audit: type=1400 audit(1515322827.621:7): avc: denied { map } for pid=3492 comm="syzkaller901534" path="/root/syzkaller901534613" 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:3305 Read of size 8 at addr ffff8801c9f54330 by task syzkaller901534/3492 CPU: 0 PID: 3492 Comm: syzkaller901534 Not tainted 4.15.0-rc6+ #160 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:3305 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:3914 __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 do_syscall_32_irqs_on arch/x86/entry/common.c:327 [inline] do_fast_syscall_32+0x3ee/0xf9d arch/x86/entry/common.c:389 entry_SYSENTER_compat+0x54/0x63 arch/x86/entry/entry_64_compat.S:129 RIP: 0023:0xf7f5fc79 RSP: 002b:00000000ffaf868c EFLAGS: 00000292 ORIG_RAX: 00000000000000fc RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000080f0298 RDX: 0000000000000000 RSI: 00000000080d9ad8 RDI: 00000000080f02a0 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 3492: 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 do_syscall_32_irqs_on arch/x86/entry/common.c:327 [inline] do_fast_syscall_32+0x3ee/0xf9d arch/x86/entry/common.c:389 entry_SYSENTER_compat+0x54/0x63 arch/x86/entry/entry_64_compat.S:129 Freed by task 3492: 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 C_SYSC_ioctl fs/compat_ioctl.c:1473 [inline] compat_SyS_ioctl+0x151/0x2a30 fs/compat_ioctl.c:1419 do_syscall_32_irqs_on arch/x86/entry/common.c:327 [inline] do_fast_syscall_32+0x3ee/0xf9d arch/x86/entry/common.c:389 entry_SYSENTER_compat+0x54/0x63 arch/x86/entry/entry_64_compat.S:129 The buggy address belongs to the object at ffff8801c9f54280 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 176 bytes inside of 512-byte region [ffff8801c9f54280, ffff8801c9f54480) The buggy address belongs to the page: page:ffffea000727d500 count:1 mapcount:0 mapping:ffff8801c9f54000 index:0x0 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffff8801c9f54000 0000000000000000 0000000100000006 raw: ffffea000727b120 ffffea000727b2a0 ffff8801dac00940 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801c9f54200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801c9f54280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8801c9f54300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801c9f54380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801c9f54400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================