[v6.1] INFO: task hung in shmem_swapin_folio
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syzbot
Aug 5, 2026, 8:22:27 PM (11 days ago) Aug 5
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: fb28aa725e05 Linux 6.1.180
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1274bbb9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=31dfefc4a14efea3
dashboard link: https://syzkaller.appspot.com/bug?extid=3fa11958a78f11c4fbc6
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9a6fe2a54d0f/disk-fb28aa72.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/742b23a1d931/vmlinux-fb28aa72.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b3f257c16d2e/bzImage-fb28aa72.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3fa119...@syzkaller.appspotmail.com
INFO: task syz.7.871:7828 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.7.871 state:D stack:24976 pid:7828 ppid:6157 flags:0x00004006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5246 [inline]
__schedule+0x107f/0x4030 kernel/sched/core.c:6563
schedule+0xb9/0x180 kernel/sched/core.c:6639
io_schedule+0x7c/0xd0 kernel/sched/core.c:8799
folio_wait_bit_common+0x877/0xfa0 mm/filemap.c:1324
folio_wait_writeback+0xe3/0x1f0 mm/page-writeback.c:3058
shmem_swapin_folio+0xe09/0x1600 mm/shmem.c:1796
shmem_get_folio_gfp+0x3f7/0x35e0 mm/shmem.c:1892
shmem_fault+0x1b6/0x790 mm/shmem.c:2156
__do_fault+0x13b/0x4e0 mm/memory.c:4278
do_read_fault mm/memory.c:4629 [inline]
do_fault mm/memory.c:4758 [inline]
handle_pte_fault mm/memory.c:5029 [inline]
__handle_mm_fault mm/memory.c:5171 [inline]
handle_mm_fault+0x2610/0x3d40 mm/memory.c:5292
do_user_addr_fault+0x58e/0xb20 arch/x86/mm/fault.c:1338
handle_page_fault arch/x86/mm/fault.c:1429 [inline]
exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1482
asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608
RIP: 0010:do_strncpy_from_user lib/strncpy_from_user.c:41 [inline]
RIP: 0010:strncpy_from_user+0x148/0x340 lib/strncpy_from_user.c:139
Code: 00 00 00 4c 89 e6 e8 77 2d 45 fd 49 83 fc 07 0f 86 9a 00 00 00 4c 89 74 24 08 48 c7 44 24 10 f8 ff ff ff 45 31 ed 4c 89 3c 24 <4f> 8b 3c 2f 48 b8 ff fe fe fe fe fe fe fe 49 8d 2c 07 4d 89 fe 49
RSP: 0018:ffffc90004cdfd90 EFLAGS: 00050246
RAX: ffffffff843d0489 RBX: ffff888065aa4420 RCX: ffff88807d969e00
RDX: 0000000000000002 RSI: 0000000000000fe0 RDI: 0000000000000007
RBP: 0000000000000000 R08: ffffea000196a807 R09: 1ffffd400032d500
R10: dffffc0000000000 R11: fffff9400032d501 R12: 0000000000000fe0
R13: 0000000000000000 R14: 0000000000000fe0 R15: 0000200000000000
getname_flags+0xf2/0x500 fs/namei.c:150
user_path_at_empty+0x28/0x60 fs/namei.c:2912
user_path_at include/linux/namei.h:57 [inline]
path_listxattr+0xac/0x1b0 fs/xattr.c:825
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f6cf119e0d9
RSP: 002b:00007f6cf1fac028 EFLAGS: 00000246 ORIG_RAX: 00000000000000c3
RAX: ffffffffffffffda RBX: 00007f6cf1425fa0 RCX: 00007f6cf119e0d9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000000
RBP: 00007f6cf1235024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6cf1426038 R14: 00007f6cf1425fa0 R15: 00007ffe28fbe8a8
</TASK>
Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8cb2e4f0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
#0: ffffffff8cb2ed10 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
#0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6527
1 lock held by klogd/3628:
#0: ffff8880b8f3ad18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x25/0x130 kernel/sched/core.c:538
2 locks held by getty/4030:
#0: ffff88802fc9e098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
#1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41e/0x1360 drivers/tty/n_tty.c:2198
3 locks held by syz-executor/4259:
#0: ffff88801dbd97d8 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88801dbd97d8 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5320 [inline]
#0: ffff88801dbd97d8 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x2e/0x2f0 mm/memory.c:5382
#1: ffff88814dec8558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1891 [inline]
#1: ffff88814dec8558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1995 [inline]
#1: ffff88814dec8558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x192/0x10d0 fs/ext4/inode.c:6273
#2: ffff88814decc990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x2014/0x2240 fs/jbd2/transaction.c:463
