INFO: task kworker/u4:2:154 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:2    state:D stack:20912 pid:  154 ppid:     2 flags:0x00004000
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 io_schedule+0x7c/0xd0 kernel/sched/core.c:8503
 rq_qos_wait+0x21d/0x330 block/blk-rq-qos.c:288
 __wbt_wait block/blk-wbt.c:522 [inline]
 wbt_wait+0x39e/0x680 block/blk-wbt.c:586
 __rq_qos_throttle+0x61/0xa0 block/blk-rq-qos.c:72
 rq_qos_throttle block/blk-rq-qos.h:203 [inline]
 blk_mq_submit_bio+0x434/0x1950 block/blk-mq.c:2233
 __submit_bio+0x73e/0x780 block/blk-core.c:917
 __submit_bio_noacct_mq block/blk-core.c:997 [inline]
 submit_bio_noacct+0x6b1/0x800 block/blk-core.c:1027
 submit_bio+0x2c6/0x550 block/blk-core.c:1089
 __block_write_full_page+0x8f0/0x1180 fs/buffer.c:1811
 __writepage+0x63/0x130 mm/page-writeback.c:2342
 write_cache_pages+0x997/0xfb0 mm/page-writeback.c:2277
 generic_writepages+0x104/0x170 mm/page-writeback.c:2368
 do_writepages+0x493/0x700 mm/page-writeback.c:2386
 __writeback_single_inode+0x153/0xda0 fs/fs-writeback.c:1657
 writeback_sb_inodes+0xaaa/0x1750 fs/fs-writeback.c:1940
 __writeback_inodes_wb+0x12a/0x3f0 fs/fs-writeback.c:2011
 wb_writeback+0x45e/0xbc0 fs/fs-writeback.c:2116
 wb_check_old_data_flush fs/fs-writeback.c:2216 [inline]
 wb_do_writeback fs/fs-writeback.c:2269 [inline]
 wb_workfn+0xb15/0xf20 fs/fs-writeback.c:2298
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
INFO: task jbd2/sda1-8:3521 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:jbd2/sda1-8     state:D stack:25872 pid: 3521 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 io_schedule+0x7c/0xd0 kernel/sched/core.c:8503
 rq_qos_wait+0x266/0x330 block/blk-rq-qos.c:288
 __wbt_wait block/blk-wbt.c:522 [inline]
 wbt_wait+0x39e/0x680 block/blk-wbt.c:586
 __rq_qos_throttle+0x61/0xa0 block/blk-rq-qos.c:72
 rq_qos_throttle block/blk-rq-qos.h:203 [inline]
 blk_mq_submit_bio+0x434/0x1950 block/blk-mq.c:2233
 __submit_bio+0x73e/0x780 block/blk-core.c:917
 __submit_bio_noacct_mq block/blk-core.c:997 [inline]
 submit_bio_noacct+0x6b1/0x800 block/blk-core.c:1027
 submit_bio+0x2c6/0x550 block/blk-core.c:1089
 submit_bh+0x23/0x30 fs/buffer.c:3062
 jbd2_journal_commit_transaction+0x252c/0x5c30 fs/jbd2/commit.c:765
 kjournald2+0x45a/0x900 fs/jbd2/journal.c:213
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
INFO: task syz-executor:4172 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:22224 pid: 4172 ppid:  4170 flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 io_schedule+0x7c/0xd0 kernel/sched/core.c:8503
 bit_wait_io+0xd/0xc0 kernel/sched/wait_bit.c:209
 __wait_on_bit kernel/sched/wait_bit.c:49 [inline]
 out_of_line_wait_on_bit+0x173/0x230 kernel/sched/wait_bit.c:64
 wait_on_bit_io include/linux/wait_bit.h:101 [inline]
 do_get_write_access+0x134/0xe40 fs/jbd2/transaction.c:1116
 jbd2_journal_get_write_access+0x108/0x140 fs/jbd2/transaction.c:1251
 __ext4_journal_get_write_access+0x24d/0x6e0 fs/ext4/ext4_jbd2.c:235
 ext4_reserve_inode_write+0x203/0x2e0 fs/ext4/inode.c:5866
 __ext4_mark_inode_dirty+0x136/0x6c0 fs/ext4/inode.c:6040
 ext4_dirty_inode+0xbf/0x100 fs/ext4/inode.c:6077
 __mark_inode_dirty+0x2c8/0xc90 fs/fs-writeback.c:2480
 generic_update_time+0x1cd/0x1f0 fs/inode.c:1881
 inode_update_time fs/inode.c:1894 [inline]
 file_update_time+0x3c0/0x440 fs/inode.c:2083
 ext4_page_mkwrite+0x1bc/0x1250 fs/ext4/inode.c:6195
 do_page_mkwrite+0x168/0x3c0 mm/memory.c:2922
 do_shared_fault mm/memory.c:4328 [inline]
 do_fault mm/memory.c:4396 [inline]
 handle_pte_fault mm/memory.c:4650 [inline]
 __handle_mm_fault mm/memory.c:4785 [inline]
 handle_mm_fault+0x1e47/0x4440 mm/memory.c:4883
