================================================================== 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 ffff8881ea51b1c8 by task syz-executor.1/4402 CPU: 0 PID: 4402 Comm: syz-executor.1 Not tainted 5.4.219-syzkaller-00012-ga8aad8851131 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1d8/0x241 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+0xaad/0x1c90 kernel/time/timer.c:1065 tun_set_iff+0x8ca/0x1050 drivers/net/tun.c:2865 __tun_chr_ioctl+0x88e/0x1ee0 drivers/net/tun.c:3160 do_vfs_ioctl+0x744/0x1730 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+0x5c/0xc1 Allocated by task 4397: save_stack mm/kasan/common.c:70 [inline] set_track mm/kasan/common.c:78 [inline] __kasan_kmalloc+0x131/0x1e0 mm/kasan/common.c:529 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+0xd0/0x210 mm/slub.c:2842 kmem_cache_alloc_node include/linux/slab.h:427 [inline] __alloc_skb+0x78/0x4d0 net/core/skbuff.c:198 alloc_skb_fclone include/linux/skbuff.h:1110 [inline] tipc_buf_acquire net/tipc/msg.c:66 [inline] tipc_msg_build+0x138/0x1100 net/tipc/msg.c:332 __tipc_sendstream+0x84f/0xee0 net/tipc/socket.c:1493 tipc_sendstream+0x51/0x70 net/tipc/socket.c:1450 sock_sendmsg_nosec net/socket.c:638 [inline] sock_sendmsg net/socket.c:658 [inline] ____sys_sendmsg+0x5a6/0x8f0 net/socket.c:2287 ___sys_sendmsg net/socket.c:2341 [inline] __sys_sendmsg+0x2b7/0x3a0 net/socket.c:2387 do_syscall_64+0xcb/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 Freed by task 4382: 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+0x178/0x240 mm/kasan/common.c:487 slab_free_hook mm/slub.c:1455 [inline] slab_free_freelist_hook+0x80/0x150 mm/slub.c:1494 slab_free mm/slub.c:3080 [inline] kmem_cache_free+0xa9/0x1d0 mm/slub.c:3096 tipc_recvstream+0x856/0xfa0 net/tipc/socket.c:1959 sock_recvmsg_nosec net/socket.c:872 [inline] sock_recvmsg net/socket.c:890 [inline] ____sys_recvmsg net/socket.c:2519 [inline] ___sys_recvmsg net/socket.c:2560 [inline] __sys_recvmsg+0x4d4/0x7c0 net/socket.c:2607 do_syscall_64+0xcb/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 The buggy address belongs to the object at ffff8881ea51b180 which belongs to the cache skbuff_fclone_cache of size 488 The buggy address is located 72 bytes inside of 488-byte region [ffff8881ea51b180, ffff8881ea51b368) The buggy address belongs to the page: page:ffffea0007a94680 refcount:1 mapcount:0 mapping:ffff8881f1dddb80 index:0x0 compound_mapcount: 0 flags: 0x8000000000010200(slab|head) raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881f1dddb80 raw: 0000000000000000 00000000000c000c 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 1, 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+0x194/0x380 mm/page_alloc.c:2171 get_page_from_freelist+0x524/0x560 mm/page_alloc.c:3794 __alloc_pages_nodemask+0x372/0x860 mm/page_alloc.c:4891 alloc_slab_page+0x39/0x3e0 mm/slub.c:343 allocate_slab mm/slub.c:1683 [inline] new_slab+0x97/0x450 mm/slub.c:1749 new_slab_objects mm/slub.c:2505 [inline] ___slab_alloc+0x320/0x4a0 mm/slub.c:2667 __slab_alloc+0x5a/0x90 mm/slub.c:2707 slab_alloc_node mm/slub.c:2792 [inline] slab_alloc mm/slub.c:2837 [inline] kmem_cache_alloc+0x100/0x210 mm/slub.c:2842 kmem_cache_alloc_node include/linux/slab.h:427 [inline] __alloc_skb+0x78/0x4d0 net/core/skbuff.c:198 alloc_skb_fclone include/linux/skbuff.h:1110 [inline] tipc_buf_acquire net/tipc/msg.c:66 [inline] tipc_msg_build+0x138/0x1100 net/tipc/msg.c:332 __tipc_sendstream+0x84f/0xee0 net/tipc/socket.c:1493 tipc_sendstream+0x51/0x70 net/tipc/socket.c:1450 sock_sendmsg_nosec net/socket.c:638 [inline] sock_sendmsg net/socket.c:658 [inline] ____sys_sendmsg+0x5a6/0x8f0 net/socket.c:2287 ___sys_sendmsg net/socket.c:2341 [inline] __sys_sendmsg+0x2b7/0x3a0 net/socket.c:2387 do_syscall_64+0xcb/0x1c0 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_pages_ok+0x7fe/0x930 mm/page_alloc.c:1438 free_the_page mm/page_alloc.c:4953 [inline] __free_pages+0x8f/0x250 mm/page_alloc.c:4959 kfree+0x1ef/0x260 mm/slub.c:4068 device_release+0x70/0x1a0 drivers/base/core.c:1776 kobject_cleanup lib/kobject.c:708 [inline] kobject_release+0x20c/0x330 lib/kobject.c:739 tun_set_iff+0xc0b/0x1050 drivers/net/tun.c:2917 __tun_chr_ioctl+0x88e/0x1ee0 drivers/net/tun.c:3160 do_vfs_ioctl+0x744/0x1730 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+0x5c/0xc1 Memory state around the buggy address: ffff8881ea51b080: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc ffff8881ea51b100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8881ea51b180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881ea51b200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881ea51b280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================