INFO: task syz.4.834:9411 blocked for more than 143 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.834 state:D stack:23936 pid:9411 tgid:9410 ppid:6091 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 __schedule_loop kernel/sched/core.c:6948 [inline] schedule+0x165/0x360 kernel/sched/core.c:6963 io_schedule+0x80/0xd0 kernel/sched/core.c:7792 folio_wait_bit_common+0x6b0/0xb80 mm/filemap.c:1323 folio_lock include/linux/pagemap.h:1159 [inline] migrate_folio_unmap mm/migrate.c:1249 [inline] migrate_pages_batch+0x14cd/0x35e0 mm/migrate.c:1890 migrate_pages_sync mm/migrate.c:2034 [inline] migrate_pages+0x2006/0x28e0 mm/migrate.c:2116 compact_zone+0x25ba/0x4760 mm/compaction.c:2647 compact_node mm/compaction.c:2916 [inline] compact_nodes mm/compaction.c:2938 [inline] sysctl_compaction_handler+0x3a1/0x7b0 mm/compaction.c:2989 proc_sys_call_handler+0x4cb/0x700 fs/proc/proc_sysctl.c:600 iter_file_splice_write+0x972/0x10b0 fs/splice.c:738 do_splice_from fs/splice.c:938 [inline] direct_splice_actor+0x101/0x160 fs/splice.c:1161 splice_direct_to_actor+0x5a8/0xcc0 fs/splice.c:1105 do_splice_direct_actor fs/splice.c:1204 [inline] do_splice_direct+0x181/0x270 fs/splice.c:1230 do_sendfile+0x4da/0x7e0 fs/read_write.c:1370 __do_sys_sendfile64 fs/read_write.c:1425 [inline] __se_sys_sendfile64+0xd9/0x190 fs/read_write.c:1417 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2ae9f8f749 RSP: 002b:00007f2aeae45038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f2aea1e5fa0 RCX: 00007f2ae9f8f749 RDX: 00002000000000c0 RSI: 0000000000000004 RDI: 0000000000000005 RBP: 00007f2aea013f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000005 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f2aea1e6038 R14: 00007f2aea1e5fa0 R15: 00007ffc3d52bb38 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e33f2e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e33f2e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8e33f2e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by getty/5588: #0: ffff8880308910a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x449/0x1460 drivers/tty/n_tty.c:2211 1 lock held by udevd/6093: #0: ffff888025e2d358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:962 1 lock held by syz.4.834/9411: #0: ffff888034d6e420 (sb_writers#3){.+.+}-{0:0}, at: direct_splice_actor+0x49/0x160 fs/splice.c:1160 1 lock held by syz.0.1038/10428: #0: ffff888025e2d358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:962 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [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:363 [inline] watchdog+0xe40/0xe90 kernel/hung_task.c:557 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 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: 0 Comm: swapper/1 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 33 0e 21 00 f3 0f 1e fa fb f4 48 ee 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90000197de0 EFLAGS: 000002c6 RAX: 2048e84a4c317b00 RBX: ffffffff8197c6ba RCX: 2048e84a4c317b00 RDX: 0000000000000001 RSI: ffffffff8daa9dc3 RDI: ffffffff8be247e0 RBP: ffffc90000197f10 R08: ffff8880b87336db R09: 1ffff110170e66db R10: dffffc0000000000 R11: ffffed10170e66dc R12: ffffffff8fc3d070 R13: 1ffff11003b5eb70 R14: 0000000000000001 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888125adc000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f02b0bb6ad8 CR3: 0000000078bf8000 CR4: 00000000003526f0 DR0: 0000000000000001 DR1: 0000000000000005 DR2: 0000000000000000 DR3: 000000000000000a DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x73/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x1ea/0x520 kernel/sched/idle.c:332 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x147