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BUG: KASAN: use-after-free in ext4_xattr_rehash fs/ext4/xattr.c:3154 [inline]
BUG: KASAN: use-after-free in ext4_xattr_set_entry+0xe22/0x37d0 fs/ext4/xattr.c:1832
Read of size 4 at addr ffff88813037805c by task syz.3.2963/11715

CPU: 0 PID: 11715 Comm: syz.3.2963 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:88
 dump_stack_lvl+0xee/0x150 lib/dump_stack.c:106
 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:427 [inline]
 kasan_report+0xf1/0x140 mm/kasan/report.c:444
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308
 ext4_xattr_rehash fs/ext4/xattr.c:3154 [inline]
 ext4_xattr_set_entry+0xe22/0x37d0 fs/ext4/xattr.c:1832
 ext4_xattr_block_set+0x4fc/0x2cb0 fs/ext4/xattr.c:1936
 ext4_xattr_set_handle+0xbd5/0x12b0 fs/ext4/xattr.c:2422
 ext4_xattr_set+0x22a/0x320 fs/ext4/xattr.c:2523
 ext4_xattr_trusted_set+0x3c/0x50 fs/ext4/xattr_trusted.c:38
 __vfs_setxattr+0x3e1/0x430 fs/xattr.c:182
 __vfs_setxattr_noperm+0x12a/0x5e0 fs/xattr.c:216
 __vfs_setxattr_locked+0x212/0x230 fs/xattr.c:277
 vfs_setxattr+0x168/0x2f0 fs/xattr.c:303
 do_setxattr fs/xattr.c:588 [inline]
 setxattr+0x2da/0x300 fs/xattr.c:611
 path_setxattr+0x142/0x280 fs/xattr.c:630
 __do_sys_lsetxattr fs/xattr.c:653 [inline]
 __se_sys_lsetxattr fs/xattr.c:649 [inline]
 __x64_sys_lsetxattr+0xc2/0xe0 fs/xattr.c:649
 x64_sys_call+0x8cc/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:190
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f26d7d9f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f26d67e6038 EFLAGS: 00000246 ORIG_RAX: 00000000000000bd
RAX: ffffffffffffffda RBX: 00007f26d7ff6090 RCX: 00007f26d7d9f749
RDX: 0000200000000440 RSI: 00002000000000c0 RDI: 0000200000000100
RBP: 00007f26d7e23f91 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000fe37 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f26d7ff6128 R14: 00007f26d7ff6090 R15: 00007ffe85c5a348
 </TASK>

The buggy address belongs to the page:
page:ffffea0004c0de00 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x100 pfn:0x130378
flags: 0x4000000000000000(zone=1)
raw: 4000000000000000 ffffea0005265e08 ffffea000503b408 0000000000000000
raw: 0000000000000100 0000000000000003 00000000ffffff7f 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Movable, gfp_mask 0x100cca(GFP_HIGHUSER_MOVABLE), pid 11433, ts 504019918365, free_ts 504333625107
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x192/0x1b0 mm/page_alloc.c:2605
 prep_new_page+0x1c/0x110 mm/page_alloc.c:2611
 get_page_from_freelist+0x2cc5/0x2d50 mm/page_alloc.c:4485
 __alloc_pages+0x18f/0x440 mm/page_alloc.c:5808
 __alloc_pages_node include/linux/gfp.h:595 [inline]
 alloc_pages_node include/linux/gfp.h:609 [inline]
 alloc_pages include/linux/gfp.h:622 [inline]
 shmem_alloc_page mm/shmem.c:1591 [inline]
 shmem_alloc_and_acct_page+0x42b/0x870 mm/shmem.c:1616
 shmem_getpage_gfp+0xfe5/0x2310 mm/shmem.c:1912
 shmem_getpage mm/shmem.c:156 [inline]
 shmem_fallocate+0x7f7/0xcf0 mm/shmem.c:2764
 vfs_fallocate+0x4b4/0x590 fs/open.c:309
 ksys_fallocate fs/open.c:332 [inline]
 __do_sys_fallocate fs/open.c:340 [inline]
 __se_sys_fallocate fs/open.c:338 [inline]
 __x64_sys_fallocate+0xc0/0x110 fs/open.c:338
 x64_sys_call+0x7ec/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:286
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1472 [inline]
 free_pcp_prepare mm/page_alloc.c:1544 [inline]
 free_unref_page_prepare+0x542/0x550 mm/page_alloc.c:3534
 free_unref_page_list+0x134/0x9d0 mm/page_alloc.c:3671
 release_pages+0xfda/0x1030 mm/swap.c:1014
 __pagevec_release+0x71/0xe0 mm/swap.c:1034
 pagevec_release include/linux/pagevec.h:81 [inline]
 shmem_undo_range+0x53f/0x13d0 mm/shmem.c:969
 shmem_truncate_range mm/shmem.c:1068 [inline]
 shmem_evict_inode+0x1fd/0x9c0 mm/shmem.c:1150
 evict+0x485/0x870 fs/inode.c:650
 iput_final fs/inode.c:1779 [inline]
 iput+0x635/0x7c0 fs/inode.c:1805
 do_unlinkat+0x375/0x6b0 fs/namei.c:4363
 __do_sys_unlink fs/namei.c:4404 [inline]
 __se_sys_unlink fs/namei.c:4402 [inline]
 __x64_sys_unlink+0x49/0x50 fs/namei.c:4402
 x64_sys_call+0x878/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:88
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Memory state around the buggy address:
 ffff888130377f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888130377f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888130378000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                    ^
 ffff888130378080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888130378100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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