==================================================================
BUG: KASAN: use-after-free in ax25_heartbeat_expiry+0x10c/0x130 net/ax25/ax25_timer.c:125
Read of size 4 at addr ffff88802453df50 by task syz.2.552/7144
CPU: 1 PID: 7144 Comm: syz.2.552 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
dump_stack_lvl+0x188/0x250 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_heartbeat_expiry+0x10c/0x130 net/ax25/ax25_timer.c:125
call_timer_fn+0x17b/0x540 kernel/time/timer.c:1648
expire_timers kernel/time/timer.c:1699 [inline]
__run_timers+0x53e/0x800 kernel/time/timer.c:1970
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1983
handle_softirqs+0x339/0x830 kernel/softirq.c:576
__do_softirq kernel/softirq.c:610 [inline]
invoke_softirq kernel/softirq.c:450 [inline]
__irq_exit_rcu+0x13b/0x230 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
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202
Code: 00 00 00 66 90 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 be a9 97 f7 48 89 df e8 f6 81 98 f7 e8 61 74 b9 f7 fb bf 01 00 00 00 a6 89 8c f7 65 8b 05 47 97 3c 76 85 c0 74 02 5b c3 e8 94 a4 3a
RSP: 0018:ffffc90003f0fbc0 EFLAGS: 00000282
RAX: 3715be7dad16d300 RBX: ffff88807a6e5340 RCX: 3715be7dad16d300
RDX: dffffc0000000000 RSI: ffffffff8a2b2780 RDI: 0000000000000001
RBP: 0000000000000000 R08: ffff88807a6e5343 R09: 1ffff1100f4dca68
R10: dffffc0000000000 R11: ffffed100f4dca69 R12: ffff88807a6e5340
R13: 0000000000000021 R14: dffffc0000000000 R15: 000000001c000004
spin_unlock_irq include/linux/spinlock.h:414 [inline]
get_signal+0x11d6/0x12c0 kernel/signal.c:2903
arch_do_signal_or_restart+0xe7/0x12c0 arch/x86/kernel/signal.c:867
handle_signal_work kernel/entry/common.c:154 [inline]
exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
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
RIP: 0033:0x7fd319866799
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fd317ac0028 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007fd319adffa0 RCX: 00007fd319866799
RDX: 0000200000000040 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 00007fd3198fcc99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd319ae0038 R14: 00007fd319adffa0 R15: 00007ffd525003c8
Allocated by task 6789:
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:2074 [inline]
call_netdevice_notifiers net/core/dev.c:2088 [inline]
__dev_notify_flags+0x194/0x300 net/core/dev.c:8917
dev_change_flags+0xe3/0x1a0 net/core/dev.c:8955
dev_ifsioc+0x130/0xd50 net/core/dev_ioctl.c:324
dev_ioctl+0x545/0xe30 net/core/dev_ioctl.c:572
sock_do_ioctl+0x245/0x320 net/socket.c:1161
sock_ioctl+0x4d2/0x710 net/socket.c:1266
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 6938:
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:1345
__fput+0x234/0x930 fs/file_table.c:311
task_work_run+0x125/0x1a0 kernel/task_work.c:188
get_signal+0x1222/0x12c0 kernel/signal.c:2672
arch_do_signal_or_restart+0xe7/0x12c0 arch/x86/kernel/signal.c:867
handle_signal_work kernel/entry/common.c:154 [inline]
exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
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
kvfree_call_rcu+0x105/0x7d0 kernel/rcu/tree.c:3600
free_vmap_block mm/vmalloc.c:1945 [inline]
purge_fragmented_blocks mm/vmalloc.c:1979 [inline]
purge_fragmented_blocks_allcpus+0x89b/0x9e0 mm/vmalloc.c:1988
_vm_unmap_aliases+0x400/0x4a0 mm/vmalloc.c:2113
change_page_attr_set_clr+0x323/0xca0 arch/x86/mm/pat/set_memory.c:1740
change_page_attr_clear arch/x86/mm/pat/set_memory.c:1797 [inline]
set_memory_ro+0x89/0xd0 arch/x86/mm/pat/set_memory.c:1943
bpf_jit_binary_lock_ro include/linux/filter.h:919 [inline]
bpf_int_jit_compile+0xc6d8/0xcd80 arch/x86/net/bpf_jit_comp.c:2478
bpf_prog_select_runtime+0x46f/0x7c0 kernel/bpf/core.c:1977
bpf_migrate_filter net/core/filter.c:1307 [inline]
bpf_prepare_filter+0x1020/0x11d0 net/core/filter.c:1355
bpf_prog_create_from_user+0x2ce/0x420 net/core/filter.c:1449
seccomp_prepare_filter kernel/seccomp.c:669 [inline]
