[EXT4 FS bs=1024, gc=1, bpg=131072, ipg=32, mo=e000c01c, mo2=0002]
System zones: 0-1, 3-36
EXT4-fs error (device loop7): ext4_orphan_get:1431: comm syz.7.898: bad orphan inode 134217728
==================================================================
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 ffff8881310c44f0 by task syz.7.898/3552

CPU: 1 PID: 3552 Comm: syz.7.898 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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+0x859/0xc00 kernel/time/timer.c:1137
 mod_timer+0x1f/0x30 kernel/time/timer.c:1196
 ext4_update_super+0xa57/0xe30 fs/ext4/super.c:6095
 ext4_commit_super+0xd8/0x4a0 fs/ext4/super.c:6114
 ext4_handle_error+0x6b6/0x870 fs/ext4/super.c:678
 __ext4_error+0x24f/0x440 fs/ext4/super.c:779
 ext4_orphan_get+0xef/0x620 fs/ext4/ialloc.c:1431
 ext4_orphan_cleanup+0xa02/0x1270 fs/ext4/orphan.c:465
 __ext4_fill_super fs/ext4/super.c:5561 [inline]
 ext4_fill_super+0x6a53/0x73e0 fs/ext4/super.c:5680
 get_tree_bdev+0x450/0x6a0 fs/super.c:1371
 ext4_get_tree+0x1c/0x20 fs/ext4/super.c:5710
 vfs_get_tree+0x9a/0x270 fs/super.c:1578
 do_new_mount+0x251/0xb40 fs/namespace.c:3081
 path_mount+0x640/0xfd0 fs/namespace.c:3411
 do_mount fs/namespace.c:3424 [inline]
 __do_sys_mount fs/namespace.c:3632 [inline]
 __se_sys_mount+0x320/0x390 fs/namespace.c:3609
 __x64_sys_mount+0xbf/0xd0 fs/namespace.c:3609
 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: 0033:0x7f4bedb9f34a
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:00007f4beeaede58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f4beeaedee0 RCX: 00007f4bedb9f34a
RDX: 0000200000000080 RSI: 00002000000002c0 RDI: 00007f4beeaedea0
RBP: 0000200000000080 R08: 00007f4beeaedee0 R09: 0000000000000404
R10: 0000000000000404 R11: 0000000000000246 R12: 00002000000002c0
R13: 00007f4beeaedea0 R14: 00000000000005fd R15: 00002000000001c0
 </TASK>

Allocated by task 3552:
 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_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]
 scm_fp_copy net/core/scm.c:86 [inline]
 __scm_send+0x5f9/0x13c0 net/core/scm.c:177
 scm_send include/net/scm.h:100 [inline]
 unix_stream_sendmsg+0x142/0xa80 net/unix/af_unix.c:2173
 sock_sendmsg_nosec net/socket.c:716 [inline]
 __sock_sendmsg net/socket.c:728 [inline]
 ____sys_sendmsg+0x5fb/0x9c0 net/socket.c:2508
 ___sys_sendmsg+0x2a2/0x360 net/socket.c:2562
 __sys_sendmsg net/socket.c:2591 [inline]
 __do_sys_sendmsg net/socket.c:2600 [inline]
 __se_sys_sendmsg net/socket.c:2598 [inline]
 __x64_sys_sendmsg+0x20d/0x2e0 net/socket.c:2598
 x64_sys_call+0x171/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:47
 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 3552:
 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+0xb7/0x1b0 mm/slub.c:3728
 kfree+0x6f/0xf0 mm/slab_common.c:990
 __scm_destroy+0xf1/0x120 net/core/scm.c:145
 scm_destroy+0x7c/0x90 include/net/scm.h:86
 unix_stream_sendmsg+0x9c5/0xa80 net/unix/af_unix.c:2261
 sock_sendmsg_nosec net/socket.c:716 [inline]
 __sock_sendmsg net/socket.c:728 [inline]
 ____sys_sendmsg+0x5fb/0x9c0 net/socket.c:2508
 ___sys_sendmsg+0x2a2/0x360 net/socket.c:2562
 __sys_sendmsg net/socket.c:2591 [inline]
 __do_sys_sendmsg net/socket.c:2600 [inline]
 __se_sys_sendmsg net/socket.c:2598 [inline]
 __x64_sys_sendmsg+0x20d/0x2e0 net/socket.c:2598
 x64_sys_call+0x171/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:47
 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 ffff8881310c4000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 1264 bytes inside of
 4096-byte region [ffff8881310c4000, ffff8881310c5000)

The buggy address belongs to the physical page:
page:ffffea0004c43000 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1310c0
head:ffffea0004c43000 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head|zone=1)
raw: 4000000000010200 ffffea000439bc00 dead000000000002 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 289, tgid 289 (syz-executor), ts 32017968817, 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]
 __kmem_cache_alloc_node+0x204/0x2d0 mm/slub.c:3423
 __do_kmalloc_node mm/slab_common.c:937 [inline]
 __kmalloc+0xa4/0x1e0 mm/slab_common.c:951
 kmalloc include/linux/slab.h:568 [inline]
 kzalloc include/linux/slab.h:699 [inline]
 ops_init+0x88/0x470 net/core/net_namespace.c:128
 setup_net+0x4b4/0xcd0 net/core/net_namespace.c:335
 copy_net_ns+0x355/0x5c0 net/core/net_namespace.c:481
 create_new_namespaces+0x3a8/0x660 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x120/0x170 kernel/nsproxy.c:226
 ksys_unshare+0x4d7/0x820 kernel/fork.c:3426
page_owner free stack trace missing

Memory state around the buggy address:
 ffff8881310c4380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881310c4400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881310c4480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                             ^
 ffff8881310c4500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881310c4580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
EXT4-fs (loop7): mounted filesystem without journal. Quota mode: writeback.