==================================================================
BUG: KASAN: slab-use-after-free in rxrpc_destroy_all_peers+0x1ce/0x1d0 net/rxrpc/peer_object.c:461
Read of size 8 at addr ffff8880572e4420 by task kworker/u8:31/6440

CPU: 0 UID: 0 PID: 6440 Comm: kworker/u8:31 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x13d/0x4b0 mm/kasan/report.c:482
 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
 rxrpc_destroy_all_peers+0x1ce/0x1d0 net/rxrpc/peer_object.c:461
 rxrpc_exit_net+0x83/0xc0 net/rxrpc/net_ns.c:114
 ops_exit_list net/core/net_namespace.c:200 [inline]
 ops_undo_list+0x2ee/0xab0 net/core/net_namespace.c:253
 cleanup_net+0x499/0x920 net/core/net_namespace.c:706
 process_one_work+0xac7/0x1b10 kernel/workqueue.c:3387
 process_scheduled_works kernel/workqueue.c:3470 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3551
 kthread+0x373/0x450 kernel/kthread.c:436
 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 10019:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x2f8/0x6d0 mm/slub.c:5563
 _kmalloc_noprof include/linux/slab.h:991 [inline]
 _kzalloc_noprof include/linux/slab.h:1312 [inline]
 rxrpc_alloc_peer+0xa7/0x400 net/rxrpc/peer_object.c:229
 rxrpc_create_peer net/rxrpc/peer_object.c:293 [inline]
 rxrpc_lookup_peer+0x168/0x680 net/rxrpc/peer_object.c:354
 rxrpc_kernel_lookup_peer+0xa8/0xe0 net/rxrpc/af_rxrpc.c:285
 afs_merge_fs_addr6+0x186/0x460 fs/afs/addr_list.c:344
 afs_parse_text_addrs+0x3f2/0xa10 fs/afs/addr_list.c:222
 afs_alloc_cell fs/afs/cell.c:181 [inline]
 afs_lookup_cell+0xbb6/0x1940 fs/afs/cell.c:273
 afs_proc_cells_write+0x2a3/0x3a0 fs/afs/proc.c:125
 proc_simple_write+0x10e/0x1a0 fs/proc/generic.c:843
 pde_write fs/proc/inode.c:330 [inline]
 proc_reg_write+0x240/0x330 fs/proc/inode.c:342
 vfs_write+0x2aa/0x1050 fs/read_write.c:685
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 15:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2748 [inline]
 __rcu_free_sheaf_prepare+0x5d/0x300 mm/slub.c:3009
 rcu_free_sheaf+0x1a/0xe0 mm/slub.c:6052
 rcu_do_batch kernel/rcu/tree.c:2650 [inline]
 rcu_core+0x5f0/0x1260 kernel/rcu/tree.c:2919
 handle_softirqs+0x1e6/0x9d0 kernel/softirq.c:645
 run_ksoftirqd kernel/softirq.c:1108 [inline]
 run_ksoftirqd+0x38/0x60 kernel/softirq.c:1100
 smpboot_thread_fn+0x3d3/0xab0 kernel/smpboot.c:160
 kthread+0x373/0x450 kernel/kthread.c:436
 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff8880572e4400
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 32 bytes inside of
 freed 512-byte region [ffff8880572e4400, ffff8880572e4600)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x572e4
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801c02bc80 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801c02bc80 dead000000000100 dead000000000122
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffffffffffff01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 143, tgid 143 (kworker/u8:5), ts 72810304994
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1871
 prep_new_page mm/page_alloc.c:1879 [inline]
 get_page_from_freelist+0x110d/0x35b0 mm/page_alloc.c:3943
 __alloc_frozen_pages_noprof+0x2eb/0x3300 mm/page_alloc.c:5436
 alloc_slab_page mm/slub.c:3347 [inline]
 allocate_slab mm/slub.c:3462 [inline]
 new_slab+0xa9/0x6e0 mm/slub.c:3513
 refill_objects+0xe3/0x410 mm/slub.c:7410
 refill_sheaf mm/slub.c:2885 [inline]
 __pcs_replace_empty_main+0x35e/0x650 mm/slub.c:4774
 alloc_from_pcs mm/slub.c:4850 [inline]
 slab_alloc_node mm/slub.c:4984 [inline]
 __do_kmalloc_node mm/slub.c:5413 [inline]
 __kmalloc_noprof+0x67c/0x840 mm/slub.c:5439
 _kmalloc_noprof include/linux/slab.h:995 [inline]
 _kzalloc_noprof include/linux/slab.h:1312 [inline]
 fib6_info_alloc+0x40/0x160 net/ipv6/ip6_fib.c:155
 ip6_route_info_create+0x14c/0xad0 net/ipv6/route.c:3833
 ip6_route_add+0x4b/0x1d0 net/ipv6/route.c:3962
 addrconf_add_mroute+0x1de/0x350 net/ipv6/addrconf.c:2568
 addrconf_add_dev+0x14e/0x1a0 net/ipv6/addrconf.c:2586
 addrconf_dev_config net/ipv6/addrconf.c:3508 [inline]
 addrconf_init_auto_addrs+0x10e/0x780 net/ipv6/addrconf.c:3596
 addrconf_notify+0xa10/0x1ba0 net/ipv6/addrconf.c:3776
 notifier_call_chain+0x99/0x3f0 kernel/notifier.c:85
 call_netdevice_notifiers_info+0xbe/0x110 net/core/dev.c:2275
page last free pid 1 tgid 1 ts 21277484219 stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 __free_pages_prepare mm/page_alloc.c:1418 [inline]
 free_pages_prepare+0x586/0xe00 mm/page_alloc.c:1463
 __free_contig_range_common+0x14f/0x250 mm/page_alloc.c:7060
 debug_vm_pgtable_free_huge_page mm/debug_vm_pgtable.c:980 [inline]
 destroy_args+0xa8/0x7a0 mm/debug_vm_pgtable.c:993
 debug_vm_pgtable+0x1d69/0x3490 mm/debug_vm_pgtable.c:1368
 do_one_initcall+0x11c/0x6f0 init/main.c:1353
 do_initcall_level init/main.c:1415 [inline]
 do_initcalls init/main.c:1431 [inline]
 do_basic_setup init/main.c:1451 [inline]
 kernel_init_freeable+0x6ea/0x7b0 init/main.c:1666
 kernel_init+0x21/0x1e0 init/main.c:1556
 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff8880572e4300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880572e4380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880572e4400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                               ^
 ffff8880572e4480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880572e4500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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