syzbot
INFO: task hung in add_transaction_credits (2)
Status:
upstream: reported on 2026/08/11 23:45
Reported-by: syzbot+5d7db782bd14d7a4a98a@syzkaller.appspotmail.com
First crash: 51d, last: 27d
Sample crash report:
INFO: task kworker/u4:3:380 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:3 state:D stack:22096 pid: 380 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
add_transaction_credits+0x864/0xcb0 fs/jbd2/transaction.c:316
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_writepages+0xd7e/0x2d40 fs/ext4/inode.c:2814
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 syz-executor:4174 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:22960 pid: 4174 ppid: 4173 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
wp_page_shared+0x163/0x6c0 mm/memory.c:3259
handle_pte_fault mm/memory.c:4668 [inline]
__handle_mm_fault mm/memory.c:4785 [inline]
handle_mm_fault+0x1fbd/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: 0033:0x7f5bc35231e3
RSP: 002b:00007ffdb057fd90 EFLAGS: 00010206
RAX: 00007f5bbf4b0af8 RBX: 00007ffdb057fec0 RCX: 0000000000000000
RDX: 00007f5bbf4b0af4 RSI: 0000000000000008 RDI: 00007ffdb057fec0
RBP: 00000000000003e6 R08: 0000000000000000 R09: 0000000000000000
R10: 00007ffdb057fea0 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000002508 R14: ffffffffffffdaf8 R15: 0000000000000000
</TASK>
INFO: task syz.0.89:4572 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.89 state:D stack:27440 pid: 4572 ppid: 4199 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: 0033:0x7f74562ca7a9
RSP: 002b:00007ffea3e7c2f0 EFLAGS: 00010202
RAX: 0000001b32523000 RBX: ffffffff811be78a RCX: 0000001b32522ff8
RDX: 0000001b32124220 RSI: 0000000000000008 RDI: 00007f74571ad720
RBP: 00000000000001db R08: 00007f7456668000 R09: 00007f745666a000
R10: 00000000811be78e R11: 0000000000000010 R12: 00007f745667e038
R13: 00000000000014fa R14: ffffffff811be72a R15: 00007f74571ad720
</TASK>
INFO: task syz.4.90:4575 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.90 state:D stack:26960 pid: 4575 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: 0033:0x7fd427ca5f32
RSP: 002b:00007ffde9c3a300 EFLAGS: 00010202
RAX: 0000000000003008 RBX: 00007fd428b88720 RCX: 0000000000000000
RDX: 0000001b32b21000 RSI: 0000000000000008 RDI: 00007fd428b88720
RBP: 00000000000004c9 R08: 00007fd428043000 R09: 00007fd428059128
R10: 0000000000000003 R11: 0000000000000009 R12: ffffffff87e0047a
R13: 00007fd428059128 R14: 0000000000000050 R15: ffffffffffffd000
</TASK>
INFO: task syz.2.92:4581 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.92 state:D stack:27440 pid: 4581 ppid: 4195 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: 0033:0x7fc34da41809
RSP: 002b:00007ffdd6626f60 EFLAGS: 00010202
RAX: 0000001b32724000 RBX: 0000000000000000 RCX: 00000000003ffde8
RDX: 0000001b32723ffc RSI: 00000000003ffde8 RDI: 00007fc34e924700
RBP: 0000000000000000 R08: 0000000000000000 R09: 00007fc34dde1000
R10: 00007fc34e924700 R11: 0000000000000000 R12: 0000000000000000
R13: 000000000000e190 R14: ffffffff819d5b94 R15: 00007fc34e924720
</TASK>
INFO: task syz.3.93:4584 blocked for more than 145 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.93 state:D stack:27152 pid: 4584 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: 0033:0x7f09330ed809
RSP: 002b:00007ffd6ba74db0 EFLAGS: 00010202
RAX: 0000001b32a24000 RBX: 0000000000000000 RCX: 00000000005ffde8
RDX: 0000001b32a23ffc RSI: 00000000005ffde8 RDI: 00007f0933fd0700
RBP: 0000000000000000 R08: 0000000000000000 R09: 00007f093348d000
R10: 00007f0933fd0700 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000034560 R14: ffffffff819d5b94 R15: 00007f0933fd0720
</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
4 locks held by kworker/u4:3/380:
#0: ffff8881429fb138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
#1: ffffc90002fcfd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
#2: ffff88814d0f00e0 (&type->s_umount_key#32){++++}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
#3: ffff88814d0f2c58 (&sbi->s_writepages_rwsem){.+.+}-{0:0}, at: ext4_writepages+0x213/0x2d40 fs/ext4/inode.c:2691
2 locks held by getty/3946:
