[v5.15] INFO: task hung in exec_mmap
0 views
Skip to first unread message
syzbot
Jan 9, 2026, 2:29:21 PM (2 days ago) Jan 9
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: 68efe5a6c16a Linux 5.15.197
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14f9df92580000
kernel config: https://syzkaller.appspot.com/x/.config?x=7e6ed99963d6ee1d
dashboard link: https://syzkaller.appspot.com/bug?extid=8cb7b9e5e396cb6449ca
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/900f9b9bd850/disk-68efe5a6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1e089a5019a6/vmlinux-68efe5a6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b319f477b907/bzImage-68efe5a6.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8cb7b9...@syzkaller.appspotmail.com
INFO: task dhcpcd:5862 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:dhcpcd state:D stack:25128 pid: 5862 ppid: 3852 flags:0x00004002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
rwsem_down_read_slowpath+0x528/0x990 kernel/locking/rwsem.c:1055
__down_read_common kernel/locking/rwsem.c:1239 [inline]
__down_read kernel/locking/rwsem.c:1252 [inline]
down_read+0x96/0x2e0 kernel/locking/rwsem.c:1500
mmap_read_lock include/linux/mmap_lock.h:117 [inline]
exec_mmap+0x174/0x5c0 fs/exec.c:1000
begin_new_exec+0x7e8/0x1160 fs/exec.c:1293
load_elf_binary+0x98e/0x2890 fs/binfmt_elf.c:1001
search_binary_handler fs/exec.c:1742 [inline]
exec_binprm fs/exec.c:1783 [inline]
bprm_execve+0xa92/0x17d0 fs/exec.c:1852
do_execveat_common+0x51e/0x6d0 fs/exec.c:1957
do_execve fs/exec.c:2027 [inline]
__do_sys_execve fs/exec.c:2103 [inline]
__se_sys_execve fs/exec.c:2098 [inline]
__x64_sys_execve+0x8e/0xa0 fs/exec.c:2098
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: 0033:0x7fd3c6f97107
RSP: 002b:00007fd3c6e00e68 EFLAGS: 00000202 ORIG_RAX: 000000000000003b
RAX: ffffffffffffffda RBX: 00007ffe697fd1c0 RCX: 00007fd3c6f97107
RDX: 0000560579656e20 RSI: 00007ffe697fd3b0 RDI: 00005605704236bd
RBP: 00007fd3c6e00ff0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000008 R11: 0000000000000202 R12: 0000000000000001
R13: 00007ffe697fcea0 R14: 00007fd3c6e00f20 R15: 0000000000000040
</TASK>
Showing all locks held in the system:
1 lock held by khungtaskd/27:
#0: ffffffff8c11c720 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
1 lock held by klogd/3548:
1 lock held by udevd/3559:
#0: ffff88807e19f828 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#0: ffff88807e19f828 (&mm->mmap_lock){++++}-{3:3}, at: __do_sys_brk mm/mmap.c:204 [inline]
#0: ffff88807e19f828 (&mm->mmap_lock){++++}-{3:3}, at: __se_sys_brk+0x10b/0x710 mm/mmap.c:194
1 lock held by dhcpcd/3852:
#0: ffff8880232bdc28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#0: ffff8880232bdc28 (&mm->mmap_lock){++++}-{3:3}, at: __vm_munmap+0xf3/0x230 mm/mmap.c:2949
2 locks held by getty/3948:
#0: ffff88802bee5098 (&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+0x5ba/0x1a30 drivers/tty/n_tty.c:2158
1 lock held by syz-executor/4170:
#0: ffff88807ab74728 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#0: ffff88807ab74728 (&mm->mmap_lock){++++}-{3:3}, at: vm_mmap_pgoff+0x15d/0x2b0 mm/util.c:549
2 locks held by syz-executor/4185:
#0: ffffffff8c1a68b0 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mmap kernel/fork.c:503 [inline]
#0: ffffffff8c1a68b0 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1466 [inline]
#0: ffffffff8c1a68b0 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x21f/0x1380 kernel/fork.c:1518
#1: ffff88807ab77128 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#1: ffff88807ab77128 (&mm->mmap_lock){++++}-{3:3}, at: dup_mmap kernel/fork.c:504 [inline]
#1: ffff88807ab77128 (&mm->mmap_lock){++++}-{3:3}, at: dup_mm kernel/fork.c:1466 [inline]
#1: ffff88807ab77128 (&mm->mmap_lock){++++}-{3:3}, at: copy_mm+0x238/0x1380 kernel/fork.c:1518