1 lock held by syz.7.871/7828:
#0: ffff88807e0bf958 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807e0bf958 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5320 [inline]
#0: ffff88807e0bf958 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x2e/0x2f0 mm/memory.c:5382
3 locks held by syz.8.891/7878:
#0: ffff88807c3f53d8 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807c3f53d8 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5320 [inline]
#0: ffff88807c3f53d8 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x2e/0x2f0 mm/memory.c:5382
#1: ffff88814dec8558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1891 [inline]
#1: ffff88814dec8558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1995 [inline]
#1: ffff88814dec8558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x192/0x10d0 fs/ext4/inode.c:6273
#2: ffff88814decc990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x2014/0x2240 fs/jbd2/transaction.c:463
3 locks held by syz.3.890/7879:
#0: ffff88807c3f6a58 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807c3f6a58 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5320 [inline]
#0: ffff88807c3f6a58 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x2e/0x2f0 mm/memory.c:5382
#1: ffff88814dec8558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1891 [inline]
#1: ffff88814dec8558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1995 [inline]
#1: ffff88814dec8558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x192/0x10d0 fs/ext4/inode.c:6273
#2: ffff88814decc990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x2014/0x2240 fs/jbd2/transaction.c:463
3 locks held by syz.6.892/7880:
#0: ffff88807c3f44d8 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807c3f44d8 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5320 [inline]
#0: ffff88807c3f44d8 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x2e/0x2f0 mm/memory.c:5382
#1: ffff88814dec8558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1891 [inline]
#1: ffff88814dec8558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1995 [inline]
#1: ffff88814dec8558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x192/0x10d0 fs/ext4/inode.c:6273
#2: ffff88814decc990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x2014/0x2240 fs/jbd2/transaction.c:463
3 locks held by syz.5.893/7882:
#0: ffff88807c3f0158 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807c3f0158 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5320 [inline]
#0: ffff88807c3f0158 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x2e/0x2f0 mm/memory.c:5382
#1: ffff88814dec8558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1891 [inline]
#1: ffff88814dec8558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1995 [inline]
#1: ffff88814dec8558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x192/0x10d0 fs/ext4/inode.c:6273
#2: ffff88814decc990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x2014/0x2240 fs/jbd2/transaction.c:463
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 28 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+0x188/0x24e lib/dump_stack.c:106
nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
watchdog+0xf0e/0xf50 kernel/hung_task.c:377
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 3628 Comm: klogd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline]
RIP: 0010:check_kcov_mode kernel/kcov.c:182 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:245 [inline]
RIP: 0010:__sanitizer_cov_trace_const_cmp8+0xc/0x80 kernel/kcov.c:320
Code: c0 4c 89 01 48 c7 44 11 08 05 00 00 00 48 89 7c 11 10 48 89 74 11 18 48 89 44 11 20 c3 90 48 8b 04 24 65 48 8b 0d 34 3d 80 7e <65> 8b 15 35 3d 80 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75
RSP: 0018:ffffc900032676f8 EFLAGS: 00000206
RAX: ffffffff8a213871 RBX: 0000000000000000 RCX: ffff88807ca79e00
RDX: ffff88807ca79e00 RSI: 00000a0000000000 RDI: 00000a0000000000
RBP: ffffc90003267820 R08: ffff88807ca79e00 R09: 0000000000000012
R10: 0000000000000012 R11: 0000000000000000 R12: 00000a0000000000
R13: 00000000ffff0a00 R14: ffffc90003267a01 R15: ffff0a00ffffff0f
FS: 00007fd037bddc80(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055a6b069a168 CR3: 00000000307db000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000460
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
