==================================================================
BUG: KASAN: use-after-free in ext4_htree_fill_tree+0x1066/0x10d0 fs/ext4/namei.c:1221
Read of size 1 at addr ffff88811b5be365 by task syz-executor/1544

CPU: 1 PID: 1544 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 __dump_stack+0x21/0x24 lib/dump_stack.c:77
 dump_stack_lvl+0x169/0x1d8 lib/dump_stack.c:118
 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:435 [inline]
 kasan_report+0xe2/0x130 mm/kasan/report.c:452
 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report_generic.c:306
 ext4_htree_fill_tree+0x1066/0x10d0 fs/ext4/namei.c:1221
 ext4_dx_readdir fs/ext4/dir.c:601 [inline]
 ext4_readdir+0x2b45/0x39b0 fs/ext4/dir.c:145
 iterate_dir+0x260/0x570 fs/readdir.c:-1
 __do_sys_getdents64 fs/readdir.c:369 [inline]
 __se_sys_getdents64+0xe5/0x240 fs/readdir.c:354
 __x64_sys_getdents64+0x7b/0x90 fs/readdir.c:354
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f26e4876993
Code: c1 66 0f 1f 44 00 00 48 83 c4 08 48 89 ef 5b 5d e9 32 43 f8 ff 66 90 b8 ff ff ff 7f 48 39 c2 48 0f 47 d0 b8 d9 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 05 c3 0f 1f 40 00 48 c7 c2 a8 ff ff ff f7 d8
RSP: 002b:00007ffc4d111878 EFLAGS: 00000293 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 000055557bd7e4e0 RCX: 00007f26e4876993
RDX: 0000000000008000 RSI: 000055557bd7e4e0 RDI: 0000000000000005
RBP: 000055557bd7e4b4 R08: 0000000000028b61 R09: 0000000000000000
R10: 00007f26e49d4ca0 R11: 0000000000000293 R12: ffffffffffffffa8
R13: 0000000000000010 R14: 000055557bd7e4b0 R15: 00007ffc4d113b20

Allocated by task 403:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:45 [inline]
 set_alloc_info mm/kasan/common.c:430 [inline]
 ____kasan_kmalloc mm/kasan/common.c:509 [inline]
 __kasan_kmalloc+0xda/0x110 mm/kasan/common.c:518
 kasan_kmalloc include/linux/kasan.h:254 [inline]
 __kmalloc+0x1a7/0x330 mm/slub.c:4038
 kmalloc_array include/linux/slab.h:592 [inline]
 kcalloc include/linux/slab.h:603 [inline]
 alloc_pipe_info+0x1fc/0x4b0 fs/pipe.c:804
 get_pipe_inode fs/pipe.c:878 [inline]
 create_pipe_files+0x8d/0x6c0 fs/pipe.c:910
 __do_pipe_flags+0x4f/0x200 fs/pipe.c:959
 do_pipe2+0x99/0x170 fs/pipe.c:1007
 __do_sys_pipe2 fs/pipe.c:1025 [inline]
 __se_sys_pipe2 fs/pipe.c:1023 [inline]
 __x64_sys_pipe2+0x5a/0x70 fs/pipe.c:1023
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

Freed by task 1092:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4a/0x70 mm/kasan/common.c:45
 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370
 ____kasan_slab_free+0x125/0x160 mm/kasan/common.c:362
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:370
 kasan_slab_free include/linux/kasan.h:220 [inline]
 slab_free_hook mm/slub.c:1600 [inline]
 slab_free_freelist_hook+0xc5/0x190 mm/slub.c:1626
 slab_free mm/slub.c:3208 [inline]
 kfree+0xc0/0x270 mm/slub.c:4196
 skb_free_head net/core/skbuff.c:606 [inline]
 skb_release_data+0x532/0x670 net/core/skbuff.c:626
 skb_release_all net/core/skbuff.c:680 [inline]
 __kfree_skb net/core/skbuff.c:694 [inline]
 kfree_skb+0xb9/0x2f0 net/core/skbuff.c:713
 ip6_mc_input+0x235/0x2a0 net/ipv6/ip6_input.c:574
 dst_input include/net/dst.h:461 [inline]
 ip6_sublist_rcv_finish net/ipv6/ip6_input.c:89 [inline]
 ip6_list_rcv_finish net/ipv6/ip6_input.c:146 [inline]
 ip6_sublist_rcv+0xd37/0xe60 net/ipv6/ip6_input.c:311
 ipv6_list_rcv+0x3dd/0x430 net/ipv6/ip6_input.c:346
 __netif_receive_skb_list_ptype net/core/dev.c:5445 [inline]
 __netif_receive_skb_list_core+0x574/0x740 net/core/dev.c:5493
 __netif_receive_skb_list net/core/dev.c:5545 [inline]
 netif_receive_skb_list_internal+0x7d2/0xa60 net/core/dev.c:5655
 gro_normal_list net/core/dev.c:5809 [inline]
 napi_complete_done+0x36f/0x770 net/core/dev.c:6558
 wg_packet_rx_poll+0x198f/0x1a10 drivers/net/wireguard/receive.c:495
 napi_poll net/core/dev.c:6874 [inline]
 net_rx_action+0x432/0xdd0 net/core/dev.c:6944
 __do_softirq+0x255/0x563 kernel/softirq.c:309

