================================================================== BUG: KASAN: use-after-free in instrument_atomic_read_write include/linux/instrumented.h:102 [inline] BUG: KASAN: use-after-free in test_and_set_bit include/asm-generic/bitops/instrumented-atomic.h:71 [inline] BUG: KASAN: use-after-free in l2tp_session_delete+0x27/0x520 net/l2tp/l2tp_core.c:1561 Write of size 8 at addr ffff888109782808 by task kworker/u4:1/10 CPU: 1 PID: 10 Comm: kworker/u4:1 Not tainted 6.1.124-syzkaller-00008-gccc915784332 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 Workqueue: l2tp l2tp_tunnel_del_work Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x151/0x1b7 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:316 [inline] print_report+0x158/0x4e0 mm/kasan/report.c:427 kasan_report+0x13c/0x170 mm/kasan/report.c:531 kasan_check_range+0x294/0x2a0 mm/kasan/generic.c:189 __kasan_check_write+0x14/0x20 mm/kasan/shadow.c:37 instrument_atomic_read_write include/linux/instrumented.h:102 [inline] test_and_set_bit include/asm-generic/bitops/instrumented-atomic.h:71 [inline] l2tp_session_delete+0x27/0x520 net/l2tp/l2tp_core.c:1561 l2tp_tunnel_closeall net/l2tp/l2tp_core.c:1216 [inline] l2tp_tunnel_del_work+0x1f8/0x400 net/l2tp/l2tp_core.c:1256 process_one_work+0x73d/0xcb0 kernel/workqueue.c:2299 worker_thread+0xa60/0x1260 kernel/workqueue.c:2446 kthread+0x26d/0x300 kernel/kthread.c:386 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Allocated by task 1596: kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:52 kasan_save_alloc_info+0x1f/0x30 mm/kasan/generic.c:505 ____kasan_kmalloc mm/kasan/common.c:379 [inline] __kasan_kmalloc+0x9c/0xb0 mm/kasan/common.c:388 kasan_kmalloc include/linux/kasan.h:212 [inline] __do_kmalloc_node mm/slab_common.c:938 [inline] __kmalloc+0xb4/0x1e0 mm/slab_common.c:951 kmalloc include/linux/slab.h:568 [inline] kzalloc include/linux/slab.h:699 [inline] l2tp_session_create+0x38/0xbe0 net/l2tp/l2tp_core.c:1597 pppol2tp_connect+0xc5d/0x1690 net/l2tp/l2tp_ppp.c:781 __sys_connect_file net/socket.c:2001 [inline] __sys_connect+0x2c9/0x300 net/socket.c:2018 __do_sys_connect net/socket.c:2028 [inline] __se_sys_connect net/socket.c:2025 [inline] __x64_sys_connect+0x7a/0x90 net/socket.c:2025 x64_sys_call+0x14e/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:43 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 Freed by task 425: kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:52 kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:516 ____kasan_slab_free+0x131/0x180 mm/kasan/common.c:241 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:249 kasan_slab_free include/linux/kasan.h:178 [inline] slab_free_hook mm/slub.c:1745 [inline] slab_free_freelist_hook mm/slub.c:1771 [inline] slab_free mm/slub.c:3686 [inline] __kmem_cache_free+0x21d/0x410 mm/slub.c:3702 kfree+0x7a/0xf0 mm/slab_common.c:990 l2tp_session_free net/l2tp/l2tp_core.c:168 [inline] l2tp_session_dec_refcount+0xa9/0x1b0 net/l2tp/l2tp_core.c:205 pppol2tp_session_destruct+0xaf/0xf0 net/l2tp/l2tp_ppp.c:418 __sk_destruct+0x56/0x5c0 net/core/sock.c:2148 sk_destruct net/core/sock.c:2193 [inline] __sk_free+0x36c/0x470 net/core/sock.c:2204 sk_free+0x51/0x80 net/core/sock.c:2215 sock_put include/net/sock.h:2049 [inline] pppol2tp_put_sk+0x77/0xb0 net/l2tp/l2tp_ppp.c:401 rcu_do_batch+0x552/0xbe0 kernel/rcu/tree.c:2297 rcu_core+0x502/0xf40 kernel/rcu/tree.c:2557 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2574 handle_softirqs+0x1db/0x650 kernel/softirq.c:617 __do_softirq+0xb/0xd kernel/softirq.c:655 Last potentially related work creation: kasan_save_stack+0x3b/0x60 mm/kasan/common.c:45 __kasan_record_aux_stack+0xb4/0xc0 mm/kasan/generic.c:486 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:496 __call_rcu_common kernel/rcu/tree.c:2807 [inline] call_rcu+0xdc/0x10f0 kernel/rcu/tree.c:2926 pppol2tp_release+0x20f/0x2d0 net/l2tp/l2tp_ppp.c:457 __sock_release net/socket.c:652 [inline] sock_close+0xdf/0x270 net/socket.c:1390 __fput+0x1e5/0x870 