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BUG: KASAN: use-after-free in hlist_add_head include/linux/list.h:814 [inline]
BUG: KASAN: use-after-free in enqueue_timer+0x9e/0x2c0 kernel/time/timer.c:541
Write of size 8 at addr ffff8881f20df1c8 by task syz.4.1100/4430

CPU: 0 PID: 4430 Comm: syz.4.1100 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_add_head include/linux/list.h:814 [inline]
 enqueue_timer+0x9e/0x2c0 kernel/time/timer.c:541
 __internal_add_timer kernel/time/timer.c:554 [inline]
 internal_add_timer+0x208/0x3e0 kernel/time/timer.c:604
 __mod_timer+0x5ab/0x1150 kernel/time/timer.c:1065
 mod_timer+0x1f/0x30 kernel/time/timer.c:1117
 can_pernet_init+0x1e9/0x2e0 net/can/af_can.c:811
 ops_init+0x1ba/0x4a0 net/core/net_namespace.c:141
 setup_net+0x20c/0x9b0 net/core/net_namespace.c:348
 copy_net_ns+0x314/0x520 net/core/net_namespace.c:489
 create_new_namespaces+0x49c/0x590 kernel/nsproxy.c:103
 copy_namespaces+0x17e/0x1c0 kernel/nsproxy.c:161
 copy_process+0x1194/0x2cf0 kernel/fork.c:2055
 _do_fork+0x190/0x860 kernel/fork.c:2399
 __do_sys_clone kernel/fork.c:2557 [inline]
 __se_sys_clone kernel/fork.c:2538 [inline]
 __x64_sys_clone+0x12e/0x160 kernel/fork.c:2538
 do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1
RIP: 0033:0x7f1126d6c969
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f11253d4fe8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007f1126f93fa0 RCX: 00007f1126d6c969
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040b04000
RBP: 00007f1126deeab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f1126f93fa0 R15: 00007ffcd2b564f8

The buggy address belongs to the page:
page:ffffea0007c837c0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x8000000000000000()
raw: 8000000000000000 ffffea0007d1fd08 ffffea0007c83788 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x102cc2(GFP_HIGHUSER|__GFP_NOWARN)
 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_pages include/linux/gfp.h:503 [inline]
 __alloc_pages_node include/linux/gfp.h:516 [inline]
 alloc_pages_node include/linux/gfp.h:530 [inline]
 pcpu_alloc_pages mm/percpu-vm.c:94 [inline]
 pcpu_populate_chunk+0x1b6/0xce0 mm/percpu-vm.c:284
 pcpu_alloc+0x8ec/0x1120 mm/percpu.c:1714
 __alloc_percpu_gfp+0x25/0x30 mm/percpu.c:1783
 prealloc_init+0x24b/0x810 kernel/bpf/hashtab.c:154
 htab_map_alloc+0x65f/0x940 kernel/bpf/hashtab.c:385
 find_and_alloc_map kernel/bpf/syscall.c:122 [inline]
 map_create+0x2d8/0x980 kernel/bpf/syscall.c:573
 __do_sys_bpf kernel/bpf/syscall.c:2873 [inline]
 __se_sys_bpf+0x2dc/0x570 kernel/bpf/syscall.c:2849
 __x64_sys_bpf+0x7b/0x90 kernel/bpf/syscall.c:2849
 do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1
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_pcp_prepare mm/page_alloc.c:1233 [inline]
 free_unref_page_prepare+0x2a9/0x3a0 mm/page_alloc.c:3085
 free_unref_page mm/page_alloc.c:3134 [inline]
 free_the_page mm/page_alloc.c:4954 [inline]
 __free_pages+0xaa/0x110 mm/page_alloc.c:4962
 pcpu_free_pages mm/percpu-vm.c:64 [inline]
 pcpu_depopulate_chunk mm/percpu-vm.c:328 [inline]
 pcpu_balance_workfn+0x8c7/0x14b0 mm/percpu.c:1865
 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:
 ffff8881f20df080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881f20df100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8881f20df180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                              ^
 ffff8881f20df200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881f20df280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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