================================================================== 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 ffff8881ce3cb1c8 by task syz.4.68/626 CPU: 1 PID: 626 Comm: syz.4.68 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: 0033:0x7fb7791fe969 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:00007fb777866fe8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007fb779425fa0 RCX: 00007fb7791fe969 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000e50c1600 RBP: 00007fb779280ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fb779425fa0 R15: 00007ffeca23a098 Allocated by task 588: 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_kmalloc+0xd/0x20 mm/kasan/common.c:543 __kmalloc+0x12a/0x2f0 mm/slub.c:3913 kmalloc include/linux/slab.h:561 [inline] kzalloc include/linux/slab.h:690 [inline] fib6_info_alloc+0x34/0xe0 net/ipv6/ip6_fib.c:154 ip6_route_info_create+0x4d2/0x1510 net/ipv6/route.c:3672 ip6_route_add+0x27/0x130 net/ipv6/route.c:3770 addrconf_prefix_route net/ipv6/addrconf.c:2443 [inline] addrconf_add_linklocal+0x3cf/0x620 net/ipv6/addrconf.c:3249 addrconf_addr_gen+0x468/0x5b0 net/ipv6/addrconf.c:3366 addrconf_dev_config+0x20c/0x330 net/ipv6/addrconf.c:3425 addrconf_notify+0x9fe/0xeb0 net/ipv6/addrconf.c:3660 notifier_call_chain kernel/notifier.c:98 [inline] __raw_notifier_call_chain kernel/notifier.c:399 [inline] raw_notifier_call_chain+0xa0/0x120 kernel/notifier.c:406 call_netdevice_notifiers_info net/core/dev.c:1670 [inline] call_netdevice_notifiers_extack net/core/dev.c:1682 [inline] call_netdevice_notifiers net/core/dev.c:1696 [inline] __dev_notify_flags+0x1e2/0x3d0 net/core/dev.c:-1 dev_change_flags+0xe8/0x1a0 net/core/dev.c:8034 dev_ifsioc+0x110/0xa40 net/core/dev_ioctl.c:226 dev_ioctl+0x550/0xb80 net/core/dev_ioctl.c:483 sock_do_ioctl+0x235/0x330 net/socket.c:1081 sock_ioctl+0x505/0x710 net/socket.c:1198 do_vfs_ioctl+0x753/0x13f0 fs/ioctl.c:47 ksys_ioctl fs/ioctl.c:742 [inline] __do_sys_ioctl fs/ioctl.c:749 [inline] __se_sys_ioctl fs/ioctl.c:747 [inline] __x64_sys_ioctl+0xe1/0x120 fs/ioctl.c:747 do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 Freed by task 17: 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] kfree+0xbe/0x260 mm/slub.c:4071 fib6_info_destroy_rcu+0x171/0x1c0 net/ipv6/ip6_fib.c:177 __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 ffff8881ce3cb000 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 456 bytes inside of 512-byte region [ffff8881ce3cb000, ffff8881ce3cb200) The buggy address belongs to the page: page:ffffea000738f200 refcount:1 mapcount:0 mapping:ffff8881f5c02500 index:0x0 compound_mapcount: 0 flags: 0x8000000000010200(slab|head) raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881f5c02500 raw: 0000000000000000 0000000000100010 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 0x1d2a20(GFP_ATOMIC|__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] __kmalloc_track_caller+0x17c/0x2d0 mm/slub.c:4449 __kmalloc_reserve net/core/skbuff.c:142 [inline] pskb_expand_head+0x123/0x1110 net/core/skbuff.c:1653 skb_ensure_writable+0x2e7/0x460 net/core/skbuff.c:5569 __bpf_try_make_writable net/core/filter.c:1635 [inline] bpf_try_make_writable net/core/filter.c:1641 [inline] bpf_try_make_head_writable net/core/filter.c:1649 [inline] ____bpf_clone_redirect net/core/filter.c:2145 [inline] bpf_clone_redirect+0x10b/0x380 net/core/filter.c:2123 0xffffffffa0058324 bpf_call_func include/linux/filter.h:627 [inline] bpf_test_run+0x1ea/0x5d0 net/bpf/test_run.c:44 bpf_prog_test_run_skb+0x721/0xdc0 net/bpf/test_run.c:311 bpf_prog_test_run+0x21a/0x2a0 kernel/bpf/syscall.c:2124 __do_sys_bpf kernel/bpf/syscall.c:2909 [inline] __se_sys_bpf+0x49a/0x570 kernel/bpf/syscall.c:2849 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: ffff8881ce3cb080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881ce3cb100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881ce3cb180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881ce3cb200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8881ce3cb280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================