Last potentially related work creation:
 kasan_save_stack+0x3a/0x60 mm/kasan/common.c:38
 __kasan_record_aux_stack+0xd2/0x100 mm/kasan/generic.c:348
 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358
 kvfree_call_rcu+0x10c/0x620 kernel/rcu/tree.c:3539
 drop_sysctl_table+0x2ef/0x410 fs/proc/proc_sysctl.c:1684
 unregister_sysctl_table+0x75/0x120 fs/proc/proc_sysctl.c:1722
 unregister_net_sysctl_table+0x15/0x20 net/sysctl_net.c:127
 neigh_sysctl_unregister+0x78/0x90 net/core/neighbour.c:3737
 addrconf_sysctl_unregister net/ipv6/addrconf.c:7121 [inline]
 addrconf_ifdown+0x1598/0x1800 net/ipv6/addrconf.c:3940
 addrconf_notify+0x3bd/0xe90 net/ipv6/addrconf.c:-1
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0x90/0x100 kernel/notifier.c:410
 call_netdevice_notifiers_info net/core/dev.c:2054 [inline]
 call_netdevice_notifiers_extack net/core/dev.c:2066 [inline]
 call_netdevice_notifiers net/core/dev.c:2080 [inline]
 unregister_netdevice_many+0xf8b/0x1980 net/core/dev.c:10767
 default_device_exit_batch+0x330/0x390 net/core/dev.c:11287
 ops_exit_list net/core/net_namespace.c:190 [inline]
 cleanup_net+0x5fb/0xb70 net/core/net_namespace.c:609
 process_one_work+0x6e1/0xba0 kernel/workqueue.c:2301
 worker_thread+0xa6a/0x13b0 kernel/workqueue.c:2447
 kthread+0x346/0x3d0 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298

Second to last potentially related work creation:
 kasan_save_stack+0x3a/0x60 mm/kasan/common.c:38
 __kasan_record_aux_stack+0xd2/0x100 mm/kasan/generic.c:348
 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358
 __call_rcu kernel/rcu/tree.c:2980 [inline]
 call_rcu+0x10e/0x1050 kernel/rcu/tree.c:3054
 in6_dev_finish_destroy+0x147/0x180 net/ipv6/addrconf_core.c:271
 in6_dev_put include/net/addrconf.h:420 [inline]
 addrconf_ifdown+0x160f/0x1800 net/ipv6/addrconf.c:3943
 addrconf_notify+0x3bd/0xe90 net/ipv6/addrconf.c:-1
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0x90/0x100 kernel/notifier.c:410
 call_netdevice_notifiers_info net/core/dev.c:2054 [inline]
 call_netdevice_notifiers_extack net/core/dev.c:2066 [inline]
 call_netdevice_notifiers net/core/dev.c:2080 [inline]
 unregister_netdevice_many+0xf8b/0x1980 net/core/dev.c:10767
 unregister_netdevice_queue+0x31c/0x360 net/core/dev.c:10701
 unregister_netdevice include/linux/netdevice.h:2937 [inline]
 __tun_detach+0xca6/0x1450 drivers/net/tun.c:697
 tun_detach drivers/net/tun.c:713 [inline]
 tun_chr_close+0x92/0x140 drivers/net/tun.c:3486
 __fput+0x2fb/0x770 fs/file_table.c:281
 ____fput+0x15/0x20 fs/file_table.c:314
 task_work_run+0x127/0x190 kernel/task_work.c:189
 exit_task_work include/linux/task_work.h:33 [inline]
 do_exit+0xa4f/0x2480 kernel/exit.c:872
 do_group_exit+0x141/0x310 kernel/exit.c:986
 __do_sys_exit_group kernel/exit.c:997 [inline]
 __se_sys_exit_group kernel/exit.c:995 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:995
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

