================================================================== 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 ffff888034c8d4b0 by task syz.2.1100/9744 CPU: 0 UID: 0 PID: 9744 Comm: syz.2.1100 Not tainted 6.14.0-rc6-syzkaller-01313-g23c9ff659140 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __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 l2tp_tunnel_register+0xf9a/0x19f0 net/l2tp/l2tp_core.c:1679 pppol2tp_tunnel_get net/l2tp/l2tp_ppp.c:672 [inline] pppol2tp_connect+0x925/0x1960 net/l2tp/l2tp_ppp.c:720 __sys_connect_file net/socket.c:2036 [inline] __sys_connect+0x288/0x2d0 net/socket.c:2055 __do_sys_connect net/socket.c:2061 [inline] __se_sys_connect net/socket.c:2058 [inline] __x64_sys_connect+0x7a/0x90 net/socket.c:2058 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: 0033:0x7fceee38d169 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:00007fceef1a3038 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: ffffffffffffffda RBX: 00007fceee5a6160 RCX: 00007fceee38d169 RDX: 0000000000000032 RSI: 0000400000000240 RDI: 000000000000000d RBP: 00007fceee40e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007fceee5a6160 R15: 00007ffc6f17f868 Allocated by task 9682: 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 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 Freed by task 9683: 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_close+0xbc/0x240 net/socket.c:1389 __fput+0x3e9/0x9f0 fs/file_table.c:464 task_work_run+0x24f/0x310 kernel/task_work.c:227 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0xa2a/0x28e0 kernel/exit.c:938 do_group_exit+0x207/0x2c0 kernel/exit.c:1087 get_signal+0x168c/0x1720 kernel/signal.c:3036 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0xce/0x340 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888034c8cd80 which belongs to the cache UDP of size 1856 The buggy address is located 1840 bytes inside of freed 1856-byte region [ffff888034c8cd80, ffff888034c8d4c0) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x34c88 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 memcg:ffff888078ce0901 anon flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff888022ab78c0 0000000000000000 0000000000000001 raw: 0000000000000000 0000000080100010 00000000f5000000 ffff888078ce0901 head: 00fff00000000040 ffff888022ab78c0 0000000000000000 0000000000000001 head: 0000000000000000 0000000080100010 00000000f5000000 ffff888078ce0901 head: 00fff00000000003 ffffea0000d32201 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 5504, tgid 5504 (dhcpcd), ts 43896968336, free_ts 43764340794 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 5499 tgid 5499 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 discard_slab mm/slub.c:2684 [inline] __put_partials+0x160/0x1c0 mm/slub.c:3153 put_cpu_partial+0x17c/0x250 mm/slub.c:3228 __slab_free+0x290/0x380 mm/slub.c:4479 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286 __kasan_kmalloc+0x23/0xb0 mm/kasan/common.c:385 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4294 [inline] __kmalloc_noprof+0x285/0x4c0 mm/slub.c:4306 kmalloc_noprof include/linux/slab.h:905 [inline] tomoyo_add_entry security/tomoyo/common.c:2132 [inline] tomoyo_supervisor+0xe57/0x1860 security/tomoyo/common.c:2204 tomoyo_audit_env_log security/tomoyo/environ.c:36 [inline] tomoyo_env_perm+0x178/0x210 security/tomoyo/environ.c:63 tomoyo_environ security/tomoyo/domain.c:672 [inline] tomoyo_find_next_domain+0x1495/0x1dd0 security/tomoyo/domain.c:888 tomoyo_bprm_check_security+0x117/0x180 security/tomoyo/tomoyo.c:102 security_bprm_check+0x86/0x250 security/security.c:1302 search_binary_handler fs/exec.c:1765 [inline] exec_binprm fs/exec.c:1807 [inline] bprm_execve+0x8d3/0x1430 fs/exec.c:1859 do_execveat_common+0x57f/0x710 fs/exec.c:1966 do_execve fs/exec.c:2040 [inline] __do_sys_execve fs/exec.c:2116 [inline] __se_sys_execve fs/exec.c:2111 [inline] __x64_sys_execve+0x92/0xb0 fs/exec.c:2111 Memory state around the buggy address: ffff888034c8d380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888034c8d400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888034c8d480: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ^ ffff888034c8d500: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb ffff888034c8d580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================