==================================================================
BUG: KASAN: slab-use-after-free in llc_conn_ac_send_sabme_cmd_p_set_x+0x38a/0x420 net/llc/llc_c_ac.c:782
Read of size 1 at addr ffff88802f7a6010 by task kworker/u8:9/1174
CPU: 0 UID: 0 PID: 1174 Comm: kworker/u8:9 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/10/2026
Workqueue: events_unbound nsim_dev_trap_report_work
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_address_description+0x55/0x1e0 mm/kasan/report.c:378
print_report+0x58/0x70 mm/kasan/report.c:482
kasan_report+0x117/0x150 mm/kasan/report.c:595
llc_conn_ac_send_sabme_cmd_p_set_x+0x38a/0x420 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+0x4fb/0x1380 net/llc/llc_conn.c:66
llc_process_tmr_ev net/llc/llc_c_ac.c:1442 [inline]
llc_conn_tmr_common_cb+0x34a/0x780 net/llc/llc_c_ac.c:1325
call_timer_fn+0x192/0x5e0 kernel/time/timer.c:1748
expire_timers kernel/time/timer.c:1799 [inline]
__run_timers kernel/time/timer.c:2374 [inline]
__run_timer_base+0x652/0x8b0 kernel/time/timer.c:2386
run_timer_base kernel/time/timer.c:2395 [inline]
run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405
handle_softirqs+0x225/0x840 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0xca/0x220 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+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:trace_lock_acquire include/trace/events/lock.h:23 [inline]
RIP: 0010:lock_acquire+0x5f/0x350 kernel/locking/lockdep.c:5831
Code: 89 44 24 58 0f 1f 44 00 00 65 8b 05 2f 7c ca 11 83 f8 08 0f 83 83 01 00 00 89 c0 48 0f a3 05 d8 5d b5 0e 73 0d e8 f1 29 09 00 <84> c0 0f 84 ca 01 00 00 83 3d d2 90 b5 0e 00 0f 84 d3 00 00 00 48
RSP: 0018:ffffc900047df480 EFLAGS: 00000212
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000002
RDX: 0000000000000000 RSI: ffffffff8c4bd960 RDI: ffffffff8c4bd920
RBP: ffffffff8176f27f R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff81b16a10 R12: 0000000000000002
R13: ffffffff8eb59c60 R14: 0000000000000000 R15: 0000000000000000
rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
rcu_read_lock include/linux/rcupdate.h:840 [inline]
class_rcu_constructor include/linux/rcupdate.h:1183 [inline]
unwind_next_frame+0xac/0x2550 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
kasan_kmalloc include/linux/kasan.h:263 [inline]
__do_kmalloc_node mm/slub.c:5362 [inline]
__kmalloc_node_track_caller_noprof+0x4c3/0x730 mm/slub.c:5497
kmalloc_reserve net/core/skbuff.c:637 [inline]
__alloc_skb+0x2bd/0x7a0 net/core/skbuff.c:715
alloc_skb include/linux/skbuff.h:1384 [inline]
nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:819 [inline]
nsim_dev_trap_report drivers/net/netdevsim/dev.c:876 [inline]
nsim_dev_trap_report_work+0x25f/0xb40 drivers/net/netdevsim/dev.c:922
process_one_work kernel/workqueue.c:3322 [inline]
process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Allocated by task 11396:
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
kasan_kmalloc include/linux/kasan.h:263 [inline]
__kmalloc_cache_noprof+0x32d/0x660 mm/slub.c:5515
_kmalloc_noprof include/linux/slab.h:969 [inline]
_kzalloc_noprof include/linux/slab.h:1290 [inline]
llc_sap_alloc net/llc/llc_core.c:29 [inline]
llc_sap_open+0xe1/0x3b0 net/llc/llc_core.c:96
llc_ui_autobind+0x1f1/0x560 net/llc/af_llc.c:301
llc_ui_connect+0x1d7/0xd50 net/llc/af_llc.c:498
__sys_connect_file net/socket.c:2135 [inline]
__sys_connect+0x323/0x460 net/socket.c:2154
__do_sys_connect net/socket.c:2160 [inline]
__se_sys_connect net/socket.c:2157 [inline]
__x64_sys_connect+0x7a/0x90 net/socket.c:2157
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 11365:
