==================================================================
BUG: KASAN: slab-use-after-free in llc_conn_ac_send_sabme_cmd_p_set_x+0x442/0x470 net/llc/llc_c_ac.c:782
Read of size 1 at addr ffff88807e4ca010 by task syz-executor/7816
CPU: 0 UID: 0 PID: 7816 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0x13d/0x4b0 mm/kasan/report.c:482
kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
llc_conn_ac_send_sabme_cmd_p_set_x+0x442/0x470 net/llc/llc_c_ac.c:782
llc_exec_conn_trans_actions net/llc/llc_conn.c:437 [inline]
llc_conn_service net/llc/llc_conn.c:362 [inline]
llc_conn_state_process+0x3ec/0x1480 net/llc/llc_conn.c:66
llc_process_tmr_ev net/llc/llc_c_ac.c:1442 [inline]
llc_conn_tmr_common_cb+0x2d4/0x880 net/llc/llc_c_ac.c:1325
call_timer_fn+0x19a/0x610 kernel/time/timer.c:1748
expire_timers kernel/time/timer.c:1799 [inline]
__run_timers+0x757/0xb00 kernel/time/timer.c:2374
__run_timer_base kernel/time/timer.c:2386 [inline]
__run_timer_base kernel/time/timer.c:2378 [inline]
run_timer_base+0x114/0x190 kernel/time/timer.c:2395
run_timer_softirq+0x1a/0x50 kernel/time/timer.c:2405
handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x162/0x210 kernel/softirq.c:735
irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
sysvec_apic_timer_interrupt+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1062
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:ilookup+0x182/0x210 fs/inode.c:1745
Code: 48 8d bb 80 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 8a 00 00 00 48 83 bb 80 01 00 00 00 <74> 53 e8 07 a4 72 ff 48 b8 00 00 00 00 00 fc ff df 49 c7 44 05 00
RSP: 0018:ffffc9000418f3a0 EFLAGS: 00000282
RAX: dffffc0000000000 RBX: ffff88807665b440 RCX: ffffffff8297bffe
RDX: 1ffff1100eccb6b8 RSI: ffffffff8297c008 RDI: ffff88807665b5c0
RBP: 00000000000251f0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff888036ece000
R13: 1ffff92000831e75 R14: 0000000000000000 R15: ffffc90000f750f8
kernfs_clear_inode_nlink fs/kernfs/dir.c:1528 [inline]
__kernfs_remove+0x4ce/0xb80 fs/kernfs/dir.c:1591
kernfs_remove_by_name_ns+0x7c/0x120 fs/kernfs/dir.c:1797
kernfs_remove_by_name include/linux/kernfs.h:644 [inline]
remove_files+0x96/0x1c0 fs/sysfs/group.c:28
sysfs_remove_group+0x8b/0x1b0 fs/sysfs/group.c:328
sysfs_remove_groups fs/sysfs/group.c:352 [inline]
sysfs_remove_groups+0x60/0xb0 fs/sysfs/group.c:344
device_remove_groups drivers/base/core.c:2914 [inline]
device_remove_attrs+0x203/0x290 drivers/base/core.c:3050
device_del+0x36e/0x9b0 drivers/base/core.c:3960
unregister_netdevice_many_notify+0x1503/0x2150 net/core/dev.c:12485
unregister_netdevice_many net/core/dev.c:12513 [inline]
unregister_netdevice_queue net/core/dev.c:12324 [inline]
unregister_netdevice_queue+0x30b/0x3c0 net/core/dev.c:12314
unregister_netdevice include/linux/netdevice.h:3474 [inline]
nsim_destroy+0x23e/0x970 drivers/net/netdevsim/netdev.c:1196
__nsim_dev_port_del+0x194/0x2b0 drivers/net/netdevsim/dev.c:1547
nsim_dev_port_del_all drivers/net/netdevsim/dev.c:1561 [inline]
nsim_dev_reload_destroy+0x10a/0x4a0 drivers/net/netdevsim/dev.c:1785
nsim_drv_remove+0x52/0x1e0 drivers/net/netdevsim/dev.c:1800
device_remove+0xcb/0x180 drivers/base/dd.c:616
__device_release_driver drivers/base/dd.c:1349 [inline]
device_release_driver_internal+0x44e/0x620 drivers/base/dd.c:1372
bus_remove_device+0x2bc/0x560 drivers/base/bus.c:664
device_del+0x376/0x9b0 drivers/base/core.c:3961
device_unregister+0x1d/0xe0 drivers/base/core.c:4002
nsim_bus_dev_del drivers/net/netdevsim/bus.c:491 [inline]
