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BUG: KASAN: slab-out-of-bounds in ext4_htree_fill_tree+0x1066/0x10d0 fs/ext4/namei.c:1221
Read of size 1 at addr ffff8881286caa67 by task syz-executor/466

CPU: 1 PID: 466 Comm: syz-executor Not tainted 5.10.240-syzkaller-1008085-g1154f779f3f3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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: 0033:0x7fcd73130193
Code: c1 66 0f 1f 44 00 00 48 83 c4 08 48 89 ef 5b 5d e9 42 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:00007ffebefc6688 EFLAGS: 00000293 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 000055556aa914e0 RCX: 00007fcd73130193
RDX: 0000000000008000 RSI: 000055556aa914e0 RDI: 0000000000000005
RBP: 000055556aa914b4 R08: 0000000000028b61 R09: 0000000000000000
R10: 00007fcd7328bca0 R11: 0000000000000293 R12: ffffffffffffffa8
R13: 0000000000000010 R14: 000055556aa914b0 R15: 00007ffebefc8930

Allocated by task 0:
(stack is not available)

The buggy address belongs to the object at ffff8881286caa00
 which belongs to the cache bio-0 of size 216
The buggy address is located 103 bytes inside of
 216-byte region [ffff8881286caa00, ffff8881286caad8)
The buggy address belongs to the page:
page:ffffea0004a1b280 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1286ca
flags: 0x4000000000000200(slab)
raw: 4000000000000200 dead000000000100 dead000000000122 ffff888107fdc900
raw: 0000000000000000 00000000800c000c 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 0x192880(GFP_NOWAIT|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 415, ts 54718532456, free_ts 54326951601
 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:5357
 alloc_slab_page mm/slub.c:-1 [inline]
 allocate_slab mm/slub.c:1808 [inline]
 new_slab+0x84/0x3f0 mm/slub.c:1869
 new_slab_objects mm/slub.c:2627 [inline]
 ___slab_alloc+0x2a6/0x450 mm/slub.c:2791
 __slab_alloc+0x63/0xa0 mm/slub.c:2831
 slab_alloc_node mm/slub.c:2913 [inline]
 slab_alloc mm/slub.c:2955 [inline]
 kmem_cache_alloc+0x1af/0x2e0 mm/slub.c:2960
 mempool_alloc_slab+0x1d/0x30 mm/mempool.c:513
 mempool_alloc+0x110/0x450 mm/mempool.c:393
 bio_alloc_bioset+0x18c/0x570 block/bio.c:486
 bio_alloc include/linux/bio.h:412 [inline]
 mpage_alloc fs/mpage.c:115 [inline]
 do_mpage_readpage+0x1424/0x1a10 fs/mpage.c:342
 mpage_readahead+0x242/0x4f0 fs/mpage.c:425
 blkdev_readahead+0x1c/0x20 fs/block_dev.c:653
 read_pages+0x16e/0xb50 mm/readahead.c:140
 page_cache_ra_unbounded+0x67f/0x7d0 mm/readahead.c:248
 do_page_cache_ra mm/readahead.c:277 [inline]
 force_page_cache_ra+0x3a9/0x400 mm/readahead.c:308
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_pcp_prepare mm/page_alloc.c:1421 [inline]
 free_unref_page_prepare+0x2b7/0x2d0 mm/page_alloc.c:3336
 free_unref_page mm/page_alloc.c:3391 [inline]
 free_the_page mm/page_alloc.c:5416 [inline]
 __free_pages+0x14b/0x380 mm/page_alloc.c:5427
 __vunmap+0x84d/0x9d0 mm/vmalloc.c:2301
 __vfree mm/vmalloc.c:2350 [inline]
 vfree+0x61/0x90 mm/vmalloc.c:2381
 kcov_put kernel/kcov.c:408 [inline]
 kcov_close+0x2b/0x50 kernel/kcov.c:510
 __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
 get_signal+0xf7d/0x12e0 kernel/signal.c:2793
 arch_do_signal_or_restart+0xbf/0x10f0 arch/x86/kernel/signal.c:805
 handle_signal_work kernel/entry/common.c:145 [inline]
 exit_to_user_mode_loop+0xa2/0xe0 kernel/entry/common.c:169
 exit_to_user_mode_prepare kernel/entry/common.c:199 [inline]
 syscall_exit_to_user_mode+0x68/0x90 kernel/entry/common.c:274
 do_syscall_64+0x3d/0x40 arch/x86/entry/common.c:56
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

Memory state around the buggy address:
 ffff8881286ca900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881286ca980: fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8881286caa00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                                       ^
 ffff8881286caa80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881286cab00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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