 do_user_addr_fault+0x494/0xc90 arch/x86/mm/fault.c:1355
 handle_page_fault arch/x86/mm/fault.c:1443 [inline]
 exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1496
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0033:0x7f6bf1b17163
RSP: 002b:00007ffe9d9205a0 EFLAGS: 00010216
RAX: 00007f6beca98b04 RBX: 00007ffe9d9206d0 RCX: 0000000000000000
RDX: 00007f6beca98b00 RSI: 0000000000000008 RDI: 00007ffe9d9206d0
RBP: 00000000000003e6 R08: 0000000000000000 R09: 0000000000000000
R10: 00007ffe9d9206b0 R11: 0000000000000000 R12: 0000000000000000
R13: 000000000000e4fc R14: ffffffffffff1b04 R15: 0000000000000000
 </TASK>
INFO: task syz.3.31:4343 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.31        state:D stack:27696 pid: 4343 ppid:  4194 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 io_schedule+0x7c/0xd0 kernel/sched/core.c:8503
 bit_wait_io+0xd/0xc0 kernel/sched/wait_bit.c:209
 __wait_on_bit kernel/sched/wait_bit.c:49 [inline]
 out_of_line_wait_on_bit+0x173/0x230 kernel/sched/wait_bit.c:64
 wait_on_bit_io include/linux/wait_bit.h:101 [inline]
 do_get_write_access+0x134/0xe40 fs/jbd2/transaction.c:1116
 jbd2_journal_get_write_access+0x108/0x140 fs/jbd2/transaction.c:1251
 __ext4_journal_get_write_access+0x24d/0x6e0 fs/ext4/ext4_jbd2.c:235
 ext4_reserve_inode_write+0x203/0x2e0 fs/ext4/inode.c:5866
 __ext4_mark_inode_dirty+0x136/0x6c0 fs/ext4/inode.c:6040
 ext4_dirty_inode+0xbf/0x100 fs/ext4/inode.c:6077
 __mark_inode_dirty+0x2c8/0xc90 fs/fs-writeback.c:2480
 generic_update_time+0x1cd/0x1f0 fs/inode.c:1881
 inode_update_time fs/inode.c:1894 [inline]
 file_update_time+0x3c0/0x440 fs/inode.c:2083
 ext4_page_mkwrite+0x1bc/0x1250 fs/ext4/inode.c:6195
 do_page_mkwrite+0x168/0x3c0 mm/memory.c:2922
 do_shared_fault mm/memory.c:4328 [inline]
 do_fault mm/memory.c:4396 [inline]
 handle_pte_fault mm/memory.c:4650 [inline]
 __handle_mm_fault mm/memory.c:4785 [inline]
 handle_mm_fault+0x1e47/0x4440 mm/memory.c:4883
 do_user_addr_fault+0x494/0xc90 arch/x86/mm/fault.c:1355
 handle_page_fault arch/x86/mm/fault.c:1443 [inline]
 exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1496
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0033:0x7fe42c38aeb2
RSP: 002b:00007fff359a3830 EFLAGS: 00010202
RAX: 000000000000f008 RBX: 00007fe42d26d720 RCX: 0000000000000000
RDX: 0000001b32a15000 RSI: 0000000000000008 RDI: 00007fe42d26d720
RBP: 00000000000013af R08: 00007fe42c728000 R09: 00007fe42c73e038
R10: 0000000000000003 R11: 0000000000000004 R12: ffffffff84dcf0a2
R13: 00007fe42c73e038 R14: 00000000000000aa R15: ffffffffffff1000
 </TASK>
INFO: task syz.4.32:4345 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.32        state:D stack:27696 pid: 4345 ppid:  4188 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 io_schedule+0x7c/0xd0 kernel/sched/core.c:8503
 bit_wait_io+0xd/0xc0 kernel/sched/wait_bit.c:209
 __wait_on_bit kernel/sched/wait_bit.c:49 [inline]
 out_of_line_wait_on_bit+0x173/0x230 kernel/sched/wait_bit.c:64
 wait_on_bit_io include/linux/wait_bit.h:101 [inline]
 do_get_write_access+0x134/0xe40 fs/jbd2/transaction.c:1116
 jbd2_journal_get_write_access+0x108/0x140 fs/jbd2/transaction.c:1251
 __ext4_journal_get_write_access+0x24d/0x6e0 fs/ext4/ext4_jbd2.c:235
 ext4_reserve_inode_write+0x203/0x2e0 fs/ext4/inode.c:5866
 __ext4_mark_inode_dirty+0x136/0x6c0 fs/ext4/inode.c:6040
 ext4_dirty_inode+0xbf/0x100 fs/ext4/inode.c:6077
 __mark_inode_dirty+0x2c8/0xc90 fs/fs-writeback.c:2480
 generic_update_time+0x1cd/0x1f0 fs/inode.c:1881
 inode_update_time fs/inode.c:1894 [inline]
 file_update_time+0x3c0/0x440 fs/inode.c:2083
 ext4_page_mkwrite+0x1bc/0x1250 fs/ext4/inode.c:6195
 do_page_mkwrite+0x168/0x3c0 mm/memory.c:2922
