syzbot

INFO: task kworker/u8:2:36 blocked for more than 143 seconds.
      Not tainted 6.14.0-syzkaller-01103-g2df0c02dab82 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:2    state:D stack:25112 pid:36    tgid:36    ppid:2      task_flags:0x4248060 flags:0x00004000
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5367 [inline]
 __schedule+0x1129/0x5c00 kernel/sched/core.c:6748
 __schedule_loop kernel/sched/core.c:6825 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6840
 io_schedule+0xbf/0x130 kernel/sched/core.c:7722
 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+0xd9/0x110 kernel/sched/wait_bit.c:64
 wait_on_bit_io include/linux/wait_bit.h:105 [inline]
 do_get_write_access+0x93d/0x12a0 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:5835
 __ext4_mark_inode_dirty+0x197/0x870 fs/ext4/inode.c:6009
 __ext4_ext_dirty+0x1ae/0x230 fs/ext4/extents.c:207
 ext4_ext_insert_extent+0x19bb/0x4610 fs/ext4/extents.c:2190
 ext4_ext_map_blocks+0x205b/0x5d60 fs/ext4/extents.c:4400
 ext4_map_create_blocks fs/ext4/inode.c:516 [inline]
 ext4_map_blocks+0x45b/0x1390 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+0x1969/0x3360 fs/ext4/inode.c:2735
 ext4_writepages+0x302/0x730 fs/ext4/inode.c:2824
 do_writepages+0x1b2/0x820 mm/page-writeback.c:2687
 __writeback_single_inode+0x160/0xfb0 fs/fs-writeback.c:1680
 writeback_sb_inodes+0x601/0xf90 fs/fs-writeback.c:1976
 __writeback_inodes_wb+0xf8/0x2d0 fs/fs-writeback.c:2047
 wb_writeback+0x7f3/0xb70 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+0x8ca/0xbe0 fs/fs-writeback.c:2343
 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c1/0xef0 kernel/workqueue.c:3400
 kthread+0x3a4/0x760 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
INFO: task jbd2/sda1-8:5171 blocked for more than 144 seconds.
      Not tainted 6.14.0-syzkaller-01103-g2df0c02dab82 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:jbd2/sda1-8     state:D stack:26968 pid:5171  tgid:5171  ppid:2      task_flags:0x240040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5367 [inline]
 __schedule+0x1129/0x5c00 kernel/sched/core.c:6748
 __schedule_loop kernel/sched/core.c:6825 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6840
 io_schedule+0xbf/0x130 kernel/sched/core.c:7722
 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+0xd9/0x110 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+0x382c/0x6890 fs/jbd2/commit.c:810
 kjournald2+0x1f4/0x760 fs/jbd2/journal.c:201
 kthread+0x3a4/0x760 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8e1be0c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e1be0c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8e1be0c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6761
6 locks held by kworker/u8:2/36:
 #0: ffff888143e85948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213
 #1: ffffc90000ac7d18 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214
 #2: ffff8880355260e0 (&type->s_umount_key#32){++++}-{4:4}, at: super_trylock_shared+0x1e/0xf0 fs/super.c:562
 #3: ffff888035528b98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: do_writepages+0x1b2/0x820 mm/page-writeback.c:2687
 #4: ffff88803552a950 (jbd2_handle){.+.+}-{0:0}, at: start_this_handle+0x5e4/0x1480 fs/jbd2/transaction.c:448
 #5: ffff888078033df8 (&ei->i_data_sem){++++}-{4:4}, at: ext4_map_blocks+0x355/0x1390 fs/ext4/inode.c:701
1 lock held by klogd/5198:
 #0: ffff8880b8739ed8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:595
2 locks held by getty/5596:
 #0: ffff888031b2d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000330b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0xfa1/0x1450 drivers/tty/n_tty.c:2211
2 locks held by syz-executor988/14813:
 #0: ffff8880b8739ed8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:595
 #1: ffff8880b8723c48 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x2c1/0x8e0 kernel/sched/psi.c:987

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.14.0-syzkaller-01103-g2df0c02dab82 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:236 [inline]
 watchdog+0xf70/0x12c0 kernel/hung_task.c:399
 kthread+0x3a4/0x760 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 14821 Comm: syz-executor988 Not tainted 6.14.0-syzkaller-01103-g2df0c02dab82 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:__outl arch/x86/include/asm/shared/io.h:24 [inline]
RIP: 0010:pci_conf1_write+0x13d/0x150 arch/x86/pci/direct.c:72
Code: fc 0c 00 00 66 ef eb bf e8 e0 4d 6c f6 83 e5 03 44 89 f0 8d 95 fc 0c 00 00 ee eb ab e8 cc 4d 6c f6 ba fc 0c 00 00 44 89 f0 ef <eb> 9b bb ea ff ff ff eb aa 66 2e 0f 1f 84 00 00 00 00 00 90 90 90
RSP: 0018:ffffc90011477bd8 EFLAGS: 00000093
RAX: 0000000000000000 RBX: 0000000080001814 RCX: ffffffff8b4ea758
RDX: 0000000000000cfc RSI: ffffffff8b4ea7c4 RDI: 0000000000000005
RBP: 0000000000000014 R08: 0000000000000005 R09: 0000000000000004
R10: 0000000000000004 R11: 0000000000000000 R12: 0000000000000004
R13: 0000000000000006 R14: 0000000000000000 R15: 0000000000000000
FS:  00005555620b6380(0000) GS:ffff888124f5a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000014 CR3: 000000007c3f4000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 raw_pci_write arch/x86/pci/common.c:54 [inline]
 pci_write+0x185/0x1d0 arch/x86/pci/common.c:68
 pci_user_write_config_dword+0x13f/0x240 drivers/pci/access.c:278
 proc_bus_pci_write+0x390/0x4c0 drivers/pci/proc.c:158
 pde_write fs/proc/inode.c:330 [inline]
 proc_reg_write+0x23d/0x330 fs/proc/inode.c:342
 vfs_write+0x25c/0x1180 fs/read_write.c:682
 ksys_write+0x12a/0x240 fs/read_write.c:736
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb2225c4a39
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 17 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc5e0de028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb2225c4a39
RDX: 0000000000000200 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00000000000697e1 R08: 0000000000000006 R09: 0000000000000006
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc5e0de03c
R13: 431bde82d7b634db R14: 0000000000000001 R15: 0000000000000001
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.618 msecs