INFO: task kworker/u4:11:4475 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:11   state:D stack:21512 pid:4475  ppid:2      flags:0x00004000
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 schedule+0xbd/0x170 kernel/sched/core.c:6775
 io_schedule+0x80/0xd0 kernel/sched/core.c:9024
 rq_qos_wait+0x22b/0x360 block/blk-rq-qos.c:282
 __wbt_wait block/blk-wbt.c:595 [inline]
 wbt_wait+0x34a/0x580 block/blk-wbt.c:659
 __rq_qos_throttle+0x65/0xb0 block/blk-rq-qos.c:66
 rq_qos_throttle block/blk-rq-qos.h:151 [inline]
 blk_mq_get_new_requests block/blk-mq.c:2955 [inline]
 blk_mq_submit_bio+0x8fb/0x2220 block/blk-mq.c:3056
 __submit_bio+0x12b/0x260 block/blk-core.c:610
 __submit_bio_noacct_mq block/blk-core.c:689 [inline]
 submit_bio_noacct_nocheck+0x6e8/0x9c0 block/blk-core.c:718
 ext4_io_submit+0xdc/0x140 fs/ext4/page-io.c:389
 ext4_do_writepages+0xb5f/0x3990 fs/ext4/inode.c:2678
 ext4_writepages+0x1dd/0x350 fs/ext4/inode.c:2810
 do_writepages+0x351/0x590 mm/page-writeback.c:2575
 __writeback_single_inode+0x14e/0xee0 fs/fs-writeback.c:1686
 writeback_sb_inodes+0x813/0x1020 fs/fs-writeback.c:1977
 __writeback_inodes_wb+0x114/0x240 fs/fs-writeback.c:2048
 wb_writeback+0x472/0xbe0 fs/fs-writeback.c:2158
 wb_check_background_flush fs/fs-writeback.c:2228 [inline]
 wb_do_writeback fs/fs-writeback.c:2316 [inline]
 wb_workfn+0xb8e/0xe60 fs/fs-writeback.c:2343
 process_one_work kernel/workqueue.c:2657 [inline]
 process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734
 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
INFO: task syz-executor:5764 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:22280 pid:5764  ppid:5763   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 schedule+0xbd/0x170 kernel/sched/core.c:6775
 io_schedule+0x80/0xd0 kernel/sched/core.c:9024
 bit_wait_io+0x11/0xd0 kernel/sched/wait_bit.c:209
 __wait_on_bit+0x9f/0x2c0 kernel/sched/wait_bit.c:49
 out_of_line_wait_on_bit+0x13c/0x190 kernel/sched/wait_bit.c:64
 wait_on_bit_io include/linux/wait_bit.h:101 [inline]
 do_get_write_access+0x5c9/0xe00 fs/jbd2/transaction.c:1096
 jbd2_journal_get_write_access+0x10c/0x140 fs/jbd2/transaction.c:1231
 __ext4_journal_get_write_access+0x208/0x6d0 fs/ext4/ext4_jbd2.c:241
 ext4_reserve_inode_write+0x205/0x2a0 fs/ext4/inode.c:5933
 __ext4_mark_inode_dirty+0x13f/0x6d0 fs/ext4/inode.c:6107
 ext4_dirty_inode+0xcb/0x110 fs/ext4/inode.c:6144
 __mark_inode_dirty+0x2cc/0xc90 fs/fs-writeback.c:2522
 generic_update_time fs/inode.c:1981 [inline]
 inode_update_time fs/inode.c:1994 [inline]
 __file_update_time fs/inode.c:2180 [inline]
 file_update_time+0x187/0x1a0 fs/inode.c:2210
 ext4_page_mkwrite+0x1f9/0x11a0 fs/ext4/inode.c:6262
 do_page_mkwrite+0x153/0x3f0 mm/memory.c:2951
 wp_page_shared mm/memory.c:3311 [inline]
 do_wp_page+0xd4d/0x34d0 mm/memory.c:3396
 handle_pte_fault mm/memory.c:5063 [inline]
 __handle_mm_fault mm/memory.c:5188 [inline]
 handle_mm_fault+0x1306/0x4a50 mm/memory.c:5353
 do_user_addr_fault+0x736/0x12d0 arch/x86/mm/fault.c:1371
 handle_page_fault arch/x86/mm/fault.c:1463 [inline]
 exc_page_fault+0x64/0x100 arch/x86/mm/fault.c:1516
