================================================================== BUG: KASAN: use-after-free in dx_insert_block+0xd9/0x240 fs/ext4/namei.c:1387 Read of size 157024 at addr ffff88812f013028 by task syz.2.247/1159 CPU: 0 PID: 1159 Comm: syz.2.247 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Call Trace: __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 check_region_inline mm/kasan/generic.c:-1 [inline] kasan_check_range+0x249/0x2a0 mm/kasan/generic.c:189 memmove+0x2d/0x70 mm/kasan/shadow.c:54 dx_insert_block+0xd9/0x240 fs/ext4/namei.c:1387 do_split+0x1a36/0x1df0 fs/ext4/namei.c:2080 make_indexed_dir+0xdd4/0x1480 fs/ext4/namei.c:2392 ext4_add_entry+0xb81/0xdb0 fs/ext4/namei.c:2504 __ext4_link+0x4de/0x770 fs/ext4/namei.c:3522 ext4_link+0x1de/0x270 fs/ext4/namei.c:3563 vfs_link+0x64b/0x800 fs/namei.c:4606 do_linkat+0x1e7/0x750 fs/namei.c:4677 __do_sys_link fs/namei.c:4711 [inline] __se_sys_link fs/namei.c:4709 [inline] __x64_sys_link+0x86/0x90 fs/namei.c:4709 x64_sys_call+0x266/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:87 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: 0033:0x7f97f3397479 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f97f4210028 EFLAGS: 00000246 ORIG_RAX: 0000000000000056 RAX: ffffffffffffffda RBX: 00007f97f35c5fa0 RCX: 00007f97f3397479 RDX: 0000000000000000 RSI: 0000400000000bc0 RDI: 0000400000001240 RBP: 00007f97f34281bc R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f97f35c5fa0 R15: 00007ffde3b6f388 The buggy address belongs to the physical page: page:ffffea0004bc04c0 refcount:4 mapcount:1 mapping:ffff88810048b2d0 index:0x1 pfn:0x12f013 memcg:ffff888100238000 aops:def_blk_aops ino:700002 flags: 0x560000000022205e(referenced|uptodate|dirty|lru|workingset|private|mappedtodisk|mlocked|zone=1) raw: 560000000022205e ffffea0004422348 ffffea0004783148 ffff88810048b2d0 raw: 0000000000000001 ffff88811746a540 0000000400000000 ffff888100238000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x152c40(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_HARDWALL), pid 398, tgid 398 (udevd), ts 120327288909, free_ts 120222125558 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x1f5/0x210 mm/page_alloc.c:2672 prep_new_page+0x1c/0x110 mm/page_alloc.c:2679 get_page_from_freelist+0x2d12/0x2d80 mm/page_alloc.c:4585 __alloc_pages+0x1fa/0x610 mm/page_alloc.c:5926 __folio_alloc+0x12/0x40 mm/page_alloc.c:5959 __folio_alloc_node include/linux/gfp.h:245 [inline] folio_alloc include/linux/gfp.h:274 [inline] filemap_alloc_folio include/linux/pagemap.h:515 [inline] page_cache_ra_unbounded+0x256/0x850 mm/readahead.c:260 do_page_cache_ra mm/readahead.c:313 [inline] force_page_cache_ra mm/readahead.c:344 [inline] page_cache_sync_ra+0x3e3/0x490 mm/readahead.c:735 page_cache_sync_readahead include/linux/pagemap.h:1259 [inline] filemap_get_pages mm/filemap.c:2692 [inline] filemap_read+0x69c/0x2480 mm/filemap.c:2787 blkdev_read_iter+0x426/0x560 block/fops.c:668 call_read_iter include/linux/fs.h:2276 [inline] new_sync_read fs/read_write.c:389 [inline] vfs_read+0x454/0x910 fs/read_write.c:470 ksys_read+0x149/0x250 fs/read_write.c:613 __do_sys_read fs/read_write.c:623 [inline] __se_sys_read fs/read_write.c:621 [inline] __x64_sys_read+0x7b/0x90 fs/read_write.c:621 x64_sys_call+0x2f/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:1 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 page last free stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] free_pages_prepare mm/page_alloc.c:1580 [inline] free_pcp_prepare mm/page_alloc.c:1654 [inline] free_unref_page_prepare+0x7f8/0x800 mm/page_alloc.c:3620 free_unref_page+0x95/0x540 mm/page_alloc.c:3718 free_the_page mm/page_alloc.c:863 [inline] __free_pages+0x67/0x100 mm/page_alloc.c:6016 __free_slab+0xca/0x1a0 mm/slub.c:2044 free_slab mm/slub.c:2059 [inline] discard_slab mm/slub.c:2065 [inline] __unfreeze_partials+0x160/0x190 mm/slub.c:2614 put_cpu_partial+0xa9/0x100 mm/slub.c:2690 __slab_free+0x1c4/0x280 mm/slub.c:3589 do_slab_free mm/slub.c:3666 [inline] ___cache_free+0xbf/0xd0 mm/slub.c:3722 qlink_free mm/kasan/quarantine.c:168 [inline] qlist_free_all+0xc6/0x140 mm/kasan/quarantine.c:187 kasan_quarantine_reduce+0x14a/0x170 mm/kasan/quarantine.c:294 __kasan_slab_alloc+0x24/0x80 mm/kasan/common.c:311 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 getname_flags+0xb9/0x500 fs/namei.c:139 getname+0x19/0x20 fs/namei.c:218 do_sys_openat2+0xeb/0x810 fs/open.c:1337 Memory state around the buggy address: ffff88812f013f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88812f013f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff88812f014000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88812f014080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88812f014100: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb ================================================================== EXT4-fs error (device loop2): ext4_dx_csum_set:531: inode #2: comm syz.2.247: dir seems corrupt? Run e2fsck -D.