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:20960 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+0x735/0x800 block/blk-core.c:1027
 submit_bio+0x2c6/0x550 block/blk-core.c:1089
 ext4_io_submit fs/ext4/page-io.c:381 [inline]
 io_submit_add_bh fs/ext4/page-io.c:425 [inline]
 ext4_bio_write_page+0x14f7/0x1f20 fs/ext4/page-io.c:564
 mpage_submit_page+0x17a/0x210 fs/ext4/inode.c:2115
 mpage_map_and_submit_buffers fs/ext4/inode.c:2363 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2502 [inline]
 ext4_writepages+0x1970/0x2d40 fs/ext4/inode.c:2831
 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_background_flush fs/fs-writeback.c:2182 [inline]
 wb_do_writeback fs/fs-writeback.c:2270 [inline]
 wb_workfn+0xbd6/0xf20 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/sda1-8:3519 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:25840 pid: 3519 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
 jbd2_journal_wait_updates+0x197/0x270 fs/jbd2/transaction.c:863
 jbd2_journal_commit_transaction+0x919/0x5c30 fs/jbd2/commit.c:489
 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.0.241:4540 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.241       state:D stack:27664 pid: 4540 ppid:  4303 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
 wait_transaction_locked+0x1d8/0x270 fs/jbd2/transaction.c:179
 add_transaction_credits+0x104/0xcb0 fs/jbd2/transaction.c:242
 start_this_handle+0x723/0x1560 fs/jbd2/transaction.c:423
 jbd2__journal_start+0x2b7/0x5a0 fs/jbd2/transaction.c:521
 __ext4_journal_start_sb+0x167/0x360 fs/ext4/ext4_jbd2.c:105
 __ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline]
 ext4_dirty_inode+0x8b/0x100 fs/ext4/inode.c:6084
 __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:6205
 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: 0033:0x7f0da9f8fb23
RSP: 002b:00007ffe30525720 EFLAGS: 00010246
RAX: 000000000003fde8 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000001b31a24000 RSI: 0000000000040000 RDI: 00007f0daa306708
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 00007ffe305259b0
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8d11efa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
5 locks held by kworker/u4:2/154:
 #0: ffff88801a3e8138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc90001fc7d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffff88802cfe20e0 (&type->s_umount_key#32){++++}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
 #3: ffff88802cfe4c58 (&sbi->s_writepages_rwsem){.+.+}-{0:0}, at: ext4_writepages+0x213/0x2d40 fs/ext4/inode.c:2691
 #4: ffff88802cfe6990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x12d5/0x1560 fs/jbd2/transaction.c:462
2 locks held by getty/3943:
 #0: ffff88814d372098 (&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
2 locks held by syz.0.241/4540:
 #0: ffff88802c57ab28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
 #0: ffff88802c57ab28 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
 #1: ffff88802cfe2558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1817 [inline]
 #1: ffff88802cfe2558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1916 [inline]
 #1: ffff88802cfe2558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1a5/0x1250 fs/ext4/inode.c:6204

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

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 09/16/2026
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: 144 Comm: kworker/u4:1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Workqueue: bat_events batadv_mcast_mla_update
RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:171 [inline]
RIP: 0010:unwind_next_frame+0x1e9/0x1cf0 arch/x86/kernel/unwind_orc.c:448
Code: 89 e8 48 c1 e8 03 42 0f b6 04 38 84 c0 0f 85 dd 15 00 00 45 8b 45 00 41 ff c0 4b 8d 04 64 48 8d 94 00 44 28 e0 8e 4b 8d 04 40 <48> 8d 84 00 44 28 e0 8e 48 3d 46 35 7f 8f 0f 97 c0 48 81 fa 46 35
RSP: 0018:ffffc900016af6b0 EFLAGS: 00000202
RAX: 0000000000031047 RBX: ffffc900016af748 RCX: ffffffff9711bf00
RDX: ffffffff8ee648cc RSI: 0000000000090081 RDI: ffffffff81351ed7
RBP: 0000000000004f28 R08: 000000000001056d R09: 0000000000000002
R10: dffffc0000000000 R11: fffff520002d5ef5 R12: 000000000001056c
R13: ffffffff8f8071ec R14: ffffffff814f2896 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056331f67d168 CR3: 000000002af50000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 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_kmalloc mm/kasan/common.c:513 [inline]
 __kasan_kmalloc+0xaf/0xe0 mm/kasan/common.c:522
 kmalloc include/linux/slab.h:607 [inline]
 batadv_mcast_mla_softif_get_ipv6 net/batman-adv/multicast.c:446 [inline]
 batadv_mcast_mla_softif_get net/batman-adv/multicast.c:504 [inline]
 __batadv_mcast_mla_update net/batman-adv/multicast.c:878 [inline]
 batadv_mcast_mla_update+0x13c5/0x3150 net/batman-adv/multicast.c:915
 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>