==================================================================
BUG: KASAN: slab-use-after-free in instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
BUG: KASAN: slab-use-after-free in test_and_set_bit include/asm-generic/bitops/instrumented-atomic.h:71 [inline]
BUG: KASAN: slab-use-after-free in l2tp_session_delete+0x25/0x5c0 net/l2tp/l2tp_core.c:1595
Write of size 8 at addr ffff88802c54c008 by task kworker/u8:2/35

CPU: 0 PID: 35 Comm: kworker/u8:2 Not tainted 6.10.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Workqueue: l2tp l2tp_tunnel_del_work
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:488
 kasan_report+0x143/0x180 mm/kasan/report.c:601
 kasan_check_range+0x282/0x290 mm/kasan/generic.c:189
 instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
 test_and_set_bit include/asm-generic/bitops/instrumented-atomic.h:71 [inline]
 l2tp_session_delete+0x25/0x5c0 net/l2tp/l2tp_core.c:1595
 l2tp_tunnel_closeall net/l2tp/l2tp_core.c:1249 [inline]
 l2tp_tunnel_del_work+0x1f2/0x3b0 net/l2tp/l2tp_core.c:1289
 process_one_work kernel/workqueue.c:3248 [inline]
 process_scheduled_works+0xa2e/0x1830 kernel/workqueue.c:3329
 worker_thread+0x86d/0xd50 kernel/workqueue.c:3409
 kthread+0x2f2/0x390 kernel/kthread.c:389
 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Allocated by task 5873:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
 __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:387
 kasan_kmalloc include/linux/kasan.h:211 [inline]
 __do_kmalloc_node mm/slub.c:4123 [inline]
 __kmalloc_noprof+0x1f9/0x400 mm/slub.c:4136
 kmalloc_noprof include/linux/slab.h:664 [inline]
 kzalloc_noprof include/linux/slab.h:778 [inline]
 l2tp_session_create+0x3b/0xb20 net/l2tp/l2tp_core.c:1631
 pppol2tp_connect+0xc65/0x1750 net/l2tp/l2tp_ppp.c:781
 __sys_connect_file net/socket.c:2049 [inline]
 __sys_connect+0x2e1/0x310 net/socket.c:2066
 __do_sys_connect net/socket.c:2076 [inline]
 __se_sys_connect net/socket.c:2073 [inline]
 __x64_sys_connect+0x7a/0x90 net/socket.c:2073
 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 24:
 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:579
 poison_slab_object+0xe0/0x150 mm/kasan/common.c:240
 __kasan_slab_free+0x37/0x60 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:4438 [inline]
 kfree+0x149/0x360 mm/slub.c:4559
 __sk_destruct+0x5a/0x5f0 net/core/sock.c:2175
 rcu_do_batch kernel/rcu/tree.c:2535 [inline]
 rcu_core+0xaff/0x1830 kernel/rcu/tree.c:2809
 handle_softirqs+0x2c6/0x970 kernel/softirq.c:554
 run_ksoftirqd+0xca/0x130 kernel/softirq.c:928
 smpboot_thread_fn+0x546/0xa30 kernel/smpboot.c:164
 kthread+0x2f2/0x390 kernel/kthread.c:389
 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Last potentially related work creation:
 kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47
 __kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:541
 __call_rcu_common kernel/rcu/tree.c:3072 [inline]
 call_rcu+0x167/0xa70 kernel/rcu/tree.c:3176
 pppol2tp_release+0x24b/0x350 net/l2tp/l2tp_ppp.c:457
 __sock_release net/socket.c:659 [inline]
 sock_close+0xbe/0x240 net/socket.c:1421
 __fput+0x24c/0x8a0 fs/file_table.c:422
 task_work_run+0x251/0x310 kernel/task_work.c:180
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x168/0x360 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 ffff88802c54c000
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 8 bytes inside of