2 locks held by syz-executor/4187:
#0: ffffffff8c1a68b0 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mmap kernel/fork.c:503 [inline]
#0: ffffffff8c1a68b0 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1466 [inline]
#0: ffffffff8c1a68b0 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x21f/0x1380 kernel/fork.c:1518
#1: ffff88807e968f28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#1: ffff88807e968f28 (&mm->mmap_lock){++++}-{3:3}, at: dup_mmap kernel/fork.c:504 [inline]
#1: ffff88807e968f28 (&mm->mmap_lock){++++}-{3:3}, at: dup_mm kernel/fork.c:1466 [inline]
#1: ffff88807e968f28 (&mm->mmap_lock){++++}-{3:3}, at: copy_mm+0x238/0x1380 kernel/fork.c:1518
2 locks held by kworker/u4:5/4271:
2 locks held by syz-executor/4522:
#0: ffffffff8c1a68b0 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mmap kernel/fork.c:503 [inline]
#0: ffffffff8c1a68b0 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1466 [inline]
#0: ffffffff8c1a68b0 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x21f/0x1380 kernel/fork.c:1518
#1: ffff88807daeb228 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#1: ffff88807daeb228 (&mm->mmap_lock){++++}-{3:3}, at: dup_mmap kernel/fork.c:504 [inline]
#1: ffff88807daeb228 (&mm->mmap_lock){++++}-{3:3}, at: dup_mm kernel/fork.c:1466 [inline]
#1: ffff88807daeb228 (&mm->mmap_lock){++++}-{3:3}, at: copy_mm+0x238/0x1380 kernel/fork.c:1518
1 lock held by udevd/4531:
#0: ffff88807bef9628 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#0: ffff88807bef9628 (&mm->mmap_lock){++++}-{3:3}, at: __vm_munmap+0xf3/0x230 mm/mmap.c:2949
2 locks held by syz-executor/4605:
#0: ffffffff8c1a68b0 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mmap kernel/fork.c:503 [inline]
#0: ffffffff8c1a68b0 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1466 [inline]
#0: ffffffff8c1a68b0 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x21f/0x1380 kernel/fork.c:1518
#1: ffff88807ec56328 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#1: ffff88807ec56328 (&mm->mmap_lock){++++}-{3:3}, at: dup_mmap kernel/fork.c:504 [inline]
#1: ffff88807ec56328 (&mm->mmap_lock){++++}-{3:3}, at: dup_mm kernel/fork.c:1466 [inline]
#1: ffff88807ec56328 (&mm->mmap_lock){++++}-{3:3}, at: copy_mm+0x238/0x1380 kernel/fork.c:1518
1 lock held by udevd/5023:
#0: ffff8880232bf828 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#0: ffff8880232bf828 (&mm->mmap_lock){++++}-{3:3}, at: __vm_munmap+0xf3/0x230 mm/mmap.c:2949
3 locks held by dhcpcd/5862:
#0: ffff888026082c40 (&sig->cred_guard_mutex){+.+.}-{3:3}, at: prepare_bprm_creds fs/exec.c:1479 [inline]
#0: ffff888026082c40 (&sig->cred_guard_mutex){+.+.}-{3:3}, at: bprm_execve+0xc4/0x17d0 fs/exec.c:1820
#1: ffff888026082cd8 (&sig->exec_update_lock){++++}-{3:3}, at: exec_mmap+0xf0/0x5c0 fs/exec.c:989
#2: ffff8880232bdc28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_lock include/linux/mmap_lock.h:117 [inline]
#2: ffff8880232bdc28 (&mm->mmap_lock){++++}-{3:3}, at: exec_mmap+0x174/0x5c0 fs/exec.c:1000
=============================================
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 10/25/2025
Call Trace:
<TASK>
dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
nmi_cpu_backtrace+0x397/0x3d0 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+0xe0f/0xe50 kernel/hung_task.c:369
kthread+0x436/0x520 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 10/25/2025
RIP: 0010:free_pages_prepare mm/page_alloc.c:1349 [inline]
RIP: 0010:free_pcp_prepare mm/page_alloc.c:1391 [inline]
RIP: 0010:free_unref_page_prepare+0x23a/0x6c0 mm/page_alloc.c:3317
Code: 00 00 83 fd 40 0f 83 77 03 00 00 44 89 f9 49 d3 e5 4c 89 e7 4c 89 ee e8 d4 7b aa ff 4c 89 e7 4c 89 ee e8 59 0c 2d 02 41 b5 01 <83> fd 20 0f 83 93 03 00 00 41 bc 01 00 00 00 89 e9 41 d3 e4 0f 1f
RSP: 0018:ffffc900010df458 EFLAGS: 00000292