number+0xd1/0xef0 lib/vsprintf.c:461
vsnprintf+0x12d3/0x1c20 lib/vsprintf.c:2871
snprintf+0xe5/0x140 lib/vsprintf.c:2940
print_caller kernel/printk/printk.c:1283 [inline]
info_print_prefix+0x1fa/0x360 kernel/printk/printk.c:1302
record_print_text+0x17e/0x4a0 kernel/printk/printk.c:1349
syslog_print+0x3c7/0x630 kernel/printk/printk.c:1560
do_syslog+0x817/0x900 kernel/printk/printk.c:1679
__do_sys_syslog kernel/printk/printk.c:1771 [inline]
__se_sys_syslog kernel/printk/printk.c:1769 [inline]
__x64_sys_syslog+0x78/0x90 kernel/printk/printk.c:1769
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fd037da7a37
Code: 73 01 c3 48 8b 0d c1 f3 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 67 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 91 f3 0c 00 f7 d8 64 89 01 48
RSP: 002b:00007ffcdfd3ae98 EFLAGS: 00000206 ORIG_RAX: 0000000000000067
RAX: ffffffffffffffda RBX: 00007fd037f47490 RCX: 00007fd037da7a37
RDX: 00000000000003ff RSI: 00007fd037f47490 RDI: 0000000000000002
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000004000 R11: 0000000000000206 R12: 00007fd037f47490
R13: 00007fd037f24dfe R14: 00007fd037f474f3 R15: 00007fd037f474f3
</TASK>
---
This report is generated by a bot. It may contain errors.
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If the report is a duplicate of another one, reply with:
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If you want to undo deduplication, reply with:
#syz undup
syzbot found the following issue on:
HEAD commit: fb28aa725e05 Linux 6.1.180
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1274bbb9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=31dfefc4a14efea3
dashboard link: https://syzkaller.appspot.com/bug?extid=3fa11958a78f11c4fbc6
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9a6fe2a54d0f/disk-fb28aa72.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/742b23a1d931/vmlinux-fb28aa72.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b3f257c16d2e/bzImage-fb28aa72.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3fa119...@syzkaller.appspotmail.com
INFO: task syz.7.871:7828 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.7.871 state:D stack:24976 pid:7828 ppid:6157 flags:0x00004006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5246 [inline]
__schedule+0x107f/0x4030 kernel/sched/core.c:6563
schedule+0xb9/0x180 kernel/sched/core.c:6639
io_schedule+0x7c/0xd0 kernel/sched/core.c:8799
folio_wait_bit_common+0x877/0xfa0 mm/filemap.c:1324
folio_wait_writeback+0xe3/0x1f0 mm/page-writeback.c:3058
shmem_swapin_folio+0xe09/0x1600 mm/shmem.c:1796
shmem_get_folio_gfp+0x3f7/0x35e0 mm/shmem.c:1892
shmem_fault+0x1b6/0x790 mm/shmem.c:2156
__do_fault+0x13b/0x4e0 mm/memory.c:4278
do_read_fault mm/memory.c:4629 [inline]
do_fault mm/memory.c:4758 [inline]
handle_pte_fault mm/memory.c:5029 [inline]
__handle_mm_fault mm/memory.c:5171 [inline]
handle_mm_fault+0x2610/0x3d40 mm/memory.c:5292
do_user_addr_fault+0x58e/0xb20 arch/x86/mm/fault.c:1338
handle_page_fault arch/x86/mm/fault.c:1429 [inline]
exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1482
asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608
RIP: 0010:do_strncpy_from_user lib/strncpy_from_user.c:41 [inline]
RIP: 0010:strncpy_from_user+0x148/0x340 lib/strncpy_from_user.c:139
Code: 00 00 00 4c 89 e6 e8 77 2d 45 fd 49 83 fc 07 0f 86 9a 00 00 00 4c 89 74 24 08 48 c7 44 24 10 f8 ff ff ff 45 31 ed 4c 89 3c 24 <4f> 8b 3c 2f 48 b8 ff fe fe fe fe fe fe fe 49 8d 2c 07 4d 89 fe 49
RSP: 0018:ffffc90004cdfd90 EFLAGS: 00050246
RAX: ffffffff843d0489 RBX: ffff888065aa4420 RCX: ffff88807d969e00
RDX: 0000000000000002 RSI: 0000000000000fe0 RDI: 0000000000000007
RBP: 0000000000000000 R08: ffffea000196a807 R09: 1ffffd400032d500
R10: dffffc0000000000 R11: fffff9400032d501 R12: 0000000000000fe0
R13: 0000000000000000 R14: 0000000000000fe0 R15: 0000200000000000
getname_flags+0xf2/0x500 fs/namei.c:150
user_path_at_empty+0x28/0x60 fs/namei.c:2912
user_path_at include/linux/namei.h:57 [inline]
path_listxattr+0xac/0x1b0 fs/xattr.c:825
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f6cf119e0d9
RSP: 002b:00007f6cf1fac028 EFLAGS: 00000246 ORIG_RAX: 00000000000000c3
RAX: ffffffffffffffda RBX: 00007f6cf1425fa0 RCX: 00007f6cf119e0d9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000000
RBP: 00007f6cf1235024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6cf1426038 R14: 00007f6cf1425fa0 R15: 00007ffe28fbe8a8
