[syzbot] [bridge?] KASAN: slab-use-after-free Read in br_multicast_port_group_expired

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 24ca36a562d6 Merge tag 'wq-for-6.10-rc5-fixes' of git://gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1253533e980000
kernel config: https://syzkaller.appspot.com/x/.config?x=68f694eee402f940
dashboard link: https://syzkaller.appspot.com/bug?extid=263426984509be19c9a0
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/47d6afa6532e/disk-24ca36a5.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f72fd72615a8/vmlinux-24ca36a5.xz
kernel image: https://storage.googleapis.com/syzbot-assets/01d7fd05f768/bzImage-24ca36a5.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+263426...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in br_multicast_port_group_expired+0x4c0/0x550 net/bridge/br_multicast.c:861
Read of size 8 at addr ffff888071d6d000 by task syz.5.1232/9699

CPU: 1 PID: 9699 Comm: syz.5.1232 Not tainted 6.10.0-rc5-syzkaller-00021-g24ca36a562d6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
print_address_description mm/kasan/report.c:377 [inline]
print_report+0xc3/0x620 mm/kasan/report.c:488
kasan_report+0xd9/0x110 mm/kasan/report.c:601
br_multicast_port_group_expired+0x4c0/0x550 net/bridge/br_multicast.c:861
call_timer_fn+0x1a3/0x610 kernel/time/timer.c:1792
expire_timers kernel/time/timer.c:1843 [inline]
__run_timers+0x74b/0xaf0 kernel/time/timer.c:2417
__run_timer_base kernel/time/timer.c:2428 [inline]
__run_timer_base kernel/time/timer.c:2421 [inline]
run_timer_base+0x111/0x190 kernel/time/timer.c:2437
run_timer_softirq+0x1a/0x40 kernel/time/timer.c:2447
handle_softirqs+0x219/0x8f0 kernel/softirq.c:554
__do_softirq kernel/softirq.c:588 [inline]
invoke_softirq kernel/softirq.c:428 [inline]
__irq_exit_rcu kernel/softirq.c:637 [inline]
irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1043
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:finish_task_switch.isra.0+0x220/0xcc0 kernel/sched/core.c:5282
Code: a9 0a 00 00 44 8b 0d 17 b0 85 0e 45 85 c9 0f 85 c0 01 00 00 48 89 df e8 ae f8 ff ff e8 b9 da 36 00 fb 65 48 8b 1d a0 3d a4 7e <48> 8d bb f8 15 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1
RSP: 0018:ffffc90004177d18 EFLAGS: 00000206
RAX: 00000000000085f5 RBX: ffff888028bf8000 RCX: 1ffffffff1fc9ac1
RDX: 0000000000000000 RSI: ffffffff8b2cc140 RDI: ffffffff8b9024c0
RBP: ffffc90004177d60 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff8fe51897 R11: 0000000000000000 R12: ffff8880b933f938
R13: ffff888028bf9e00 R14: 0000000000000000 R15: ffff8880b933ebc0
context_switch kernel/sched/core.c:5411 [inline]
__schedule+0xf1d/0x5d00 kernel/sched/core.c:6745
__schedule_loop kernel/sched/core.c:6822 [inline]
schedule+0xe7/0x350 kernel/sched/core.c:6837
exit_to_user_mode_loop kernel/entry/common.c:102 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
irqentry_exit_to_user_mode+0xde/0x280 kernel/entry/common.c:231
asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707
RIP: 0033:0x7fd43064cb94
Code: 0f 82 b9 00 00 00 48 39 f2 72 6e 41 0f 11 0c 24 48 8b 77 f8 48 89 f8 48 89 eb eb 12 66 2e 0f 1f 84 00 00 00 00 00 48 8b 4b 08 <48> 83 c3 08 48 39 d1 72 f3 48 83 e8 08 48 39 f2 73 17 66 2e 0f 1f
RSP: 002b:00007ffc97d21a80 EFLAGS: 00000293
RAX: 00007fd42fab7e40 RBX: 00007fd42fa86f98 RCX: ffffffff88b96ebe
RDX: ffffffff88b9717d RSI: ffffffff88b97253 RDI: 00007fd42fac5e28
RBP: 00007fd42fa7b318 R08: 00007fd42faa0898 R09: 0000000000000008
R10: 0000000088ba1cfe R11: 0000000088ba1d02 R12: 00007fd42fa7b310
R13: 000000000000001f R14: 00007fd42fa01008 R15: 00007fd430904140
</TASK>

