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BUG: KASAN: slab-use-after-free in hlist_add_head include/linux/list.h:1026 [inline]
BUG: KASAN: slab-use-after-free in udp_tunnel_update_gro_lookup+0xfe/0x2c0 net/ipv4/udp_offload.c:60
Write of size 8 at addr ffff888028780730 by task syz.2.194/6671

CPU: 0 UID: 0 PID: 6671 Comm: syz.2.194 Not tainted 6.14.0-rc7-syzkaller-01431-gbfc17c165835 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0x16e/0x5b0 mm/kasan/report.c:521
 kasan_report+0x143/0x180 mm/kasan/report.c:634
 hlist_add_head include/linux/list.h:1026 [inline]
 udp_tunnel_update_gro_lookup+0xfe/0x2c0 net/ipv4/udp_offload.c:60
 rxrpc_open_socket net/rxrpc/local_object.c:197 [inline]
 rxrpc_lookup_local+0xea5/0x1890 net/rxrpc/local_object.c:293
 rxrpc_sendmsg+0x323/0x5f0 net/rxrpc/af_rxrpc.c:608
 sock_sendmsg_nosec net/socket.c:709 [inline]
 __sock_sendmsg+0x221/0x270 net/socket.c:724
 ____sys_sendmsg+0x53a/0x860 net/socket.c:2564
 ___sys_sendmsg net/socket.c:2618 [inline]
 __sys_sendmmsg+0x36a/0x720 net/socket.c:2707
 __do_sys_sendmmsg net/socket.c:2734 [inline]
 __se_sys_sendmmsg net/socket.c:2731 [inline]
 __x64_sys_sendmmsg+0xa0/0xb0 net/socket.c:2731
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7f94d8d169
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f7f95b70038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007f7f94fa5fa0 RCX: 00007f7f94d8d169
RDX: 0000000000000001 RSI: 0000200000000180 RDI: 0000000000000003
RBP: 00007f7f94e0e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f7f94fa5fa0 R15: 00007ffd005f8ca8
 </TASK>

Allocated by task 6559:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:319 [inline]
 __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:345
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4115 [inline]
 slab_alloc_node mm/slub.c:4164 [inline]
 kmem_cache_alloc_noprof+0x1d9/0x380 mm/slub.c:4171
 sk_prot_alloc+0x58/0x210 net/core/sock.c:2190
 sk_alloc+0x3e/0x370 net/core/sock.c:2249
 inet_create+0x648/0xea0 net/ipv4/af_inet.c:326
 __sock_create+0x4c0/0xa30 net/socket.c:1539
 inet_ctl_sock_create+0xc2/0x250 net/ipv4/af_inet.c:1637
 igmp_net_init+0xbb/0x150 net/ipv4/igmp.c:3125
 ops_init+0x349/0x5b0 net/core/net_namespace.c:138
 setup_net+0x287/0x9e0 net/core/net_namespace.c:362
 copy_net_ns+0x33f/0x570 net/core/net_namespace.c:516
 create_new_namespaces+0x425/0x7b0 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x124/0x180 kernel/nsproxy.c:228
 ksys_unshare+0x57d/0xa70 kernel/fork.c:3342
 __do_sys_unshare kernel/fork.c:3413 [inline]
 __se_sys_unshare kernel/fork.c:3411 [inline]
 __x64_sys_unshare+0x38/0x40 kernel/fork.c:3411
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 54:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2353 [inline]
 slab_free mm/slub.c:4609 [inline]
 kmem_cache_free+0x195/0x410 mm/slub.c:4711
 sk_prot_free net/core/sock.c:2230 [inline]
 __sk_destruct+0x4fd/0x690 net/core/sock.c:2327
 inet_release+0x17d/0x200 net/ipv4/af_inet.c:435
 __sock_release net/socket.c:647 [inline]
 sock_release+0x82/0x150 net/socket.c:675
 ops_exit_list net/core/net_namespace.c:172 [inline]
 cleanup_net+0x812/0xd60 net/core/net_namespace.c:652
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xabe/0x18e0 kernel/workqueue.c:3319
 worker_thread+0x870/0xd30 kernel/workqueue.c:3400
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

The buggy address belongs to the object at ffff888028780000
 which belongs to the cache UDP of size 1856
The buggy address is located 1840 bytes inside of
 freed 1856-byte region [ffff888028780000, ffff888028780740)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8880287807c0 pfn:0x28780
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888029bbc801
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff888143adaa00 dead000000000122 0000000000000000
raw: ffff8880287807c0 000000008010000f 00000000f5000000 ffff888029bbc801
head: 00fff00000000040 ffff888143adaa00 dead000000000122 0000000000000000
head: ffff8880287807c0 000000008010000f 00000000f5000000 ffff888029bbc801
head: 00fff00000000003 ffffea0000a1e001 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 6044, tgid 6041 (syz.2.22), ts 93031733609, free_ts 90734119705
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1551
 prep_new_page mm/page_alloc.c:1559 [inline]
 get_page_from_freelist+0x365c/0x37a0 mm/page_alloc.c:3477
 __alloc_frozen_pages_noprof+0x292/0x710 mm/page_alloc.c:4740
 alloc_pages_mpol+0x311/0x660 mm/mempolicy.c:2270
 alloc_slab_page mm/slub.c:2423 [inline]
 allocate_slab+0x8f/0x3a0 mm/slub.c:2587
 new_slab mm/slub.c:2640 [inline]
 ___slab_alloc+0xc27/0x14a0 mm/slub.c:3826
 __slab_alloc+0x58/0xa0 mm/slub.c:3916
 __slab_alloc_node mm/slub.c:3991 [inline]
 slab_alloc_node mm/slub.c:4152 [inline]
 kmem_cache_alloc_noprof+0x268/0x380 mm/slub.c:4171
 sk_prot_alloc+0x58/0x210 net/core/sock.c:2190
 sk_alloc+0x3e/0x370 net/core/sock.c:2249
 inet_create+0x648/0xea0 net/ipv4/af_inet.c:326
 __sock_create+0x4c0/0xa30 net/socket.c:1539
 sock_create net/socket.c:1597 [inline]
 __sys_socket_create net/socket.c:1634 [inline]
 __sys_socket+0x150/0x3c0 net/socket.c:1681
 __do_sys_socket net/socket.c:1695 [inline]
 __se_sys_socket net/socket.c:1693 [inline]
 __x64_sys_socket+0x7a/0x90 net/socket.c:1693
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5884 tgid 5884 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1127 [inline]
 free_frozen_pages+0xe0d/0x10e0 mm/page_alloc.c:2660
 kasan_depopulate_vmalloc_pte+0x74/0x90 mm/kasan/shadow.c:408
 apply_to_pte_range mm/memory.c:2910 [inline]
 apply_to_pmd_range mm/memory.c:2954 [inline]
 apply_to_pud_range mm/memory.c:2990 [inline]
 apply_to_p4d_range mm/memory.c:3026 [inline]
 __apply_to_page_range+0x806/0xde0 mm/memory.c:3062
 kasan_release_vmalloc+0xa5/0xd0 mm/kasan/shadow.c:529
 kasan_release_vmalloc_node mm/vmalloc.c:2196 [inline]
 purge_vmap_node+0x22f/0x8d0 mm/vmalloc.c:2213
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xabe/0x18e0 kernel/workqueue.c:3319
 worker_thread+0x870/0xd30 kernel/workqueue.c:3400
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Memory state around the buggy address:
 ffff888028780600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888028780680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888028780700: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
                                     ^
 ffff888028780780: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
 ffff888028780800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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