The buggy address belongs to the object at ffff88811b5be000
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 869 bytes inside of
 1024-byte region [ffff88811b5be000, ffff88811b5be400)
The buggy address belongs to the page:
page:ffffea00046d6e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88811b5bd800 pfn:0x11b5b8
head:ffffea00046d6e00 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head)
raw: 4000000000010200 ffffea0004c01c08 ffffea00044c5008 ffff888100042f00
raw: ffff88811b5bd800 000000000010000e 00000001ffffffff 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 0xd2a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 221, ts 15390985888, free_ts 15390687711
 set_page_owner include/linux/page_owner.h:35 [inline]
 post_alloc_hook mm/page_alloc.c:2456 [inline]
 prep_new_page+0x179/0x180 mm/page_alloc.c:2462
 get_page_from_freelist+0x2235/0x23d0 mm/page_alloc.c:4254
 __alloc_pages_nodemask+0x268/0x5f0 mm/page_alloc.c:5370
 alloc_slab_page mm/slub.c:-1 [inline]
 allocate_slab mm/slub.c:1813 [inline]
 new_slab+0x84/0x3f0 mm/slub.c:1874
 new_slab_objects mm/slub.c:2632 [inline]
 ___slab_alloc+0x2a6/0x450 mm/slub.c:2796
 __slab_alloc+0x63/0xa0 mm/slub.c:2836
 slab_alloc_node mm/slub.c:2918 [inline]
 slab_alloc mm/slub.c:2960 [inline]
 __kmalloc_track_caller+0x1ef/0x320 mm/slub.c:4541
 __kmalloc_reserve net/core/skbuff.c:144 [inline]
 __alloc_skb+0xdc/0x520 net/core/skbuff.c:212
 __napi_alloc_skb+0x158/0x2e0 net/core/skbuff.c:522
 napi_alloc_skb include/linux/skbuff.h:2975 [inline]
 page_to_skb+0x40/0x8b0 drivers/net/virtio_net.c:432
 receive_mergeable drivers/net/virtio_net.c:1049 [inline]
 receive_buf+0xba1/0x45a0 drivers/net/virtio_net.c:1159
 virtnet_receive drivers/net/virtio_net.c:1451 [inline]
 virtnet_poll+0x4f2/0xef0 drivers/net/virtio_net.c:1560
 napi_poll net/core/dev.c:6874 [inline]
 net_rx_action+0x432/0xdd0 net/core/dev.c:6944
 __do_softirq+0x255/0x563 kernel/softirq.c:309
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:28 [inline]
 free_pages_prepare mm/page_alloc.c:1349 [inline]
 __free_pages_ok+0x7fc/0x820 mm/page_alloc.c:1629
 free_compound_page+0x73/0x90 mm/page_alloc.c:710
 destroy_compound_page include/linux/mm.h:970 [inline]
 __put_compound_page+0x77/0xb0 mm/swap.c:117
 __put_page+0xbd/0xe0 mm/swap.c:133
 put_page include/linux/mm.h:1268 [inline]
 __skb_frag_unref include/linux/skbuff.h:3124 [inline]
 skb_release_data+0x21f/0x670 net/core/skbuff.c:620
 skb_release_all net/core/skbuff.c:680 [inline]
 __kfree_skb+0x50/0x70 net/core/skbuff.c:694
 sk_eat_skb include/net/sock.h:2653 [inline]
 tcp_recvmsg+0x1515/0x2e10 net/ipv4/tcp.c:2337
 inet_recvmsg+0x134/0x470 net/ipv4/af_inet.c:864
 sock_recvmsg_nosec net/socket.c:905 [inline]
 sock_recvmsg net/socket.c:923 [inline]
 sock_read_iter+0x2a2/0x340 net/socket.c:996
 call_read_iter include/linux/fs.h:2060 [inline]
 new_sync_read fs/read_write.c:415 [inline]
 vfs_read+0x874/0xa10 fs/read_write.c:496
 ksys_read+0x140/0x240 fs/read_write.c:634
 __do_sys_read fs/read_write.c:644 [inline]
 __se_sys_read fs/read_write.c:642 [inline]
 __x64_sys_read+0x7b/0x90 fs/read_write.c:642
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

Memory state around the buggy address:
 ffff88811b5be200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88811b5be280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88811b5be300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                       ^
 ffff88811b5be380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88811b5be400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
EXT4-fs error (device loop7): htree_dirblock_to_tree:1092: inode #2: block 20: comm syz-executor: bad entry in directory: inode out of bounds - offset=1024, inode=2033530174, rec_len=1012, size=1024 fake=0