Allocated by task 6702:
kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:387
kmalloc_noprof include/linux/slab.h:660 [inline]
kzalloc_noprof include/linux/slab.h:778 [inline]
new_nbp net/bridge/br_if.c:431 [inline]
br_add_if+0x427/0x1b80 net/bridge/br_if.c:599
do_set_master+0x1bf/0x230 net/core/rtnetlink.c:2701
do_setlink+0xcaf/0x3ff0 net/core/rtnetlink.c:2907
__rtnl_newlink+0xc35/0x1960 net/core/rtnetlink.c:3696
rtnl_newlink+0x67/0xa0 net/core/rtnetlink.c:3743
rtnetlink_rcv_msg+0x3ca/0xea0 net/core/rtnetlink.c:6635
netlink_rcv_skb+0x16e/0x440 net/netlink/af_netlink.c:2564
netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline]
netlink_unicast+0x545/0x820 net/netlink/af_netlink.c:1361
netlink_sendmsg+0x8b8/0xd70 net/netlink/af_netlink.c:1905
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
__sys_sendto+0x482/0x4e0 net/socket.c:2192
__do_sys_sendto net/socket.c:2204 [inline]
__se_sys_sendto net/socket.c:2200 [inline]
__x64_sys_sendto+0xe0/0x1c0 net/socket.c:2200
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 9700:
kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:579
poison_slab_object+0xf7/0x160 mm/kasan/common.c:240
__kasan_slab_free+0x32/0x50 mm/kasan/common.c:256
kasan_slab_free include/linux/kasan.h:184 [inline]
slab_free_hook mm/slub.c:2196 [inline]
slab_free mm/slub.c:4437 [inline]
kfree+0x12a/0x3b0 mm/slub.c:4558
kobject_cleanup lib/kobject.c:689 [inline]
kobject_release lib/kobject.c:720 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x1fd/0x5b0 lib/kobject.c:737
rcu_do_batch kernel/rcu/tree.c:2535 [inline]
rcu_core+0x82b/0x16b0 kernel/rcu/tree.c:2809
handle_softirqs+0x219/0x8f0 kernel/softirq.c:554
__do_softirq kernel/softirq.c:588 [inline]
invoke_softirq kernel/softirq.c:428 [inline]
__irq_exit_rcu kernel/softirq.c:637 [inline]
irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1043
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702

Last potentially related work creation:
kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
__kasan_record_aux_stack+0xba/0xd0 mm/kasan/generic.c:541
__call_rcu_common.constprop.0+0x9a/0x790 kernel/rcu/tree.c:3072
br_dev_delete+0x99/0x1a0 net/bridge/br_if.c:386
br_net_exit_batch_rtnl+0x116/0x1f0 net/bridge/br.c:369
cleanup_net+0x54b/0xbf0 net/core/net_namespace.c:633
process_one_work+0x9c8/0x1b40 kernel/workqueue.c:3248
process_scheduled_works kernel/workqueue.c:3329 [inline]
worker_thread+0x6c8/0xf30 kernel/workqueue.c:3409
kthread+0x2c4/0x3a0 kernel/kthread.c:389
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

The buggy address belongs to the object at ffff888071d6d000
which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 0 bytes inside of
freed 1024-byte region [ffff888071d6d000, ffff888071d6d400)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x71d68
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffefff(slab)
raw: 00fff00000000040 ffff888015441dc0 0000000000000000 dead000000000001
raw: 0000000000000000 0000000080100010 00000001ffffefff 0000000000000000
head: 00fff00000000040 ffff888015441dc0 0000000000000000 dead000000000001
head: 0000000000000000 0000000080100010 00000001ffffefff 0000000000000000
head: 00fff00000000003 ffffea0001c75a01 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 1096, tgid 1096 (kworker/u8:8), ts 118658703752, free_ts 118015241497
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1468
prep_new_page mm/page_alloc.c:1476 [inline]
get_page_from_freelist+0x136a/0x2e50 mm/page_alloc.c:3420
__alloc_pages_noprof+0x22b/0x2460 mm/page_alloc.c:4678
__alloc_pages_node_noprof include/linux/gfp.h:269 [inline]
alloc_pages_node_noprof include/linux/gfp.h:296 [inline]
alloc_slab_page+0x56/0x110 mm/slub.c:2265
allocate_slab mm/slub.c:2428 [inline]
new_slab+0x84/0x260 mm/slub.c:2481
___slab_alloc+0xdac/0x1870 mm/slub.c:3667
__slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3757
__slab_alloc_node mm/slub.c:3810 [inline]
slab_alloc_node mm/slub.c:3989 [inline]
__do_kmalloc_node mm/slub.c:4121 [inline]
kmalloc_node_track_caller_noprof+0x355/0x430 mm/slub.c:4142
kmalloc_reserve+0xef/0x2c0 net/core/skbuff.c:597
__alloc_skb+0x164/0x380 net/core/skbuff.c:666
alloc_skb include/linux/skbuff.h:1308 [inline]
nlmsg_new include/net/netlink.h:1015 [inline]
inet6_rt_notify+0xf0/0x2b0 net/ipv6/route.c:6182
fib6_del_route net/ipv6/ip6_fib.c:2012 [inline]
fib6_del+0xf08/0x17b0 net/ipv6/ip6_fib.c:2047
fib6_clean_node+0x426/0x5b0 net/ipv6/ip6_fib.c:2209
fib6_walk_continue+0x452/0x8d0 net/ipv6/ip6_fib.c:2131
fib6_walk+0x182/0x370 net/ipv6/ip6_fib.c:2179
fib6_clean_tree+0xd7/0x120 net/ipv6/ip6_fib.c:2259
page last free pid 5094 tgid 5094 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1088 [inline]
free_unref_page+0x64a/0xe40 mm/page_alloc.c:2583
__put_partials+0x14c/0x170 mm/slub.c:2995
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x4e/0x140 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x192/0x1e0 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:322
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook mm/slub.c:3941 [inline]
slab_alloc_node mm/slub.c:4001 [inline]
__do_kmalloc_node mm/slub.c:4121 [inline]
__kmalloc_node_noprof+0x1c7/0x440 mm/slub.c:4129
kmalloc_node_noprof include/linux/slab.h:681 [inline]
__vmalloc_area_node mm/vmalloc.c:3628 [inline]
__vmalloc_node_range_noprof+0x401/0x1520 mm/vmalloc.c:3823
__vmalloc_node_noprof mm/vmalloc.c:3888 [inline]
vzalloc_noprof+0x6b/0x90 mm/vmalloc.c:3961
alloc_counters net/ipv6/netfilter/ip6_tables.c:815 [inline]
copy_entries_to_user net/ipv6/netfilter/ip6_tables.c:837 [inline]
get_entries net/ipv6/netfilter/ip6_tables.c:1039 [inline]
do_ip6t_get_ctl+0x6ba/0xaf0 net/ipv6/netfilter/ip6_tables.c:1677
nf_getsockopt+0x7c/0xe0 net/netfilter/nf_sockopt.c:116
ipv6_getsockopt+0x1fd/0x2c0 net/ipv6/ipv6_sockglue.c:1494
tcp_getsockopt+0xa1/0x100 net/ipv4/tcp.c:4406
do_sock_getsockopt+0x2e8/0x760 net/socket.c:2374
__sys_getsockopt+0x1a1/0x270 net/socket.c:2403
__do_sys_getsockopt net/socket.c:2413 [inline]
__se_sys_getsockopt net/socket.c:2410 [inline]
__x64_sys_getsockopt+0xbd/0x160 net/socket.c:2410
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83