RAX: 87533c27fe874d00 RBX: ffffea00011c3e00 RCX: ffffffff8c1f1000
RDX: dffffc0000000000 RSI: 0000000000008000 RDI: ffff8880470f8000
RBP: 0000000000000003 R08: dffffc0000000000 R09: ffffed10030ea5fb
R10: ffffed10030ea5fb R11: 1ffff110030ea5fa R12: ffff8880470f8000
R13: 0000000000008001 R14: 00000000000470f8 R15: 0000000000000003
FS: 00007f77dfb46c80(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f454d368218 CR3: 000000002aec6000 CR4: 00000000003526e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
free_unref_page+0x94/0x280 mm/page_alloc.c:3396
free_slab mm/slub.c:2020 [inline]
discard_slab mm/slub.c:2026 [inline]
__unfreeze_partials+0x1a5/0x200 mm/slub.c:2512
put_cpu_partial+0x12d/0x190 mm/slub.c:2592
qlist_free_all+0x35/0x90 mm/kasan/quarantine.c:176
kasan_quarantine_reduce+0x150/0x160 mm/kasan/quarantine.c:283
____kasan_kmalloc mm/kasan/common.c:479 [inline]
__kasan_kmalloc+0x2f/0xf0 mm/kasan/common.c:522
kmalloc_reserve net/core/skbuff.c:356 [inline]
__alloc_skb+0x22c/0x750 net/core/skbuff.c:427
alloc_skb include/linux/skbuff.h:1162 [inline]
alloc_skb_with_frags+0xa7/0x730 net/core/skbuff.c:6170
sock_alloc_send_pskb+0x853/0x980 net/core/sock.c:2536
unix_dgram_sendmsg+0x5ef/0x1890 net/unix/af_unix.c:1809
sock_sendmsg_nosec net/socket.c:706 [inline]
__sock_sendmsg net/socket.c:718 [inline]
__sys_sendto+0x423/0x580 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: 0033:0x7f77dfc96407
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:00007fffd139b2c0 EFLAGS: 00000202 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f77dfb46c80 RCX: 00007f77dfc96407
RDX: 000000000000005e RSI: 00007fffd139b400 RDI: 0000000000000003
RBP: 00007fffd139b830 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000004000 R11: 0000000000000202 R12: 00007fffd139b848
R13: 00007fffd139b400 R14: 0000000000000043 R15: 00007fffd139b400
</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.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
syzbot found the following issue on:
HEAD commit: 68efe5a6c16a Linux 5.15.197
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14f9df92580000
kernel config: https://syzkaller.appspot.com/x/.config?x=7e6ed99963d6ee1d
dashboard link: https://syzkaller.appspot.com/bug?extid=8cb7b9e5e396cb6449ca
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/900f9b9bd850/disk-68efe5a6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1e089a5019a6/vmlinux-68efe5a6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b319f477b907/bzImage-68efe5a6.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8cb7b9...@syzkaller.appspotmail.com
INFO: task dhcpcd:5862 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:dhcpcd state:D stack:25128 pid: 5862 ppid: 3852 flags:0x00004002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
rwsem_down_read_slowpath+0x528/0x990 kernel/locking/rwsem.c:1055
__down_read_common kernel/locking/rwsem.c:1239 [inline]
__down_read kernel/locking/rwsem.c:1252 [inline]
down_read+0x96/0x2e0 kernel/locking/rwsem.c:1500
mmap_read_lock include/linux/mmap_lock.h:117 [inline]
exec_mmap+0x174/0x5c0 fs/exec.c:1000
begin_new_exec+0x7e8/0x1160 fs/exec.c:1293
load_elf_binary+0x98e/0x2890 fs/binfmt_elf.c:1001
search_binary_handler fs/exec.c:1742 [inline]
exec_binprm fs/exec.c:1783 [inline]
bprm_execve+0xa92/0x17d0 fs/exec.c:1852
do_execveat_common+0x51e/0x6d0 fs/exec.c:1957
do_execve fs/exec.c:2027 [inline]
__do_sys_execve fs/exec.c:2103 [inline]
__se_sys_execve fs/exec.c:2098 [inline]
__x64_sys_execve+0x8e/0xa0 fs/exec.c:2098
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: 0033:0x7fd3c6f97107
RSP: 002b:00007fd3c6e00e68 EFLAGS: 00000202 ORIG_RAX: 000000000000003b
RAX: ffffffffffffffda RBX: 00007ffe697fd1c0 RCX: 00007fd3c6f97107
RDX: 0000560579656e20 RSI: 00007ffe697fd3b0 RDI: 00005605704236bd
