==================================================================
BUG: KASAN: slab-out-of-bounds in ext4_htree_fill_tree+0x10f0/0x1160 fs/ext4/namei.c:1246
Read of size 1 at addr ffff88812545cd1b by task syz-executor/463

CPU: 0 PID: 463 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x24 lib/dump_stack.c:88
 dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
 print_address_description+0x71/0x200 mm/kasan/report.c:316
 print_report+0x4a/0x60 mm/kasan/report.c:420
 kasan_report+0x122/0x150 mm/kasan/report.c:524
 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report_generic.c:348
 ext4_htree_fill_tree+0x10f0/0x1160 fs/ext4/namei.c:1246
 ext4_dx_readdir fs/ext4/dir.c:608 [inline]
 ext4_readdir+0x2f80/0x3e10 fs/ext4/dir.c:145
 iterate_dir+0x271/0x610 fs/readdir.c:-1
 __do_sys_getdents64 fs/readdir.c:369 [inline]
 __se_sys_getdents64+0xf2/0x250 fs/readdir.c:354
 __x64_sys_getdents64+0x7b/0x90 fs/readdir.c:354
 x64_sys_call+0x15c/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:218
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f6c14fbfd73
Code: c7 c0 e8 ff ff ff 64 c7 00 16 00 00 00 31 c0 eb 9e e8 81 9b fd ff 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 e8 ff ff ff f7 d8
RSP: 002b:00007ffe8ad241f8 EFLAGS: 00000293 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 0000555560cc3910 RCX: 00007f6c14fbfd73
RDX: 0000000000008000 RSI: 0000555560cc3940 RDI: 0000000000000005
RBP: 0000555560cc3940 R08: 0000000000028701 R09: 0000000000000001
R10: 00007f6c15193ca0 R11: 0000000000000293 R12: 0000555560cc3914
R13: ffffffffffffffe8 R14: 0000000000000010 R15: 0000000000000001
 </TASK>

Allocated by task 474:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
 kasan_save_alloc_info+0x25/0x30 mm/kasan/generic.c:505
 __kasan_slab_alloc+0x72/0x80 mm/kasan/common.c:334
 kasan_slab_alloc include/linux/kasan.h:202 [inline]
 slab_post_alloc_hook+0x4f/0x2d0 mm/slab.h:768
 slab_alloc_node mm/slub.c:3382 [inline]
 slab_alloc mm/slub.c:3392 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3399 [inline]
 kmem_cache_alloc+0x16e/0x330 mm/slub.c:3408
 kmem_cache_zalloc include/linux/slab.h:689 [inline]
 __kernfs_new_node+0xe3/0x6b0 fs/kernfs/dir.c:614
 kernfs_new_node+0x150/0x260 fs/kernfs/dir.c:690
 __kernfs_create_file+0x4e/0x270 fs/kernfs/file.c:1068
 sysfs_add_file_mode_ns+0x1ce/0x270 fs/sysfs/file.c:294
 create_files fs/sysfs/group.c:64 [inline]
 internal_create_group+0x4a1/0xd10 fs/sysfs/group.c:148
 sysfs_create_group+0x1f/0x30 fs/sysfs/group.c:174
 loop_sysfs_init drivers/block/loop.c:742 [inline]
 loop_configure+0xf14/0x1530 drivers/block/loop.c:1093
 lo_ioctl+0x227/0x1fb0 drivers/block/loop.c:1546
 blkdev_ioctl+0x367/0x720 block/ioctl.c:626
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0x12f/0x1b0 fs/ioctl.c:856
 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:856
 x64_sys_call+0x58b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

The buggy address belongs to the object at ffff88812545cc80
 which belongs to the cache kernfs_node_cache of size 136
The buggy address is located 19 bytes to the right of
 136-byte region [ffff88812545cc80, ffff88812545cd08)