 do_shared_fault mm/memory.c:4328 [inline]
 do_fault mm/memory.c:4396 [inline]
 handle_pte_fault mm/memory.c:4650 [inline]
 __handle_mm_fault mm/memory.c:4785 [inline]
 handle_mm_fault+0x1e47/0x4440 mm/memory.c:4883
 do_user_addr_fault+0x494/0xc90 arch/x86/mm/fault.c:1355
 handle_page_fault arch/x86/mm/fault.c:1443 [inline]
 exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1496
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0033:0x7fb93f76feb2
RSP: 002b:00007ffead006a10 EFLAGS: 00010202
RAX: 0000000000003008 RBX: 00007fb940652720 RCX: 0000000000000000
RDX: 0000001b32b21000 RSI: 0000000000000008 RDI: 00007fb940652720
RBP: 0000000000000142 R08: 00007fb93fb0d000 R09: 00007fb93fb23038
R10: 0000000000000003 R11: 0000000000000002 R12: ffffffff83a9bad6
R13: 00007fb93fb23038 R14: 0000000000000067 R15: ffffffffffffd000
 </TASK>
INFO: task syz.0.33:4354 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.33        state:D stack:27440 pid: 4354 ppid:  4186 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 io_schedule+0x7c/0xd0 kernel/sched/core.c:8503
 bit_wait_io+0xd/0xc0 kernel/sched/wait_bit.c:209
 __wait_on_bit kernel/sched/wait_bit.c:49 [inline]
 out_of_line_wait_on_bit+0x173/0x230 kernel/sched/wait_bit.c:64
 wait_on_bit_io include/linux/wait_bit.h:101 [inline]
 do_get_write_access+0x134/0xe40 fs/jbd2/transaction.c:1116
 jbd2_journal_get_write_access+0x108/0x140 fs/jbd2/transaction.c:1251
 __ext4_journal_get_write_access+0x24d/0x6e0 fs/ext4/ext4_jbd2.c:235
 ext4_reserve_inode_write+0x203/0x2e0 fs/ext4/inode.c:5866
 __ext4_mark_inode_dirty+0x136/0x6c0 fs/ext4/inode.c:6040
 ext4_dirty_inode+0xbf/0x100 fs/ext4/inode.c:6077
 __mark_inode_dirty+0x2c8/0xc90 fs/fs-writeback.c:2480
 generic_update_time+0x1cd/0x1f0 fs/inode.c:1881
 inode_update_time fs/inode.c:1894 [inline]
 file_update_time+0x3c0/0x440 fs/inode.c:2083
 ext4_page_mkwrite+0x1bc/0x1250 fs/ext4/inode.c:6195
 do_page_mkwrite+0x168/0x3c0 mm/memory.c:2922
 do_shared_fault mm/memory.c:4328 [inline]
 do_fault mm/memory.c:4396 [inline]
 handle_pte_fault mm/memory.c:4650 [inline]
 __handle_mm_fault mm/memory.c:4785 [inline]
 handle_mm_fault+0x1e47/0x4440 mm/memory.c:4883
 do_user_addr_fault+0x494/0xc90 arch/x86/mm/fault.c:1355
 handle_page_fault arch/x86/mm/fault.c:1443 [inline]
 exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1496
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0033:0x7fada37f9eb2
RSP: 002b:00007ffe451e6dd0 EFLAGS: 00010202
RAX: 000000000000e008 RBX: 00007fada46dc720 RCX: 0000000000000000
RDX: 0000001b32716000 RSI: 0000000000000008 RDI: 00007fada46dc720
RBP: 000000000000089d R08: 00007fada3b97000 R09: 00007fada3bad038
R10: 0000000000000003 R11: 0000000000000004 R12: ffffffff83d5ada1
R13: 00007fada3bad038 R14: 00000000000000ce R15: ffffffffffff2000
 </TASK>
INFO: task syz.1.35:4364 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.35        state:D stack:27120 pid: 4364 ppid:  4187 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 io_schedule+0x7c/0xd0 kernel/sched/core.c:8503
 bit_wait_io+0xd/0xc0 kernel/sched/wait_bit.c:209
 __wait_on_bit kernel/sched/wait_bit.c:49 [inline]
 out_of_line_wait_on_bit+0x173/0x230 kernel/sched/wait_bit.c:64
 wait_on_bit_io include/linux/wait_bit.h:101 [inline]
 do_get_write_access+0x134/0xe40 fs/jbd2/transaction.c:1116
 jbd2_journal_get_write_access+0x108/0x140 fs/jbd2/transaction.c:1251
 __ext4_journal_get_write_access+0x24d/0x6e0 fs/ext4/ext4_jbd2.c:235
 ext4_reserve_inode_write+0x203/0x2e0 fs/ext4/inode.c:5866
 __ext4_mark_inode_dirty+0x136/0x6c0 fs/ext4/inode.c:6040
 ext4_dirty_inode+0xbf/0x100 fs/ext4/inode.c:6077
