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loop2: detected capacity change from 0 to 4096
EXT4-fs (loop2): mounted filesystem without journal. Quota mode: writeback.
EXT4-fs error (device loop2): xattr_find_entry:297: inode #15: comm syz.2.21: corrupted xattr entries
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BUG: KASAN: use-after-free in ext4_get_inode_usage+0x371/0x520 fs/ext4/xattr.c:823
Read of size 4 at addr ffff88812980e000 by task syz.2.21/381

CPU: 0 PID: 381 Comm: syz.2.21 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
 <TASK>
 __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
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:350
 ext4_get_inode_usage+0x371/0x520 fs/ext4/xattr.c:823
 __dquot_transfer+0x1a0/0x2370 fs/quota/dquot.c:2015
 dquot_transfer+0x620/0x7d0 fs/quota/dquot.c:2174
 ext4_setattr+0xa01/0x1c80 fs/ext4/inode.c:5529
 notify_change+0xd33/0x1030 fs/attr.c:499
 chown_common+0x448/0x5f0 fs/open.c:737
 do_fchownat+0x147/0x240 fs/open.c:768
 __do_sys_lchown fs/open.c:793 [inline]
 __se_sys_lchown fs/open.c:791 [inline]
 __x64_sys_lchown+0x85/0x90 fs/open.c:791
 x64_sys_call+0x951/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:95
 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: 0033:0x7f484639de59
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:00007fff4867e348 EFLAGS: 00000246 ORIG_RAX: 000000000000005e
RAX: ffffffffffffffda RBX: 00007f4846625fa0 RCX: 00007f484639de59
RDX: 0000000000000000 RSI: 00000000000000ff RDI: 00002000000004c0
RBP: 00007f4846433e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4846625fac R14: 00007f4846625fa0 R15: 00007f4846625fa0
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0004a60380 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x12980e
flags: 0x4000000000000000(zone=1)
raw: 4000000000000000 ffffea0004a603c8 ffffea0004a70208 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 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 0x140cca(GFP_HIGHUSER_MOVABLE|__GFP_COMP), pid 379, tgid 379 (syz.2.20), ts 29458302815, free_ts 29542081346
 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+0x2ca9/0x2d20 mm/page_alloc.c:4586
 __alloc_pages+0x1fa/0x610 mm/page_alloc.c:5930
 __folio_alloc+0x12/0x40 mm/page_alloc.c:5963
 __folio_alloc_node include/linux/gfp.h:245 [inline]
 folio_alloc include/linux/gfp.h:274 [inline]
 shmem_alloc_folio mm/shmem.c:1597 [inline]
 shmem_alloc_and_acct_folio+0x6dd/0x8c0 mm/shmem.c:1622
 shmem_get_folio_gfp+0xd6d/0x20f0 mm/shmem.c:1951
 shmem_get_folio mm/shmem.c:2082 [inline]
 shmem_write_begin+0xea/0x2c0 mm/shmem.c:2567
 generic_perform_write+0x32d/0x740 mm/filemap.c:3915
 __generic_file_write_iter+0x17a/0x230 mm/filemap.c:4014
 generic_file_write_iter+0xae/0x310 mm/filemap.c:4043
 call_write_iter include/linux/fs.h:2282 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x5ef/0xd00 fs/read_write.c:584
 ksys_write+0x14a/0x260 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x7b/0x90 fs/read_write.c:646
 x64_sys_call+0x27b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
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+0x80c/0x820 mm/page_alloc.c:3621
 free_unref_page_list+0x117/0x8d0 mm/page_alloc.c:3772
 release_pages+0xc7e/0xce0 mm/swap.c:1053
 __pagevec_release+0x71/0xe0 mm/swap.c:1073
 pagevec_release include/linux/pagevec.h:71 [inline]
 folio_batch_release include/linux/pagevec.h:135 [inline]
 shmem_undo_range+0x564/0x14e0 mm/shmem.c:951
 shmem_truncate_range mm/shmem.c:1067 [inline]
 shmem_evict_inode+0x21f/0x9c0 mm/shmem.c:1176
 evict+0x4c4/0x8c0 fs/inode.c:709
 iput_final fs/inode.c:1845 [inline]
 iput+0x633/0x690 fs/inode.c:1871
 dentry_unlink_inode+0x346/0x3f0 fs/dcache.c:405
 __dentry_kill+0x46c/0x680 fs/dcache.c:611
 dentry_kill+0xc0/0x2a0 fs/dcache.c:-1
 dput+0x42/0x80 fs/dcache.c:918
 __fput+0x5c0/0x8f0 fs/file_table.c:328
 ____fput+0x15/0x20 fs/file_table.c:348
 task_work_run+0x1e1/0x250 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0x9b/0xb0 kernel/entry/common.c:177

Memory state around the buggy address:
 ffff88812980df00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88812980df80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88812980e000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff88812980e080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88812980e100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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