==================================================================
BUG: KASAN: use-after-free in hlist_add_head include/linux/list.h:930 [inline]
BUG: KASAN: use-after-free in enqueue_timer+0xae/0x480 kernel/time/timer.c:611
Write of size 8 at addr ffff8881448224c0 by task syz.6.2933/9983

CPU: 0 PID: 9983 Comm: syz.6.2933 Tainted: G        W          syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
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_store8_noabort+0x17/0x20 mm/kasan/report_generic.c:356
 hlist_add_head include/linux/list.h:930 [inline]
 enqueue_timer+0xae/0x480 kernel/time/timer.c:611
 internal_add_timer kernel/time/timer.c:640 [inline]
 __mod_timer+0x84c/0xc00 kernel/time/timer.c:1137
 mod_timer+0x1f/0x30 kernel/time/timer.c:1196
 ext4_update_super+0xa54/0xe40 fs/ext4/super.c:6065
 ext4_commit_super+0xe3/0x4b0 fs/ext4/super.c:6084
 ext4_handle_error+0x5c8/0x860 fs/ext4/super.c:678
 __ext4_error_inode+0x2eb/0x590 fs/ext4/super.c:811
 __xattr_check_inode fs/ext4/xattr.c:278 [inline]
 ext4_xattr_ibody_find+0x3ab/0x550 fs/ext4/xattr.c:2200
 ext4_find_inline_data_nolock+0x154/0x3a0 fs/ext4/inline.c:157
 ext4_iget_extra_inode+0x179/0x340 fs/ext4/inode.c:4758
 __ext4_iget+0x1e40/0x3e40 fs/ext4/inode.c:5053
 ext4_orphan_get+0x1d1/0x620 fs/ext4/ialloc.c:1399
 ext4_orphan_cleanup+0x9cd/0x1220 fs/ext4/orphan.c:465
 __ext4_fill_super fs/ext4/super.c:5519 [inline]
 ext4_fill_super+0x7508/0x7a40 fs/ext4/super.c:5650
 get_tree_bdev+0x447/0x690 fs/super.c:1368
 ext4_get_tree+0x1c/0x20 fs/ext4/super.c:5680
 vfs_get_tree+0x9a/0x270 fs/super.c:1575
 do_new_mount+0x25a/0xa20 fs/namespace.c:3078
 path_mount+0x659/0xfc0 fs/namespace.c:3408
 do_mount fs/namespace.c:3421 [inline]
 __do_sys_mount fs/namespace.c:3629 [inline]
 __se_sys_mount+0x320/0x390 fs/namespace.c:3606
 __x64_sys_mount+0xbf/0xd0 fs/namespace.c:3606
 x64_sys_call+0x65d/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:166
 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: 0033:0x7f2cf7d9d20a
Code: 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007f2cf8c93e58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f2cf8c93ee0 RCX: 00007f2cf7d9d20a
RDX: 0000200000000080 RSI: 0000200000000840 RDI: 00007f2cf8c93ea0
RBP: 0000200000000080 R08: 00007f2cf8c93ee0 R09: 00000000c0ed000e
R10: 00000000c0ed000e R11: 0000000000000246 R12: 0000200000000840
R13: 00007f2cf8c93ea0 R14: 000000000000047c R15: 0000200000000940
 </TASK>

Allocated by task 9736:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
 kasan_save_alloc_info+0x25/0x30 mm/kasan/generic.c:505
 ____kasan_kmalloc mm/kasan/common.c:380 [inline]
 __kasan_kmalloc+0x95/0xb0 mm/kasan/common.c:389
 kasan_kmalloc include/linux/kasan.h:212 [inline]
 kmalloc_trace+0x40/0xb0 mm/slab_common.c:1033
 kmalloc include/linux/slab.h:563 [inline]
 kzalloc include/linux/slab.h:699 [inline]
 ext4_alloc_sbi fs/ext4/super.c:4258 [inline]
 ext4_fill_super+0x11d/0x7a40 fs/ext4/super.c:5637
 get_tree_bdev+0x447/0x690 fs/super.c:1368
 ext4_get_tree+0x1c/0x20 fs/ext4/super.c:5680
 vfs_get_tree+0x9a/0x270 fs/super.c:1575
 do_new_mount+0x25a/0xa20 fs/namespace.c:3078
 path_mount+0x659/0xfc0 fs/namespace.c:3408
 do_mount fs/namespace.c:3421 [inline]
 __do_sys_mount fs/namespace.c:3629 [inline]
 __se_sys_mount+0x320/0x390 fs/namespace.c:3606
 __x64_sys_mount+0xbf/0xd0 fs/namespace.c:3606
 x64_sys_call+0x65d/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:166
 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

