* [syzbot ci] Re: mm/page_owner: warn when stack trace depth hits PAGE_OWNER_STACK_DEPTH limit
2026-03-28 21:44 ` [PATCH v2] mm/page_owner: warn when stack trace depth hits PAGE_OWNER_STACK_DEPTH limit Jiayuan Liang
@ 2026-03-28 17:28 ` syzbot ci
2026-03-28 17:28 ` Request received Yail
2026-03-28 17:39 ` [syzbot ci] Re: mm/page_owner: warn when stack trace depth hits PAGE_OWNER_STACK_DEPTH limit Andrew Morton
0 siblings, 2 replies; 4+ messages in thread
From: syzbot ci @ 2026-03-28 17:28 UTC (permalink / raw)
To: akpm, linux-mm, ljykernel; +Cc: syzbot, syzkaller-bugs
syzbot ci has tested the following series
[v2] mm/page_owner: warn when stack trace depth hits PAGE_OWNER_STACK_DEPTH limit
https://lore.kernel.org/all/20260328214408.2990597-1-ljykernel@163.com
* [PATCH v2] mm/page_owner: warn when stack trace depth hits PAGE_OWNER_STACK_DEPTH limit
and found the following issue:
possible deadlock in hrtimer_start_range_ns
Full report is available here:
https://ci.syzbot.org/series/aa38ba8f-44db-4d01-8965-ed5a27174f71
***
possible deadlock in hrtimer_start_range_ns
tree: mm-new
URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/akpm/mm.git
base: f46991f1780ef97efff3b668627b763581032067
arch: amd64
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
config: https://ci.syzbot.org/builds/2808cd4a-ad2f-49d0-8b68-eb99aeb06ed6/config
syz repro: https://ci.syzbot.org/findings/6c04900a-b825-4465-90f4-694fc3a9d29b/syz_repro
page_owner: stack depth 16 exceeds limit 16
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
klogd/5246 is trying to acquire lock:
ffffffff8e750a00 (console_owner){-.-.}-{0:0}, at: console_trylock_spinning kernel/printk/printk.c:2026 [inline]
ffffffff8e750a00 (console_owner){-.-.}-{0:0}, at: vprintk_emit+0x2cf/0x560 kernel/printk/printk.c:2478
but task is already holding lock:
ffff888121028298 (hrtimer_bases.lock){-.-.}-{2:2}, at: lock_hrtimer_base kernel/time/hrtimer.c:172 [inline]
ffff888121028298 (hrtimer_bases.lock){-.-.}-{2:2}, at: hrtimer_start_range_ns+0xc8/0x1ff0 kernel/time/hrtimer.c:1328
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #3 (hrtimer_bases.lock){-.-.}-{2:2}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
_raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:162
lock_hrtimer_base kernel/time/hrtimer.c:172 [inline]
hrtimer_start_range_ns+0xc8/0x1ff0 kernel/time/hrtimer.c:1328
rpm_suspend+0x12d4/0x1750 drivers/base/power/runtime.c:632
__pm_runtime_idle+0x12f/0x1a0 drivers/base/power/runtime.c:1129
pm_runtime_put include/linux/pm_runtime.h:551 [inline]
__device_attach+0x34f/0x450 drivers/base/dd.c:1111
device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1148
bus_probe_device+0x12a/0x220 drivers/base/bus.c:613
device_add+0x7b6/0xb70 drivers/base/core.c:3691
serdev_controller_add+0x85/0x640 drivers/tty/serdev/core.c:775
serdev_tty_port_register+0x159/0x260 drivers/tty/serdev/serdev-ttyport.c:291
tty_port_register_device_attr_serdev+0xe7/0x170 drivers/tty/tty_port.c:187
serial_core_add_one_port drivers/tty/serial/serial_core.c:3109 [inline]
serial_core_register_port+0x1123/0x28a0 drivers/tty/serial/serial_core.c:3307
serial8250_register_8250_port+0x1658/0x1fd0 drivers/tty/serial/8250/8250_core.c:822
serial_pnp_probe+0x568/0x7f0 drivers/tty/serial/8250/8250_pnp.c:480
pnp_device_probe+0x30b/0x4c0 drivers/pnp/driver.c:111
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x267/0xaf0 drivers/base/dd.c:721
__driver_probe_device+0x18c/0x320 drivers/base/dd.c:863
driver_probe_device+0x4f/0x240 drivers/base/dd.c:893
