syzbot

INFO: task syz-executor308:4262 blocked for more than 143 seconds.
      Tainted: G        W          6.1.122-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor308 state:D stack:22624 pid:4262  ppid:4261   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5241 [inline]
 __schedule+0x143f/0x4570 kernel/sched/core.c:6558
 schedule+0xbf/0x180 kernel/sched/core.c:6634
 wb_wait_for_completion+0x162/0x290 fs/fs-writeback.c:191
 sync_inodes_sb+0x28f/0xb10 fs/fs-writeback.c:2739
 sync_filesystem+0x16b/0x220 fs/sync.c:64
 nilfs_remount+0x56/0x420 fs/nilfs2/super.c:1147
 reconfigure_super+0x43a/0x870 fs/super.c:977
 do_remount fs/namespace.c:2712 [inline]
 path_mount+0xe69/0x1090 fs/namespace.c:3378
 do_mount fs/namespace.c:3399 [inline]
 __do_sys_mount fs/namespace.c:3607 [inline]
 __se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3584
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fbd6a0a83ea
RSP: 002b:00007ffc47096b08 EFLAGS: 00000286 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fbd6a0a83ea
RDX: 0000000020000180 RSI: 0000000020000100 RDI: 0000000000000000
RBP: 0000000020000100 R08: 00007ffc47096ba0 R09: 0000000000000000
R10: 0000000001a4243c R11: 0000000000000286 R12: 0000000020000180
R13: 00007ffc47096ba0 R14: 0000000000000000 R15: 0000000020002d80
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8d32b290 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x34/0xde0 kernel/rcu/tasks.h:543
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8d32bab0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x34/0xde0 kernel/rcu/tasks.h:543
1 lock held by khungtaskd/28:
 #0: ffffffff8d32b0c0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8d32b0c0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8d32b0c0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6510
2 locks held by kworker/u4:3/46:
 #0: ffff888019e6c938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267
 #1: ffffc90000b77d20 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267
2 locks held by getty/4010:
 #0: ffff88814d790098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc9000325e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6a7/0x1db0 drivers/tty/n_tty.c:2198
2 locks held by syz-executor308/4262:
 #0: ffff8880733d60e0 (&type->s_umount_key#42){+.+.}-{3:3}, at: do_remount fs/namespace.c:2709 [inline]
 #0: ffff8880733d60e0 (&type->s_umount_key#42){+.+.}-{3:3}, at: path_mount+0xe26/0x1090 fs/namespace.c:3378
 #1: ffff8881443e87d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
 #1: ffff8881443e87d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x270/0xb10 fs/fs-writeback.c:2737
1 lock held by segctord/4264:

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Tainted: G        W          6.1.122-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 nmi_cpu_backtrace+0x4e1/0x560 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1ae/0x3f0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
 watchdog+0xf88/0xfd0 kernel/hung_task.c:377
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4264 Comm: segctord Tainted: G        W          6.1.122-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:clear_page_erms+0x7/0x10 arch/x86/lib/clear_page_64.S:50
Code: 48 89 47 18 48 89 47 20 48 89 47 28 48 89 47 30 48 89 47 38 48 8d 7f 40 75 d9 90 c3 0f 1f 80 00 00 00 00 b9 00 10 00 00 31 c0 <f3> aa c3 66 0f 1f 44 00 00 89 c8 48 c1 e9 03 74 18 0f 1f 84 00 00
RSP: 0018:ffffc90003df7180 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000d40
RDX: ffff88806371b000 RSI: 0000000000000001 RDI: ffff88806371b2c0
RBP: 0000000000000002 R08: dffffc0000000000 R09: ffffed100c6e3400
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000001
R13: 0000000000000000 R14: ffffea00018dc680 R15: 00000000000d2050
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055d8b5184680 CR3: 000000000d08e000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 clear_page arch/x86/include/asm/page_64.h:58 [inline]
 clear_highpage include/linux/highmem.h:242 [inline]
 clear_highpage_kasan_tagged include/linux/highmem.h:252 [inline]
 kernel_init_pages mm/page_alloc.c:1381 [inline]
 post_alloc_hook+0x145/0x1b0 mm/page_alloc.c:2527
 prep_new_page mm/page_alloc.c:2539 [inline]
 get_page_from_freelist+0x3731/0x38d0 mm/page_alloc.c:4328
 __alloc_pages+0x28d/0x770 mm/page_alloc.c:5605
 alloc_slab_page+0x6a/0x150 mm/slub.c:1794
 allocate_slab mm/slub.c:1939 [inline]
 new_slab+0x84/0x2d0 mm/slub.c:1992
 ___slab_alloc+0xc20/0x1270 mm/slub.c:3180
 __slab_alloc mm/slub.c:3279 [inline]
 slab_alloc_node mm/slub.c:3364 [inline]
 slab_alloc mm/slub.c:3406 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3413 [inline]
 kmem_cache_alloc+0x1a5/0x2d0 mm/slub.c:3422
 nilfs_segbuf_new+0x4a/0x260 fs/nilfs2/segbuf.c:38
 nilfs_segctor_begin_construction fs/nilfs2/segment.c:1318 [inline]
 nilfs_segctor_do_construct+0xb84/0x7100 fs/nilfs2/segment.c:2081
 nilfs_segctor_construct+0x181/0x6a0 fs/nilfs2/segment.c:2451
 nilfs_segctor_thread_construct fs/nilfs2/segment.c:2559 [inline]
 nilfs_segctor_thread+0x552/0x11a0 fs/nilfs2/segment.c:2643
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.559 msecs