The buggy address belongs to the physical page:
page:ffffea0004951700 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x12545c
flags: 0x4000000000000200(slab|zone=1)
raw: 4000000000000200 0000000000000000 dead000000000122 ffff8881001ede00
raw: 0000000000000000 0000000080140014 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 474, tgid 473 (syz.2.16), ts 50657565039, free_ts 50657348032
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1f5/0x210 mm/page_alloc.c:2643
 prep_new_page+0x1c/0x110 mm/page_alloc.c:2650
 get_page_from_freelist+0x2d12/0x2d80 mm/page_alloc.c:4554
 __alloc_pages+0x1d9/0x480 mm/page_alloc.c:5868
 alloc_slab_page+0x6e/0xf0 include/linux/gfp.h:-1
 allocate_slab mm/slub.c:1967 [inline]
 new_slab+0x98/0x3d0 mm/slub.c:2020
 ___slab_alloc+0x6bd/0xb20 mm/slub.c:3177
 __slab_alloc+0x5e/0xa0 mm/slub.c:3263
 slab_alloc_node mm/slub.c:3348 [inline]
 slab_alloc mm/slub.c:3392 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3399 [inline]
 kmem_cache_alloc+0x1b0/0x330 mm/slub.c:3408
 kmem_cache_zalloc include/linux/slab.h:689 [inline]
 __kernfs_new_node+0xe3/0x6b0 fs/kernfs/dir.c:614
 kernfs_new_node+0x150/0x260 fs/kernfs/dir.c:690
 __kernfs_create_file+0x4e/0x270 fs/kernfs/file.c:1068
 sysfs_add_file_mode_ns+0x1ce/0x270 fs/sysfs/file.c:294
 create_files fs/sysfs/group.c:64 [inline]
 internal_create_group+0x4a1/0xd10 fs/sysfs/group.c:148
 sysfs_create_group+0x1f/0x30 fs/sysfs/group.c:174
 loop_sysfs_init drivers/block/loop.c:742 [inline]
 loop_configure+0xf14/0x1530 drivers/block/loop.c:1093
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1551 [inline]
 free_pcp_prepare mm/page_alloc.c:1625 [inline]
 free_unref_page_prepare+0x742/0x750 mm/page_alloc.c:3589
 free_unref_page+0x95/0x540 mm/page_alloc.c:3687
 free_the_page mm/page_alloc.c:836 [inline]
 __free_pages+0x67/0x100 mm/page_alloc.c:5957
 free_pages+0x82/0x90 mm/page_alloc.c:5968
 tlb_batch_list_free mm/mmu_gather.c:75 [inline]
 tlb_finish_mmu+0x2c7/0x370 mm/mmu_gather.c:364
 unmap_region+0x2b7/0x320 mm/mmap.c:2419
 do_mas_align_munmap+0xbed/0x1320 mm/mmap.c:2693
 do_mas_munmap+0x241/0x2b0 mm/mmap.c:2751
 __vm_munmap+0x1bd/0x330 mm/mmap.c:3050
 __do_sys_munmap mm/mmap.c:3076 [inline]
 __se_sys_munmap mm/mmap.c:3072 [inline]
 __x64_sys_munmap+0x6b/0x80 mm/mmap.c:3072
 x64_sys_call+0x8a/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:12
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Memory state around the buggy address:
 ffff88812545cc00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88812545cc80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88812545cd00: 00 fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00
                            ^
 ffff88812545cd80: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
 ffff88812545ce00: fc fc 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
EXT4-fs error (device loop2): __ext4_get_inode_loc:4515: comm syz-executor: Invalid inode table block 14875662660405297151 in block_group 0
EXT4-fs error (device loop2) in ext4_reserve_inode_write:5930: Corrupt filesystem
EXT4-fs error (device loop2): ext4_dirty_inode:6134: inode #2: comm syz-executor: mark_inode_dirty error
EXT4-fs (loop2): unmounting filesystem.