__driver_attach+0x34c/0x640 drivers/base/dd.c:1287
bus_for_each_dev+0x23b/0x2c0 drivers/base/bus.c:383
bus_add_driver+0x345/0x670 drivers/base/bus.c:756
driver_register+0x23a/0x320 drivers/base/driver.c:249
serial8250_init+0x8f/0x160 drivers/tty/serial/8250/8250_platform.c:317
do_one_initcall+0x250/0x8d0 init/main.c:1382
do_initcall_level+0x104/0x190 init/main.c:1444
do_initcalls+0x59/0xa0 init/main.c:1460
kernel_init_freeable+0x2a6/0x3e0 init/main.c:1692
kernel_init+0x1d/0x1d0 init/main.c:1582
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
-> #2 (&dev->power.lock){-...}-{3:3}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
_raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:162
__pm_runtime_resume+0x10f/0x180 drivers/base/power/runtime.c:1196
pm_runtime_get include/linux/pm_runtime.h:494 [inline]
__uart_start+0x171/0x460 drivers/tty/serial/serial_core.c:149
uart_write+0x265/0xa10 drivers/tty/serial/serial_core.c:633
process_output_block drivers/tty/n_tty.c:557 [inline]
n_tty_write+0xd84/0x12a0 drivers/tty/n_tty.c:2366
iterate_tty_write drivers/tty/tty_io.c:1006 [inline]
file_tty_write+0x559/0xa20 drivers/tty/tty_io.c:1081
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x61d/0xb90 fs/read_write.c:688
ksys_write+0x150/0x270 fs/read_write.c:740
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #1 (&port_lock_key){-.-.}-{3:3}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
_raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:162
uart_port_lock_irqsave include/linux/serial_core.h:717 [inline]
serial8250_console_write+0x150/0x1ba0 drivers/tty/serial/8250/8250_port.c:3316
console_emit_next_record kernel/printk/printk.c:3183 [inline]
console_flush_one_record kernel/printk/printk.c:3269 [inline]
console_flush_all+0x718/0xb20 kernel/printk/printk.c:3343
__console_flush_and_unlock kernel/printk/printk.c:3373 [inline]
console_unlock+0xd1/0x1c0 kernel/printk/printk.c:3413
vprintk_emit+0x485/0x560 kernel/printk/printk.c:2479
_printk+0xdd/0x130 kernel/printk/printk.c:2504
register_console+0xbc2/0xfa0 kernel/printk/printk.c:4208
univ8250_console_init+0x3a/0x70 drivers/tty/serial/8250/8250_core.c:515
console_init+0x10b/0x4d0 kernel/printk/printk.c:4407
start_kernel+0x22b/0x3d0 init/main.c:1147
x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x147
-> #0 (console_owner){-.-.}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237
lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868
console_trylock_spinning kernel/printk/printk.c:2026 [inline]
vprintk_emit+0x2eb/0x560 kernel/printk/printk.c:2478
_printk+0xdd/0x130 kernel/printk/printk.c:2504
save_stack+0x238/0x2a0 mm/page_owner.c:167
__set_page_owner+0x8d/0x4c0 mm/page_owner.c:344
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x231/0x280 mm/page_alloc.c:1860
prep_new_page mm/page_alloc.c:1868 [inline]
get_page_from_freelist+0x24ba/0x2540 mm/page_alloc.c:3948
alloc_frozen_pages_nolock_noprof+0xac/0x140 mm/page_alloc.c:7795
alloc_slab_page mm/slub.c:3287 [inline]
allocate_slab+0xf2/0x660 mm/slub.c:3481
new_slab mm/slub.c:3539 [inline]
___slab_alloc+0x150/0x6b0 mm/slub.c:4413
__slab_alloc_node mm/slub.c:4479 [inline]
slab_alloc_node mm/slub.c:4854 [inline]
kmem_cache_alloc_noprof+0x12d/0x650 mm/slub.c:4873
kmem_alloc_batch lib/debugobjects.c:371 [inline]
fill_pool+0x156/0x590 lib/debugobjects.c:420
debug_objects_fill_pool lib/debugobjects.c:742 [inline]
debug_object_activate+0x4a3/0x580 lib/debugobjects.c:831
debug_hrtimer_activate kernel/time/hrtimer.c:446 [inline]
debug_activate kernel/time/hrtimer.c:485 [inline]