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2705 [inline]
__rcu_free_sheaf_prepare+0x12d/0x2a0 mm/slub.c:2956
rcu_free_sheaf+0x31/0x200 mm/slub.c:6004
rcu_do_batch kernel/rcu/tree.c:2645 [inline]
rcu_core+0x78b/0x10a0 kernel/rcu/tree.c:2897
handle_softirqs+0x225/0x840 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0xca/0x220 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+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
The buggy address belongs to the object at ffff88802f7a6000
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 16 bytes inside of
freed 2048-byte region [ffff88802f7a6000, ffff88802f7a6800)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2f7a0
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801b004000 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800080008 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801b004000 dead000000000100 dead000000000122
head: 0000000000000000 0000000800080008 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 18506607564, free_ts 0
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1859
prep_new_page mm/page_alloc.c:1867 [inline]
get_page_from_freelist+0x21fa/0x2270 mm/page_alloc.c:3946
__alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5304
alloc_slab_page mm/slub.c:3294 [inline]
allocate_slab+0x79/0x5e0 mm/slub.c:3408
new_slab mm/slub.c:3454 [inline]
refill_objects+0x2d5/0x350 mm/slub.c:7338
refill_sheaf mm/slub.c:2832 [inline]
__pcs_replace_empty_main+0x2bf/0x6b0 mm/slub.c:4703
alloc_from_pcs mm/slub.c:4801 [inline]
slab_alloc_node mm/slub.c:4933 [inline]
__kmalloc_cache_noprof+0x3a7/0x660 mm/slub.c:5511
_kmalloc_noprof include/linux/slab.h:969 [inline]
_kzalloc_noprof include/linux/slab.h:1290 [inline]
__media_device_register+0x57/0x3c0 drivers/media/mc/mc-device.c:740
vivid_create_devnodes+0x2090/0x2c60 drivers/media/test-drivers/vivid/vivid-core.c:1749
vivid_create_instance drivers/media/test-drivers/vivid/vivid-core.c:2042 [inline]
vivid_probe+0x5038/0x70c0 drivers/media/test-drivers/vivid/vivid-core.c:2095
platform_probe+0xf9/0x190 drivers/base/platform.c:1439
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x254/0xae0 drivers/base/dd.c:706
__driver_probe_device+0x1e8/0x360 drivers/base/dd.c:868
driver_probe_device+0x4f/0x240 drivers/base/dd.c:898
__driver_attach+0x339/0x600 drivers/base/dd.c:1292
bus_for_each_dev+0x23b/0x2c0 drivers/base/bus.c:383
page_owner free stack trace missing
Memory state around the buggy address:
ffff88802f7a5f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88802f7a5f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88802f7a6000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88802f7a6080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88802f7a6100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
0: 89 44 24 58 mov %eax,0x58(%rsp)
4: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1)
9: 65 8b 05 2f 7c ca 11 mov %gs:0x11ca7c2f(%rip),%eax # 0x11ca7c3f
10: 83 f8 08 cmp $0x8,%eax
13: 0f 83 83 01 00 00 jae 0x19c
19: 89 c0 mov %eax,%eax
1b: 48 0f a3 05 d8 5d b5 bt %rax,0xeb55dd8(%rip) # 0xeb55dfb
22: 0e
23: 73 0d jae 0x32
25: e8 f1 29 09 00 call 0x92a1b
* 2a: 84 c0 test %al,%al <-- trapping instruction
2c: 0f 84 ca 01 00 00 je 0x1fc
32: 83 3d d2 90 b5 0e 00 cmpl $0x0,0xeb590d2(%rip) # 0xeb5910b
39: 0f 84 d3 00 00 00 je 0x112
3f: 48 rex.W