EXT4-fs (loop0): mounted filesystem without journal. Opts: jqfmt=vfsold,mblk_io_submit,nomblk_io_submit,noload,nombcache,noblock_validity,init_itable=0x0000000000000601,nolazytime,,errors=continue
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BUG: KASAN: use-after-free in ext4_insert_dentry+0x3a0/0x720 fs/ext4/namei.c:2106
Write of size 254 at addr ffff8881da1e1f18 by task syz-executor284/372

CPU: 1 PID: 372 Comm: syz-executor284 Not tainted 5.4.292-syzkaller-00021-gcd8e74fa0fa3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 __dump_stack+0x1e/0x20 lib/dump_stack.c:77
 dump_stack+0x15b/0x1b8 lib/dump_stack.c:118
 print_address_description+0x8d/0x4c0 mm/kasan/report.c:384
 __kasan_report+0xef/0x120 mm/kasan/report.c:516
 kasan_report+0x30/0x60 mm/kasan/common.c:653
 check_memory_region_inline mm/kasan/generic.c:141 [inline]
 check_memory_region+0x274/0x280 mm/kasan/generic.c:191
 memcpy+0x3b/0x60 mm/kasan/common.c:124
 ext4_insert_dentry+0x3a0/0x720 fs/ext4/namei.c:2106
 add_dirent_to_buf+0x2c0/0x6d0 fs/ext4/namei.c:2150
 make_indexed_dir+0xd92/0x1490 fs/ext4/namei.c:2341
 ext4_add_entry+0xc49/0xed0 fs/ext4/namei.c:2445
 ext4_mkdir+0xd58/0x15d0 fs/ext4/namei.c:2991
 vfs_mkdir+0x4c7/0x6a0 fs/namei.c:3965
 do_mkdirat+0x14c/0x340 fs/namei.c:3987
 __do_sys_mkdir fs/namei.c:4003 [inline]
 __se_sys_mkdir fs/namei.c:4001 [inline]
 __x64_sys_mkdir+0x60/0x70 fs/namei.c:4001
 do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1
RIP: 0033:0x7f50be522369
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 21 18 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffdf96d2a38 EFLAGS: 00000246 ORIG_RAX: 0000000000000053
RAX: ffffffffffffffda RBX: 00007f50be56b0e0 RCX: 00007f50be522369
RDX: 0000000000000000 RSI: 0000000000000045 RDI: 00002000000003c0
RBP: 0000000000000000 R08: 00007ffdf96d2a70 R09: 00007ffdf96d2a70
R10: 00007ffdf96d2a70 R11: 0000000000000246 R12: 00007ffdf96d2a5c
R13: 0000000000000003 R14: 431bde82d7b634db R15: 00007ffdf96d2a90

The buggy address belongs to the page:
page:ffffea0007687840 refcount:3 mapcount:0 mapping:ffff8881f11579b8 index:0x3f
def_blk_aops
flags: 0x800000000000202a(referenced|dirty|active|private)
raw: 800000000000202a dead000000000100 dead000000000122 ffff8881f11579b8
raw: 000000000000003f ffff8881dcede690 00000003ffffffff ffff8881f5cb6000
page dumped because: kasan: bad access detected
page->mem_cgroup:ffff8881f5cb6000
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Movable, gfp_mask 0x108c48(GFP_NOFS|__GFP_NOFAIL|__GFP_HARDWALL|__GFP_MOVABLE)
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook mm/page_alloc.c:2165 [inline]
 prep_new_page+0x35e/0x370 mm/page_alloc.c:2171
 get_page_from_freelist+0x1296/0x1310 mm/page_alloc.c:3794
 __alloc_pages_nodemask+0x202/0x4b0 mm/page_alloc.c:4894
 __alloc_pages include/linux/gfp.h:503 [inline]
 __alloc_pages_node include/linux/gfp.h:516 [inline]
 alloc_pages_node include/linux/gfp.h:530 [inline]
 __page_cache_alloc include/linux/pagemap.h:218 [inline]
 pagecache_get_page+0x48d/0x780 mm/filemap.c:1829
 find_or_create_page include/linux/pagemap.h:313 [inline]
 grow_dev_page fs/buffer.c:950 [inline]
 grow_buffers fs/buffer.c:1019 [inline]
 __getblk_slow fs/buffer.c:1046 [inline]
 __getblk_gfp+0x212/0x760 fs/buffer.c:1323
 sb_getblk include/linux/buffer_head.h:367 [inline]
 ext4_getblk+0x18e/0x490 fs/ext4/inode.c:992
 ext4_bread+0x8a/0x2d0 fs/ext4/inode.c:1035
 ext4_append+0x253/0x470 fs/ext4/namei.c:83
 make_indexed_dir+0x4f4/0x1490 fs/ext4/namei.c:2267
 ext4_add_entry+0xc49/0xed0 fs/ext4/namei.c:2445
 ext4_mkdir+0xd58/0x15d0 fs/ext4/namei.c:2991
 vfs_mkdir+0x4c7/0x6a0 fs/namei.c:3965
 do_mkdirat+0x14c/0x340 fs/namei.c:3987
 __do_sys_mkdir fs/namei.c:4003 [inline]
 __se_sys_mkdir fs/namei.c:4001 [inline]
 __x64_sys_mkdir+0x60/0x70 fs/namei.c:4001
 do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1176 [inline]
 free_pcp_prepare mm/page_alloc.c:1233 [inline]
 free_unref_page_prepare+0x2a9/0x3a0 mm/page_alloc.c:3085
 free_unref_page_list+0x110/0x4c0 mm/page_alloc.c:3154
 release_pages+0xa62/0xaa0 mm/swap.c:842
 free_pages_and_swap_cache+0x86/0xa0 mm/swap_state.c:297
 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:189 [inline]
 tlb_flush_mmu mm/mmu_gather.c:196 [inline]
 tlb_finish_mmu+0x175/0x300 mm/mmu_gather.c:277
 unmap_region+0x32c/0x380 mm/mmap.c:2644
 __do_munmap+0x639/0x840 mm/mmap.c:2875
 __vm_munmap mm/mmap.c:2898 [inline]
 __do_sys_munmap mm/mmap.c:2924 [inline]
 __se_sys_munmap+0x124/0x1b0 mm/mmap.c:2920
 __x64_sys_munmap+0x5b/0x70 mm/mmap.c:2920
 do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1

Memory state around the buggy address:
 ffff8881da1e1f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8881da1e1f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8881da1e2000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff8881da1e2080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881da1e2100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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