EXT4-fs error (device loop5): ext4_lookup:1791: inode #2: comm syz-executor: deleted inode referenced: 15
EXT4-fs error (device loop5): ext4_lookup:1791: inode #2: comm syz-executor: deleted inode referenced: 15
==================================================================
BUG: KASAN: slab-use-after-free in __hlist_del include/linux/list.h:982 [inline]
BUG: KASAN: slab-use-after-free in hlist_del_init include/linux/list.h:1008 [inline]
BUG: KASAN: slab-use-after-free in binder_remove_device+0xa1/0xe0 drivers/android/binder.c:7006
Write of size 8 at addr ffff888033013008 by task syz-executor/6843

CPU: 0 UID: 0 PID: 6843 Comm: syz-executor Not tainted 6.15.0-rc7-next-20250523-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xd2/0x2b0 mm/kasan/report.c:521
 kasan_report+0x118/0x150 mm/kasan/report.c:634
 __hlist_del include/linux/list.h:982 [inline]
 hlist_del_init include/linux/list.h:1008 [inline]
 binder_remove_device+0xa1/0xe0 drivers/android/binder.c:7006
 binderfs_evict_inode+0x16b/0x240 drivers/android/binderfs.c:277
 evict+0x501/0x9c0 fs/inode.c:810
 __dentry_kill+0x209/0x660 fs/dcache.c:669
 shrink_kill+0xa9/0x2c0 fs/dcache.c:1114
 shrink_dentry_list+0x2e0/0x5e0 fs/dcache.c:1141
 shrink_dcache_parent+0xa1/0x2c0 fs/dcache.c:-1
 do_one_tree+0x23/0xe0 fs/dcache.c:1604
 shrink_dcache_for_umount+0xa0/0x170 fs/dcache.c:1621
 generic_shutdown_super+0x67/0x2c0 fs/super.c:621
 kill_anon_super fs/super.c:1280 [inline]
 kill_litter_super+0x76/0xb0 fs/super.c:1290
 binderfs_kill_super+0x44/0x90 drivers/android/binderfs.c:792
 deactivate_locked_super+0xb9/0x130 fs/super.c:474
 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1417
 task_work_run+0x1d4/0x260 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x6ad/0x22e0 kernel/exit.c:955
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1104
 __do_sys_exit_group kernel/exit.c:1115 [inline]
 __se_sys_exit_group kernel/exit.c:1113 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1113
 x64_sys_call+0x21ba/0x21c0 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa70378e969
Code: Unable to access opcode bytes at 0x7fa70378e93f.
RSP: 002b:00007ffec10d5248 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007fa7038108c2 RCX: 00007fa70378e969
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001
RBP: 0000000000000075 R08: 00007ffec10d2fe5 R09: 00007ffec10d6500
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffec10d6500
R13: 00007fa70381089d R14: 000000000005769b R15: 00007ffec10d75d0
 </TASK>

Allocated by task 9012:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4358
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 mca_alloc net/ipv6/mcast.c:884 [inline]
 __ipv6_dev_mc_inc+0x420/0xaf0 net/ipv6/mcast.c:975
 ipv6_add_dev+0xe54/0x1370 net/ipv6/addrconf.c:470
 addrconf_notify+0x794/0x1010 net/ipv6/addrconf.c:3654
 notifier_call_chain+0x1b6/0x3e0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2268 [inline]
 call_netdevice_notifiers net/core/dev.c:2282 [inline]
 register_netdevice+0x1608/0x1ae0 net/core/dev.c:11141
 register_netdev+0x40/0x60 net/core/dev.c:11219
 ip6_tnl_init_net+0x259/0x3b0 net/ipv6/ip6_tunnel.c:2277
 ops_init+0x359/0x5c0 net/core/net_namespace.c:138
 setup_net+0x219/0x4b0 net/core/net_namespace.c:442
 copy_net_ns+0x32e/0x590 net/core/net_namespace.c:574
 create_new_namespaces+0x3f3/0x720 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x11c/0x170 kernel/nsproxy.c:218
 ksys_unshare+0x4c8/0x8c0 kernel/fork.c:3121
 __do_sys_unshare kernel/fork.c:3192 [inline]
 __se_sys_unshare kernel/fork.c:3190 [inline]
 __x64_sys_unshare+0x38/0x50 kernel/fork.c:3190
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 3503:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2380 [inline]
 slab_free_freelist_hook mm/slub.c:2409 [inline]