 freed 1024-byte region [ffff88802c54c000, ffff88802c54c400)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2c548
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffefff(slab)
raw: 00fff00000000040 ffff888015041dc0 ffffea0001fb0200 dead000000000002
raw: 0000000000000000 0000000000100010 00000001ffffefff 0000000000000000
head: 00fff00000000040 ffff888015041dc0 ffffea0001fb0200 dead000000000002
head: 0000000000000000 0000000000100010 00000001ffffefff 0000000000000000
head: 00fff00000000003 ffffea0000b15201 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 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5096, tgid 5096 (kworker/0:3), ts 82908348004, free_ts 82848479481
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1473
 prep_new_page mm/page_alloc.c:1481 [inline]
 get_page_from_freelist+0x2e4c/0x2f10 mm/page_alloc.c:3425
 __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4683
 __alloc_pages_node_noprof include/linux/gfp.h:269 [inline]
 alloc_pages_node_noprof include/linux/gfp.h:296 [inline]
 alloc_slab_page+0x5f/0x120 mm/slub.c:2265
 allocate_slab+0x5a/0x2f0 mm/slub.c:2428
 new_slab mm/slub.c:2481 [inline]
 ___slab_alloc+0xcd1/0x14b0 mm/slub.c:3667
 __slab_alloc+0x58/0xa0 mm/slub.c:3757
 __slab_alloc_node mm/slub.c:3810 [inline]
 slab_alloc_node mm/slub.c:3990 [inline]
 __do_kmalloc_node mm/slub.c:4122 [inline]
 kmalloc_node_track_caller_noprof+0x281/0x440 mm/slub.c:4143
 kmalloc_reserve+0x111/0x2a0 net/core/skbuff.c:597
 __alloc_skb+0x1f3/0x440 net/core/skbuff.c:666
 alloc_skb include/linux/skbuff.h:1308 [inline]
 nlmsg_new include/net/netlink.h:1015 [inline]
 inet6_rt_notify+0xdf/0x290 net/ipv6/route.c:6182
 fib6_add_rt2node net/ipv6/ip6_fib.c:1266 [inline]
 fib6_add+0x1e33/0x4430 net/ipv6/ip6_fib.c:1495
 __ip6_ins_rt net/ipv6/route.c:1316 [inline]
 ip6_route_add+0x8b/0x160 net/ipv6/route.c:3859
 addrconf_prefix_route net/ipv6/addrconf.c:2485 [inline]
 addrconf_add_linklocal+0x61a/0xa30 net/ipv6/addrconf.c:3316
 addrconf_addr_gen+0x510/0xbb0
 addrconf_dev_config net/ipv6/addrconf.c:3491 [inline]
 addrconf_init_auto_addrs+0x96a/0xeb0 net/ipv6/addrconf.c:3569
page last free pid 5172 tgid 5172 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1093 [inline]
 free_unref_page+0xd22/0xea0 mm/page_alloc.c:2588
 discard_slab mm/slub.c:2527 [inline]
 __put_partials+0xeb/0x130 mm/slub.c:2995
 put_cpu_partial+0x17c/0x250 mm/slub.c:3070
 __slab_free+0x2ea/0x3d0 mm/slub.c:4308
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x9e/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:322
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slub.c:3940 [inline]
 slab_alloc_node mm/slub.c:4002 [inline]
 kmem_cache_alloc_noprof+0x135/0x2a0 mm/slub.c:4009
 getname_flags+0xbd/0x4f0 fs/namei.c:139
 vfs_fstatat+0x11c/0x190 fs/stat.c:303
 __do_sys_newfstatat fs/stat.c:468 [inline]
 __se_sys_newfstatat fs/stat.c:462 [inline]
 __x64_sys_newfstatat+0x125/0x1b0 fs/stat.c:462
 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

Memory state around the buggy address:
 ffff88802c54bf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88802c54bf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88802c54c000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff88802c54c080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88802c54c100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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