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:608
RIP: 0033:0x7f0262a7c662
RSP: 002b:00007ffd7cdd1460 EFLAGS: 00010202
RAX: 00007f0260a14000 RBX: 0000555586887fa0 RCX: 0000000000000007
RDX: 00000000000027b5 RSI: 000055558688b550 RDI: 0000000000000080
RBP: 00007ffd7cdd1960 R08: 000055558688b580 R09: 0000000000000092
R10: 0000000000000000 R11: 0000000000000202 R12: 00007ffd7cdd17a0
R13: 00007ffd7cdd1590 R14: 585858582e7a7973 R15: 00007ffd7cdd14e0
 </TASK>
INFO: task syz.9.1101:10144 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.9.1101      state:D stack:27048 pid:10144 ppid:8447   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 schedule+0xbd/0x170 kernel/sched/core.c:6775
 io_schedule+0x80/0xd0 kernel/sched/core.c:9024
 bit_wait_io+0x11/0xd0 kernel/sched/wait_bit.c:209
 __wait_on_bit+0x9f/0x2c0 kernel/sched/wait_bit.c:49
 out_of_line_wait_on_bit+0x13c/0x190 kernel/sched/wait_bit.c:64
 wait_on_bit_io include/linux/wait_bit.h:101 [inline]
 do_get_write_access+0x5c9/0xe00 fs/jbd2/transaction.c:1096
 jbd2_journal_get_write_access+0x10c/0x140 fs/jbd2/transaction.c:1231
 __ext4_journal_get_write_access+0x208/0x6d0 fs/ext4/ext4_jbd2.c:241
 ext4_reserve_inode_write+0x205/0x2a0 fs/ext4/inode.c:5933
 __ext4_mark_inode_dirty+0x13f/0x6d0 fs/ext4/inode.c:6107
 ext4_dirty_inode+0xcb/0x110 fs/ext4/inode.c:6144
 __mark_inode_dirty+0x2cc/0xc90 fs/fs-writeback.c:2522
 generic_update_time fs/inode.c:1981 [inline]
 inode_update_time fs/inode.c:1994 [inline]
 __file_update_time fs/inode.c:2180 [inline]
 file_update_time+0x187/0x1a0 fs/inode.c:2210
 ext4_page_mkwrite+0x1f9/0x11a0 fs/ext4/inode.c:6262
 do_page_mkwrite+0x153/0x3f0 mm/memory.c:2951
 do_shared_fault mm/memory.c:4717 [inline]
 do_fault mm/memory.c:4779 [inline]
 do_pte_missing mm/memory.c:3689 [inline]
 handle_pte_fault mm/memory.c:5047 [inline]
 __handle_mm_fault mm/memory.c:5188 [inline]
 handle_mm_fault+0x1a2c/0x4a50 mm/memory.c:5353
 do_user_addr_fault+0x736/0x12d0 arch/x86/mm/fault.c:1371
 handle_page_fault arch/x86/mm/fault.c:1463 [inline]
 exc_page_fault+0x64/0x100 arch/x86/mm/fault.c:1516
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:608
RIP: 0033:0x7fe462072789
RSP: 002b:00007fff56132630 EFLAGS: 00010202
RAX: 0000001b33c24000 RBX: 0000000000000000 RCX: 00000000005ffde8
RDX: 0000001b33c23ffc RSI: 00000000005ffde8 RDI: 00007fe462f55700
RBP: 0000000000000000 R08: 0000000000000000 R09: 00007fe462412000
R10: 00007fe462f55700 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000010b50 R14: ffffffff813215fe R15: 00007fe462f55720
 </TASK>
INFO: task syz.6.1108:10170 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.1108      state:D stack:27560 pid:10170 ppid:7416   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 schedule+0xbd/0x170 kernel/sched/core.c:6775
 io_schedule+0x80/0xd0 kernel/sched/core.c:9024
 bit_wait_io+0x11/0xd0 kernel/sched/wait_bit.c:209
 __wait_on_bit+0x9f/0x2c0 kernel/sched/wait_bit.c:49
 out_of_line_wait_on_bit+0x13c/0x190 kernel/sched/wait_bit.c:64
 wait_on_bit_io include/linux/wait_bit.h:101 [inline]
 do_get_write_access+0x5c9/0xe00 fs/jbd2/transaction.c:1096
