EXT4-fs warning (device loop2): dx_probe:806: inode #2: comm syz.2.17: Unrecognised inode hash code 20
EXT4-fs warning (device loop2): dx_probe:946: inode #2: comm syz.2.17: Corrupt directory, running e2fsck is recommended
==================================================================
BUG: KASAN: use-after-free in __ext4_check_dir_entry+0x7c2/0x970 fs/ext4/dir.c:85
Read of size 2 at addr ffff888117150003 by task syz.2.17/482

CPU: 0 PID: 482 Comm: syz.2.17 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_load2_noabort+0x14/0x20 mm/kasan/report_generic.c:307
 __ext4_check_dir_entry+0x7c2/0x970 fs/ext4/dir.c:85
 ext4_readdir+0x11ca/0x39b0 fs/ext4/dir.c:261
 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: 0033:0x7f0be6a97ec9
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:00007f0be6908038 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 00007f0be6ceefa0 RCX: 00007f0be6a97ec9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006
RBP: 00007f0be6b1af91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0be6cef038 R14: 00007f0be6ceefa0 R15: 00007ffddab748b8

Allocated by task 420:
 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]
 kmem_cache_alloc_trace+0x184/0x2e0 mm/slub.c:2979
 kmalloc include/linux/slab.h:552 [inline]
 kzalloc include/linux/slab.h:664 [inline]
 uevent_show+0x160/0x330 drivers/base/core.c:2295
 dev_attr_show+0x56/0xd0 drivers/base/core.c:2002
 sysfs_kf_seq_show+0x266/0x3d0 fs/sysfs/file.c:61
 kernfs_seq_show+0x119/0x160 fs/kernfs/file.c:168
 seq_read_iter+0x490/0xd30 fs/seq_file.c:230
 kernfs_fop_read_iter+0x147/0x470 fs/kernfs/file.c:241
 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

Freed by task 420:
 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
 uevent_show+0x1fb/0x330 drivers/base/core.c:2311
 dev_attr_show+0x56/0xd0 drivers/base/core.c:2002
 sysfs_kf_seq_show+0x266/0x3d0 fs/sysfs/file.c:61
 kernfs_seq_show+0x119/0x160 fs/kernfs/file.c:168
 seq_read_iter+0x490/0xd30 fs/seq_file.c:230
 kernfs_fop_read_iter+0x147/0x470 fs/kernfs/file.c:241
 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

The buggy address belongs to the object at ffff888117150000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 3 bytes inside of
 4096-byte region [ffff888117150000, ffff888117151000)
The buggy address belongs to the page:
page:ffffea00045c5400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x117150
head:ffffea00045c5400 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head)
raw: 4000000000010200 dead000000000100 dead000000000122 ffff888100042c00
raw: 0000000000000000 0000000000040004 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 100, ts 4870879359, free_ts 0
 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]
 kmem_cache_alloc_trace+0x1b3/0x2e0 mm/slub.c:2977
 kmalloc include/linux/slab.h:552 [inline]
 kzalloc include/linux/slab.h:664 [inline]
 uevent_show+0x160/0x330 drivers/base/core.c:2295
 dev_attr_show+0x56/0xd0 drivers/base/core.c:2002
 sysfs_kf_seq_show+0x266/0x3d0 fs/sysfs/file.c:61
 kernfs_seq_show+0x119/0x160 fs/kernfs/file.c:168
 seq_read_iter+0x490/0xd30 fs/seq_file.c:230
 kernfs_fop_read_iter+0x147/0x470 fs/kernfs/file.c:241
 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
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88811714ff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88811714ff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888117150000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff888117150080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888117150100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
EXT4-fs error (device loop2): ext4_readdir:263: inode #2: block 3: comm syz.2.17: path /0/file0: bad entry in directory: rec_len % 4 != 0 - offset=2047, inode=2107473920, rec_len=33046, size=2048 fake=0
EXT4-fs error (device loop2) in ext4_reserve_inode_write:5933: Corrupt filesystem
EXT4-fs error (device loop2): ext4_dirty_inode:6143: inode #2: comm syz.2.17: mark_inode_dirty error