syzbot

device bridge_slave_0 left promiscuous mode
bridge0: port 1(bridge_slave_0) entered disabled state
device veth1_macvtap left promiscuous mode
device veth0_vlan left promiscuous mode
==================================================================
BUG: KASAN: use-after-free in instrument_atomic_read include/linux/instrumented.h:71 [inline]
BUG: KASAN: use-after-free in atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline]
BUG: KASAN: use-after-free in refcount_read include/linux/refcount.h:147 [inline]
BUG: KASAN: use-after-free in tcp_metrics_flush_all+0xd3/0x210 net/ipv4/tcp_metrics.c:909
Read of size 4 at addr ffff88812623a08c by task kworker/u4:124/11318

CPU: 0 PID: 11318 Comm: kworker/u4:124 Tainted: G        W         5.15.185-syzkaller-00071-g79bd7c447241 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:88
 dump_stack_lvl+0xee/0x150 lib/dump_stack.c:106
 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:427 [inline]
 kasan_report+0xf1/0x140 mm/kasan/report.c:444
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x280/0x290 mm/kasan/generic.c:189
 __kasan_check_read+0x11/0x20 mm/kasan/shadow.c:31
 instrument_atomic_read include/linux/instrumented.h:71 [inline]
 atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline]
 refcount_read include/linux/refcount.h:147 [inline]
 tcp_metrics_flush_all+0xd3/0x210 net/ipv4/tcp_metrics.c:909
 tcp_net_metrics_exit_batch+0x10/0x20 net/ipv4/tcp_metrics.c:1036
 ops_exit_list net/core/net_namespace.c:177 [inline]
 cleanup_net+0x602/0xad0 net/core/net_namespace.c:599
 process_one_work+0x6be/0xba0 kernel/workqueue.c:2325
 worker_thread+0xa59/0x1200 kernel/workqueue.c:2472
 kthread+0x411/0x500 kernel/kthread.c:337
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

Allocated by task 281:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:45 [inline]
 set_alloc_info mm/kasan/common.c:433 [inline]
 __kasan_slab_alloc+0xbd/0xf0 mm/kasan/common.c:466
 kasan_slab_alloc include/linux/kasan.h:217 [inline]
 slab_post_alloc_hook+0x4f/0x2b0 mm/slab.h:550
 slab_alloc_node mm/slub.c:3240 [inline]
 slab_alloc mm/slub.c:3250 [inline]
 kmem_cache_alloc+0xf7/0x260 mm/slub.c:3255
 kmem_cache_zalloc include/linux/slab.h:737 [inline]
 net_alloc net/core/net_namespace.c:408 [inline]
 copy_net_ns+0x145/0x5c0 net/core/net_namespace.c:463
 create_new_namespaces+0x3a2/0x660 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x120/0x170 kernel/nsproxy.c:226
 ksys_unshare+0x4ac/0x7b0 kernel/fork.c:3242
 __do_sys_unshare kernel/fork.c:3316 [inline]
 __se_sys_unshare kernel/fork.c:3314 [inline]
 __x64_sys_unshare+0x38/0x40 kernel/fork.c:3314
 x64_sys_call+0x442/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:273
 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 11318:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4a/0x70 mm/kasan/common.c:45
 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370
 ____kasan_slab_free+0x125/0x160 mm/kasan/common.c:365
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:373
 kasan_slab_free include/linux/kasan.h:193 [inline]
 slab_free_hook mm/slub.c:1723 [inline]
 slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1749
 slab_free mm/slub.c:3521 [inline]
 kmem_cache_free+0x100/0x320 mm/slub.c:3539
 net_free net/core/net_namespace.c:437 [inline]
 cleanup_net+0xa2d/0xad0 net/core/net_namespace.c:620
 process_one_work+0x6be/0xba0 kernel/workqueue.c:2325
 worker_thread+0xa59/0x1200 kernel/workqueue.c:2472
 kthread+0x411/0x500 kernel/kthread.c:337
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

