==================================================================
BUG: KASAN: use-after-free in __hlist_del include/linux/list.h:791 [inline]
BUG: KASAN: use-after-free in detach_timer kernel/time/timer.c:824 [inline]
BUG: KASAN: use-after-free in expire_timers kernel/time/timer.c:1482 [inline]
BUG: KASAN: use-after-free in __run_timers+0x759/0xb60 kernel/time/timer.c:1817
Write of size 8 at addr ffff8881e1e331c8 by task ksoftirqd/0/10

CPU: 0 PID: 10 Comm: ksoftirqd/0 Not tainted 5.4.292-syzkaller-00021-gcd8e74fa0fa3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 __dump_stack+0x1e/0x20 lib/dump_stack.c:77
 dump_stack+0x15b/0x1b8 lib/dump_stack.c:118
 print_address_description+0x8d/0x4c0 mm/kasan/report.c:384
 __kasan_report+0xef/0x120 mm/kasan/report.c:516
 kasan_report+0x30/0x60 mm/kasan/common.c:653
 __asan_report_store8_noabort+0x17/0x20 mm/kasan/generic_report.c:137
 __hlist_del include/linux/list.h:791 [inline]
 detach_timer kernel/time/timer.c:824 [inline]
 expire_timers kernel/time/timer.c:1482 [inline]
 __run_timers+0x759/0xb60 kernel/time/timer.c:1817
 run_timer_softirq+0x6a/0xf0 kernel/time/timer.c:1830
 __do_softirq+0x236/0x660 kernel/softirq.c:292
 run_ksoftirqd+0x23/0x30 kernel/softirq.c:603
 smpboot_thread_fn+0x474/0x850 kernel/smpboot.c:165
 kthread+0x31e/0x3a0 kernel/kthread.c:288
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:354

Allocated by task 731:
 save_stack mm/kasan/common.c:70 [inline]
 set_track mm/kasan/common.c:78 [inline]
 __kasan_kmalloc+0x162/0x200 mm/kasan/common.c:529
 kasan_slab_alloc+0x12/0x20 mm/kasan/common.c:537
 slab_post_alloc_hook mm/slab.h:584 [inline]
 slab_alloc_node mm/slub.c:2829 [inline]
 slab_alloc mm/slub.c:2837 [inline]
 kmem_cache_alloc+0xe2/0x270 mm/slub.c:2842
 shmem_alloc_inode+0x1a/0x30 mm/shmem.c:3719
 alloc_inode fs/inode.c:231 [inline]
 new_inode_pseudo+0x62/0x210 fs/inode.c:966
 new_inode+0x28/0x1e0 fs/inode.c:995
 shmem_get_inode+0x107/0x630 mm/shmem.c:2252
 shmem_symlink+0x9e/0x4d0 mm/shmem.c:3068
 vfs_symlink+0x337/0x4c0 fs/namei.c:4276
 do_symlinkat+0x103/0x3b0 fs/namei.c:4303
 __do_sys_symlinkat fs/namei.c:4317 [inline]
 __se_sys_symlinkat fs/namei.c:4314 [inline]
 __x64_sys_symlinkat+0x7b/0x90 fs/namei.c:4314
 do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1

Freed by task 331:
 save_stack mm/kasan/common.c:70 [inline]
 set_track mm/kasan/common.c:78 [inline]
 kasan_set_free_info mm/kasan/common.c:345 [inline]
 __kasan_slab_free+0x1c3/0x280 mm/kasan/common.c:487
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:496
 slab_free_hook mm/slub.c:1455 [inline]
 slab_free_freelist_hook+0xb7/0x180 mm/slub.c:1494
 slab_free mm/slub.c:3080 [inline]
 kmem_cache_free+0x10c/0x2c0 mm/slub.c:3096
 shmem_free_in_core_inode+0x90/0xb0 mm/shmem.c:3729
 i_callback+0x4c/0x70 fs/inode.c:220
 __rcu_reclaim kernel/rcu/rcu.h:222 [inline]
 rcu_do_batch+0x446/0x980 kernel/rcu/tree.c:2167
 rcu_core+0x4bd/0xbd0 kernel/rcu/tree.c:2387
 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2396
 __do_softirq+0x236/0x660 kernel/softirq.c:292