fs/file_table.c:320 ____fput+0x15/0x20 fs/file_table.c:348 task_work_run+0x24d/0x2e0 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0x94/0xa0 kernel/entry/common.c:177 exit_to_user_mode_prepare+0x5a/0xa0 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x26/0x130 kernel/entry/common.c:303 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 The buggy address belongs to the object at ffff888109782800 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 8 bytes inside of 512-byte region [ffff888109782800, ffff888109782a00) The buggy address belongs to the physical page: page:ffffea000425e000 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x109780 head:ffffea000425e000 order:2 compound_mapcount:0 compound_pincount:0 flags: 0x4000000000010200(slab|head|zone=1) raw: 4000000000010200 0000000000000000 dead000000000001 ffff888100042f00 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Unmovable, gfp_mask 0x1d2a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 425, tgid 425 (kworker/1:6), ts 193548606212, free_ts 175214936190 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x213/0x220 mm/page_alloc.c:2637 prep_new_page+0x1b/0x110 mm/page_alloc.c:2644 get_page_from_freelist+0x3a98/0x3b10 mm/page_alloc.c:4539 __alloc_pages+0x234/0x610 mm/page_alloc.c:5837 alloc_slab_page+0x6c/0xf0 allocate_slab mm/slub.c:1962 [inline] new_slab+0x90/0x3e0 mm/slub.c:2015 ___slab_alloc+0x6f9/0xb80 mm/slub.c:3203 __slab_alloc+0x5d/0xa0 mm/slub.c:3302 slab_alloc_node mm/slub.c:3387 [inline] __kmem_cache_alloc_node+0x207/0x2a0 mm/slub.c:3462 __do_kmalloc_node mm/slab_common.c:937 [inline] __kmalloc_node_track_caller+0xa2/0x1e0 mm/slab_common.c:958 kmalloc_reserve net/core/skbuff.c:446 [inline] __alloc_skb+0x125/0x2d0 net/core/skbuff.c:515 alloc_skb include/linux/skbuff.h:1290 [inline] nlmsg_new include/net/netlink.h:991 [inline] fdb_notify+0x77/0x130 net/bridge/br_fdb.c:191 br_fdb_update+0x505/0x660 net/bridge/br_fdb.c:888 br_handle_frame_finish+0x41a/0x1660 net/bridge/br_input.c:124 nf_hook_bridge_pre net/bridge/br_input.c:282 [inline] br_handle_frame+0x984/0x1070 net/bridge/br_input.c:406 __netif_receive_skb_core+0x1264/0x43d0 net/core/dev.c:5448 page last free stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] free_pages_prepare mm/page_alloc.c:1545 [inline] free_pcp_prepare mm/page_alloc.c:1619 [inline] free_unref_page_prepare+0x9f1/0xa00 mm/page_alloc.c:3581 free_unref_page+0xb2/0x5c0 mm/page_alloc.c:3677 free_the_page mm/page_alloc.c:830 [inline] __free_pages+0x61/0xf0 mm/page_alloc.c:5926 __free_slab+0xce/0x1a0 mm/slub.c:2039 free_slab mm/slub.c:2054 [inline] discard_slab mm/slub.c:2060 [inline] __unfreeze_partials+0x165/0x1a0 mm/slub.c:2609 put_cpu_partial+0xa9/0x100 mm/slub.c:2685 __slab_free+0x1c8/0x280 mm/slub.c:3563 do_slab_free mm/slub.c:3640 [inline] ___cache_free+0xc6/0xd0 mm/slub.c:3696 qlink_free mm/kasan/quarantine.c:168 [inline] qlist_free_all+0xc5/0x140 mm/kasan/quarantine.c:187 kasan_quarantine_reduce+0x15a/0x180 mm/kasan/quarantine.c:294 __kasan_slab_alloc+0x24/0x80 mm/kasan/common.c:310 kasan_slab_alloc include/linux/kasan.h:202 [inline] slab_post_alloc_hook+0x53/0x2c0 mm/slab.h:768 slab_alloc_node mm/slub.c:3421 [inline] slab_alloc mm/slub.c:3431 [inline] __kmem_cache_alloc_lru mm/slub.c:3438 [inline] kmem_cache_alloc+0x175/0x320 mm/slub.c:3447 kmem_cache_zalloc include/linux/slab.h:689 [inline] lsm_inode_alloc security/security.c:596 [inline] security_inode_alloc+0x29/0x120 security/security.c:1040 inode_init_always+0x720/0x970 fs/inode.c:232 alloc_inode fs/inode.c:268 [inline] new_inode_pseudo+0x98/0x1d0 fs/inode.c:1063 Memory state around the buggy address: ffff888109782700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888109782780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888109782800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888109782880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888109782900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================