#0: ffff88802c6d6098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
#1: ffffc90002d032e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x594/0x1a50 drivers/tty/n_tty.c:2158
3 locks held by syz-executor/4174:
#0: ffff88807b603928 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807b603928 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffff88814d0f0558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1817 [inline]
#1: ffff88814d0f0558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1916 [inline]
#1: ffff88814d0f0558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1a5/0x1250 fs/ext4/inode.c:6194
#2: ffff88814d0f4990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x12d5/0x1560 fs/jbd2/transaction.c:462
2 locks held by kworker/1:8/4400:
3 locks held by syz.0.89/4572:
#0: ffff88801e84b228 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88801e84b228 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffff88814d0f0558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1817 [inline]
#1: ffff88814d0f0558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1916 [inline]
#1: ffff88814d0f0558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1a5/0x1250 fs/ext4/inode.c:6194
#2: ffff88814d0f4990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x12d5/0x1560 fs/jbd2/transaction.c:462
3 locks held by syz.4.90/4575:
#0: ffff88807b604028 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807b604028 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffff88814d0f0558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1817 [inline]
#1: ffff88814d0f0558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1916 [inline]
#1: ffff88814d0f0558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1a5/0x1250 fs/ext4/inode.c:6194
#2: ffff88814d0f4990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x12d5/0x1560 fs/jbd2/transaction.c:462
3 locks held by syz.2.92/4581:
#0: ffff88807a5c9d28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807a5c9d28 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffff88814d0f0558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1817 [inline]
#1: ffff88814d0f0558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1916 [inline]
#1: ffff88814d0f0558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1a5/0x1250 fs/ext4/inode.c:6194
#2: ffff88814d0f4990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x12d5/0x1560 fs/jbd2/transaction.c:462
3 locks held by syz.3.93/4584:
#0: ffff88807b602428 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807b602428 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffff88814d0f0558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1817 [inline]
#1: ffff88814d0f0558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1916 [inline]
#1: ffff88814d0f0558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1a5/0x1250 fs/ext4/inode.c:6194
#2: ffff88814d0f4990 (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: 4229 Comm: kworker/u4:5 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: bat_events batadv_nc_worker
RIP: 0010:debug_lockdep_rcu_enabled+0x0/0x30 kernel/rcu/update.c:279
Code: cc ca 03 00 75 e8 48 c7 c7 80 2a 2b 8a 48 c7 c6 00 4f 2b 8a e8 01 10 f5 ff 0f 0b eb d1 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 <31> c0 83 3d 5b 99 ca 03 00 74 1d 83 3d d2 cb ca 03 00 74 14 65 48
RSP: 0018:ffffc9000317fbd8 EFLAGS: 00000286
RAX: 81755b7270dc9000 RBX: dffffc0000000000 RCX: 81755b7270dc9000
RDX: 0000000000000000 RSI: ffffffff8a2b3e80 RDI: ffffffff8a7a4540
RBP: ffff88802b7bc680 R08: dffffc0000000000 R09: 1ffffffff203de18
R10: dffffc0000000000 R11: fffffbfff203de19 R12: 0000000000000251
R13: ffff888079365288 R14: ffff888074220c80 R15: ffff88802b7bc690
FS: 0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000556aca49b660 CR3: 000000007e9eb000 CR4: 00000000003526e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
rcu_read_lock include/linux/rcupdate.h:741 [inline]
batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline]
batadv_nc_worker+0xce/0x5c0 net/batman-adv/network-coding.c:723
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>
* Struck through repros no longer work on HEAD.