The buggy address belongs to the object at ffff8881e1e33090
 which belongs to the cache shmem_inode_cache of size 760
The buggy address is located 312 bytes inside of
 760-byte region [ffff8881e1e33090, ffff8881e1e33388)
The buggy address belongs to the page:
page:ffffea0007878c00 refcount:1 mapcount:0 mapping:ffff8881f5d02280 index:0x0 compound_mapcount: 0
flags: 0x8000000000010200(slab|head)
raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881f5d02280
raw: 0000000000000000 0000000000120012 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL)
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook mm/page_alloc.c:2165 [inline]
 prep_new_page+0x35e/0x370 mm/page_alloc.c:2171
 get_page_from_freelist+0x1296/0x1310 mm/page_alloc.c:3794
 __alloc_pages_nodemask+0x202/0x4b0 mm/page_alloc.c:4894
 alloc_slab_page+0x3c/0x3b0 mm/slub.c:343
 allocate_slab mm/slub.c:1683 [inline]
 new_slab+0x93/0x420 mm/slub.c:1749
 new_slab_objects mm/slub.c:2505 [inline]
 ___slab_alloc+0x29e/0x420 mm/slub.c:2667
 __slab_alloc+0x63/0xa0 mm/slub.c:2707
 slab_alloc_node mm/slub.c:2792 [inline]
 slab_alloc mm/slub.c:2837 [inline]
 kmem_cache_alloc+0x12c/0x270 mm/slub.c:2842
 shmem_alloc_inode+0x1a/0x30 mm/shmem.c:3719
 alloc_inode fs/inode.c:231 [inline]
 new_inode_pseudo+0x62/0x210 fs/inode.c:966
 new_inode+0x28/0x1e0 fs/inode.c:995
 shmem_get_inode+0x107/0x630 mm/shmem.c:2252
 shmem_symlink+0x9e/0x4d0 mm/shmem.c:3068
 vfs_symlink+0x337/0x4c0 fs/namei.c:4276
 do_symlinkat+0x103/0x3b0 fs/namei.c:4303
 __do_sys_symlinkat fs/namei.c:4317 [inline]
 __se_sys_symlinkat fs/namei.c:4314 [inline]
 __x64_sys_symlinkat+0x7b/0x90 fs/namei.c:4314
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1176 [inline]
 __free_pages_ok+0x7e4/0x910 mm/page_alloc.c:1438
 free_the_page mm/page_alloc.c:4956 [inline]
 __free_pages+0x8c/0x110 mm/page_alloc.c:4962
 kfree+0x1ca/0x260 mm/slub.c:4068
 tipc_nametbl_stop+0x754/0x7b0 net/tipc/name_table.c:798
 tipc_exit_net+0x96/0x100 net/tipc/core.c:108
 ops_exit_list net/core/net_namespace.c:182 [inline]
 cleanup_net+0x588/0xb40 net/core/net_namespace.c:612
 process_one_work+0x73b/0xcc0 kernel/workqueue.c:2290
 worker_thread+0xa5c/0x13b0 kernel/workqueue.c:2436
 kthread+0x31e/0x3a0 kernel/kthread.c:288
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:354

Memory state around the buggy address:
 ffff8881e1e33080: fc fc fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881e1e33100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881e1e33180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                              ^
 ffff8881e1e33200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881e1e33280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 1d4cfe067 P4D 1d4cfe067 PUD 0 
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 10 Comm: ksoftirqd/0 Tainted: G    B             5.4.292-syzkaller-00021-gcd8e74fa0fa3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8881f5dd7bd0 EFLAGS: 00010006
RAX: ffffffff8150a590 RBX: 0000000000000100 RCX: ffff8881f5dc0fc0
RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffff8881e1e331c0
RBP: ffff8881f5dd7c10 R08: 0000000000000004 R09: 0000000000000003
R10: ffffed103ebbaf74 R11: 1ffff1103ebbaf74 R12: 00000000ffff95c8
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881e1e331c0
FS:  0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001ed610000 CR4: 00000000003406b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 call_timer_fn+0x3c/0x380 kernel/time/timer.c:1448
 expire_timers kernel/time/timer.c:1488 [inline]
 __run_timers+0x84b/0xb60 kernel/time/timer.c:1817
 run_timer_softirq+0x6a/0xf0 kernel/time/timer.c:1830
 __do_softirq+0x236/0x660 kernel/softirq.c:292
 run_ksoftirqd+0x23/0x30 kernel/softirq.c:603
 smpboot_thread_fn+0x474/0x850 kernel/smpboot.c:165
 kthread+0x31e/0x3a0 kernel/kthread.c:288
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:354
Modules linked in:
CR2: 0000000000000000
---[ end trace 90cba7fc6f3c1ef0 ]---
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8881f5dd7bd0 EFLAGS: 00010006
RAX: ffffffff8150a590 RBX: 0000000000000100 RCX: ffff8881f5dc0fc0
RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffff8881e1e331c0
RBP: ffff8881f5dd7c10 R08: 0000000000000004 R09: 0000000000000003
R10: ffffed103ebbaf74 R11: 1ffff1103ebbaf74 R12: 00000000ffff95c8
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881e1e331c0
FS:  0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001ed610000 CR4: 00000000003406b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600