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BUG: KASAN: use-after-free in ext4_htree_fill_tree+0x1066/0x10d0 fs/ext4/namei.c:1221
Read of size 1 at addr ffff8881268b5a67 by task syz-executor/446

CPU: 0 PID: 446 Comm: syz-executor Not tainted 5.10.236-syzkaller-1007372-gab07aeb2c93d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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: 0033:0x7f5a0cb6bbf3
Code: c1 66 0f 1f 44 00 00 48 83 c4 08 48 89 ef 5b 5d e9 f2 44 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:00007ffe3aecf3e8 EFLAGS: 00000293 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 000055556e9d94e0 RCX: 00007f5a0cb6bbf3
RDX: 0000000000008000 RSI: 000055556e9d94e0 RDI: 0000000000000005
RBP: 000055556e9d94b4 R08: 0000000000028b61 R09: 0000000000000000
R10: 00007f5a0cc98ca0 R11: 0000000000000293 R12: ffffffffffffffa8
R13: 0000000000000010 R14: 000055556e9d94b0 R15: 000000000000d95f

The buggy address belongs to the page:
page:ffffea00049a2d40 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1268b5
flags: 0x4000000000000000()
raw: 4000000000000000 ffffea00049a2d88 ffffea00049a2d08 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x102dc2(GFP_HIGHUSER|__GFP_NOWARN|__GFP_ZERO), pid 450, ts 55678122620, free_ts 55829889151
 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:5349
 __vmalloc_area_node mm/vmalloc.c:-1 [inline]
 __vmalloc_node_range+0x353/0x780 mm/vmalloc.c:2623
 alloc_thread_stack_node kernel/fork.c:253 [inline]
 dup_task_struct+0x40f/0xbd0 kernel/fork.c:916
 copy_process+0x5af/0x3310 kernel/fork.c:2016
 kernel_clone+0x23f/0x940 kernel/fork.c:2574
 __do_sys_clone3 kernel/fork.c:2858 [inline]
 __se_sys_clone3 kernel/fork.c:2842 [inline]
 __x64_sys_clone3+0x296/0x2f0 kernel/fork.c:2842
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
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:5408 [inline]
 __free_pages+0x14b/0x380 mm/page_alloc.c:5419
 __vunmap+0x84d/0x9d0 mm/vmalloc.c:2301
 free_work+0x5a/0x80 mm/vmalloc.c:69
 process_one_work+0x6e1/0xba0 kernel/workqueue.c:2301
 worker_thread+0xa6a/0x13b0 kernel/workqueue.c:2447
 kthread+0x346/0x3d0 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298

Memory state around the buggy address:
 ffff8881268b5900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881268b5980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8881268b5a00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                       ^
 ffff8881268b5a80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881268b5b00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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