del_device_store+0x346/0x480 drivers/net/netdevsim/bus.c:244
bus_attr_store+0x74/0xb0 drivers/base/bus.c:172
sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145
kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x6ac/0x1050 fs/read_write.c:687
ksys_write+0x12a/0x250 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f941775e90e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007ffed42881a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000055556d763500 RCX: 00007f941775e90e
RDX: 0000000000000001 RSI: 00007ffed4288230 RDI: 0000000000000005
RBP: 00007f94178358a7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffed4288230 R14: 00007f9418554620 R15: 0000000000000003
Allocated by task 8253:
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:78
poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415
kasan_kmalloc include/linux/kasan.h:263 [inline]
__kmalloc_cache_noprof+0x2e5/0x6c0 mm/slub.c:5489
_kmalloc_noprof include/linux/slab.h:988 [inline]
_kzalloc_noprof include/linux/slab.h:1309 [inline]
llc_sap_alloc net/llc/llc_core.c:29 [inline]
llc_sap_open+0x120/0x3b0 net/llc/llc_core.c:96
llc_ui_autobind.isra.0+0x2ae/0x580 net/llc/af_llc.c:301
llc_ui_connect+0x582/0xdb0 net/llc/af_llc.c:498
__sys_connect_file+0x141/0x1a0 net/socket.c:2160
__sys_connect+0x141/0x170 net/socket.c:2179
__do_sys_connect net/socket.c:2185 [inline]
__se_sys_connect net/socket.c:2182 [inline]
__x64_sys_connect+0x72/0xb0 net/socket.c:2182
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 7821:
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:78
kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2677 [inline]
__rcu_free_sheaf_prepare+0x5d/0x2f0 mm/slub.c:2928
rcu_free_sheaf+0x1a/0xe0 mm/slub.c:5978
rcu_do_batch kernel/rcu/tree.c:2645 [inline]
rcu_core+0x5a2/0x10d0 kernel/rcu/tree.c:2897
handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622
do_softirq kernel/softirq.c:523 [inline]
do_softirq+0xac/0xe0 kernel/softirq.c:510
__local_bh_enable_ip+0xf8/0x120 kernel/softirq.c:450
local_bh_enable include/linux/bottom_half.h:33 [inline]
__alloc_skb+0x5db/0x710 net/core/skbuff.c:699
alloc_skb include/linux/skbuff.h:1384 [inline]
netlink_alloc_large_skb+0x69/0x150 net/netlink/af_netlink.c:1185
netlink_sendmsg+0x680/0xda0 net/netlink/af_netlink.c:1875
sock_sendmsg_nosec net/socket.c:800 [inline]
__sock_sendmsg net/socket.c:815 [inline]
____sys_sendmsg+0xa4d/0xbe0 net/socket.c:2709
___sys_sendmsg+0x190/0x1e0 net/socket.c:2763
__sys_sendmsg+0x160/0x210 net/socket.c:2795
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The buggy address belongs to the object at ffff88807e4ca000
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 16 bytes inside of
freed 2048-byte region [ffff88807e4ca000, ffff88807e4ca800)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88807e4c9000 pfn:0x7e4c8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000240 ffff88801c022000 ffffea00008cbe10 ffffea0001511010
raw: ffff88807e4c9000 0000000800080005 00000000f5000000 0000000000000000
head: 00fff00000000240 ffff88801c022000 ffffea00008cbe10 ffffea0001511010
head: ffff88807e4c9000 0000000800080005 00000000f5000000 0000000000000000
head: 00fff00000000003 fffffffffffffe01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5614, tgid 5614 (syz-executor), ts 95724060413, free_ts 95440890803
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1859
prep_new_page mm/page_alloc.c:1867 [inline]
get_page_from_freelist+0xf48/0x3530 mm/page_alloc.c:3946
__alloc_frozen_pages_noprof+0x299/0x2dc0 mm/page_alloc.c:5304
alloc_slab_page mm/slub.c:3266 [inline]
