================================================================== BUG: KASAN: use-after-free in __hlist_del include/linux/list.h:791 [inline] BUG: KASAN: use-after-free in detach_timer kernel/time/timer.c:824 [inline] BUG: KASAN: use-after-free in detach_if_pending+0x188/0x360 kernel/time/timer.c:841 Write of size 8 at addr ffff8881ea9cb1c8 by task syz-executor.5/565 CPU: 1 PID: 565 Comm: syz-executor.5 Not tainted 5.4.265-syzkaller-04843-g1b3143b9b166 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1d8/0x241 lib/dump_stack.c:118 print_address_description+0x8c/0x600 mm/kasan/report.c:384 __kasan_report+0xf3/0x120 mm/kasan/report.c:516 kasan_report+0x30/0x60 mm/kasan/common.c:653 __hlist_del include/linux/list.h:791 [inline] detach_timer kernel/time/timer.c:824 [inline] detach_if_pending+0x188/0x360 kernel/time/timer.c:841 try_to_del_timer_sync kernel/time/timer.c:1238 [inline] del_timer_sync+0x13c/0x230 kernel/time/timer.c:1379 tun_flow_uninit+0x2c/0x280 drivers/net/tun.c:1451 tun_free_netdev+0x77/0x190 drivers/net/tun.c:2401 netdev_run_todo+0xb7f/0xdf0 net/core/dev.c:9450 tun_detach drivers/net/tun.c:765 [inline] tun_chr_close+0xc1/0x130 drivers/net/tun.c:3557 __fput+0x262/0x680 fs/file_table.c:281 task_work_run+0x140/0x170 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x190/0x1a0 arch/x86/entry/common.c:163 prepare_exit_to_usermode+0x199/0x200 arch/x86/entry/common.c:194 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 Allocated by task 413: save_stack mm/kasan/common.c:70 [inline] set_track mm/kasan/common.c:78 [inline] __kasan_kmalloc+0x171/0x210 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+0xd9/0x250 mm/slub.c:2842 dup_mm kernel/fork.c:1370 [inline] copy_mm+0x169/0x10d0 kernel/fork.c:1435 copy_process+0x1291/0x3230 kernel/fork.c:2052 _do_fork+0x197/0x900 kernel/fork.c:2399 __do_sys_clone kernel/fork.c:2557 [inline] __se_sys_clone kernel/fork.c:2538 [inline] __x64_sys_clone+0x26b/0x2c0 kernel/fork.c:2538 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 Freed by task 395: 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+0x1b5/0x270 mm/kasan/common.c:487 slab_free_hook mm/slub.c:1455 [inline] slab_free_freelist_hook mm/slub.c:1494 [inline] slab_free mm/slub.c:3080 [inline] kmem_cache_free+0x10b/0x2c0 mm/slub.c:3096 mmdrop include/linux/sched/mm.h:49 [inline] finish_task_switch+0x1e6/0x590 kernel/sched/core.c:3466 context_switch kernel/sched/core.c:3611 [inline] __schedule+0xb0d/0x1320 kernel/sched/core.c:4307 schedule+0x12c/0x1d0 kernel/sched/core.c:4375 schedule_hrtimeout_range_clock+0x1ef/0x330 kernel/time/hrtimer.c:2196 freezable_schedule_hrtimeout_range include/linux/freezer.h:239 [inline] ep_poll fs/eventpoll.c:1937 [inline] do_epoll_wait+0x1036/0x1280 fs/eventpoll.c:2332 __do_sys_epoll_pwait fs/eventpoll.c:2363 [inline] __se_sys_epoll_pwait+0x56/0x180 fs/eventpoll.c:2349 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 The buggy address belongs to the object at ffff8881ea9caf80 which belongs to the cache mm_struct of size 1048 The buggy address is located 584 bytes inside of 1048-byte region [ffff8881ea9caf80, ffff8881ea9cb398) The buggy address belongs to the page: page:ffffea0007aa7200 refcount:1 mapcount:0 mapping:ffff8881f5c22f00 index:0x0 compound_mapcount: 0 flags: 0x8000000000010200(slab|head) raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881f5c22f00 raw: 0000000000000000 00000000800d000d 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC) set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook mm/page_alloc.c:2165 [inline] prep_new_page+0x18f/0x370 mm/page_alloc.c:2171 get_page_from_freelist+0x2d13/0x2d90 mm/page_alloc.c:3794 __alloc_pages_nodemask+0x393/0x840 mm/page_alloc.c:4891 alloc_slab_page+0x39/0x3c0 mm/slub.c:343 allocate_slab mm/slub.c:1683 [inline] new_slab+0x97/0x440 mm/slub.c:1749 new_slab_objects mm/slub.c:2505 [inline] ___slab_alloc+0x2fe/0x490 mm/slub.c:2667 __slab_alloc+0x62/0xa0 mm/slub.c:2707 slab_alloc_node mm/slub.c:2792 [inline] slab_alloc mm/slub.c:2837 [inline] kmem_cache_alloc+0x109/0x250 mm/slub.c:2842 dup_mm kernel/fork.c:1370 [inline] copy_mm+0x169/0x10d0 kernel/fork.c:1435 copy_process+0x1291/0x3230 kernel/fork.c:2052 _do_fork+0x197/0x900 kernel/fork.c:2399 __do_sys_clone kernel/fork.c:2557 [inline] __se_sys_clone kernel/fork.c:2538 [inline] __x64_sys_clone+0x26b/0x2c0 kernel/fork.c:2538 do_syscall_64+0xca/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+0x847/0x950 mm/page_alloc.c:1438 free_the_page mm/page_alloc.c:4953 [inline] __free_pages+0x91/0x140 mm/page_alloc.c:4959 device_release+0x6b/0x190 drivers/base/core.c:1776 kobject_cleanup lib/kobject.c:716 [inline] kobject_release lib/kobject.c:747 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x1e6/0x2f0 lib/kobject.c:764 tun_set_iff+0x870/0xdc0 drivers/net/tun.c:2918 __tun_chr_ioctl+0x8a9/0x1d00 drivers/net/tun.c:3181 do_vfs_ioctl+0x742/0x1720 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+0xca/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 Memory state around the buggy address: ffff8881ea9cb080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881ea9cb100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881ea9cb180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881ea9cb200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881ea9cb280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================