enqueue_hrtimer+0x30/0x3c0 kernel/time/hrtimer.c:1089
__hrtimer_start_range_ns kernel/time/hrtimer.c:1271 [inline]
hrtimer_start_range_ns+0x15ea/0x1ff0 kernel/time/hrtimer.c:1330
hrtimer_start include/linux/hrtimer.h:244 [inline]
dummy_timer+0x4436/0x45d0 drivers/usb/gadget/udc/dummy_hcd.c:2008
__run_hrtimer kernel/time/hrtimer.c:1785 [inline]
__hrtimer_run_queues+0x53a/0xcc0 kernel/time/hrtimer.c:1849
hrtimer_run_softirq+0x182/0x5a0 kernel/time/hrtimer.c:1866
handle_softirqs+0x22a/0x870 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723
irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
check_kcov_mode kernel/kcov.c:183 [inline]
__sanitizer_cov_trace_pc+0x30/0x70 kernel/kcov.c:217
number+0xc0f/0xf80 lib/vsprintf.c:571
vsnprintf+0x8e5/0xee0 lib/vsprintf.c:2912
sprintf+0xe7/0x140 lib/vsprintf.c:3111
print_time kernel/printk/printk.c:1359 [inline]
info_print_prefix+0x16b/0x360 kernel/printk/printk.c:1385
record_print_text+0x176/0x450 kernel/printk/printk.c:1434
syslog_print+0x3b0/0x610 kernel/printk/printk.c:1645
do_syslog+0x583/0x7d0 kernel/printk/printk.c:1763
__do_sys_syslog kernel/printk/printk.c:1855 [inline]
__se_sys_syslog kernel/printk/printk.c:1853 [inline]
__x64_sys_syslog+0x7c/0x90 kernel/printk/printk.c:1853
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Chain exists of:
console_owner --> &dev->power.lock --> hrtimer_bases.lock
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(hrtimer_bases.lock);
lock(&dev->power.lock);
lock(hrtimer_bases.lock);
lock(console_owner);
*** DEADLOCK ***
4 locks held by klogd/5246:
#0: ffffffff8e750948 (syslog_lock){+.+.}-{4:4}, at: syslog_print+0x4ad/0x610 kernel/printk/printk.c:1663
#1: ffff88816eebc018 (&dum_hcd->dum->lock){..-.}-{3:3}, at: dummy_timer+0x151/0x45d0 drivers/usb/gadget/udc/dummy_hcd.c:1821
#2: ffff888121028298 (hrtimer_bases.lock){-.-.}-{2:2}, at: lock_hrtimer_base kernel/time/hrtimer.c:172 [inline]
#2: ffff888121028298 (hrtimer_bases.lock){-.-.}-{2:2}, at: hrtimer_start_range_ns+0xc8/0x1ff0 kernel/time/hrtimer.c:1328
#3: ffffffff8ef08700 (fill_pool_map-wait-type-override){+.+.}-{3:3}, at: debug_objects_fill_pool lib/debugobjects.c:741 [inline]
#3: ffffffff8ef08700 (fill_pool_map-wait-type-override){+.+.}-{3:3}, at: debug_object_activate+0x47a/0x580 lib/debugobjects.c:831
stack backtrace:
CPU: 0 UID: 0 PID: 5246 Comm: klogd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
<IRQ>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2043
check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2175
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237
lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868
console_trylock_spinning kernel/printk/printk.c:2026 [inline]
vprintk_emit+0x2eb/0x560 kernel/printk/printk.c:2478
_printk+0xdd/0x130 kernel/printk/printk.c:2504
save_stack+0x238/0x2a0 mm/page_owner.c:167
__set_page_owner+0x8d/0x4c0 mm/page_owner.c:344
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x231/0x280 mm/page_alloc.c:1860
prep_new_page mm/page_alloc.c:1868 [inline]
get_page_from_freelist+0x24ba/0x2540 mm/page_alloc.c:3948
alloc_frozen_pages_nolock_noprof+0xac/0x140 mm/page_alloc.c:7795
alloc_slab_page mm/slub.c:3287 [inline]
allocate_slab+0xf2/0x660 mm/slub.c:3481
new_slab mm/slub.c:3539 [inline]
___slab_alloc+0x150/0x6b0 mm/slub.c:4413
__slab_alloc_node mm/slub.c:4479 [inline]
slab_alloc_node mm/slub.c:4854 [inline]
kmem_cache_alloc_noprof+0x12d/0x650 mm/slub.c:4873
kmem_alloc_batch lib/debugobjects.c:371 [inline]
fill_pool+0x156/0x590 lib/debugobjects.c:420
debug_objects_fill_pool lib/debugobjects.c:742 [inline]