Freed by task 9205:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
 kasan_save_free_info+0x31/0x50 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+0xb7/0x1b0 mm/slub.c:3728
 kfree+0x6f/0xf0 mm/slab_common.c:990
 ext4_put_super+0x9b6/0xac0 fs/ext4/super.c:1313
 generic_shutdown_super+0x15f/0x370 fs/super.c:503
 kill_block_super+0x7f/0xf0 fs/super.c:1472
 deactivate_locked_super+0xb5/0x120 fs/super.c:334
 deactivate_super+0xaf/0xe0 fs/super.c:365
 cleanup_mnt+0x474/0x500 fs/namespace.c:1191
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1198
 task_work_run+0x1e1/0x250 kernel/task_work.c:203
 exit_task_work include/linux/task_work.h:39 [inline]
 do_exit+0xa35/0x2660 kernel/exit.c:886
 do_group_exit+0x210/0x2d0 kernel/exit.c:1028
 __do_sys_exit_group kernel/exit.c:1039 [inline]
 __se_sys_exit_group kernel/exit.c:1037 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1037
 x64_sys_call+0x7b4/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:232
 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 ffff888144822000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 1216 bytes inside of
 4096-byte region [ffff888144822000, ffff888144823000)

The buggy address belongs to the physical page:
page:ffffea0005120800 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x144820
head:ffffea0005120800 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head|zone=1)
raw: 4000000000010200 dead000000000100 dead000000000122 ffff888100043380
raw: 0000000000000000 0000000000040004 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 3107, tgid 3107 (syz-executor), ts 137961772005, free_ts 114483339831
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1f5/0x210 mm/page_alloc.c:2643
 prep_new_page+0x1c/0x110 mm/page_alloc.c:2650
 get_page_from_freelist+0x2d12/0x2d80 mm/page_alloc.c:4554
 __alloc_pages+0x1d9/0x480 mm/page_alloc.c:5868
 alloc_slab_page+0x6e/0xf0 include/linux/gfp.h:-1
 allocate_slab mm/slub.c:1967 [inline]
 new_slab+0x98/0x3d0 mm/slub.c:2020
 ___slab_alloc+0x6bd/0xb20 mm/slub.c:3177
 __slab_alloc+0x5e/0xa0 mm/slub.c:3263
 slab_alloc_node mm/slub.c:3348 [inline]
 __kmem_cache_alloc_node+0x203/0x2c0 mm/slub.c:3423
 kmalloc_trace+0x29/0xb0 mm/slab_common.c:1028
 kmalloc include/linux/slab.h:563 [inline]
 kzalloc include/linux/slab.h:699 [inline]
 kobject_uevent_env+0x287/0x730 lib/kobject_uevent.c:539
 kobject_uevent+0x1d/0x30 lib/kobject_uevent.c:657
 netdev_queue_add_kobject net/core/net-sysfs.c:1671 [inline]
 netdev_queue_update_kobjects+0x22c/0x470 net/core/net-sysfs.c:1712
 register_queue_kobjects net/core/net-sysfs.c:1773 [inline]
 netdev_register_kobject+0x2af/0x360 net/core/net-sysfs.c:2013
 register_netdevice+0xeb1/0x1530 net/core/dev.c:10168
 veth_newlink+0x60f/0xc80 drivers/net/veth.c:1745
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1551 [inline]
 free_pcp_prepare mm/page_alloc.c:1625 [inline]
 free_unref_page_prepare+0x742/0x750 mm/page_alloc.c:3589
 free_unref_page+0x95/0x540 mm/page_alloc.c:3687
 free_the_page mm/page_alloc.c:836 [inline]
 __free_pages+0x67/0x100 mm/page_alloc.c:5957
 __vunmap+0x9c0/0xb80 mm/vmalloc.c:2739
 __vfree mm/vmalloc.c:2788 [inline]
 vfree+0x61/0x90 mm/vmalloc.c:2819
 kvfree+0x26/0x40 mm/util.c:637
 ext4_xattr_move_to_block fs/ext4/xattr.c:2642 [inline]
 ext4_xattr_make_inode_space fs/ext4/xattr.c:2705 [inline]
 ext4_expand_extra_isize_ea+0x1023/0x1a50 fs/ext4/xattr.c:2797
 __ext4_expand_extra_isize+0x2fe/0x3e0 fs/ext4/inode.c:5981
 ext4_try_to_expand_extra_isize fs/ext4/inode.c:6024 [inline]
 __ext4_mark_inode_dirty+0x3cf/0x600 fs/ext4/inode.c:6102
 ext4_evict_inode+0xc17/0x1470 fs/ext4/inode.c:279
 evict+0x4d7/0x8f0 fs/inode.c:708
 iput_final fs/inode.c:1844 [inline]
 iput+0x620/0x670 fs/inode.c:1870
 ext4_process_orphan+0x2b1/0x320 fs/ext4/orphan.c:358
 ext4_orphan_cleanup+0xb1a/0x1220 fs/ext4/orphan.c:472
 __ext4_fill_super fs/ext4/super.c:5519 [inline]
 ext4_fill_super+0x7508/0x7a40 fs/ext4/super.c:5650
 get_tree_bdev+0x447/0x690 fs/super.c:1368

Memory state around the buggy address:
 ffff888144822380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888144822400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888144822480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff888144822500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888144822580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
EXT4-fs error (device loop6): ext4_orphan_get:1404: comm syz.6.2933: couldn't read orphan inode 15 (err -117)
EXT4-fs (loop6): mounted filesystem without journal. Quota mode: none.
EXT4-fs (loop6): unmounting filesystem.