EXT4-fs warning (device loop0): dx_probe:861: inode #2: comm syz.0.18: dx entry: limit 65535 != root limit 120
EXT4-fs warning (device loop0): dx_probe:934: inode #2: comm syz.0.18: Corrupt directory, running e2fsck is recommended
==================================================================
BUG: KASAN: slab-use-after-free in __ext4_check_dir_entry+0x755/0x8e0 fs/ext4/dir.c:85
Read of size 2 at addr ffff8880124e4003 by task syz.0.18/5519

CPU: 0 UID: 0 PID: 5519 Comm: syz.0.18 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 __ext4_check_dir_entry+0x755/0x8e0 fs/ext4/dir.c:85
 ext4_readdir+0x13ee/0x3e90 fs/ext4/dir.c:262
 iterate_dir+0x399/0x570 fs/readdir.c:108
 __do_sys_getdents64 fs/readdir.c:410 [inline]
 __se_sys_getdents64+0xe4/0x260 fs/readdir.c:396
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f335ad8f7c9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe15889468 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 00007f335afe5fa0 RCX: 00007f335ad8f7c9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007f335ae13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f335afe5fa0 R14: 00007f335afe5fa0 R15: 0000000000000003
 </TASK>

Allocated by task 4724:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5657 [inline]
 __kmalloc_node_track_caller_noprof+0x575/0x820 mm/slub.c:5764
 kmalloc_reserve+0x136/0x290 net/core/skbuff.c:608
 __alloc_skb+0x204/0x3a0 net/core/skbuff.c:690
 alloc_skb include/linux/skbuff.h:1383 [inline]
 alloc_skb_with_frags+0xca/0x890 net/core/skbuff.c:6712
 sock_alloc_send_pskb+0x84d/0x980 net/core/sock.c:2995
 unix_dgram_sendmsg+0x501/0x18c0 net/unix/af_unix.c:2130
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg+0x21c/0x270 net/socket.c:742
 __sys_sendto+0x3bd/0x520 net/socket.c:2206
 __do_sys_sendto net/socket.c:2213 [inline]
 __se_sys_sendto net/socket.c:2209 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2209
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 4717:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2540 [inline]
 slab_free mm/slub.c:6670 [inline]
 kfree+0x1c0/0x660 mm/slub.c:6878
 skb_release_data+0x62d/0x7c0 net/core/skbuff.c:1107
 skb_release_all net/core/skbuff.c:1182 [inline]
 __kfree_skb net/core/skbuff.c:1196 [inline]
 consume_skb+0x9e/0xf0 net/core/skbuff.c:1428
 __unix_dgram_recvmsg+0xa03/0xdc0 net/unix/af_unix.c:2658
 sock_recvmsg_nosec net/socket.c:1078 [inline]
 sock_recvmsg+0x22c/0x270 net/socket.c:1100
 sock_read_iter+0x231/0x2f0 net/socket.c:1170
 new_sync_read fs/read_write.c:491 [inline]
 vfs_read+0x55a/0xa30 fs/read_write.c:572
 ksys_read+0x145/0x250 fs/read_write.c:715
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff8880124e4000
 which belongs to the cache kmalloc-cg-512 of size 512
The buggy address is located 3 bytes inside of
 freed 512-byte region [ffff8880124e4000, ffff8880124e4200)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x124e4
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff88801a352781
anon flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801a44b140 ffffea000068b300 dead000000000005
raw: 0000000000000000 0000000000080008 00000000f5000000 ffff88801a352781
head: 00fff00000000040 ffff88801a44b140 ffffea000068b300 dead000000000005
head: 0000000000000000 0000000000080008 00000000f5000000 ffff88801a352781
head: 00fff00000000001 ffffea0000493901 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5369, tgid 5369 (syz-executor), ts 93751039655, free_ts 93368309387
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x234/0x290 mm/page_alloc.c:1857
 prep_new_page mm/page_alloc.c:1865 [inline]
 get_page_from_freelist+0x24e0/0x2580 mm/page_alloc.c:3915
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486
 alloc_slab_page mm/slub.c:3075 [inline]
 allocate_slab+0x86/0x3b0 mm/slub.c:3248
 new_slab mm/slub.c:3302 [inline]
 ___slab_alloc+0xe53/0x1820 mm/slub.c:4656
 __slab_alloc+0x65/0x100 mm/slub.c:4779
 __slab_alloc_node mm/slub.c:4855 [inline]
 slab_alloc_node mm/slub.c:5251 [inline]
 __kmalloc_cache_noprof+0x41e/0x700 mm/slub.c:5771
 kmalloc_noprof include/linux/slab.h:957 [inline]
 kzalloc_noprof include/linux/slab.h:1094 [inline]
 ipv6_add_addr+0x530/0x1090 net/ipv6/addrconf.c:1120
 inet6_addr_add+0x3c3/0xce0 net/ipv6/addrconf.c:3050
 inet6_rtm_newaddr+0x93d/0xd20 net/ipv6/addrconf.c:5059
 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6958
 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg+0x21c/0x270 net/socket.c:742
page last free pid 76 tgid 76 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1406 [inline]
 free_unref_folios+0xdb3/0x14f0 mm/page_alloc.c:3000
 shrink_folio_list+0x289b/0x4f90 mm/vmscan.c:1534
 evict_folios+0x473e/0x57f0 mm/vmscan.c:4711
 try_to_shrink_lruvec+0x8a3/0xb50 mm/vmscan.c:4874
 shrink_one+0x25c/0x720 mm/vmscan.c:4919
 shrink_many mm/vmscan.c:4982 [inline]
 lru_gen_shrink_node mm/vmscan.c:5060 [inline]
 shrink_node+0x2f7d/0x35b0 mm/vmscan.c:6047
 kswapd_shrink_node mm/vmscan.c:6901 [inline]
 balance_pgdat mm/vmscan.c:7084 [inline]
 kswapd+0x145a/0x2820 mm/vmscan.c:7354
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

Memory state around the buggy address:
 ffff8880124e3f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880124e3f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880124e4000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff8880124e4080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880124e4100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================