 jbd2_journal_get_write_access+0x10c/0x140 fs/jbd2/transaction.c:1231
 __ext4_journal_get_write_access+0x208/0x6d0 fs/ext4/ext4_jbd2.c:241
 ext4_reserve_inode_write+0x205/0x2a0 fs/ext4/inode.c:5933
 __ext4_mark_inode_dirty+0x13f/0x6d0 fs/ext4/inode.c:6107
 ext4_dirty_inode+0xcb/0x110 fs/ext4/inode.c:6144
 __mark_inode_dirty+0x2cc/0xc90 fs/fs-writeback.c:2522
 generic_update_time fs/inode.c:1981 [inline]
 inode_update_time fs/inode.c:1994 [inline]
 __file_update_time fs/inode.c:2180 [inline]
 file_update_time+0x187/0x1a0 fs/inode.c:2210
 ext4_page_mkwrite+0x1f9/0x11a0 fs/ext4/inode.c:6262
 do_page_mkwrite+0x153/0x3f0 mm/memory.c:2951
 do_shared_fault mm/memory.c:4717 [inline]
 do_fault mm/memory.c:4779 [inline]
 do_pte_missing mm/memory.c:3689 [inline]
 handle_pte_fault mm/memory.c:5047 [inline]
 __handle_mm_fault mm/memory.c:5188 [inline]
 handle_mm_fault+0x1a2c/0x4a50 mm/memory.c:5353
 do_user_addr_fault+0x736/0x12d0 arch/x86/mm/fault.c:1371
 handle_page_fault arch/x86/mm/fault.c:1463 [inline]
 exc_page_fault+0x64/0x100 arch/x86/mm/fault.c:1516
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:608
RIP: 0033:0x7f6b55c6ba23
RSP: 002b:00007ffd4eb3ac60 EFLAGS: 00010246
RAX: 00000000005ffde8 RBX: 0000000000000000 RCX: 0000001b33864000
RDX: 0000001b33824000 RSI: 0000000000600000 RDI: 00007f6b55fe0708
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 00007ffd4eb3aef0
 </TASK>
INFO: task syz.3.1107:10172 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.1107      state:D stack:27560 pid:10172 ppid:8472   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 schedule+0xbd/0x170 kernel/sched/core.c:6775
 io_schedule+0x80/0xd0 kernel/sched/core.c:9024
 bit_wait_io+0x11/0xd0 kernel/sched/wait_bit.c:209
 __wait_on_bit+0x9f/0x2c0 kernel/sched/wait_bit.c:49
 out_of_line_wait_on_bit+0x13c/0x190 kernel/sched/wait_bit.c:64
 wait_on_bit_io include/linux/wait_bit.h:101 [inline]
 do_get_write_access+0x5c9/0xe00 fs/jbd2/transaction.c:1096
 jbd2_journal_get_write_access+0x10c/0x140 fs/jbd2/transaction.c:1231
 __ext4_journal_get_write_access+0x208/0x6d0 fs/ext4/ext4_jbd2.c:241
 ext4_reserve_inode_write+0x205/0x2a0 fs/ext4/inode.c:5933
 __ext4_mark_inode_dirty+0x13f/0x6d0 fs/ext4/inode.c:6107
 ext4_dirty_inode+0xcb/0x110 fs/ext4/inode.c:6144
 __mark_inode_dirty+0x2cc/0xc90 fs/fs-writeback.c:2522
 generic_update_time fs/inode.c:1981 [inline]
 inode_update_time fs/inode.c:1994 [inline]
 __file_update_time fs/inode.c:2180 [inline]
 file_update_time+0x187/0x1a0 fs/inode.c:2210
 ext4_page_mkwrite+0x1f9/0x11a0 fs/ext4/inode.c:6262
 do_page_mkwrite+0x153/0x3f0 mm/memory.c:2951
 do_shared_fault mm/memory.c:4717 [inline]
 do_fault mm/memory.c:4779 [inline]
 do_pte_missing mm/memory.c:3689 [inline]
 handle_pte_fault mm/memory.c:5047 [inline]
 __handle_mm_fault mm/memory.c:5188 [inline]
 handle_mm_fault+0x1a2c/0x4a50 mm/memory.c:5353
 do_user_addr_fault+0x736/0x12d0 arch/x86/mm/fault.c:1371
 handle_page_fault arch/x86/mm/fault.c:1463 [inline]
 exc_page_fault+0x64/0x100 arch/x86/mm/fault.c:1516
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:608
RIP: 0033:0x7f269d46ba23
