==================================================================
BUG: KASAN: use-after-free in ax25_t1timer_expiry+0xec/0x110 net/ax25/ax25_timer.c:148
Read of size 4 at addr ffff888021dc8e50 by task swapper/1/0
CPU: 1 PID: 0 Comm: swapper/1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
<IRQ>
dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
print_address_description+0x60/0x2d0 mm/kasan/report.c:248
__kasan_report mm/kasan/report.c:434 [inline]
kasan_report+0xdf/0x130 mm/kasan/report.c:451
ax25_t1timer_expiry+0xec/0x110 net/ax25/ax25_timer.c:148
call_timer_fn+0x16c/0x530 kernel/time/timer.c:1451
expire_timers kernel/time/timer.c:1496 [inline]
__run_timers+0x525/0x7c0 kernel/time/timer.c:1767
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780
handle_softirqs+0x328/0x820 kernel/softirq.c:576
__do_softirq kernel/softirq.c:610 [inline]
invoke_softirq kernel/softirq.c:450 [inline]
__irq_exit_rcu+0x12f/0x220 kernel/softirq.c:659
irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:steal_cookie_task kernel/sched/core.c:6061 [inline]
RIP: 0010:sched_core_balance+0x4f3/0xbb0 kernel/sched/core.c:6080
Code: 48 8b 3c 24 e8 ae 01 59 08 e9 f8 03 00 00 4c 8b 74 24 18 4c 8b 64 24 48 48 8b 7c 24 28 e8 95 01 59 08 e8 10 9d 2b 00 fb 84 db <48> 8b 9c 24 88 00 00 00 49 c7 c5 40 a3 03 00 8b 44 24 0c 0f 84 7d
RSP: 0018:ffffc90000d67960 EFLAGS: 00000246
RAX: 6857a738f7699e00 RBX: 0000000000000000 RCX: 6857a738f7699e00
RDX: dffffc0000000000 RSI: ffffffff8a0b1be0 RDI: ffffffff8a59e800
RBP: ffffc90000d67ab0 R08: dffffc0000000000 R09: ffffed1017207469
R10: ffffed1017207469 R11: 1ffff11017207468 R12: ffffffff8bbc0828
R13: ffff8880b903a340 R14: 0000000000000001 R15: dffffc0000000000
do_balance_callbacks kernel/sched/core.c:4692 [inline]
__balance_callbacks kernel/sched/core.c:4746 [inline]
finish_lock_switch+0x17b/0x280 kernel/sched/core.c:4802
finish_task_switch+0x12f/0x640 kernel/sched/core.c:4921
context_switch kernel/sched/core.c:5052 [inline]
__schedule+0x11c3/0x4390 kernel/sched/core.c:6395
schedule_idle+0x4a/0x90 kernel/sched/core.c:6506
do_idle+0x556/0x5b0 kernel/sched/idle.c:334
cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:403
start_secondary+0x31f/0x430 arch/x86/kernel/smpboot.c:281
secondary_startup_64_no_verify+0xb1/0xbb
</TASK>
Allocated by task 4687:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track mm/kasan/common.c:46 [inline]
set_alloc_info mm/kasan/common.c:434 [inline]
____kasan_kmalloc mm/kasan/common.c:513 [inline]
__kasan_kmalloc+0xb5/0xf0 mm/kasan/common.c:522
kmalloc include/linux/slab.h:607 [inline]
kzalloc include/linux/slab.h:738 [inline]
ax25_dev_device_up+0x50/0x580 net/ax25/ax25_dev.c:55
ax25_device_event+0x483/0x4f0 net/ax25/af_ax25.c:139
notifier_call_chain kernel/notifier.c:83 [inline]
raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:391
call_netdevice_notifiers_extack net/core/dev.c:2061 [inline]
call_netdevice_notifiers net/core/dev.c:2075 [inline]
__dev_notify_flags+0x178/0x2d0 net/core/dev.c:-1
dev_change_flags+0xe3/0x1a0 net/core/dev.c:8929
dev_ifsioc+0x147/0xe70 net/core/dev_ioctl.c:324
dev_ioctl+0x55f/0xe50 net/core/dev_ioctl.c:587
sock_do_ioctl+0x222/0x2f0 net/socket.c:1164
sock_ioctl+0x4ed/0x6e0 net/socket.c:1267
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
