================================================================== 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 ffff8881b47931c8 by task syz-executor.5/18551 CPU: 1 PID: 18551 Comm: syz-executor.5 Not tainted 5.4.197-syzkaller-00015-gf0306959ab7c #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022 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 tun_set_iff+0x8ca/0x1050 drivers/net/tun.c:2854 __tun_chr_ioctl+0x6c7/0x1b70 drivers/net/tun.c:3149 do_vfs_ioctl+0x6d1/0x15b0 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+0xd4/0x110 fs/ioctl.c:747 do_syscall_64+0xcb/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f38f7540279 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f38f66b6168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f38f7652f80 RCX: 00007f38f7540279 RDX: 0000000020000240 RSI: 00000000400454ca RDI: 0000000000000003 RBP: 00007f38f759a2e9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffe7827e98f R14: 00007f38f66b6300 R15: 0000000000022000 The buggy address belongs to the page: page:ffffea0006d1e4c0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 flags: 0x8000000000000000() raw: 8000000000000000 0000000000000000 dead000000000122 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: ffff8881b4793080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8881b4793100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff8881b4793180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff8881b4793200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8881b4793280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ==================================================================