RSP: 002b:00007ffc4f6f7e80 EFLAGS: 00010246
RAX: 00000000005ffde8 RBX: 0000000000000000 RCX: 0000001b2d964000
RDX: 0000001b2d924000 RSI: 0000000000600000 RDI: 00007f269d7e0708
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 00007ffc4f6f8110
 </TASK>
INFO: task syz.8.1109:10173 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.8.1109      state:D stack:27560 pid:10173 ppid:8158   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 schedule+0xbd/0x170 kernel/sched/core.c:6775
 io_schedule+0x80/0xd0 kernel/sched/core.c:9024
 bit_wait_io+0x11/0xd0 kernel/sched/wait_bit.c:209
 __wait_on_bit+0x9f/0x2c0 kernel/sched/wait_bit.c:49
 out_of_line_wait_on_bit+0x13c/0x190 kernel/sched/wait_bit.c:64
 wait_on_bit_io include/linux/wait_bit.h:101 [inline]
 do_get_write_access+0x5c9/0xe00 fs/jbd2/transaction.c:1096
 jbd2_journal_get_write_access+0x10c/0x140 fs/jbd2/transaction.c:1231
 __ext4_journal_get_write_access+0x208/0x6d0 fs/ext4/ext4_jbd2.c:241
 ext4_reserve_inode_write+0x205/0x2a0 fs/ext4/inode.c:5933
 __ext4_mark_inode_dirty+0x13f/0x6d0 fs/ext4/inode.c:6107
 ext4_dirty_inode+0xcb/0x110 fs/ext4/inode.c:6144
 __mark_inode_dirty+0x2cc/0xc90 fs/fs-writeback.c:2522
 generic_update_time fs/inode.c:1981 [inline]
 inode_update_time fs/inode.c:1994 [inline]
 __file_update_time fs/inode.c:2180 [inline]
 file_update_time+0x187/0x1a0 fs/inode.c:2210
 ext4_page_mkwrite+0x1f9/0x11a0 fs/ext4/inode.c:6262
 do_page_mkwrite+0x153/0x3f0 mm/memory.c:2951
 do_shared_fault mm/memory.c:4717 [inline]
 do_fault mm/memory.c:4779 [inline]
 do_pte_missing mm/memory.c:3689 [inline]
 handle_pte_fault mm/memory.c:5047 [inline]
 __handle_mm_fault mm/memory.c:5188 [inline]
 handle_mm_fault+0x1a2c/0x4a50 mm/memory.c:5353
 do_user_addr_fault+0x736/0x12d0 arch/x86/mm/fault.c:1371
 handle_page_fault arch/x86/mm/fault.c:1463 [inline]
 exc_page_fault+0x64/0x100 arch/x86/mm/fault.c:1516
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:608
RIP: 0033:0x7f8427c6ba23
RSP: 002b:00007ffc4cdb9be0 EFLAGS: 00010246
RAX: 00000000005ffde8 RBX: 0000000000000000 RCX: 0000001b31f64000
RDX: 0000001b31f24000 RSI: 0000000000600000 RDI: 00007f8427fe0708
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 00007ffc4cdb9e70
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/29:
 #0: ffffffff8d131da0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 #0: ffffffff8d131da0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
 #0: ffffffff8d131da0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633
4 locks held by kworker/u4:11/4475:
 #0: ffff888140054138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline]
 #0: ffff888140054138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734
 #1: ffffc9000eaafd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline]
 #1: ffffc9000eaafd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734
 #2: ffff888031a920e0 (&type->s_umount_key#31){++++}-{3:3}, at: super_trylock_shared+0x20/0xf0 fs/super.c:607
 #3: ffff888031a94c58 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages_down_read fs/ext4/ext4.h:1768 [inline]
