805ae9f3d8 (&sb->s_type->i_mutex_key#23){++++}-{4:4}, at: f2fs_llseek+0x1f7/0x1890 fs/f2fs/file.c:551 2 locks held by udevd/6980: 3 locks held by syz.2.81/7173: ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x135/0x170 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline] watchdog+0xf90/0xfe0 kernel/hung_task.c:515 kthread+0x726/0x8b0 kernel/kthread.c:463 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 6665 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026 RIP: 0010:__kernel_text_address+0x23/0x30 kernel/extable.c:79 Code: 90 90 90 90 90 90 90 0f 1f 40 d6 53 48 89 fb e8 33 00 00 00 48 81 fb 00 20 9f 90 0f 93 c1 48 81 fb e0 7a b6 90 0f 92 c2 20 ca <08> c2 0f b6 c2 5b c3 cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90003a663d8 EFLAGS: 00000246 RAX: 0000000000000001 RBX: ffffffff841f6e49 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8d592237 RDI: ffffffff841f6e49 RBP: ffffc90003a66490 R08: ffffc90003a66910 R09: 0000000000000000 R10: ffffc90003a66458 R11: fffff5200074cc8d R12: ffff88802ff11e40 R13: ffffffff81fe8355 R14: dffffc0000000000 R15: 1ffff9200074cc8a FS: 00007fae2560e6c0(0000) GS:ffff8881266c9000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f782ee95000 CR3: 000000004261e000 CR4: 00000000003526f0 Call Trace: unwind_get_return_address+0x4d/0x90 arch/x86/kernel/unwind_orc.c:385 arch_stack_walk+0xfb/0x150 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556 __call_rcu_common kernel/rcu/tree.c:3119 [inline] call_rcu+0xee/0x890 kernel/rcu/tree.c:3239 slab_free_hook mm/slub.c:2504 [inline] slab_free mm/slub.c:6674 [inline] kmem_cache_free+0x71c/0x8c0 mm/slub.c:6785 mempool_free+0xf5/0x140 mm/mempool.c:712 f2fs_finish_read_bio+0x599/0x5f0 fs/f2fs/data.c:159 f2fs_get_read_data_folio+0x4bb/0x7c0 fs/f2fs/data.c:1261 gc_data_segment fs/f2fs/gc.c:1647 [inline] do_garbage_collect+0x46af/0x6d40 fs/f2fs/gc.c:1858 f2fs_gc+0xd0f/0x25f0 fs/f2fs/gc.c:1965 f2fs_balance_fs+0x624/0x800 fs/f2fs/segment.c:466 f2fs_map_blocks+0x3523/0x41b0 fs/f2fs/data.c:1789 f2fs_expand_inode_data+0x5fc/0xa80 fs/f2fs/file.c:1934 f2fs_fallocate+0x4e8/0x970 fs/f2fs/file.c:2037 vfs_fallocate+0x672/0x7f0 fs/open.c:339 ioctl_preallocate fs/ioctl.c:289 [inline] file_ioctl+0x5cb/0x870 fs/ioctl.c:329 do_vfs_ioctl+0xc29/0x1540 fs/ioctl.c:576 __do_sys_ioctl fs/ioctl.c:595 [inline] __se_sys_ioctl+0x82/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fae25faa379 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fae2560e028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fae261e5fa0 RCX: 00007fae25faa379 RDX: 00002000000000c0 RSI: 0000000040305828 RDI: 0000000000000004 RBP: 00007fae2603dd68 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fae261e6038 R14: 00007fae261e5fa0 R15: 00007ffc3b46dda8