audit: type=1400 audit(1517301751.310:7): avc: denied { map } for pid=4170 comm="syzkaller027604" path="/root/syzkaller027604084" dev="sda1" ino=16481 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 ================================================================== BUG: KASAN: use-after-free in __lock_acquire+0x3d4d/0x3e00 kernel/locking/lockdep.c:3306 Read of size 8 at addr ffff8801b15730f0 by task syzkaller027604/4170 CPU: 0 PID: 4170 Comm: syzkaller027604 Not tainted 4.15.0+ #286 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+0x194/0x257 lib/dump_stack.c:53 print_address_description+0x73/0x250 mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report+0x25b/0x340 mm/kasan/report.c:409 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:430 __lock_acquire+0x3d4d/0x3e00 kernel/locking/lockdep.c:3306 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:3915 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x96/0xc0 kernel/locking/spinlock.c:152 remove_wait_queue+0x81/0x350 kernel/sched/wait.c:50 ep_remove_wait_queue fs/eventpoll.c:595 [inline] ep_unregister_pollwait.isra.7+0x18c/0x590 fs/eventpoll.c:613 ep_free+0x13f/0x320 fs/eventpoll.c:830 ep_eventpoll_release+0x44/0x60 fs/eventpoll.c:862 __fput+0x327/0x7e0 fs/file_table.c:210 ____fput+0x15/0x20 fs/file_table.c:244 task_work_run+0x199/0x270 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x9bb/0x1ad0 kernel/exit.c:865 do_group_exit+0x149/0x400 kernel/exit.c:968 SYSC_exit_group kernel/exit.c:979 [inline] SyS_exit_group+0x1d/0x20 kernel/exit.c:977 entry_SYSCALL_64_fastpath+0x29/0xa0 RIP: 0033:0x4429f8 RSP: 002b:00007fff44e7d538 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00000000004002e0 RCX: 00000000004429f8 RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 RBP: 00000000006ce018 R08: 00000000000000e7 R09: ffffffffffffffd0 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401a40 R13: 0000000000401ad0 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 4170: 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 kmem_cache_alloc_trace+0x136/0x750 mm/slab.c:3610 kmalloc include/linux/slab.h:499 [inline] kzalloc include/linux/slab.h:688 [inline] binder_get_thread+0x1cf/0x870 drivers/android/binder.c:4219 binder_poll+0x8c/0x390 drivers/android/binder.c:4321 ep_item_poll.isra.10+0xec/0x320 fs/eventpoll.c:884 ep_insert+0x6a3/0x1b10 fs/eventpoll.c:1455 SYSC_epoll_ctl fs/eventpoll.c:2106 [inline] SyS_epoll_ctl+0x12e4/0x1ab0 fs/eventpoll.c:1992 entry_SYSCALL_64_fastpath+0x29/0xa0 Freed by task 4170: 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:3488 [inline] kfree+0xd6/0x260 mm/slab.c:3803 binder_free_thread drivers/android/binder.c:4246 [inline] binder_thread_dec_tmpref+0x27f/0x310 drivers/android/binder.c:1821 binder_thread_release+0x27d/0x540 drivers/android/binder.c:4310 binder_ioctl+0xc02/0x1417 drivers/android/binder.c:4527 vfs_ioctl fs/ioctl.c:46 [inline] do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:686 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 entry_SYSCALL_64_fastpath+0x29/0xa0 The buggy address belongs to the object at ffff8801b1573040 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 176 bytes inside of 512-byte region [ffff8801b1573040, ffff8801b1573240) The buggy address belongs to the page: page:ffffea0006c55cc0 count:1 mapcount:0 mapping:ffff8801b1573040 index:0x0 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffff8801b1573040 0000000000000000 0000000100000006 raw: ffffea0006c57da0 ffffea00072d91e0 ffff8801db000940 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801b1572f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8801b1573000: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb >ffff8801b1573080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801b1573100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801b1573180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================