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BUG: KASAN: use-after-free in ext4_get_inode_usage+0x39c/0x520 fs/ext4/xattr.c:821
Read of size 4 at addr ffff88811e59c070 by task syz.6.38/465

CPU: 0 PID: 465 Comm: syz.6.38 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026
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+0x39c/0x520 fs/ext4/xattr.c:821
 __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: 0033:0x7fb6e0d9de99
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:00007fb6e0bff028 EFLAGS: 00000246 ORIG_RAX: 000000000000005e
RAX: ffffffffffffffda RBX: 00007fb6e1025fa0 RCX: 00007fb6e0d9de99
RDX: 000000000000ee01 RSI: 0000000000000000 RDI: 00002000000006c0
RBP: 00007fb6e0e33eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb6e1026038 R14: 00007fb6e1025fa0 R15: 00007ffeb62896b8
 </TASK>

Allocated by task 449:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
 kasan_save_alloc_info+0x1f/0x30 mm/kasan/generic.c:505
 __kasan_slab_alloc+0x72/0x80 mm/kasan/common.c:334
 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+0x166/0x320 mm/slub.c:3408
 anon_vma_chain_alloc mm/rmap.c:145 [inline]
 __anon_vma_prepare+0x51/0x410 mm/rmap.c:199
 anon_vma_prepare include/linux/rmap.h:164 [inline]
 do_anonymous_page mm/memory.c:4284 [inline]
 handle_pte_fault mm/memory.c:5181 [inline]
 __handle_mm_fault mm/memory.c:5325 [inline]
 handle_mm_fault+0x2488/0x26b0 mm/memory.c:5465
 do_user_addr_fault+0x61e/0x1030 arch/x86/mm/fault.c:1372
 handle_page_fault arch/x86/mm/fault.c:1464 [inline]
 exc_page_fault+0x51/0xb0 arch/x86/mm/fault.c:1517
 asm_exc_page_fault+0x27/0x30 arch/x86/include/asm/idtentry.h:608

Freed by task 449:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
 kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:516
 ____kasan_slab_free+0x132/0x180 mm/kasan/common.c:242
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:250
 kasan_slab_free include/linux/kasan.h:178 [inline]
 slab_free_hook mm/slub.c:1750 [inline]
 slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1776
 slab_free mm/slub.c:3712 [inline]
 kmem_cache_free+0x12d/0x300 mm/slub.c:3737
 anon_vma_chain_free mm/rmap.c:150 [inline]
 unlink_anon_vmas+0x2c7/0x5b0 mm/rmap.c:424
 anon_vma_merge include/linux/rmap.h:171 [inline]
 __vma_adjust+0x177b/0x1f10 mm/mmap.c:904
 vma_merge+0x9eb/0xb20 mm/mmap.c:1140
 mprotect_fixup+0x41e/0x940 mm/mprotect.c:607
 do_mprotect_pkey+0x80a/0xbe0 mm/mprotect.c:795
 __do_sys_mprotect mm/mprotect.c:822 [inline]
 __se_sys_mprotect mm/mprotect.c:819 [inline]
 __x64_sys_mprotect+0x80/0x90 mm/mprotect.c:819
 x64_sys_call+0x997/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:11
 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

The buggy address belongs to the object at ffff88811e59c060
 which belongs to the cache anon_vma_chain of size 64
The buggy address is located 16 bytes inside of
 64-byte region [ffff88811e59c060, ffff88811e59c0a0)

The buggy address belongs to the physical page:
page:ffffea0004796700 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11e59c
flags: 0x4000000000000200(slab|zone=1)
raw: 4000000000000200 ffffea0004768b80 dead000000000004 ffff8881001eb980
raw: 0000000000000000 00000000002a002a 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 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 146, tgid 146 (dhcpcd-run-hook), ts 7362653227, free_ts 0
 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
 alloc_slab_page+0x6e/0xf0 include/linux/gfp.h:-1
 allocate_slab mm/slub.c:1967 [inline]
 new_slab+0x98/0x3e0 mm/slub.c:2020
 ___slab_alloc+0x70f/0xb70 mm/slub.c:3177
 __slab_alloc+0x5e/0xa0 mm/slub.c:3263
 slab_alloc_node mm/slub.c:3348 [inline]
 slab_alloc mm/slub.c:3392 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3399 [inline]
 kmem_cache_alloc+0x1a8/0x320 mm/slub.c:3408
 anon_vma_chain_alloc mm/rmap.c:145 [inline]
 anon_vma_fork+0x1f6/0x510 mm/rmap.c:367
 dup_mmap kernel/fork.c:742 [inline]
 dup_mm kernel/fork.c:1670 [inline]
 copy_mm+0xcab/0x1ad0 kernel/fork.c:1722
 copy_process+0x12d8/0x3500 kernel/fork.c:2485
 kernel_clone+0x22f/0x7f0 kernel/fork.c:2900
 __do_sys_clone kernel/fork.c:3043 [inline]
 __se_sys_clone kernel/fork.c:3027 [inline]
 __x64_sys_clone+0x193/0x200 kernel/fork.c:3027
 x64_sys_call+0x990/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:57
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88811e59bf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88811e59bf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88811e59c000: fa fb fb fb fb fb fb fb fc fc fc fc fa fb fb fb
                                                             ^
 ffff88811e59c080: fb fb fb fb fc fc fc fc fa fb fb fb fb fb fb fb
 ffff88811e59c100: fc fc fc fc fa fb fb fb fb fb fb fb fc fc fc fc
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