RBP: 00007fd3c6e00ff0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000008 R11: 0000000000000202 R12: 0000000000000001
R13: 00007ffe697fcea0 R14: 00007fd3c6e00f20 R15: 0000000000000040
</TASK>
Showing all locks held in the system:
1 lock held by khungtaskd/27:
#0: ffffffff8c11c720 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
1 lock held by klogd/3548:
1 lock held by udevd/3559:
#0: ffff88807e19f828 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#0: ffff88807e19f828 (&mm->mmap_lock){++++}-{3:3}, at: __do_sys_brk mm/mmap.c:204 [inline]
#0: ffff88807e19f828 (&mm->mmap_lock){++++}-{3:3}, at: __se_sys_brk+0x10b/0x710 mm/mmap.c:194
1 lock held by dhcpcd/3852:
#0: ffff8880232bdc28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#0: ffff8880232bdc28 (&mm->mmap_lock){++++}-{3:3}, at: __vm_munmap+0xf3/0x230 mm/mmap.c:2949
2 locks held by getty/3948:
#0: ffff88802bee5098 (&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+0x5ba/0x1a30 drivers/tty/n_tty.c:2158
1 lock held by syz-executor/4170:
#0: ffff88807ab74728 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#0: ffff88807ab74728 (&mm->mmap_lock){++++}-{3:3}, at: vm_mmap_pgoff+0x15d/0x2b0 mm/util.c:549
2 locks held by syz-executor/4185:
#0: ffffffff8c1a68b0 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mmap kernel/fork.c:503 [inline]
#0: ffffffff8c1a68b0 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1466 [inline]
#0: ffffffff8c1a68b0 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x21f/0x1380 kernel/fork.c:1518
#1: ffff88807ab77128 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#1: ffff88807ab77128 (&mm->mmap_lock){++++}-{3:3}, at: dup_mmap kernel/fork.c:504 [inline]
#1: ffff88807ab77128 (&mm->mmap_lock){++++}-{3:3}, at: dup_mm kernel/fork.c:1466 [inline]
#1: ffff88807ab77128 (&mm->mmap_lock){++++}-{3:3}, at: copy_mm+0x238/0x1380 kernel/fork.c:1518
2 locks held by syz-executor/4187:
#0: ffffffff8c1a68b0 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mmap kernel/fork.c:503 [inline]
#0: ffffffff8c1a68b0 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1466 [inline]
#0: ffffffff8c1a68b0 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x21f/0x1380 kernel/fork.c:1518
#1: ffff88807e968f28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#1: ffff88807e968f28 (&mm->mmap_lock){++++}-{3:3}, at: dup_mmap kernel/fork.c:504 [inline]
#1: ffff88807e968f28 (&mm->mmap_lock){++++}-{3:3}, at: dup_mm kernel/fork.c:1466 [inline]
#1: ffff88807e968f28 (&mm->mmap_lock){++++}-{3:3}, at: copy_mm+0x238/0x1380 kernel/fork.c:1518
2 locks held by kworker/u4:5/4271:
2 locks held by syz-executor/4522:
#0: ffffffff8c1a68b0 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mmap kernel/fork.c:503 [inline]
#0: ffffffff8c1a68b0 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1466 [inline]
#0: ffffffff8c1a68b0 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x21f/0x1380 kernel/fork.c:1518
#1: ffff88807daeb228 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#1: ffff88807daeb228 (&mm->mmap_lock){++++}-{3:3}, at: dup_mmap kernel/fork.c:504 [inline]
#1: ffff88807daeb228 (&mm->mmap_lock){++++}-{3:3}, at: dup_mm kernel/fork.c:1466 [inline]
#1: ffff88807daeb228 (&mm->mmap_lock){++++}-{3:3}, at: copy_mm+0x238/0x1380 kernel/fork.c:1518
1 lock held by udevd/4531:
#0: ffff88807bef9628 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#0: ffff88807bef9628 (&mm->mmap_lock){++++}-{3:3}, at: __vm_munmap+0xf3/0x230 mm/mmap.c:2949
2 locks held by syz-executor/4605:
#0: ffffffff8c1a68b0 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mmap kernel/fork.c:503 [inline]
#0: ffffffff8c1a68b0 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1466 [inline]
#0: ffffffff8c1a68b0 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x21f/0x1380 kernel/fork.c:1518