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
Freed by task 5177:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:46
kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366
kasan_slab_free include/linux/kasan.h:230 [inline]
slab_free_hook mm/slub.c:1710 [inline]
slab_free_freelist_hook+0xea/0x170 mm/slub.c:1736
slab_free mm/slub.c:3504 [inline]
kfree+0xef/0x2a0 mm/slub.c:4564
ax25_dev_put include/net/ax25.h:302 [inline]
ax25_release+0x661/0x870 net/ax25/af_ax25.c:1062
__sock_release net/socket.c:651 [inline]
sock_close+0xd5/0x240 net/socket.c:1346
__fput+0x234/0x930 fs/file_table.c:311
task_work_run+0x125/0x1a0 kernel/task_work.c:188
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
__syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0
Last potentially related work creation:
kasan_save_stack+0x35/0x60 mm/kasan/common.c:38
kasan_record_aux_stack+0xb8/0x100 mm/kasan/generic.c:348
insert_work+0x54/0x3d0 kernel/workqueue.c:1366
__queue_work+0x9c5/0xd50 kernel/workqueue.c:1532
queue_work_on+0x11d/0x1d0 kernel/workqueue.c:1559
queue_work include/linux/workqueue.h:512 [inline]
netdevice_queue_work drivers/infiniband/core/roce_gid_mgmt.c:659 [inline]
netdevice_event+0x803/0x900 drivers/infiniband/core/roce_gid_mgmt.c:802
notifier_call_chain kernel/notifier.c:83 [inline]
raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:391
call_netdevice_notifiers_extack net/core/dev.c:2061 [inline]
call_netdevice_notifiers net/core/dev.c:2075 [inline]
register_netdevice+0x1275/0x16b0 net/core/dev.c:10428
hsr_dev_finalize+0x5f6/0x870 net/hsr/hsr_device.c:689
hsr_newlink+0x627/0x6e0 net/hsr/hsr_netlink.c:102
__rtnl_newlink net/core/rtnetlink.c:3526 [inline]
rtnl_newlink+0x114c/0x17d0 net/core/rtnetlink.c:3574
rtnetlink_rcv_msg+0x7ff/0xe90 net/core/rtnetlink.c:5684
netlink_rcv_skb+0x1e0/0x430 net/netlink/af_netlink.c:2507
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x774/0x920 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x8ab/0xbc0 net/netlink/af_netlink.c:1918
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
Second to last potentially related work creation:
kasan_save_stack+0x35/0x60 mm/kasan/common.c:38
kasan_record_aux_stack+0xb8/0x100 mm/kasan/generic.c:348
__call_rcu kernel/rcu/tree.c:3011 [inline]
call_rcu+0x182/0x930 kernel/rcu/tree.c:3091
blk_release_queue+0xda/0x290 block/blk-sysfs.c:806
kobject_cleanup lib/kobject.c:713 [inline]
kobject_release lib/kobject.c:744 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x21d/0x460 lib/kobject.c:761
scsi_device_dev_release_usercontext+0x625/0xb40 drivers/scsi/scsi_sysfs.c:478
execute_in_process_context+0x11a/0x130 kernel/workqueue.c:3378
device_release+0x92/0x1c0 drivers/base/core.c:-1
kobject_cleanup lib/kobject.c:713 [inline]
kobject_release lib/kobject.c:744 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x21d/0x460 lib/kobject.c:761
scsi_probe_and_add_lun+0x1484/0x3d00 drivers/scsi/scsi_scan.c:-1
__scsi_scan_target+0x1d8/0x1010 drivers/scsi/scsi_scan.c:1638
scsi_scan_channel drivers/scsi/scsi_scan.c:1726 [inline]
scsi_scan_host_selected+0x36e/0x690 drivers/scsi/scsi_scan.c:1755
do_scsi_scan_host drivers/scsi/scsi_scan.c:1894 [inline]
do_scan_async+0x11a/0x700 drivers/scsi/scsi_scan.c:1904
async_run_entry_fn+0x9f/0x3e0 kernel/async.c:127
process_one_work+0x863/0x1000 kernel/workqueue.c:2310
worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
The buggy address belongs to the object at ffff888021dc8e00
which belongs to the cache kmalloc-192 of size 192
The buggy address is located 80 bytes inside of
192-byte region [ffff888021dc8e00, ffff888021dc8ec0)
The buggy address belongs to the page:
page:ffffea0000877200 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x21dc8
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 ffffea0000897380 0000000700000005 ffff888016841a00
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 1, ts 6786948848, free_ts 6786156686
prep_new_page mm/page_alloc.c:2426 [inline]
get_page_from_freelist+0x1b77/0x1c60 mm/page_alloc.c:4192
__alloc_pages+0x1e1/0x470 mm/page_alloc.c:5487
alloc_page_interleave+0x24/0x1e0 mm/mempolicy.c:2031
alloc_slab_page mm/slub.c:1780 [inline]
allocate_slab mm/slub.c:1917 [inline]
new_slab+0xc0/0x4b0 mm/slub.c:1980
___slab_alloc+0x81e/0xdf0 mm/slub.c:3013
__slab_alloc mm/slub.c:3100 [inline]
slab_alloc_node mm/slub.c:3191 [inline]
kmem_cache_alloc_node_trace+0x1dd/0x300 mm/slub.c:3275
kmalloc_node include/linux/slab.h:625 [inline]
kzalloc_node include/linux/slab.h:749 [inline]
alloc_worker kernel/workqueue.c:1861 [inline]
init_rescuer+0x91/0x290 kernel/workqueue.c:4288
alloc_workqueue+0xe98/0x13f0 kernel/workqueue.c:4368
nvme_core_init+0x61/0x220 drivers/nvme/host/core.c:4820
do_one_initcall+0x1ee/0x680 init/main.c:1316
do_initcall_level+0x137/0x1f0 init/main.c:1389
do_initcalls+0x4b/0x90 init/main.c:1405
kernel_init_freeable+0x3ce/0x560 init/main.c:1629
kernel_init+0x19/0x1b0 init/main.c:1520
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1340 [inline]
free_pcp_prepare mm/page_alloc.c:1391 [inline]
free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317
free_unref_page_list+0x122/0x7e0 mm/page_alloc.c:3433
release_pages+0x184b/0x1bb0 mm/swap.c:963
tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:240 [inline]
tlb_flush_mmu mm/mmu_gather.c:247 [inline]
tlb_finish_mmu+0x164/0x2e0 mm/mmu_gather.c:338
exit_mmap+0x3a6/0x5f0 mm/mmap.c:3218
__mmput+0x115/0x3b0 kernel/fork.c:1127
free_bprm+0x141/0x300 fs/exec.c:1494
kernel_execve+0x380/0x900 fs/exec.c:2015
call_usermodehelper_exec_async+0x207/0x350 kernel/umh.c:112
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
Memory state around the buggy address:
ffff888021dc8d00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff888021dc8d80: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888021dc8e00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888021dc8e80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
ffff888021dc8f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
vkms_vblank_simulate: vblank timer overrun
----------------
Code disassembly (best guess):
0: 48 8b 3c 24 mov (%rsp),%rdi
4: e8 ae 01 59 08 call 0x85901b7
9: e9 f8 03 00 00 jmp 0x406
e: 4c 8b 74 24 18 mov 0x18(%rsp),%r14
13: 4c 8b 64 24 48 mov 0x48(%rsp),%r12
18: 48 8b 7c 24 28 mov 0x28(%rsp),%rdi
1d: e8 95 01 59 08 call 0x85901b7
22: e8 10 9d 2b 00 call 0x2b9d37
27: fb sti
28: 84 db test %bl,%bl
* 2a: 48 8b 9c 24 88 00 00 mov 0x88(%rsp),%rbx <-- trapping instruction
31: 00
32: 49 c7 c5 40 a3 03 00 mov $0x3a340,%r13
39: 8b 44 24 0c mov 0xc(%rsp),%eax
3d: 0f .byte 0xf
3e: 84 .byte 0x84
3f: 7d .byte 0x7d