Memory state around the buggy address:
ffff888071d6cf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888071d6cf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888071d6d000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888071d6d080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888071d6d100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
------------[ cut here ]------------
UBSAN: array-index-out-of-bounds in kernel/locking/qspinlock.c:131:9
index 15933 is out of range for type 'long unsigned int [8]'
CPU: 1 PID: 9699 Comm: syz.5.1232 Tainted: G B 6.10.0-rc5-syzkaller-00021-g24ca36a562d6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x16c/0x1f0 lib/dump_stack.c:114
ubsan_epilogue lib/ubsan.c:231 [inline]
__ubsan_handle_out_of_bounds+0x110/0x150 lib/ubsan.c:429
decode_tail kernel/locking/qspinlock.c:131 [inline]
__pv_queued_spin_lock_slowpath+0xcb2/0xcc0 kernel/locking/qspinlock.c:468
pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:584 [inline]
queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline]
queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
do_raw_spin_lock+0x210/0x2c0 kernel/locking/spinlock_debug.c:116
spin_lock include/linux/spinlock.h:351 [inline]
br_multicast_port_group_expired+0x70/0x550 net/bridge/br_multicast.c:865
call_timer_fn+0x1a3/0x610 kernel/time/timer.c:1792
expire_timers kernel/time/timer.c:1843 [inline]
__run_timers+0x74b/0xaf0 kernel/time/timer.c:2417
__run_timer_base kernel/time/timer.c:2428 [inline]
__run_timer_base kernel/time/timer.c:2421 [inline]
run_timer_base+0x111/0x190 kernel/time/timer.c:2437
run_timer_softirq+0x1a/0x40 kernel/time/timer.c:2447
handle_softirqs+0x219/0x8f0 kernel/softirq.c:554
__do_softirq kernel/softirq.c:588 [inline]
invoke_softirq kernel/softirq.c:428 [inline]
__irq_exit_rcu kernel/softirq.c:637 [inline]
irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1043
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:finish_task_switch.isra.0+0x220/0xcc0 kernel/sched/core.c:5282
Code: a9 0a 00 00 44 8b 0d 17 b0 85 0e 45 85 c9 0f 85 c0 01 00 00 48 89 df e8 ae f
----------------
Code disassembly (best guess):
0: a9 0a 00 00 44 test $0x4400000a,%eax
5: 8b 0d 17 b0 85 0e mov 0xe85b017(%rip),%ecx # 0xe85b022
b: 45 85 c9 test %r9d,%r9d
e: 0f 85 c0 01 00 00 jne 0x1d4
14: 48 89 df mov %rbx,%rdi
17: e8 ae f8 ff ff call 0xfffff8ca
1c: e8 b9 da 36 00 call 0x36dada
21: fb sti
22: 65 48 8b 1d a0 3d a4 mov %gs:0x7ea43da0(%rip),%rbx # 0x7ea43dca
29: 7e
* 2a: 48 8d bb f8 15 00 00 lea 0x15f8(%rbx),%rdi <-- trapping instruction
31: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
38: fc ff df
3b: 48 89 fa mov %rdi,%rdx
3e: 48 rex.W
3f: c1 .byte 0xc1


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup