================================================================== BUG: KASAN: use-after-free in __write_once_size include/linux/compiler.h:295 [inline] BUG: KASAN: use-after-free in __hlist_del include/linux/list.h:771 [inline] BUG: KASAN: use-after-free in detach_timer kernel/time/timer.c:824 [inline] BUG: KASAN: use-after-free in detach_if_pending kernel/time/timer.c:841 [inline] BUG: KASAN: use-after-free in try_to_del_timer_sync+0x27c/0x460 kernel/time/timer.c:1238 Write of size 8 at addr ffff8881d50431c0 by task syz-executor.4/16621 CPU: 0 PID: 16621 Comm: syz-executor.4 Not tainted 5.4.180-syzkaller-00002-gb730087e9a5d #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 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 __write_once_size include/linux/compiler.h:295 [inline] __hlist_del include/linux/list.h:771 [inline] detach_timer kernel/time/timer.c:824 [inline] detach_if_pending kernel/time/timer.c:841 [inline] try_to_del_timer_sync+0x27c/0x460 kernel/time/timer.c:1238 del_timer_sync+0x74/0xd0 kernel/time/timer.c:1379 tun_flow_uninit drivers/net/tun.c:1387 [inline] tun_free_netdev+0x99/0x3b0 drivers/net/tun.c:2328 netdev_run_todo+0xa3c/0xc80 net/core/dev.c:9445 tun_detach drivers/net/tun.c:751 [inline] tun_chr_close+0xc0/0xd0 drivers/net/tun.c:3522 __fput+0x261/0x680 fs/file_table.c:281 task_work_run+0x186/0x1b0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x1ba/0x1d0 arch/x86/entry/common.c:163 prepare_exit_to_usermode+0x17c/0x1d0 arch/x86/entry/common.c:194 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7fedca942c8b Code: 0f 05 48 3d 00 f0 ff ff 77 45 c3 0f 1f 40 00 48 83 ec 18 89 7c 24 0c e8 63 fc ff ff 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 44 89 c7 89 44 24 0c e8 a1 fc ff ff 8b 44 RSP: 002b:00007ffca85ff260 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000004 RCX: 00007fedca942c8b RDX: 00007fedcaaaa0e8 RSI: ffffffffffffffff RDI: 0000000000000003 RBP: 00007fedcaaa4960 R08: 0000000000000000 R09: 00007fedcaaaa0f0 R10: 00007ffca85ff360 R11: 0000000000000293 R12: 000000000010344d R13: 00007ffca85ff360 R14: 00007fedcaaa32a0 R15: 0000000000000032 The buggy address belongs to the page: page:ffffea00075410c0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 flags: 0x8000000000000000() raw: 8000000000000000 0000000000000000 ffffea0007541088 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 0x146dc0(GFP_USER|__GFP_NOWARN|__GFP_RETRY_MAYFAIL|__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_node include/linux/slab.h:422 [inline] kmalloc_node include/linux/slab.h:599 [inline] kvmalloc_node+0x7e/0xf0 mm/util.c:564 kvmalloc include/linux/mm.h:758 [inline] kvzalloc include/linux/mm.h:766 [inline] alloc_netdev_mqs+0x86/0xc30 net/core/dev.c:9597 tun_set_iff+0x4f9/0x1050 drivers/net/tun.c:2813 __tun_chr_ioctl+0x69a/0x1ba0 drivers/net/tun.c:3148 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 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+0x7c6/0x900 mm/page_alloc.c:1438 free_the_page mm/page_alloc.c:4919 [inline] __free_pages+0x45/0x1d0 mm/page_alloc.c:4925 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+0x1f3/0x3d0 lib/kobject.c:739 tun_set_iff+0xc0b/0x1050 drivers/net/tun.c:2905 __tun_chr_ioctl+0x69a/0x1ba0 drivers/net/tun.c:3148 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 Memory state around the buggy address: ffff8881d5043080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8881d5043100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff8881d5043180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff8881d5043200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8881d5043280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ==================================================================