 #3: ffff888031a94c58 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages+0x1a4/0x350 fs/ext4/inode.c:2809
2 locks held by getty/5531:
 #0: ffff88814c85c0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900032832f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x428/0x1370 drivers/tty/n_tty.c:2217
3 locks held by syz-executor/5764:
 #0: ffff88802ef90b20 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:165 [inline]
 #0: ffff88802ef90b20 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5380 [inline]
 #0: ffff88802ef90b20 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x32/0x2f0 mm/memory.c:5440
 #1: ffff888031a92510 (sb_pagefaults){++++}-{0:0}, at: __sb_start_write include/linux/fs.h:1633 [inline]
 #1: ffff888031a92510 (sb_pagefaults){++++}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1737 [inline]
 #1: ffff888031a92510 (sb_pagefaults){++++}-{0:0}, at: ext4_page_mkwrite+0x1e2/0x11a0 fs/ext4/inode.c:6261
 #2: ffff888031a96990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x1f3f/0x2170 fs/jbd2/transaction.c:448
3 locks held by syz.9.1101/10144:
 #0: ffff888031364da0 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:165 [inline]
 #0: ffff888031364da0 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5380 [inline]
 #0: ffff888031364da0 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x32/0x2f0 mm/memory.c:5440
 #1: ffff888031a92510 (sb_pagefaults){++++}-{0:0}, at: __sb_start_write include/linux/fs.h:1633 [inline]
 #1: ffff888031a92510 (sb_pagefaults){++++}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1737 [inline]
 #1: ffff888031a92510 (sb_pagefaults){++++}-{0:0}, at: ext4_page_mkwrite+0x1e2/0x11a0 fs/ext4/inode.c:6261
 #2: ffff888031a96990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x1f3f/0x2170 fs/jbd2/transaction.c:448
3 locks held by syz.6.1108/10170:
 #0: ffff88807ad7baa0 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:165 [inline]
 #0: ffff88807ad7baa0 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5380 [inline]
 #0: ffff88807ad7baa0 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x32/0x2f0 mm/memory.c:5440
 #1: ffff888031a92510 (sb_pagefaults){++++}-{0:0}, at: __sb_start_write include/linux/fs.h:1633 [inline]
 #1: ffff888031a92510 (sb_pagefaults){++++}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1737 [inline]
 #1: ffff888031a92510 (sb_pagefaults){++++}-{0:0}, at: ext4_page_mkwrite+0x1e2/0x11a0 fs/ext4/inode.c:6261
 #2: ffff888031a96990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x1f3f/0x2170 fs/jbd2/transaction.c:448
3 locks held by syz.3.1107/10172:
 #0: ffff88807dcdbaa0 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:165 [inline]
 #0: ffff88807dcdbaa0 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5380 [inline]
 #0: ffff88807dcdbaa0 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x32/0x2f0 mm/memory.c:5440
 #1: ffff888031a92510 (sb_pagefaults){++++}-{0:0}, at: __sb_start_write include/linux/fs.h:1633 [inline]
 #1: ffff888031a92510 (sb_pagefaults){++++}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1737 [inline]
 #1: ffff888031a92510 (sb_pagefaults){++++}-{0:0}, at: ext4_page_mkwrite+0x1e2/0x11a0 fs/ext4/inode.c:6261
