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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 ffff8881166e00d4 by task syz.3.3048/11287

CPU: 0 PID: 11287 Comm: syz.3.3048 Tainted: G        W         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: 0033:0x7fd9d4b7be59
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:00007fd9d35d6028 EFLAGS: 00000246 ORIG_RAX: 000000000000005d
RAX: ffffffffffffffda RBX: 00007fd9d4df4fa0 RCX: 00007fd9d4b7be59
RDX: 000000000000ee01 RSI: 0000000000000000 RDI: 0000000000000006
RBP: 00007fd9d4c11d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd9d4df5038 R14: 00007fd9d4df4fa0 R15: 00007fff99566708

Allocated by task 11083:
 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
 sk_prot_alloc+0x5c/0x340 net/core/sock.c:1712
 sk_alloc+0x38/0x4e0 net/core/sock.c:1779
 inet6_create+0x5c0/0xf80 net/ipv6/af_inet6.c:190
 __sock_create+0x38d/0x770 net/socket.c:1436
 sock_create net/socket.c:1487 [inline]
 __sys_socket+0xec/0x190 net/socket.c:1529
 __do_sys_socket net/socket.c:1538 [inline]
 __se_sys_socket net/socket.c:1536 [inline]
 __x64_sys_socket+0x7a/0x90 net/socket.c:1536
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

Freed by task 11080:
 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
 sk_prot_free net/core/sock.c:1760 [inline]
 __sk_destruct+0x4ad/0x600 net/core/sock.c:1848
 sk_destruct net/core/sock.c:1863 [inline]
 __sk_free+0x313/0x410 net/core/sock.c:1874
 sk_free net/core/sock.c:1885 [inline]
 sock_put include/net/sock.h:1907 [inline]
 sk_common_release+0x1ef/0x2c0 net/core/sock.c:3364
 udp_lib_close+0x15/0x20 include/net/udp.h:210
 inet_release+0x183/0x200 net/ipv4/af_inet.c:432
 inet6_release+0x57/0x70 net/ipv6/af_inet6.c:488
 __sock_release net/socket.c:597 [inline]
 sock_close+0xe0/0x270 net/socket.c:1286
 __fput+0x2fb/0x770 fs/file_table.c:281
 ____fput+0x15/0x20 fs/file_table.c:314
 task_work_run+0x127/0x190 kernel/task_work.c:189
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_user_mode_loop+0xcb/0xe0 kernel/entry/common.c:172
 exit_to_user_mode_prepare+0x76/0xa0 kernel/entry/common.c:199
 syscall_exit_to_user_mode+0x1d/0x40 kernel/entry/common.c:274
 do_syscall_64+0x3d/0x40 arch/x86/entry/common.c:56
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

Last potentially related work creation:
 kasan_save_stack+0x3a/0x60 mm/kasan/common.c:38
 __kasan_record_aux_stack+0xd2/0x100 mm/kasan/generic.c:348
 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358
 __call_rcu kernel/rcu/tree.c:2980 [inline]
 call_rcu+0x11a/0x10b0 kernel/rcu/tree.c:3054
 sk_destruct net/core/sock.c:1861 [inline]
 __sk_free+0x330/0x410 net/core/sock.c:1874
 sk_free net/core/sock.c:1885 [inline]
 sock_put include/net/sock.h:1907 [inline]
 sk_common_release+0x1ef/0x2c0 net/core/sock.c:3364
 udp_lib_close+0x15/0x20 include/net/udp.h:210
 inet_release+0x183/0x200 net/ipv4/af_inet.c:432
 inet6_release+0x57/0x70 net/ipv6/af_inet6.c:488
 __sock_release net/socket.c:597 [inline]
 sock_close+0xe0/0x270 net/socket.c:1286
 __fput+0x2fb/0x770 fs/file_table.c:281
 ____fput+0x15/0x20 fs/file_table.c:314
 task_work_run+0x127/0x190 kernel/task_work.c:189
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_user_mode_loop+0xcb/0xe0 kernel/entry/common.c:172
 exit_to_user_mode_prepare+0x76/0xa0 kernel/entry/common.c:199
 syscall_exit_to_user_mode+0x1d/0x40 kernel/entry/common.c:274
 do_syscall_64+0x3d/0x40 arch/x86/entry/common.c:56
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

The buggy address belongs to the object at ffff8881166e0000
 which belongs to the cache UDPv6 of size 1408
The buggy address is located 212 bytes inside of
 1408-byte region [ffff8881166e0000, ffff8881166e0580)
The buggy address belongs to the page:
page:ffffea000459b800 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8881166e0600 pfn:0x1166e0
head:ffffea000459b800 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head)
raw: 4000000000010200 0000000000000000 0000000100000001 ffff88810c12e600
raw: ffff8881166e0600 000000008015000d 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 1447, ts 57027694487, free_ts 57023730670
 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
 sk_prot_alloc+0x5c/0x340 net/core/sock.c:1712
 sk_alloc+0x38/0x4e0 net/core/sock.c:1779
 inet6_create+0x5c0/0xf80 net/ipv6/af_inet6.c:190
 __sock_create+0x38d/0x770 net/socket.c:1436
 sock_create net/socket.c:1487 [inline]
 __sys_socket+0xec/0x190 net/socket.c:1529
 __do_sys_socket net/socket.c:1538 [inline]
 __se_sys_socket net/socket.c:1536 [inline]
 __x64_sys_socket+0x7a/0x90 net/socket.c:1536
 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_pages_ok+0x80b/0x830 mm/page_alloc.c:1629
 free_the_page mm/page_alloc.c:5445 [inline]
 __free_pages+0xd8/0x3b0 mm/page_alloc.c:5454
 __free_slab+0xcf/0x190 mm/slub.c:1899
 free_slab mm/slub.c:1914 [inline]
 discard_slab mm/slub.c:1920 [inline]
 unfreeze_partials+0x15f/0x190 mm/slub.c:2415
 put_cpu_partial+0xc1/0x180 mm/slub.c:2451
 __slab_free+0x2c9/0x3a0 mm/slub.c:3100
 do_slab_free mm/slub.c:3196 [inline]
 ___cache_free+0x10e/0x130 mm/slub.c:3215
 qlink_free+0x50/0x90 mm/kasan/quarantine.c:157
 qlist_free_all+0x5f/0xb0 mm/kasan/quarantine.c:176
 kasan_quarantine_reduce+0x14a/0x160 mm/kasan/quarantine.c:283
 __kasan_slab_alloc+0x2f/0xf0 mm/kasan/common.c:440
 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
 getname+0x19/0x20 fs/namei.c:212
 do_sys_openat2+0xde/0x750 fs/open.c:1213

Memory state around the buggy address:
 ffff8881166dff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8881166e0000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881166e0080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                 ^
 ffff8881166e0100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881166e0180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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