netlink: 4 bytes leftover after parsing attributes in process `syz-executor7'. ================================================================== BUG: KASAN: use-after-free in hlist_move_list include/linux/list.h:729 [inline] BUG: KASAN: use-after-free in __collect_expired_timers kernel/time/timer.c:1339 [inline] BUG: KASAN: use-after-free in collect_expired_timers kernel/time/timer.c:1569 [inline] BUG: KASAN: use-after-free in __run_timers+0xa2e/0xb90 kernel/time/timer.c:1616 Write of size 8 at addr ffff8801d2c345c8 by task syz-executor4/12436 CPU: 1 PID: 12436 Comm: syz-executor4 Not tainted 4.13.0+ #79 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:16 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:52 print_address_description+0x73/0x250 mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report+0x24e/0x340 mm/kasan/report.c:409 __asan_report_store8_noabort+0x17/0x20 mm/kasan/report.c:435 hlist_move_list include/linux/list.h:729 [inline] __collect_expired_timers kernel/time/timer.c:1339 [inline] collect_expired_timers kernel/time/timer.c:1569 [inline] __run_timers+0xa2e/0xb90 kernel/time/timer.c:1616 run_timer_softirq+0x4c/0xb0 kernel/time/timer.c:1646 __do_softirq+0x2bb/0xbd0 kernel/softirq.c:284 invoke_softirq kernel/softirq.c:364 [inline] irq_exit+0x1d3/0x210 kernel/softirq.c:405 exiting_irq arch/x86/include/asm/apic.h:638 [inline] smp_apic_timer_interrupt+0x177/0x710 arch/x86/kernel/apic/apic.c:1048 apic_timer_interrupt+0x9d/0xb0 arch/x86/entry/entry_64.S:770 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:814 [inline] RIP: 0010:lock_release+0x69b/0xd70 kernel/locking/lockdep.c:4024 RSP: 0018:ffff88019dbf7670 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff10 RAX: dffffc0000000000 RBX: 1ffff10033b7eed3 RCX: ffff8801cf34eec8 RDX: 1ffffffff0b592fd RSI: 0000000000000001 RDI: 0000000000000282 RBP: ffff88019dbf7820 R08: 0000000000000000 R09: 1ffff10033b7eedf R10: ffff8801cf34e600 R11: 0000000000000000 R12: ffff88019dbf76f8 R13: ffff8801cf34e600 R14: 0000000000000000 R15: 0000000000000003 rcu_lock_release include/linux/rcupdate.h:249 [inline] rcu_read_unlock include/linux/rcupdate.h:686 [inline] __is_insn_slot_addr+0x225/0x330 kernel/kprobes.c:301 is_kprobe_optinsn_slot include/linux/kprobes.h:344 [inline] __kernel_text_address+0x8f/0xe0 kernel/extable.c:111 unwind_get_return_address+0x61/0xa0 arch/x86/kernel/unwind_frame.c:18 __save_stack_trace+0x7e/0xd0 arch/x86/kernel/stacktrace.c:45 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489 slab_post_alloc_hook mm/slab.h:444 [inline] slab_alloc mm/slab.c:3397 [inline] kmem_cache_alloc+0x11b/0x760 mm/slab.c:3559 getname_flags+0xcb/0x580 fs/namei.c:137 user_path_at_empty+0x2d/0x50 fs/namei.c:2599 user_path_at include/linux/namei.h:56 [inline] vfs_statx+0xe9/0x190 fs/stat.c:184 vfs_lstat include/linux/fs.h:3040 [inline] SYSC_newlstat+0x87/0xf0 fs/stat.c:349 SyS_newlstat+0x1d/0x30 fs/stat.c:343 entry_SYSCALL_64_fastpath+0x1f/0xbe RIP: 0033:0x451335 RSP: 002b:0000000000a68448 EFLAGS: 00000246 ORIG_RAX: 0000000000000006 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000451335 RDX: 0000000000a68460 RSI: 0000000000a68460 RDI: 0000000000a684f0 RBP: 0000000000000082 R08: 0000000000000000 R09: 0000000000000023 R10: 0000000000000006 R11: 0000000000000246 R12: 0000000002848e20 R13: 0000000000000000 R14: 0000000000022a12 R15: 0000000000000010 Allocated by task 15355: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551 __do_kmalloc_node mm/slab.c:3689 [inline] __kmalloc_node+0x47/0x70 mm/slab.c:3696 kmalloc_node include/linux/slab.h:535 [inline] kvmalloc_node+0x64/0xd0 mm/util.c:397 kvmalloc include/linux/mm.h:529 [inline] kvzalloc include/linux/mm.h:537 [inline] alloc_netdev_mqs+0x16e/0xed0 net/core/dev.c:8018 tun_set_iff drivers/net/tun.c:2022 [inline] __tun_chr_ioctl+0x12be/0x3d20 drivers/net/tun.c:2276 tun_chr_ioctl+0x2a/0x40 drivers/net/tun.c:2521 vfs_ioctl fs/ioctl.c:45 [inline] do_vfs_ioctl+0x1b1/0x1530 fs/ioctl.c:685 SYSC_ioctl fs/ioctl.c:700 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:691 do_syscall_64+0x26c/0x8c0 arch/x86/entry/common.c:287 return_from_SYSCALL_64+0x0/0x7a Freed by task 15355: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3503 [inline] kfree+0xca/0x250 mm/slab.c:3820 kvfree+0x36/0x60 mm/util.c:416 netdev_freemem net/core/dev.c:7970 [inline] free_netdev+0x2cf/0x360 net/core/dev.c:8132 tun_set_iff drivers/net/tun.c:2105 [inline] __tun_chr_ioctl+0x2cf6/0x3d20 drivers/net/tun.c:2276 tun_chr_ioctl+0x2a/0x40 drivers/net/tun.c:2521 vfs_ioctl fs/ioctl.c:45 [inline] do_vfs_ioctl+0x1b1/0x1530 fs/ioctl.c:685 SYSC_ioctl fs/ioctl.c:700 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:691 do_syscall_64+0x26c/0x8c0 arch/x86/entry/common.c:287 return_from_SYSCALL_64+0x0/0x7a The buggy address belongs to the object at ffff8801d2c311c0 which belongs to the cache kmalloc-16384 of size 16384 The buggy address is located 13320 bytes inside of 16384-byte region [ffff8801d2c311c0, ffff8801d2c351c0) The buggy address belongs to the page: page:ffffea00074b0c00 count:1 mapcount:0 mapping:ffff8801d2c311c0 index:0x0 compound_mapcount: 0 flags: 0x200000000008100(slab|head) raw: 0200000000008100 ffff8801d2c311c0 0000000000000000 0000000100000001 raw: ffffea00072e2820 ffffea00071c9a20 ffff8801dac02200 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801d2c34480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801d2c34500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8801d2c34580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801d2c34600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801d2c34680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================