 #2: ffff888031a96990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x1f3f/0x2170 fs/jbd2/transaction.c:448
3 locks held by syz.8.1109/10173:
 #0: ffff88807ad78b20 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:165 [inline]
 #0: ffff88807ad78b20 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5380 [inline]
 #0: ffff88807ad78b20 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x32/0x2f0 mm/memory.c:5440
 #1: ffff888031a92510 (sb_pagefaults){++++}-{0:0}, at: __sb_start_write include/linux/fs.h:1633 [inline]
 #1: ffff888031a92510 (sb_pagefaults){++++}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1737 [inline]
 #1: ffff888031a92510 (sb_pagefaults){++++}-{0:0}, at: ext4_page_mkwrite+0x1e2/0x11a0 fs/ext4/inode.c:6261
 #2: ffff888031a96990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x1f3f/0x2170 fs/jbd2/transaction.c:448

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

NMI backtrace for cpu 1
CPU: 1 PID: 29 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a6/0x3e0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
 watchdog+0xf59/0xfa0 kernel/hung_task.c:379
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 1126 Comm: kworker/u4:7 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:deref_stack_reg+0x1bf/0x230 arch/x86/kernel/unwind_orc.c:406
Code: c7 9f 4b 00 49 bf 00 00 00 00 00 fc ff df 48 89 ef e8 b5 07 00 00 49 89 c6 48 8b 5c 24 10 48 89 d8 48 c1 e8 03 42 80 3c 38 00 <74> 08 48 89 df e8 a7 22 a4 00 4c 89 33 b0 01 eb 0e e8 8b 9f 4b 00
RSP: 0018:ffffc900047274c8 EFLAGS: 00000246
RAX: 1ffff920008e4ec5 RBX: ffffc90004727628 RCX: ffff888023f05a00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffc900047279f0
RBP: ffffc900047279f0 R08: ffff888023f05a00 R09: 0000000000000003
R10: 0000000000000004 R11: 0000000000000000 R12: ffffc90004728000
R13: 1ffff920008e4ebf R14: 0000000000000000 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000559862c51660 CR3: 000000000cf32000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 unwind_next_frame+0x1781/0x2990 arch/x86/kernel/unwind_orc.c:648
 arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
 kasan_save_free_info+0x28/0x40 mm/kasan/generic.c:522
 ____kasan_slab_free+0x126/0x1f0 mm/kasan/common.c:237
 kasan_slab_free include/linux/kasan.h:164 [inline]
 slab_free_hook mm/slub.c:1811 [inline]
 slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837
 slab_free mm/slub.c:3830 [inline]
 __kmem_cache_free+0xba/0x1f0 mm/slub.c:3843
 skb_kfree_head net/core/skbuff.c:946 [inline]
 skb_free_head net/core/skbuff.c:958 [inline]
 skb_release_data+0x609/0x7f0 net/core/skbuff.c:988
 skb_release_all net/core/skbuff.c:1054 [inline]
 __kfree_skb net/core/skbuff.c:1068 [inline]
 consume_skb+0xb2/0x110 net/core/skbuff.c:1284
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:821 [inline]
 nsim_dev_trap_report_work+0x723/0xa90 drivers/net/netdevsim/dev.c:851
 process_one_work kernel/workqueue.c:2657 [inline]
 process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734
 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>