seccomp_prepare_user_filter kernel/seccomp.c:706 [inline]
seccomp_set_mode_filter kernel/seccomp.c:1834 [inline]
do_seccomp+0x814/0x16c0 kernel/seccomp.c:1954
__do_sys_prctl kernel/sys.c:2380 [inline]
__se_sys_prctl+0x76d/0x1050 kernel/sys.c:2298
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
insert_work+0x54/0x3d0 kernel/workqueue.c:1366
__queue_work+0x9c5/0xd50 kernel/workqueue.c:1532
queue_work_on+0x124/0x1f0 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
__netdev_upper_dev_link+0x41e/0x590 net/core/dev.c:8225
netdev_master_upper_dev_link+0xb9/0x100 net/core/dev.c:8295
batadv_hardif_enable_interface+0x1d3/0x990 net/batman-adv/hard-interface.c:722
batadv_softif_slave_add+0x72/0xf0 net/batman-adv/soft-interface.c:842
do_set_master net/core/rtnetlink.c:2577 [inline]
do_setlink+0xe90/0x3d60 net/core/rtnetlink.c:2788
__rtnl_newlink net/core/rtnetlink.c:3452 [inline]
rtnl_newlink+0x1658/0x1a50 net/core/rtnetlink.c:3574
rtnetlink_rcv_msg+0x844/0xf30 net/core/rtnetlink.c:5684
netlink_rcv_skb+0x1f5/0x440 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+0x8ba/0xbe0 net/netlink/af_netlink.c:1918
sock_sendmsg_nosec net/socket.c:706 [inline]
__sock_sendmsg net/socket.c:718 [inline]
__sys_sendto+0x46d/0x620 net/socket.c:2072
__do_sys_sendto net/socket.c:2084 [inline]
__se_sys_sendto net/socket.c:2080 [inline]
__x64_sys_sendto+0xda/0xf0 net/socket.c:2080
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
The buggy address belongs to the object at ffff88802453df00
which belongs to the cache kmalloc-192 of size 192
The buggy address is located 80 bytes inside of
192-byte region [ffff88802453df00, ffff88802453dfc0)
The buggy address belongs to the page:
page:ffffea0000914f40 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88802453dd00 pfn:0x2453d
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 ffffea00008992c8 ffffea00008f1e08 ffff888016c41a00
raw: ffff88802453dd00 000000000010000c 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 7243473716, free_ts 0
prep_new_page mm/page_alloc.c:2426 [inline]
get_page_from_freelist+0x1bbd/0x1ca0 mm/page_alloc.c:4192
__alloc_pages+0x1ee/0x480 mm/page_alloc.c:5501
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+0x80a/0xdd0 mm/slub.c:3013
__slab_alloc mm/slub.c:3100 [inline]
slab_alloc_node mm/slub.c:3191 [inline]
slab_alloc mm/slub.c:3233 [inline]
kmem_cache_alloc_trace+0x1a5/0x2a0 mm/slub.c:3250
kmalloc include/linux/slab.h:607 [inline]
kzalloc include/linux/slab.h:738 [inline]
call_usermodehelper_setup+0x8a/0x260 kernel/umh.c:365
kobject_uevent_env+0x65e/0x890 lib/kobject_uevent.c:629
driver_register+0x3e2/0x430 drivers/base/driver.c:248
init+0x235/0x10d0 drivers/usb/gadget/udc/dummy_hcd.c:2821
do_one_initcall+0x272/0x730 init/main.c:1316
do_initcall_level+0x137/0x1f0 init/main.c:1389
do_initcalls+0x4b/0x90 init/main.c:1405
kernel_init_freeable+0x3e9/0x570 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_owner free stack trace missing
Memory state around the buggy address:
ffff88802453de00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88802453de80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff88802453df00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88802453df80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
ffff88802453e000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
----------------
Code disassembly (best guess):
0: 00 00 add %al,(%rax)
2: 00 66 90 add %ah,-0x70(%rsi)
5: 53 push %rbx
6: 48 89 fb mov %rdi,%rbx
9: 48 83 c7 18 add $0x18,%rdi
d: 48 8b 74 24 08 mov 0x8(%rsp),%rsi
12: e8 be a9 97 f7 call 0xf797a9d5
17: 48 89 df mov %rbx,%rdi
1a: e8 f6 81 98 f7 call 0xf7988215
1f: e8 61 74 b9 f7 call 0xf7b97485
24: fb sti
25: bf 01 00 00 00 mov $0x1,%edi
* 2a: e8 a6 89 8c f7 call 0xf78c89d5 <-- trapping instruction
2f: 65 8b 05 47 97 3c 76 mov %gs:0x763c9747(%rip),%eax # 0x763c977d
36: 85 c0 test %eax,%eax
38: 74 02 je 0x3c
3a: 5b pop %rbx
3b: c3 ret
3c: e8 .byte 0xe8
3d: 94 xchg %eax,%esp
3e: a4 movsb %ds:(%rsi),%es:(%rdi)
3f: 3a .byte 0x3a