================================================================== BUG: KASAN: use-after-free in hlist_add_head include/linux/list.h:796 [inline] BUG: KASAN: use-after-free in enqueue_timer kernel/time/timer.c:541 [inline] BUG: KASAN: use-after-free in __internal_add_timer+0x2a6/0x4a0 kernel/time/timer.c:554 Write of size 8 at addr ffff8881e7d4f1c8 by task kworker/u4:4/2309 CPU: 0 PID: 2309 Comm: kworker/u4:4 Not tainted 5.4.197-syzkaller-00015-gf0306959ab7c #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022 Workqueue: wg-kex-wg0 wg_packet_handshake_send_worker Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x18e/0x1d5 lib/dump_stack.c:118 print_address_description+0x8c/0x630 mm/kasan/report.c:384 __kasan_report+0xf6/0x130 mm/kasan/report.c:516 kasan_report+0x30/0x60 mm/kasan/common.c:653 hlist_add_head include/linux/list.h:796 [inline] enqueue_timer kernel/time/timer.c:541 [inline] __internal_add_timer+0x2a6/0x4a0 kernel/time/timer.c:554 internal_add_timer kernel/time/timer.c:604 [inline] __mod_timer+0x9ce/0x1a40 kernel/time/timer.c:1065 mod_peer_timer drivers/net/wireguard/timers.c:37 [inline] wg_timers_any_authenticated_packet_traversal+0x125/0x180 drivers/net/wireguard/timers.c:215 wg_packet_send_handshake_initiation drivers/net/wireguard/send.c:36 [inline] wg_packet_handshake_send_worker+0x108/0x1a0 drivers/net/wireguard/send.c:51 process_one_work+0x6ca/0xc40 kernel/workqueue.c:2287 worker_thread+0xae0/0x1440 kernel/workqueue.c:2433 kthread+0x2d8/0x360 kernel/kthread.c:288 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352 The buggy address belongs to the page: page:ffffea00079f53c0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 flags: 0x8000000000000000() raw: 8000000000000000 0000000000000000 ffffffff07a50101 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 2, migratetype Unmovable, gfp_mask 0x140dc0(GFP_USER|__GFP_COMP|__GFP_ZERO) set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook mm/page_alloc.c:2165 [inline] prep_new_page+0x194/0x380 mm/page_alloc.c:2171 get_page_from_freelist+0x524/0x560 mm/page_alloc.c:3794 __alloc_pages_nodemask+0x2ab/0x6f0 mm/page_alloc.c:4857 __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] kmalloc_order mm/slab_common.c:1342 [inline] kmalloc_order_trace+0x2a/0xf0 mm/slab_common.c:1358 kmalloc_large include/linux/slab.h:485 [inline] kmalloc include/linux/slab.h:549 [inline] kzalloc include/linux/slab.h:690 [inline] bpf_check+0x58/0xb220 kernel/bpf/verifier.c:9533 bpf_prog_load kernel/bpf/syscall.c:1724 [inline] __do_sys_bpf kernel/bpf/syscall.c:2889 [inline] __se_sys_bpf+0x7620/0xb990 kernel/bpf/syscall.c:2847 do_syscall_64+0xcb/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 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+0x7ee/0x920 mm/page_alloc.c:1438 free_the_page mm/page_alloc.c:4919 [inline] __free_pages+0x45/0x1e0 mm/page_alloc.c:4925 kfree+0x1ef/0x260 mm/slub.c:4068 bpf_check+0x4a22/0xb220 kernel/bpf/verifier.c:9703 bpf_prog_load kernel/bpf/syscall.c:1724 [inline] __do_sys_bpf kernel/bpf/syscall.c:2889 [inline] __se_sys_bpf+0x7620/0xb990 kernel/bpf/syscall.c:2847 do_syscall_64+0xcb/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Memory state around the buggy address: ffff8881e7d4f080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8881e7d4f100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff8881e7d4f180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff8881e7d4f200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8881e7d4f280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ==================================================================