syzbot
KASAN: use-after-free Read in tipc_conn_close
Status:
premoderation: reported on 2026/10/29 09:08
Reported-by: syzbot+bfa8c1c7b10f2cb5d336@syzkaller.appspotmail.com
First crash: 7h27m, last: 7h27m
Sample crash report:
==================================================================
BUG: KASAN: use-after-free in tipc_conn_close+0x39/0x120 net/tipc/topsrv.c:157
Read of size 8 at addr ffff888132ae1008 by task kworker/u4:8/2491
CPU: 0 PID: 2491 Comm: kworker/u4:8 Tainted: G W syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Workqueue: netns cleanup_net
Call Trace:
<TASK>
__dump_stack+0x21/0x24 lib/dump_stack.c:88
dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
print_address_description+0x71/0x200 mm/kasan/report.c:316
print_report+0x4a/0x60 mm/kasan/report.c:420
kasan_report+0x122/0x150 mm/kasan/report.c:524
__asan_report_load8_noabort+0x14/0x20 mm/kasan/report_generic.c:351
tipc_conn_close+0x39/0x120 net/tipc/topsrv.c:157
tipc_topsrv_stop net/tipc/topsrv.c:704 [inline]
tipc_topsrv_exit_net+0x172/0x380 net/tipc/topsrv.c:727
ops_exit_list net/core/net_namespace.c:172 [inline]
cleanup_net+0x5b0/0xb10 net/core/net_namespace.c:604
process_one_work+0x717/0xc30 kernel/workqueue.c:2302
worker_thread+0xa4d/0x11d0 kernel/workqueue.c:2449
kthread+0x281/0x320 kernel/kthread.c:386
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
Allocated by task 312:
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
kasan_save_alloc_info+0x1f/0x30 mm/kasan/generic.c:505
____kasan_kmalloc mm/kasan/common.c:380 [inline]
__kasan_kmalloc+0x95/0xb0 mm/kasan/common.c:389
kasan_kmalloc include/linux/kasan.h:212 [inline]
kmalloc_trace+0x40/0xb0 mm/slab_common.c:1033
kmalloc include/linux/slab.h:563 [inline]
kzalloc include/linux/slab.h:699 [inline]
tipc_conn_alloc+0x5a/0x460 net/tipc/topsrv.c:184
tipc_topsrv_accept+0x106/0x290 net/tipc/topsrv.c:472
process_one_work+0x717/0xc30 kernel/workqueue.c:2302
worker_thread+0xa4d/0x11d0 kernel/workqueue.c:2449
kthread+0x281/0x320 kernel/kthread.c:386
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Freed by task 835:
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:516
____kasan_slab_free+0x132/0x180 mm/kasan/common.c:242
__kasan_slab_free+0x11/0x20 mm/kasan/common.c:250
kasan_slab_free include/linux/kasan.h:178 [inline]
slab_free_hook mm/slub.c:1750 [inline]
slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1776
slab_free mm/slub.c:3712 [inline]
__kmem_cache_free+0xb7/0x1b0 mm/slub.c:3728
kfree+0x6f/0xf0 mm/slab_common.c:990
tipc_conn_kref_release net/tipc/topsrv.c:142 [inline]
kref_put include/linux/kref.h:65 [inline]
conn_put+0x2b6/0x320 net/tipc/topsrv.c:147
tipc_conn_recv_work+0x428/0x4a0 net/tipc/topsrv.c:432
process_one_work+0x717/0xc30 kernel/workqueue.c:2302
worker_thread+0xa4d/0x11d0 kernel/workqueue.c:2449
kthread+0x281/0x320 kernel/kthread.c:386
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Last potentially related work creation:
kasan_save_stack+0x3a/0x60 mm/kasan/common.c:46
__kasan_record_aux_stack+0xb6/0xc0 mm/kasan/generic.c:486
kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:496
insert_work+0x51/0x300 kernel/workqueue.c:1368
__queue_work+0x9d0/0xd50 kernel/workqueue.c:1527
queue_work_on+0xde/0x150 kernel/workqueue.c:1555
queue_work include/linux/workqueue.h:510 [inline]
tipc_topsrv_queue_evt+0x29b/0x310 net/tipc/topsrv.c:336
tipc_sub_send_event net/tipc/subscr.c:63 [inline]
tipc_sub_timeout+0x1ce/0x360 net/tipc/subscr.c:111
call_timer_fn+0x46/0x2a0 kernel/time/timer.c:1553
expire_timers kernel/time/timer.c:1604 [inline]
__run_timers+0x646/0x9b0 kernel/time/timer.c:1875
run_timer_softirq+0x6a/0xf0 kernel/time/timer.c:1888
handle_softirqs+0x1dd/0x5f0 kernel/softirq.c:642
__do_softirq kernel/softirq.c:680 [inline]
invoke_softirq kernel/softirq.c:497 [inline]