</TASK>
Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8cb2e4f0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
#0: ffffffff8cb2ed10 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
#0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6527
1 lock held by klogd/3628:
#0: ffff8880b8f3ad18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x25/0x130 kernel/sched/core.c:538
2 locks held by getty/4030:
#0: ffff88802fc9e098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
#1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41e/0x1360 drivers/tty/n_tty.c:2198
3 locks held by syz-executor/4259:
#0: ffff88801dbd97d8 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88801dbd97d8 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5320 [inline]
#0: ffff88801dbd97d8 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x2e/0x2f0 mm/memory.c:5382
#1: ffff88814dec8558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1891 [inline]
#1: ffff88814dec8558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1995 [inline]
#1: ffff88814dec8558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x192/0x10d0 fs/ext4/inode.c:6273
#2: ffff88814decc990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x2014/0x2240 fs/jbd2/transaction.c:463
1 lock held by syz.7.871/7828:
#0: ffff88807e0bf958 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807e0bf958 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5320 [inline]
#0: ffff88807e0bf958 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x2e/0x2f0 mm/memory.c:5382
3 locks held by syz.8.891/7878:
#0: ffff88807c3f53d8 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807c3f53d8 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5320 [inline]
#0: ffff88807c3f53d8 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x2e/0x2f0 mm/memory.c:5382
#1: ffff88814dec8558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1891 [inline]
#1: ffff88814dec8558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1995 [inline]
#1: ffff88814dec8558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x192/0x10d0 fs/ext4/inode.c:6273
#2: ffff88814decc990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x2014/0x2240 fs/jbd2/transaction.c:463
3 locks held by syz.3.890/7879:
#0: ffff88807c3f6a58 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807c3f6a58 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5320 [inline]
#0: ffff88807c3f6a58 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x2e/0x2f0 mm/memory.c:5382
#1: ffff88814dec8558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1891 [inline]
#1: ffff88814dec8558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1995 [inline]
#1: ffff88814dec8558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x192/0x10d0 fs/ext4/inode.c:6273
#2: ffff88814decc990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x2014/0x2240 fs/jbd2/transaction.c:463
3 locks held by syz.6.892/7880:
#0: ffff88807c3f44d8 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807c3f44d8 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5320 [inline]
#0: ffff88807c3f44d8 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x2e/0x2f0 mm/memory.c:5382
#1: ffff88814dec8558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1891 [inline]
#1: ffff88814dec8558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1995 [inline]
#1: ffff88814dec8558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x192/0x10d0 fs/ext4/inode.c:6273
#2: ffff88814decc990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x2014/0x2240 fs/jbd2/transaction.c:463
3 locks held by syz.5.893/7882:
#0: ffff88807c3f0158 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807c3f0158 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5320 [inline]
#0: ffff88807c3f0158 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x2e/0x2f0 mm/memory.c:5382
#1: ffff88814dec8558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1891 [inline]
#1: ffff88814dec8558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1995 [inline]
#1: ffff88814dec8558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x192/0x10d0 fs/ext4/inode.c:6273
#2: ffff88814decc990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x2014/0x2240 fs/jbd2/transaction.c:463
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 28 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+0x188/0x24e lib/dump_stack.c:106
nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
watchdog+0xf0e/0xf50 kernel/hung_task.c:377
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 3628 Comm: klogd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline]
RIP: 0010:check_kcov_mode kernel/kcov.c:182 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:245 [inline]
RIP: 0010:__sanitizer_cov_trace_const_cmp8+0xc/0x80 kernel/kcov.c:320
Code: c0 4c 89 01 48 c7 44 11 08 05 00 00 00 48 89 7c 11 10 48 89 74 11 18 48 89 44 11 20 c3 90 48 8b 04 24 65 48 8b 0d 34 3d 80 7e <65> 8b 15 35 3d 80 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75
RSP: 0018:ffffc900032676f8 EFLAGS: 00000206
RAX: ffffffff8a213871 RBX: 0000000000000000 RCX: ffff88807ca79e00
RDX: ffff88807ca79e00 RSI: 00000a0000000000 RDI: 00000a0000000000
RBP: ffffc90003267820 R08: ffff88807ca79e00 R09: 0000000000000012
R10: 0000000000000012 R11: 0000000000000000 R12: 00000a0000000000
R13: 00000000ffff0a00 R14: ffffc90003267a01 R15: ffff0a00ffffff0f
FS: 00007fd037bddc80(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055a6b069a168 CR3: 00000000307db000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000460
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
number+0xd1/0xef0 lib/vsprintf.c:461
vsnprintf+0x12d3/0x1c20 lib/vsprintf.c:2871
snprintf+0xe5/0x140 lib/vsprintf.c:2940
print_caller kernel/printk/printk.c:1283 [inline]
info_print_prefix+0x1fa/0x360 kernel/printk/printk.c:1302
record_print_text+0x17e/0x4a0 kernel/printk/printk.c:1349
syslog_print+0x3c7/0x630 kernel/printk/printk.c:1560
do_syslog+0x817/0x900 kernel/printk/printk.c:1679
__do_sys_syslog kernel/printk/printk.c:1771 [inline]
__se_sys_syslog kernel/printk/printk.c:1769 [inline]
__x64_sys_syslog+0x78/0x90 kernel/printk/printk.c:1769
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fd037da7a37
Code: 73 01 c3 48 8b 0d c1 f3 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 67 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 91 f3 0c 00 f7 d8 64 89 01 48
RSP: 002b:00007ffcdfd3ae98 EFLAGS: 00000206 ORIG_RAX: 0000000000000067
RAX: ffffffffffffffda RBX: 00007fd037f47490 RCX: 00007fd037da7a37
RDX: 00000000000003ff RSI: 00007fd037f47490 RDI: 0000000000000002
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000004000 R11: 0000000000000206 R12: 00007fd037f47490
R13: 00007fd037f24dfe R14: 00007fd037f474f3 R15: 00007fd037f474f3
</TASK>
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
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If the report is already addressed, let syzbot know by replying with:
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If you want to overwrite report's subsystems, reply with:
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If you want to undo deduplication, reply with:
#syz undup
syzbot
Aug 14, 2026, 10:27:37 PM (2 days ago) Aug 14
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: d27334b2888c Linux 6.6.151
syzbot found the following issue on:
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=13ff6279580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f0bc3d90c30838b5
dashboard link: https://syzkaller.appspot.com/bug?extid=47799d0a9f7a861c968d
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/695139abd971/disk-d27334b2.raw.xz
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
vmlinux: https://storage.googleapis.com/syzbot-assets/b11fc121442a/vmlinux-d27334b2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e226f54f9286/bzImage-d27334b2.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
INFO: task syz.0.73:6018 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.73 state:D stack:23864 pid:6018 ppid:5772 flags:0x00004006
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
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
folio_wait_bit_common+0x881/0xfa0 mm/filemap.c:1329
folio_wait_writeback+0xe2/0x1e0 mm/page-writeback.c:3090
shmem_swapin_folio+0xc9d/0x1400 mm/shmem.c:1891
shmem_get_folio_gfp+0x3b0/0x2b40 mm/shmem.c:1984
shmem_fault+0x1b8/0x820 mm/shmem.c:2248
__do_fault+0x13b/0x4d0 mm/memory.c:4244
do_read_fault mm/memory.c:4638 [inline]
do_fault mm/memory.c:4775 [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+0x3945/0x4a50 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: 0010:do_strncpy_from_user lib/strncpy_from_user.c:41 [inline]