allocate_slab mm/slub.c:3380 [inline]
new_slab+0xa2/0x640 mm/slub.c:3426
refill_objects+0xe3/0x410 mm/slub.c:7310
refill_sheaf mm/slub.c:2804 [inline]
__pcs_replace_empty_main+0x376/0x680 mm/slub.c:4675
alloc_from_pcs mm/slub.c:4773 [inline]
slab_alloc_node mm/slub.c:4905 [inline]
__do_kmalloc_node mm/slub.c:5333 [inline]
__kmalloc_node_track_caller_noprof+0x679/0x830 mm/slub.c:5471
kmalloc_reserve+0xe8/0x350 net/core/skbuff.c:637
pskb_expand_head+0x249/0x10e0 net/core/skbuff.c:2312
netlink_trim+0x22d/0x2f0 net/netlink/af_netlink.c:1300
netlink_broadcast_filtered+0x6d/0xf20 net/netlink/af_netlink.c:1518
nlmsg_multicast_filtered include/net/netlink.h:1165 [inline]
nlmsg_multicast include/net/netlink.h:1184 [inline]
nlmsg_notify+0xb1/0x290 net/netlink/af_netlink.c:2599
rtnl_notify net/core/rtnetlink.c:963 [inline]
rtmsg_ifinfo_send net/core/rtnetlink.c:4553 [inline]
rtmsg_ifinfo_event net/core/rtnetlink.c:4569 [inline]
rtmsg_ifinfo_event net/core/rtnetlink.c:4556 [inline]
rtmsg_ifinfo+0x177/0x1b0 net/core/rtnetlink.c:4575
__dev_notify_flags+0x24c/0x2e0 net/core/dev.c:9799
rtnl_configure_link+0x1b5/0x280 net/core/rtnetlink.c:3679
veth_newlink+0x3af/0xa00 drivers/net/veth.c:1879
page last free pid 5700 tgid 5700 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1406 [inline]
__free_frozen_pages+0x79f/0x1090 mm/page_alloc.c:2950
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x47/0xf0 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:350
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4584 [inline]
slab_alloc_node mm/slub.c:4917 [inline]
__kmalloc_cache_noprof+0x265/0x6c0 mm/slub.c:5485
_kmalloc_noprof include/linux/slab.h:988 [inline]
_kzalloc_noprof include/linux/slab.h:1309 [inline]
tomoyo_dump_page+0x410/0x540 security/tomoyo/domain.c:916
tomoyo_scan_bprm security/tomoyo/condition.c:130 [inline]
tomoyo_condition+0x749/0x3b60 security/tomoyo/condition.c:1120
tomoyo_check_acl+0x1b7/0x410 security/tomoyo/domain.c:177
tomoyo_execute_permission+0x176/0x4b0 security/tomoyo/file.c:620
tomoyo_find_next_domain+0x38d/0x2010 security/tomoyo/domain.c:763
tomoyo_bprm_check_security security/tomoyo/tomoyo.c:102 [inline]
tomoyo_bprm_check_security+0x12d/0x1d0 security/tomoyo/tomoyo.c:92
security_bprm_check+0x87/0x1e0 security/security.c:820
search_binary_handler fs/exec.c:1746 [inline]
exec_binprm fs/exec.c:1788 [inline]
bprm_execve fs/exec.c:1844 [inline]
bprm_execve+0x80b/0x1940 fs/exec.c:1820
kernel_execve+0x31e/0x3a0 fs/exec.c:1988
call_usermodehelper_exec_async+0x239/0x4b0 kernel/umh.c:107
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
Memory state around the buggy address:
ffff88807e4c9f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88807e4c9f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88807e4ca000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88807e4ca080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88807e4ca100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
0: 48 8d bb 80 01 00 00 lea 0x180(%rbx),%rdi
7: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
e: fc ff df
11: 48 89 fa mov %rdi,%rdx
14: 48 c1 ea 03 shr $0x3,%rdx
18: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1)
1c: 0f 85 8a 00 00 00 jne 0xac
22: 48 83 bb 80 01 00 00 cmpq $0x0,0x180(%rbx)
29: 00
* 2a: 74 53 je 0x7f <-- trapping instruction
2c: e8 07 a4 72 ff call 0xff72a438
31: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
38: fc ff df
3b: 49 rex.WB
3c: c7 .byte 0xc7
3d: 44 rex.R
3e: 05 .byte 0x5