#1: ffff88807ec56328 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#1: ffff88807ec56328 (&mm->mmap_lock){++++}-{3:3}, at: dup_mmap kernel/fork.c:504 [inline]
#1: ffff88807ec56328 (&mm->mmap_lock){++++}-{3:3}, at: dup_mm kernel/fork.c:1466 [inline]
#1: ffff88807ec56328 (&mm->mmap_lock){++++}-{3:3}, at: copy_mm+0x238/0x1380 kernel/fork.c:1518
1 lock held by udevd/5023:
#0: ffff8880232bf828 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#0: ffff8880232bf828 (&mm->mmap_lock){++++}-{3:3}, at: __vm_munmap+0xf3/0x230 mm/mmap.c:2949
3 locks held by dhcpcd/5862:
#0: ffff888026082c40 (&sig->cred_guard_mutex){+.+.}-{3:3}, at: prepare_bprm_creds fs/exec.c:1479 [inline]
#0: ffff888026082c40 (&sig->cred_guard_mutex){+.+.}-{3:3}, at: bprm_execve+0xc4/0x17d0 fs/exec.c:1820
#1: ffff888026082cd8 (&sig->exec_update_lock){++++}-{3:3}, at: exec_mmap+0xf0/0x5c0 fs/exec.c:989
#2: ffff8880232bdc28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_lock include/linux/mmap_lock.h:117 [inline]
#2: ffff8880232bdc28 (&mm->mmap_lock){++++}-{3:3}, at: exec_mmap+0x174/0x5c0 fs/exec.c:1000
=============================================
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 10/25/2025
Call Trace:
<TASK>
dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
nmi_cpu_backtrace+0x397/0x3d0 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+0xe0f/0xe50 kernel/hung_task.c:369
kthread+0x436/0x520 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 10/25/2025
RIP: 0010:free_pages_prepare mm/page_alloc.c:1349 [inline]
RIP: 0010:free_pcp_prepare mm/page_alloc.c:1391 [inline]
RIP: 0010:free_unref_page_prepare+0x23a/0x6c0 mm/page_alloc.c:3317
Code: 00 00 83 fd 40 0f 83 77 03 00 00 44 89 f9 49 d3 e5 4c 89 e7 4c 89 ee e8 d4 7b aa ff 4c 89 e7 4c 89 ee e8 59 0c 2d 02 41 b5 01 <83> fd 20 0f 83 93 03 00 00 41 bc 01 00 00 00 89 e9 41 d3 e4 0f 1f
RSP: 0018:ffffc900010df458 EFLAGS: 00000292
RAX: 87533c27fe874d00 RBX: ffffea00011c3e00 RCX: ffffffff8c1f1000
RDX: dffffc0000000000 RSI: 0000000000008000 RDI: ffff8880470f8000
RBP: 0000000000000003 R08: dffffc0000000000 R09: ffffed10030ea5fb
R10: ffffed10030ea5fb R11: 1ffff110030ea5fa R12: ffff8880470f8000
R13: 0000000000008001 R14: 00000000000470f8 R15: 0000000000000003
FS: 00007f77dfb46c80(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f454d368218 CR3: 000000002aec6000 CR4: 00000000003526e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
free_unref_page+0x94/0x280 mm/page_alloc.c:3396
free_slab mm/slub.c:2020 [inline]
discard_slab mm/slub.c:2026 [inline]
__unfreeze_partials+0x1a5/0x200 mm/slub.c:2512
put_cpu_partial+0x12d/0x190 mm/slub.c:2592
qlist_free_all+0x35/0x90 mm/kasan/quarantine.c:176
kasan_quarantine_reduce+0x150/0x160 mm/kasan/quarantine.c:283
____kasan_kmalloc mm/kasan/common.c:479 [inline]
__kasan_kmalloc+0x2f/0xf0 mm/kasan/common.c:522
kmalloc_reserve net/core/skbuff.c:356 [inline]
__alloc_skb+0x22c/0x750 net/core/skbuff.c:427
alloc_skb include/linux/skbuff.h:1162 [inline]
alloc_skb_with_frags+0xa7/0x730 net/core/skbuff.c:6170
sock_alloc_send_pskb+0x853/0x980 net/core/sock.c:2536
unix_dgram_sendmsg+0x5ef/0x1890 net/unix/af_unix.c:1809
sock_sendmsg_nosec net/socket.c:706 [inline]
__sock_sendmsg net/socket.c:718 [inline]
__sys_sendto+0x423/0x580 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: 0033:0x7f77dfc96407
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:00007fffd139b2c0 EFLAGS: 00000202 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f77dfb46c80 RCX: 00007f77dfc96407
RDX: 000000000000005e RSI: 00007fffd139b400 RDI: 0000000000000003
RBP: 00007fffd139b830 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000004000 R11: 0000000000000202 R12: 00007fffd139b848
R13: 00007fffd139b400 R14: 0000000000000043 R15: 00007fffd139b400
</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.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
Reply all
Reply to author
Forward
0 new messages