__irq_exit_rcu+0x52/0xf0 kernel/softirq.c:729
irq_exit_rcu+0x9/0x10 kernel/softirq.c:741
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0xa9/0xc0 arch/x86/kernel/apic/apic.c:1118
asm_sysvec_apic_timer_interrupt+0x1b/0x20 arch/x86/include/asm/idtentry.h:691
Second to last potentially related work creation:
kasan_save_stack+0x3a/0x60 mm/kasan/common.c:46
__kasan_record_aux_stack+0xb6/0xc0 mm/kasan/generic.c:486
kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:496
insert_work+0x51/0x300 kernel/workqueue.c:1368
__queue_work+0x9d0/0xd50 kernel/workqueue.c:1527
queue_work_on+0xde/0x150 kernel/workqueue.c:1555
queue_work include/linux/workqueue.h:510 [inline]
tipc_topsrv_queue_evt+0x29b/0x310 net/tipc/topsrv.c:336
tipc_sub_send_event net/tipc/subscr.c:63 [inline]
tipc_sub_timeout+0x1ce/0x360 net/tipc/subscr.c:111
call_timer_fn+0x46/0x2a0 kernel/time/timer.c:1553
expire_timers kernel/time/timer.c:1604 [inline]
__run_timers+0x646/0x9b0 kernel/time/timer.c:1875
run_timer_softirq+0x6a/0xf0 kernel/time/timer.c:1888
handle_softirqs+0x1dd/0x5f0 kernel/softirq.c:642
__do_softirq kernel/softirq.c:680 [inline]
invoke_softirq kernel/softirq.c:497 [inline]
__irq_exit_rcu+0x52/0xf0 kernel/softirq.c:729
irq_exit_rcu+0x9/0x10 kernel/softirq.c:741
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0xa9/0xc0 arch/x86/kernel/apic/apic.c:1118
asm_sysvec_apic_timer_interrupt+0x1b/0x20 arch/x86/include/asm/idtentry.h:691
The buggy address belongs to the object at ffff888132ae1000
which belongs to the cache kmalloc-192 of size 192
The buggy address is located 8 bytes inside of
192-byte region [ffff888132ae1000, ffff888132ae10c0)
The buggy address belongs to the physical page:
page:ffffea0004cab840 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x132ae1
flags: 0x4000000000000200(slab|zone=1)
raw: 4000000000000200 ffffea00043f6d40 dead000000000005 ffff888100042c00
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 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 288, tgid 288 (syz-executor), ts 22343397837, free_ts 22334934923
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0x1f5/0x210 mm/page_alloc.c:2673
prep_new_page+0x1c/0x110 mm/page_alloc.c:2680
get_page_from_freelist+0x2ca9/0x2d20 mm/page_alloc.c:4587
__alloc_pages+0x1fa/0x610 mm/page_alloc.c:5931
alloc_slab_page+0x6e/0xf0 include/linux/gfp.h:-1
allocate_slab mm/slub.c:1967 [inline]
new_slab+0x98/0x3e0 mm/slub.c:2020
___slab_alloc+0x70f/0xb70 mm/slub.c:3177
__slab_alloc+0x5e/0xa0 mm/slub.c:3263
slab_alloc_node mm/slub.c:3348 [inline]
__kmem_cache_alloc_node+0x204/0x2d0 mm/slub.c:3423
kmalloc_trace+0x29/0xb0 mm/slab_common.c:1028
kmalloc include/linux/slab.h:563 [inline]
kzalloc include/linux/slab.h:699 [inline]
binderfs_binder_device_create+0x149/0xa60 drivers/android/binderfs.c:149
binderfs_fill_super+0xabc/0xff0 drivers/android/binderfs.c:729
vfs_get_super fs/super.c:1216 [inline]
get_tree_nodev+0xc4/0x170 fs/super.c:1246
binderfs_fs_context_get_tree+0x1c/0x20 drivers/android/binderfs.c:749
vfs_get_tree+0x9a/0x270 fs/super.c:1578
do_new_mount+0x251/0xb40 fs/namespace.c:3081
page last free stack trace:
reset_page_owner include/linux/page_owner.h:26 [inline]
free_pages_prepare mm/page_alloc.c:1581 [inline]
free_pcp_prepare mm/page_alloc.c:1655 [inline]
free_unref_page_prepare+0x81b/0x820 mm/page_alloc.c:3622
free_unref_page_list+0x117/0x8d0 mm/page_alloc.c:3773
release_pages+0xc7e/0xce0 mm/swap.c:1053
free_pages_and_swap_cache+0x86/0xa0 mm/swap_state.c:316
tlb_batch_pages_flush mm/mmu_gather.c:59 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:254 [inline]
tlb_flush_mmu mm/mmu_gather.c:261 [inline]
tlb_finish_mmu+0x1b2/0x380 mm/mmu_gather.c:361
exit_mmap+0x41d/0xc10 mm/mmap.c:3384
__mmput+0x92/0x340 kernel/fork.c:1321
mmput+0x4b/0x150 kernel/fork.c:1345