debug_object_activate+0x4a3/0x580 lib/debugobjects.c:831
debug_hrtimer_activate kernel/time/hrtimer.c:446 [inline]
debug_activate kernel/time/hrtimer.c:485 [inline]
enqueue_hrtimer+0x30/0x3c0 kernel/time/hrtimer.c:1089
__hrtimer_start_range_ns kernel/time/hrtimer.c:1271 [inline]
hrtimer_start_range_ns+0x15ea/0x1ff0 kernel/time/hrtimer.c:1330
hrtimer_start include/linux/hrtimer.h:244 [inline]
dummy_timer+0x4436/0x45d0 drivers/usb/gadget/udc/dummy_hcd.c:2008
__run_hrtimer kernel/time/hrtimer.c:1785 [inline]
__hrtimer_run_queues+0x53a/0xcc0 kernel/time/hrtimer.c:1849
hrtimer_run_softirq+0x182/0x5a0 kernel/time/hrtimer.c:1866
handle_softirqs+0x22a/0x870 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723
irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:check_kcov_mode kernel/kcov.c:185 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x30/0x70 kernel/kcov.c:217
Code: 04 24 65 48 8b 0d 08 4b 56 11 65 8b 15 29 4b 56 11 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 a4 16 00 00 00 74 2c <8b> 91 80 16 00 00 83 fa 02 75 21 48 8b 91 88 16 00 00 48 8b 32 48
RSP: 0018:ffffc900036676b8 EFLAGS: 00000246
RAX: ffffffff8ba85ecf RBX: 0000000000000031 RCX: ffff888111ff0000
RDX: 0000000000000000 RSI: 0000000000000002 RDI: ffffc90003667742
RBP: ffffc900036677e0 R08: ffffc90003667757 R09: 0000000000000000
R10: ffffc90003667740 R11: fffff520006cceeb R12: ffffc90003667acd
R13: dffffc0000000000 R14: ffffc90003667ace R15: 0000000000000002
number+0xc0f/0xf80 lib/vsprintf.c:571
vsnprintf+0x8e5/0xee0 lib/vsprintf.c:2912
sprintf+0xe7/0x140 lib/vsprintf.c:3111
print_time kernel/printk/printk.c:1359 [inline]
info_print_prefix+0x16b/0x360 kernel/printk/printk.c:1385
record_print_text+0x176/0x450 kernel/printk/printk.c:1434
syslog_print+0x3b0/0x610 kernel/printk/printk.c:1645
do_syslog+0x583/0x7d0 kernel/printk/printk.c:1763
__do_sys_syslog kernel/printk/printk.c:1855 [inline]
__se_sys_syslog kernel/printk/printk.c:1853 [inline]
__x64_sys_syslog+0x7c/0x90 kernel/printk/printk.c:1853
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1089379fa7
Code: 73 01 c3 48 8b 0d 81 ce 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 51 ce 0c 00 f7 d8 64 89 01 48
RSP: 002b:00007ffed757a078 EFLAGS: 00000206 ORIG_RAX: 0000000000000067
RAX: ffffffffffffffda RBX: 00007f10895184a0 RCX: 00007f1089379fa7
RDX: 00000000000003ff RSI: 00007f10895184a0 RDI: 0000000000000002
RBP: 0000000000000000 R08: 0000000000000007 R09: 7e78de0d48eb7984
R10: 0000000000004000 R11: 0000000000000206 R12: 00007f10895184a0
R13: 00007f1089508212 R14: 00007f108951855a R15: 00007f108951855a
</TASK>
----------------
Code disassembly (best guess):
0: 04 24 add $0x24,%al
2: 65 48 8b 0d 08 4b 56 mov %gs:0x11564b08(%rip),%rcx # 0x11564b12
9: 11
a: 65 8b 15 29 4b 56 11 mov %gs:0x11564b29(%rip),%edx # 0x11564b3a
11: 81 e2 00 01 ff 00 and $0xff0100,%edx
17: 74 11 je 0x2a
19: 81 fa 00 01 00 00 cmp $0x100,%edx
1f: 75 35 jne 0x56
21: 83 b9 a4 16 00 00 00 cmpl $0x0,0x16a4(%rcx)
28: 74 2c je 0x56
* 2a: 8b 91 80 16 00 00 mov 0x1680(%rcx),%edx <-- trapping instruction
30: 83 fa 02 cmp $0x2,%edx
33: 75 21 jne 0x56
35: 48 8b 91 88 16 00 00 mov 0x1688(%rcx),%rdx
3c: 48 8b 32 mov (%rdx),%rsi
3f: 48 rex.W
***
If these findings have caused you to resend the series or submit a
separate fix, please add the following tag to your commit message:
Tested-by: syzbot@syzkaller.appspotmail.com
---
This report is generated by a bot. It may contain errors.
syzbot ci engineers can be reached at syzkaller@googlegroups.com.
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