 __mark_inode_dirty+0x2c8/0xc90 fs/fs-writeback.c:2480
 generic_update_time+0x1cd/0x1f0 fs/inode.c:1881
 inode_update_time fs/inode.c:1894 [inline]
 file_update_time+0x3c0/0x440 fs/inode.c:2083
 ext4_page_mkwrite+0x1bc/0x1250 fs/ext4/inode.c:6195
 do_page_mkwrite+0x168/0x3c0 mm/memory.c:2922
 do_shared_fault mm/memory.c:4328 [inline]
 do_fault mm/memory.c:4396 [inline]
 handle_pte_fault mm/memory.c:4650 [inline]
 __handle_mm_fault mm/memory.c:4785 [inline]
 handle_mm_fault+0x1e47/0x4440 mm/memory.c:4883
 do_user_addr_fault+0x494/0xc90 arch/x86/mm/fault.c:1355
 handle_page_fault arch/x86/mm/fault.c:1443 [inline]
 exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1496
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0033:0x7f488704b729
RSP: 002b:00007ffdf955a380 EFLAGS: 00010202
RAX: 0000001b32824000 RBX: ffffffff819d4b42 RCX: 0000001b32823ff8
RDX: 00000000005ffde8 RSI: 00000000005ffde8 RDI: 00007f4887f2e700
RBP: 0000000000000001 R08: 0000000000000000 R09: 00007f48873eb000
R10: 00007f4887f2e700 R11: 0000000000000000 R12: 00007f48873ff038
R13: 0000000000000000 R14: ffffffff819d4228 R15: 00007f4887f2e720
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8c31ef60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
3 locks held by kworker/u4:1/144:
3 locks held by kworker/u4:2/154:
 #0: ffff888019592138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc90001e37d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffff88801795a0e0 (&type->s_umount_key#41){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
2 locks held by getty/3942:
 #0: ffff88807f579098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc90002cf62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x594/0x1a50 drivers/tty/n_tty.c:2158
3 locks held by syz-executor/4172:
 #0: ffff888073efce28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
 #0: ffff888073efce28 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
 #1: ffff88814d170558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1811 [inline]
 #1: ffff88814d170558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1910 [inline]
 #1: ffff88814d170558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1a5/0x1250 fs/ext4/inode.c:6194
 #2: ffff88814d174990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x12d5/0x1560 fs/jbd2/transaction.c:462
1 lock held by udevd/4330:
 #0: ffff888021408bc0 (&sig->cred_guard_mutex){+.+.}-{3:3}, at: prepare_bprm_creds fs/exec.c:1479 [inline]
 #0: ffff888021408bc0 (&sig->cred_guard_mutex){+.+.}-{3:3}, at: bprm_execve+0xc6/0x1740 fs/exec.c:1820
3 locks held by syz.3.31/4343:
 #0: ffff88801ec77828 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
 #0: ffff88801ec77828 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
 #1: ffff88814d170558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1811 [inline]
 #1: ffff88814d170558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1910 [inline]
 #1: ffff88814d170558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1a5/0x1250 fs/ext4/inode.c:6194
 #2: ffff88814d174990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x12d5/0x1560 fs/jbd2/transaction.c:462
3 locks held by syz.4.32/4345:
 #0: ffff88807ba7f128 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
 #0: ffff88807ba7f128 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
 #1: ffff88814d170558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1811 [inline]
 #1: ffff88814d170558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1910 [inline]
 #1: ffff88814d170558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1a5/0x1250 fs/ext4/inode.c:6194
 #2: ffff88814d174990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x12d5/0x1560 fs/jbd2/transaction.c:462
