================================================================== BUG: KASAN: use-after-free in vb2_mmap+0x662/0x6f0 drivers/media/common/videobuf2/videobuf2-core.c:2147 Read of size 8 at addr ffff8801b43cd200 by task syz-executor269/6009 CPU: 1 PID: 6009 Comm: syz-executor269 Not tainted 4.20.0-rc1-next-20181109+ #110 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x244/0x39d lib/dump_stack.c:113 print_address_description.cold.7+0x9/0x1ff mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.8+0x242/0x309 mm/kasan/report.c:412 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 vb2_mmap+0x662/0x6f0 drivers/media/common/videobuf2/videobuf2-core.c:2147 vb2_fop_mmap+0x4b/0x70 drivers/media/common/videobuf2/videobuf2-v4l2.c:999 v4l2_mmap+0x153/0x200 drivers/media/v4l2-core/v4l2-dev.c:401 call_mmap include/linux/fs.h:1872 [inline] mmap_region+0xe85/0x1cd0 mm/mmap.c:1786 do_mmap+0xa22/0x1230 mm/mmap.c:1559 do_mmap_pgoff include/linux/mm.h:2328 [inline] vm_mmap_pgoff+0x213/0x2c0 mm/util.c:350 ksys_mmap_pgoff+0x4da/0x660 mm/mmap.c:1609 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:100 [inline] __se_sys_mmap arch/x86/kernel/sys_x86_64.c:91 [inline] __x64_sys_mmap+0xe9/0x1b0 arch/x86/kernel/sys_x86_64.c:91 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x444c89 Code: e8 ac e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 2b ce fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fffa898e688 EFLAGS: 00000212 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000444c89 RDX: fffffffffffffffd RSI: 0000000000002000 RDI: 0000000020ffe000 RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000000 R10: 0000000000000011 R11: 0000000000000212 R12: 000000000000d793 R13: 0000000000401fd0 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 6007: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553 __do_kmalloc mm/slab.c:3722 [inline] __kmalloc+0x15b/0x760 mm/slab.c:3731 kmalloc include/linux/slab.h:551 [inline] kzalloc include/linux/slab.h:741 [inline] __vb2_queue_alloc+0xf7/0xf90 drivers/media/common/videobuf2/videobuf2-core.c:343 vb2_core_create_bufs+0x401/0x8c0 drivers/media/common/videobuf2/videobuf2-core.c:834 vb2_create_bufs+0x3c6/0x7f0 drivers/media/common/videobuf2/videobuf2-v4l2.c:716 vb2_ioctl_create_bufs+0x25e/0x3d0 drivers/media/common/videobuf2/videobuf2-v4l2.c:916 v4l_create_bufs+0x152/0x230 drivers/media/v4l2-core/v4l2-ioctl.c:1927 __video_do_ioctl+0x8b1/0x1050 drivers/media/v4l2-core/v4l2-ioctl.c:2853 video_usercopy+0x5c1/0x1750 drivers/media/v4l2-core/v4l2-ioctl.c:3035 video_ioctl2+0x2c/0x33 drivers/media/v4l2-core/v4l2-ioctl.c:3079 v4l2_ioctl+0x154/0x1b0 drivers/media/v4l2-core/v4l2-dev.c:364 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 6007: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3498 [inline] kfree+0xcf/0x230 mm/slab.c:3817 __vb2_queue_free+0x5e2/0xa30 drivers/media/common/videobuf2/videobuf2-core.c:526 vb2_core_queue_release+0x62/0x80 drivers/media/common/videobuf2/videobuf2-core.c:2231 vb2_queue_release drivers/media/common/videobuf2/videobuf2-v4l2.c:837 [inline] _vb2_fop_release+0x1d2/0x2b0 drivers/media/common/videobuf2/videobuf2-v4l2.c:1010 vb2_fop_release+0x77/0xc0 drivers/media/common/videobuf2/videobuf2-v4l2.c:1024 vivid_fop_release+0x18e/0x440 drivers/media/platform/vivid/vivid-core.c:474 v4l2_release+0x224/0x3a0 drivers/media/v4l2-core/v4l2-dev.c:456 __fput+0x3bc/0xa70 fs/file_table.c:279 ____fput+0x15/0x20 fs/file_table.c:312 task_work_run+0x1e8/0x2a0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x1a48/0x2620 kernel/exit.c:867 do_group_exit+0x177/0x440 kernel/exit.c:970 __do_sys_exit_group kernel/exit.c:981 [inline] __se_sys_exit_group kernel/exit.c:979 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:979 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8801b43cd200 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 0 bytes inside of 1024-byte region [ffff8801b43cd200, ffff8801b43cd600) The buggy address belongs to the page: page:ffffea0006d0f300 count:1 mapcount:0 mapping:ffff8801da800ac0 index:0x0 compound_mapcount: 0 flags: 0x2fffc0000010200(slab|head) raw: 02fffc0000010200 ffffea00070a9b08 ffffea0007087a08 ffff8801da800ac0 raw: 0000000000000000 ffff8801b43cc000 0000000100000007 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801b43cd100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801b43cd180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8801b43cd200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801b43cd280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801b43cd300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================