================================================================== BUG: KASAN: use-after-free in __lock_acquire+0x3098/0x4620 kernel/locking/lockdep.c:3365 Read of size 8 at addr ffff8880985a5340 by task syz-executor686/6333 CPU: 1 PID: 6333 Comm: syz-executor686 Not tainted 4.14.175-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x13e/0x194 lib/dump_stack.c:58 print_address_description.cold+0x7c/0x1e2 mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report mm/kasan/report.c:409 [inline] kasan_report.cold+0xa9/0x2ae mm/kasan/report.c:393 __lock_acquire+0x3098/0x4620 kernel/locking/lockdep.c:3365 lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3994 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x8c/0xbf kernel/locking/spinlock.c:160 remove_wait_queue+0x1d/0x180 kernel/sched/wait.c:50 ep_remove_wait_queue fs/eventpoll.c:611 [inline] ep_unregister_pollwait.isra.0+0x9b/0x350 fs/eventpoll.c:629 ep_remove+0x48/0x450 fs/eventpoll.c:792 eventpoll_release_file+0xb9/0x130 fs/eventpoll.c:1020 eventpoll_release include/linux/eventpoll.h:66 [inline] __fput+0x53e/0x790 fs/file_table.c:201 task_work_run+0x113/0x190 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x1d6/0x220 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:270 [inline] do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x4401d9 RSP: 002b:00007ffdcf3becd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000021 RAX: 0000000000000003 RBX: 00000000004002c8 RCX: 00000000004401d9 RDX: 00000000004401d9 RSI: 0000000000000003 RDI: 0000000000000004 RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8 R10: 00000000004002c8 R11: 0000000000000246 R12: 0000000000401a60 R13: 0000000000401af0 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 6333: save_stack+0x32/0xa0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc mm/kasan/kasan.c:551 [inline] kasan_kmalloc+0xbf/0xe0 mm/kasan/kasan.c:529 __do_kmalloc_node mm/slab.c:3682 [inline] __kmalloc_node+0x4c/0x70 mm/slab.c:3689 kmalloc_node include/linux/slab.h:530 [inline] kvmalloc_node+0x46/0xd0 mm/util.c:397 kvmalloc include/linux/mm.h:531 [inline] kvzalloc include/linux/mm.h:539 [inline] alloc_netdev_mqs+0x76/0xb70 net/core/dev.c:8097 ppp_create_interface drivers/net/ppp/ppp_generic.c:3019 [inline] ppp_unattached_ioctl drivers/net/ppp/ppp_generic.c:864 [inline] ppp_ioctl+0x1313/0x221a drivers/net/ppp/ppp_generic.c:600 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xfe0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Freed by task 6333: save_stack+0x32/0xa0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0x75/0xc0 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3496 [inline] kfree+0xcb/0x260 mm/slab.c:3815 kvfree+0x45/0x50 mm/util.c:416 device_release+0x15f/0x1a0 drivers/base/core.c:833 kobject_cleanup lib/kobject.c:646 [inline] kobject_release lib/kobject.c:675 [inline] kref_put include/linux/kref.h:70 [inline] kobject_put+0x13e/0x1f0 lib/kobject.c:692 put_device+0x1c/0x30 drivers/base/core.c:2014 free_netdev+0x26f/0x360 net/core/dev.c:8219 ppp_destroy_interface drivers/net/ppp/ppp_generic.c:3101 [inline] ppp_destroy_interface+0x2d7/0x3b0 drivers/net/ppp/ppp_generic.c:3064 ppp_release+0x122/0x1a0 drivers/net/ppp/ppp_generic.c:414 ppp_ioctl+0x52d/0x221a drivers/net/ppp/ppp_generic.c:626 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xfe0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 The buggy address belongs to the object at ffff8880985a47c0 which belongs to the cache kmalloc-4096 of size 4096 The buggy address is located 2944 bytes inside of 4096-byte region [ffff8880985a47c0, ffff8880985a57c0) The buggy address belongs to the page: page:ffffea0002616900 count:1 mapcount:0 mapping:ffff8880985a47c0 index:0x0 compound_mapcount: 0 flags: 0xfffe0000008100(slab|head) raw: 00fffe0000008100 ffff8880985a47c0 0000000000000000 0000000100000001 raw: ffffea00029be3a0 ffffea00026169a0 ffff88812fe56dc0 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880985a5200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880985a5280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880985a5300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880985a5380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880985a5400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================