 slab_free_bulk mm/slub.c:4666 [inline]
 kmem_cache_free_bulk+0x2d1/0x520 mm/slub.c:5245
 kfree_bulk include/linux/slab.h:794 [inline]
 kvfree_rcu_bulk+0xe5/0x1e0 mm/slab_common.c:1516
 kfree_rcu_work+0xed/0x170 mm/slab_common.c:1594
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Last potentially related work creation:
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:47
 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:548
 kvfree_call_rcu+0xbb/0x410 mm/slab_common.c:1962
 ipv6_mc_destroy_dev+0x3c5/0x5a0 net/ipv6/mcast.c:2862
 addrconf_ifdown+0x139e/0x1880 net/ipv6/addrconf.c:4000
 addrconf_notify+0x1bc/0x1010 net/ipv6/addrconf.c:-1
 notifier_call_chain+0x1b6/0x3e0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2268 [inline]
 call_netdevice_notifiers net/core/dev.c:2282 [inline]
 unregister_netdevice_many_notify+0x15d8/0x2320 net/core/dev.c:12075
 ops_exit_rtnl_list net/core/net_namespace.c:188 [inline]
 ops_undo_list+0x3dc/0x990 net/core/net_namespace.c:249
 cleanup_net+0x4c5/0x8a0 net/core/net_namespace.c:686
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff888033013000
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 8 bytes inside of
 freed 512-byte region [ffff888033013000, ffff888033013200)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x33010
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801a441c80 0000000000000000 dead000000000001
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801a441c80 0000000000000000 dead000000000001
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffea0000cc0401 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 44, tgid 44 (kworker/u8:3), ts 82120082800, free_ts 80762038616
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1704
 prep_new_page mm/page_alloc.c:1712 [inline]
 get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3669
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4959
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2419
 alloc_slab_page mm/slub.c:2450 [inline]
 allocate_slab+0x8a/0x3b0 mm/slub.c:2618
 new_slab mm/slub.c:2672 [inline]
 ___slab_alloc+0xbfc/0x1480 mm/slub.c:3858
 __slab_alloc mm/slub.c:3948 [inline]
 __slab_alloc_node mm/slub.c:4023 [inline]
 slab_alloc_node mm/slub.c:4184 [inline]
 __kmalloc_cache_noprof+0x296/0x3d0 mm/slub.c:4353
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 mca_alloc net/ipv6/mcast.c:884 [inline]
 __ipv6_dev_mc_inc+0x420/0xaf0 net/ipv6/mcast.c:975
 addrconf_join_solict net/ipv6/addrconf.c:2242 [inline]
 addrconf_dad_begin net/ipv6/addrconf.c:4103 [inline]
 addrconf_dad_work+0x3d0/0x14b0 net/ipv6/addrconf.c:4231
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
page last free pid 5950 tgid 5950 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1248 [inline]
 __free_frozen_pages+0xc71/0xe70 mm/page_alloc.c:2706
 discard_slab mm/slub.c:2716 [inline]
 __put_partials+0x161/0x1c0 mm/slub.c:3185
 put_cpu_partial+0x17c/0x250 mm/slub.c:3260
 __slab_free+0x2f7/0x400 mm/slub.c:4512
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4147 [inline]
 slab_alloc_node mm/slub.c:4196 [inline]
 kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4203
 getname_flags+0xb8/0x540 fs/namei.c:146
 getname include/linux/fs.h:2903 [inline]
 __do_sys_symlinkat fs/namei.c:4772 [inline]
 __se_sys_symlinkat fs/namei.c:4769 [inline]
 __x64_sys_symlinkat+0x7a/0xb0 fs/namei.c:4769
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888033012f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888033012f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888033013000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff888033013080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888033013100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================