exit_mm kernel/exit.c:575 [inline]
do_exit+0xa62/0x29f0 kernel/exit.c:883
do_group_exit+0x21b/0x2e0 kernel/exit.c:1040
get_signal+0x167c/0x1700 kernel/signal.c:2904
arch_do_signal_or_restart+0xd1/0x11c0 arch/x86/kernel/signal.c:871
exit_to_user_mode_loop+0x7a/0xb0 kernel/entry/common.c:174
exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
syscall_exit_to_user_mode+0x1a/0x30 kernel/entry/common.c:303
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
Memory state around the buggy address:
ffff888132ae0f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff888132ae0f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888132ae1000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888132ae1080: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
ffff888132ae1100: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
general protection fault, probably for non-canonical address 0xe0e3dc2b0000006b: 0000 [#1] PREEMPT SMP KASAN
KASAN: maybe wild-memory-access in range [0x071f015800000358-0x071f01580000035f]
CPU: 0 PID: 2491 Comm: kworker/u4:8 Tainted: G B W syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Workqueue: netns cleanup_net
RIP: 0010:tipc_conn_close+0x47/0x120 net/tipc/topsrv.c:157
Code: 94 fc 4c 8d 7b 08 4d 89 fe 49 c1 ee 03 43 80 3c 26 00 74 08 4c 89 ff e8 17 04 da fc 4d 8b 3f 49 83 c7 18 4c 89 f8 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 ff e8 fa 03 da fc 4d 8b 27 4d 8d bc 24
RSP: 0018:ffffc9000fef7be0 EFLAGS: 00010202
RAX: 00e3e02b0000006b RBX: ffff888132ae1000 RCX: ffff88811e800000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000fef7c08 R08: ffffffff87b777e7 R09: 1ffffffff0f6eefc
R10: dffffc0000000000 R11: fffffbfff0f6eefd R12: dffffc0000000000
R13: 1ffff11023c41e63 R14: 1ffff1102655c201 R15: 071f01580000035b
FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555591db888 CR3: 000000000700f000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
tipc_topsrv_stop net/tipc/topsrv.c:704 [inline]
tipc_topsrv_exit_net+0x172/0x380 net/tipc/topsrv.c:727
ops_exit_list net/core/net_namespace.c:172 [inline]
cleanup_net+0x5b0/0xb10 net/core/net_namespace.c:604
process_one_work+0x717/0xc30 kernel/workqueue.c:2302
worker_thread+0xa4d/0x11d0 kernel/workqueue.c:2449
kthread+0x281/0x320 kernel/kthread.c:386
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:tipc_conn_close+0x47/0x120 net/tipc/topsrv.c:157
Code: 94 fc 4c 8d 7b 08 4d 89 fe 49 c1 ee 03 43 80 3c 26 00 74 08 4c 89 ff e8 17 04 da fc 4d 8b 3f 49 83 c7 18 4c 89 f8 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 ff e8 fa 03 da fc 4d 8b 27 4d 8d bc 24
RSP: 0018:ffffc9000fef7be0 EFLAGS: 00010202
RAX: 00e3e02b0000006b RBX: ffff888132ae1000 RCX: ffff88811e800000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000fef7c08 R08: ffffffff87b777e7 R09: 1ffffffff0f6eefc
R10: dffffc0000000000 R11: fffffbfff0f6eefd R12: dffffc0000000000
R13: 1ffff11023c41e63 R14: 1ffff1102655c201 R15: 071f01580000035b
FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555591db888 CR3: 000000000700f000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 94 xchg %eax,%esp
1: fc cld
2: 4c 8d 7b 08 lea 0x8(%rbx),%r15
6: 4d 89 fe mov %r15,%r14
9: 49 c1 ee 03 shr $0x3,%r14
d: 43 80 3c 26 00 cmpb $0x0,(%r14,%r12,1)
12: 74 08 je 0x1c
14: 4c 89 ff mov %r15,%rdi
17: e8 17 04 da fc call 0xfcda0433
1c: 4d 8b 3f mov (%r15),%r15
1f: 49 83 c7 18 add $0x18,%r15
23: 4c 89 f8 mov %r15,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 42 80 3c 20 00 cmpb $0x0,(%rax,%r12,1) <-- trapping instruction
2f: 74 08 je 0x39
31: 4c 89 ff mov %r15,%rdi
34: e8 fa 03 da fc call 0xfcda0433
39: 4d 8b 27 mov (%r15),%r12
3c: 4d rex.WRB
3d: 8d .byte 0x8d
3e: bc .byte 0xbc
3f: 24 .byte 0x24
Struck through repros no longer work on HEAD.