3 locks held by syz.0.33/4354:
 #0: ffff88801ec76a28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
 #0: ffff88801ec76a28 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
 #1: ffff88814d170558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1811 [inline]
 #1: ffff88814d170558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1910 [inline]
 #1: ffff88814d170558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1a5/0x1250 fs/ext4/inode.c:6194
 #2: ffff88814d174990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x12d5/0x1560 fs/jbd2/transaction.c:462
3 locks held by syz.1.35/4364:
 #0: ffff88801ec74028 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
 #0: ffff88801ec74028 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
 #1: ffff88814d170558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1811 [inline]
 #1: ffff88814d170558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1910 [inline]
 #1: ffff88814d170558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1a5/0x1250 fs/ext4/inode.c:6194
 #2: ffff88814d174990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x12d5/0x1560 fs/jbd2/transaction.c:462

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

NMI backtrace for cpu 0
CPU: 0 PID: 27 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+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
 watchdog+0xe1b/0xe60 kernel/hung_task.c:369
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 3548 Comm: klogd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:memset_erms+0xb/0x10 arch/x86/lib/memset_64.S:65
Code: 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 f3 aa <4c> 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 01 01
RSP: 0018:ffffc90002d9f3e8 EFLAGS: 00000202
RAX: 0000000000000000 RBX: ffffc90002d9f488 RCX: 0000000000000000
RDX: 0000000000000010 RSI: 0000000000000000 RDI: ffffc90002d9f4e8
RBP: dffffc0000000000 R08: ffffc90002d9f4e7 R09: ffffc90002d9f4d8
R10: dffffc0000000000 R11: fffff520005b3e9d R12: 1ffffffff1cf2f2c
R13: 1ffffffff1cf2f2c R14: ffffc90002d9f4bd R15: ffffffff8e797964
FS:  00007fb349f94c80(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055ad79419168 CR3: 000000007e3e5000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 unwind_next_frame+0x9e3/0x1cf0 arch/x86/kernel/unwind_orc.c:547
 arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 __kasan_slab_alloc+0x92/0xc0 mm/kasan/common.c:467
 kasan_slab_alloc include/linux/kasan.h:254 [inline]
 slab_post_alloc_hook+0x4c/0x380 mm/slab.h:519
 slab_alloc_node mm/slub.c:3225 [inline]
 kmem_cache_alloc_node+0x184/0x2c0 mm/slub.c:3261
 __alloc_skb+0xf4/0x750 net/core/skbuff.c:415
 alloc_skb include/linux/skbuff.h:1162 [inline]
 alloc_skb_with_frags+0xa7/0x720 net/core/skbuff.c:6196
 sock_alloc_send_pskb+0x87f/0x9a0 net/core/sock.c:2536
 unix_dgram_sendmsg+0x6f8/0x19c0 net/unix/af_unix.c:1809
 sock_sendmsg_nosec net/socket.c:706 [inline]
 __sock_sendmsg net/socket.c:718 [inline]
 __sys_sendto+0x46d/0x620 net/socket.c:2073
 __do_sys_sendto net/socket.c:2085 [inline]
 __se_sys_sendto net/socket.c:2081 [inline]
 __x64_sys_sendto+0xda/0xf0 net/socket.c:2081
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fb34a0e4407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffcb08a4d10 EFLAGS: 00000202 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007fb349f94c80 RCX: 00007fb34a0e4407
RDX: 000000000000003a RSI: 00007ffcb08a4e50 RDI: 0000000000000003
RBP: 00007ffcb08a5280 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000004000 R11: 0000000000000202 R12: 00007ffcb08a5298
R13: 00007ffcb08a4e50 R14: 000000000000001f R15: 00007ffcb08a4e50
 </TASK>