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BUG: KASAN: use-after-free in ext4_get_inode_usage+0x3a1/0x520 fs/ext4/xattr.c:817
Read of size 4 at addr ffff88811f72801c by task syz.9.605/2471

CPU: 1 PID: 2471 Comm: syz.9.605 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:77
 dump_stack_lvl+0x1a7/0x208 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_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308
 ext4_get_inode_usage+0x3a1/0x520 fs/ext4/xattr.c:817
 __dquot_transfer+0x192/0x20d0 fs/quota/dquot.c:2017
 dquot_transfer+0x2f1/0x460 fs/quota/dquot.c:2169
 ext4_setattr+0x715/0x1950 fs/ext4/inode.c:5577
 notify_change+0xab3/0xe40 fs/attr.c:410
 chown_common+0x335/0x500 fs/open.c:675
 vfs_fchown fs/open.c:742 [inline]
 ksys_fchown+0xef/0x160 fs/open.c:753
 __do_sys_fchown fs/open.c:761 [inline]
 __se_sys_fchown fs/open.c:759 [inline]
 __x64_sys_fchown+0x7a/0x90 fs/open.c:759
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fb198955e59
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:00007fb19736e028 EFLAGS: 00000246 ORIG_RAX: 000000000000005d
RAX: ffffffffffffffda RBX: 00007fb198bcf180 RCX: 00007fb198955e59
RDX: 000000000000ee01 RSI: 0000000000000000 RDI: 000000000000000f
RBP: 00007fb1989ebd6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb198bcf218 R14: 00007fb198bcf180 R15: 00007fff411e75a8

Allocated by task 95:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:45 [inline]
 set_alloc_info mm/kasan/common.c:430 [inline]
 __kasan_slab_alloc+0xbd/0xf0 mm/kasan/common.c:463
 kasan_slab_alloc include/linux/kasan.h:244 [inline]
 slab_post_alloc_hook+0x5d/0x2f0 mm/slab.h:580
 slab_alloc_node mm/slub.c:2952 [inline]
 slab_alloc mm/slub.c:2960 [inline]
 kmem_cache_alloc+0x162/0x2d0 mm/slub.c:2965
 getname_flags+0xb9/0x500 fs/namei.c:141
 user_path_at_empty+0x2f/0x50 fs/namei.c:2748
 do_readlinkat+0xd9/0x490 fs/stat.c:414
 __do_sys_readlink fs/stat.c:447 [inline]
 __se_sys_readlink fs/stat.c:444 [inline]
 __x64_sys_readlink+0x7f/0x90 fs/stat.c:444
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

Freed by task 95:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4a/0x70 mm/kasan/common.c:45
 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370
 ____kasan_slab_free+0x125/0x160 mm/kasan/common.c:362
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:370
 kasan_slab_free include/linux/kasan.h:220 [inline]
 slab_free_hook mm/slub.c:1600 [inline]
 slab_free_freelist_hook+0xc5/0x190 mm/slub.c:1626
 slab_free mm/slub.c:3208 [inline]
 kmem_cache_free+0x100/0x2d0 mm/slub.c:3224
 putname fs/namei.c:262 [inline]
 filename_lookup+0x4b3/0x6a0 fs/namei.c:2478
 user_path_at_empty+0x43/0x50 fs/namei.c:2748
 do_readlinkat+0xd9/0x490 fs/stat.c:414
 __do_sys_readlink fs/stat.c:447 [inline]
 __se_sys_readlink fs/stat.c:444 [inline]
 __x64_sys_readlink+0x7f/0x90 fs/stat.c:444
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

The buggy address belongs to the object at ffff88811f728000
 which belongs to the cache names_cache of size 4096
The buggy address is located 28 bytes inside of
 4096-byte region [ffff88811f728000, ffff88811f729000)
The buggy address belongs to the page:
page:ffffea00047dca00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11f728
head:ffffea00047dca00 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head)
raw: 4000000000010200 dead000000000100 dead000000000122 ffff88810018b800
raw: 0000000000000000 0000000000070007 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 303, ts 54074112066, free_ts 53974323496
 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+0x223b/0x23d0 mm/page_alloc.c:4254
 __alloc_pages_nodemask+0x290/0x620 mm/page_alloc.c:5384
 alloc_slab_page mm/slub.c:-1 [inline]
 allocate_slab mm/slub.c:1813 [inline]
 new_slab+0x84/0x3f0 mm/slub.c:1874
 new_slab_objects mm/slub.c:2632 [inline]
 ___slab_alloc+0x2a6/0x450 mm/slub.c:2796
 __slab_alloc+0x63/0xa0 mm/slub.c:2836
 slab_alloc_node mm/slub.c:2918 [inline]
 slab_alloc mm/slub.c:2960 [inline]
 kmem_cache_alloc+0x1ac/0x2d0 mm/slub.c:2965
 getname_flags+0xb9/0x500 fs/namei.c:141
 getname fs/namei.c:212 [inline]
 __do_sys_rename fs/namei.c:4679 [inline]
 __se_sys_rename fs/namei.c:4676 [inline]
 __x64_sys_rename+0x6e/0x90 fs/namei.c:4676
 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:5443 [inline]
 __free_pages+0x146/0x3b0 mm/page_alloc.c:5454
 free_pages+0x82/0x90 mm/page_alloc.c:5465
 kasan_depopulate_vmalloc_pte+0x6b/0x90 mm/kasan/shadow.c:354
 apply_to_pte_range mm/memory.c:2504 [inline]
 apply_to_pmd_range mm/memory.c:2540 [inline]
 apply_to_pud_range mm/memory.c:2568 [inline]
 apply_to_p4d_range mm/memory.c:2596 [inline]
 __apply_to_page_range+0x74e/0x9e0 mm/memory.c:2623
 apply_to_existing_page_range+0x38/0x50 mm/memory.c:2874
 kasan_release_vmalloc+0x97/0xb0 mm/kasan/shadow.c:464
 __purge_vmap_area_lazy+0x1322/0x1440 mm/vmalloc.c:1382
 _vm_unmap_aliases+0x2f8/0x380 mm/vmalloc.c:1779
 vm_unmap_aliases+0x19/0x20 mm/vmalloc.c:1802
 change_page_attr_set_clr+0x323/0xc80 arch/x86/mm/pat/set_memory.c:1732
 change_page_attr_clear arch/x86/mm/pat/set_memory.c:1789 [inline]
 set_memory_ro+0x89/0xd0 arch/x86/mm/pat/set_memory.c:1935
 bpf_jit_binary_lock_ro include/linux/filter.h:846 [inline]
 bpf_int_jit_compile+0x84af/0x8960 arch/x86/net/bpf_jit_comp.c:2134
 bpf_prog_select_runtime+0x742/0x9e0 kernel/bpf/core.c:1876
 bpf_prog_load+0xff5/0x14a0 kernel/bpf/syscall.c:2238
 __do_sys_bpf kernel/bpf/syscall.c:4435 [inline]
 __se_sys_bpf+0x49a/0x740 kernel/bpf/syscall.c:4391

Memory state around the buggy address:
 ffff88811f727f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88811f727f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88811f728000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff88811f728080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88811f728100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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