Last potentially related work creation:
 kasan_save_stack+0x3a/0x60 mm/kasan/common.c:38
 __kasan_record_aux_stack+0xd2/0x100 mm/kasan/generic.c:348
 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358
 insert_work+0x51/0x310 kernel/workqueue.c:1373
 __queue_work+0x8e5/0xc60 kernel/workqueue.c:1539
 queue_work_on+0xd2/0x140 kernel/workqueue.c:1566
 queue_work include/linux/workqueue.h:510 [inline]
 schedule_work include/linux/workqueue.h:571 [inline]
 xfrm_hash_grow_check+0xd7/0x140 net/xfrm/xfrm_state.c:1024
 xfrm_state_find+0x26a0/0x2a70 net/xfrm/xfrm_state.c:1184
 xfrm_tmpl_resolve_one net/xfrm/xfrm_policy.c:2396 [inline]
 xfrm_tmpl_resolve net/xfrm/xfrm_policy.c:2441 [inline]
 xfrm_resolve_and_create_bundle+0x626/0x28d0 net/xfrm/xfrm_policy.c:2734
 xfrm_lookup_with_ifid+0xa3e/0x2120 net/xfrm/xfrm_policy.c:3068
 xfrm_lookup net/xfrm/xfrm_policy.c:3197 [inline]
 xfrm_lookup_route+0x3c/0x170 net/xfrm/xfrm_policy.c:3208
 ip6_dst_lookup_flow+0x9b/0xc0 net/ipv6/ip6_output.c:1238
 rawv6_sendmsg+0xc07/0x16d0 net/ipv6/raw.c:933
 inet_sendmsg+0xa5/0xc0 net/ipv4/af_inet.c:830
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 ____sys_sendmsg+0x5a2/0x8c0 net/socket.c:2436
 ___sys_sendmsg+0x1f0/0x260 net/socket.c:2490
 __sys_sendmmsg+0x278/0x480 net/socket.c:2576
 __do_sys_sendmmsg net/socket.c:2605 [inline]
 __se_sys_sendmmsg net/socket.c:2602 [inline]
 __x64_sys_sendmmsg+0xa0/0xb0 net/socket.c:2602
 x64_sys_call+0x6c6/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:308
 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 ffff88812623a000
 which belongs to the cache net_namespace of size 3968
The buggy address is located 140 bytes inside of
 3968-byte region [ffff88812623a000, ffff88812623af80)
The buggy address belongs to the page:
page:ffffea0004988e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88812623c000 pfn:0x126238
head:ffffea0004988e00 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head|zone=1)
raw: 4000000000010200 ffffea0004d4a808 ffffea00043d2e08 ffff8881001c5680
raw: ffff88812623c000 0000000000080001 00000001ffffffff 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 281, ts 25602507684, free_ts 0
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x192/0x1b0 mm/page_alloc.c:2605
 prep_new_page+0x1c/0x110 mm/page_alloc.c:2611
 get_page_from_freelist+0x2cc5/0x2d50 mm/page_alloc.c:4485
 __alloc_pages+0x18f/0x440 mm/page_alloc.c:5795
 alloc_slab_page mm/slub.c:-1 [inline]
 allocate_slab mm/slub.c:1932 [inline]
 new_slab+0xa1/0x4d0 mm/slub.c:1995
 ___slab_alloc+0x381/0x810 mm/slub.c:3028
 __slab_alloc+0x49/0x90 mm/slub.c:3115
 slab_alloc_node mm/slub.c:3206 [inline]
 slab_alloc mm/slub.c:3250 [inline]
 kmem_cache_alloc+0x138/0x260 mm/slub.c:3255
 kmem_cache_zalloc include/linux/slab.h:737 [inline]
 net_alloc net/core/net_namespace.c:408 [inline]
 copy_net_ns+0x145/0x5c0 net/core/net_namespace.c:463
 create_new_namespaces+0x3a2/0x660 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x120/0x170 kernel/nsproxy.c:226
 ksys_unshare+0x4ac/0x7b0 kernel/fork.c:3242
 __do_sys_unshare kernel/fork.c:3316 [inline]
 __se_sys_unshare kernel/fork.c:3314 [inline]
 __x64_sys_unshare+0x38/0x40 kernel/fork.c:3314
 x64_sys_call+0x442/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:273
 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
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888126239f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88812623a000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88812623a080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff88812623a100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88812623a180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================