RIP: 0010:strncpy_from_user+0x10b/0x2f0 lib/strncpy_from_user.c:139
Code: 00 00 48 89 de e8 d5 0f 21 fd 48 83 fb 07 0f 86 9d 00 00 00 49 c7 c6 f8 ff ff ff 45 31 e4 4c 89 3c 24 4c 89 6c 24 08 4d 89 e5 <4f> 8b 3c 27 48 b8 ff fe fe fe fe fe fe fe 4d 8d 24 07 4c 89 fd 48
RSP: 0018:ffffc90004bafdf0 EFLAGS: 00050246
RAX: ffffffff8466668b RBX: 0000000000000020 RCX: ffff888029845a00
RDX: 0000000000000002 RSI: 0000000000000020 RDI: 0000000000000007
RBP: ffffc90004baff10 R08: ffff888029845a00 R09: 0000000000000003
R10: 0000000000000002 R11: 0000000000000002 R12: 0000000000000000
R13: 0000000000000000 R14: fffffffffffffff8 R15: 0000200000000140
key_get_type_from_user security/keys/keyctl.c:51 [inline]
__do_sys_add_key security/keys/keyctl.c:90 [inline]
__se_sys_add_key+0xdc/0x410 security/keys/keyctl.c:74
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f65aed9e0d9
RSP: 002b:00007f65afb92028 EFLAGS: 00000246 ORIG_RAX: 00000000000000f8
RAX: ffffffffffffffda RBX: 00007f65af025fa0 RCX: 00007f65aed9e0d9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000140
RBP: 00007f65aee35024 R08: fffffffffffffffe R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f65af026038 R14: 00007f65af025fa0 R15: 00007ffc986b1638
</TASK>
INFO: task syz.2.79:6031 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.79 state:D stack:27048 pid:6031 ppid:5775 flags:0x00004004
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
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: 0033:0x7f6040872789
RSP: 002b:00007ffc01ef1330 EFLAGS: 00010202
RAX: 0000001b2da24000 RBX: 0000000000000000 RCX: 00000000003ffde8
RDX: 0000001b2da23ffc RSI: 00000000003ffde8 RDI: 00007f6041755700
RBP: 0000000000000000 R08: 0000000000000000 R09: 00007f6040c12000
R10: 00007f6041755700 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000005aa7 R14: ffffffff81321410 R15: 00007f6041755720
</TASK>
INFO: task syz.1.80:6033 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.80 state:D stack:27496 pid:6033 ppid:5776 flags:0x00004004
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
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: 0033:0x7f0fe1e6ba23
RSP: 002b:00007ffc667e1380 EFLAGS: 00010246
RAX: 00000000003ffde8 RBX: 0000000000000000 RCX: 0000001b2d564000
RDX: 0000001b2d524000 RSI: 0000000000400000 RDI: 00007f0fe21e0708
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 00007ffc667e1610
</TASK>
INFO: task syz.3.81:6034 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.81 state:D stack:27560 pid:6034 ppid:5778 flags:0x00004004
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
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: 0033:0x7f9b80e6ba23
RSP: 002b:00007ffedeb2d5b0 EFLAGS: 00010246
RAX: 00000000003ffde8 RBX: 0000000000000000 RCX: 0000001b2d764000
RDX: 0000001b2d724000 RSI: 0000000000400000 RDI: 00007f9b811e0708
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 00007ffedeb2d840
</TASK>
Showing all locks held in the system:
1 lock held by khungtaskd/29:
Showing all locks held in the system:
#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
6 locks held by kworker/u4:8/3465:
#0: ffff88801ce40138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline]
#0: ffff88801ce40138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734
#1: ffffc9000cdafd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline]
#1: ffffc9000cdafd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734
#2: ffff88802cc080e0 (&type->s_umount_key#31){++++}-{3:3}, at: super_trylock_shared+0x20/0xf0 fs/super.c:607
#3: ffff88802cc0ac58 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages_down_read fs/ext4/ext4.h:1768 [inline]
#3: ffff88802cc0ac58 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages+0x1a4/0x350 fs/ext4/inode.c:2809
#4: ffff88802cc0c990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x1f3f/0x2170 fs/jbd2/transaction.c:448
#5: ffff8880770a7088 (&ei->i_data_sem){++++}-{3:3}, at: ext4_map_blocks+0x918/0x1a90 fs/ext4/inode.c:647
1 lock held by klogd/5129:
#0: ffff8880b8f3c298 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:559
2 locks held by getty/5529:
#0: ffff8880316820a0 (&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/5761:
#0: ffff88802d13baa0 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:165 [inline]
#0: ffff88802d13baa0 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5380 [inline]
#0: ffff88802d13baa0 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x32/0x2f0 mm/memory.c:5440
#1: ffff88802cc08510 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1633 [inline]
#1: ffff88802cc08510 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1737 [inline]
#1: ffff88802cc08510 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1e2/0x11a0 fs/ext4/inode.c:6261
#2: ffff88802cc0c990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x1f3f/0x2170 fs/jbd2/transaction.c:448
1 lock held by syz.0.73/6018:
#0: ffff888031708b20 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:165 [inline]
#0: ffff888031708b20 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5380 [inline]
#0: ffff888031708b20 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x32/0x2f0 mm/memory.c:5440
3 locks held by syz.2.79/6031:
#0: ffff88803170a7a0 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:165 [inline]
#0: ffff88803170a7a0 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5380 [inline]
#0: ffff88803170a7a0 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x32/0x2f0 mm/memory.c:5440
#1: ffff88802cc08510 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1633 [inline]
#1: ffff88802cc08510 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1737 [inline]
#1: ffff88802cc08510 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1e2/0x11a0 fs/ext4/inode.c:6261
#2: ffff88802cc0c990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x1f3f/0x2170 fs/jbd2/transaction.c:448
3 locks held by syz.1.80/6033:
#0: ffff88801b7a8b20 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:165 [inline]
#0: ffff88801b7a8b20 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5380 [inline]
#0: ffff88801b7a8b20 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x32/0x2f0 mm/memory.c:5440
#1: ffff88802cc08510 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1633 [inline]
#1: ffff88802cc08510 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1737 [inline]
#1: ffff88802cc08510 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1e2/0x11a0 fs/ext4/inode.c:6261
#2: ffff88802cc0c990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x1f3f/0x2170 fs/jbd2/transaction.c:448
3 locks held by syz.3.81/6034:
#0: ffff888017c68b20 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:165 [inline]
#0: ffff888017c68b20 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5380 [inline]
#0: ffff888017c68b20 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x32/0x2f0 mm/memory.c:5440
#1: ffff88802cc08510 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1633 [inline]
#1: ffff88802cc08510 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1737 [inline]
#1: ffff88802cc08510 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1e2/0x11a0 fs/ext4/inode.c:6261
#2: ffff88802cc0c990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x1f3f/0x2170 fs/jbd2/transaction.c:448
=============================================
NMI backtrace for cpu 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
Call Trace:
<TASK>
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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 2971 Comm: kworker/u4:7 Not tainted syzkaller #0
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: bat_events batadv_nc_worker
RIP: 0010:__local_bh_enable_ip+0xd3/0x1c0 kernel/softirq.c:-1
Code: d9 00 00 00 43 c6 44 37 04 00 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 8b 44 24 20 43 c6 44 37 04 f8 fa a9 00 02 00 00 74 0b <49> 89 fc e8 05 18 3b 00 4c 89 e7 65 8b 05 e3 eb b0 7e 25 00 ff 00
RSP: 0018:ffffc9000c04fa40 EFLAGS: 00000006
RAX: 0000000000000202 RBX: 0000000000000201 RCX: 0000000000000001
RDX: 0000000000000000 RSI: 0000000000000201 RDI: ffffffff8a56d600
RBP: ffffc9000c04fac0 R08: ffff88805f0fd343 R09: 1ffff1100be1fa68
R10: dffffc0000000000 R11: ffffed100be1fa69 R12: ffff88805f091268
R13: ffff88805f6b3690 R14: dffffc0000000000 R15: 1ffff92001809f48
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056163ec2da38 CR3: 000000000cf32000 CR4: 00000000003506e0
Call Trace:
<TASK>
spin_unlock_bh include/linux/spinlock.h:396 [inline]
batadv_nc_purge_paths+0x300/0x3a0 net/batman-adv/network-coding.c:471
batadv_nc_worker+0x322/0x600 net/batman-adv/network-coding.c:720
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
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