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BUG: KASAN: use-after-free in __vb2_perform_fileio+0xce9/0xda0 drivers/media/v4l2-core/videobuf2-core.c:2379
Read of size 4 at addr ffff88808db679dc by task syz-executor.0/12030

CPU: 1 PID: 12030 Comm: syz-executor.0 Not tainted 4.14.215-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+0x1b2/0x283 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:252
 kasan_report_error.cold+0x8a/0x194 mm/kasan/report.c:351
 kasan_report mm/kasan/report.c:409 [inline]
 __asan_report_load4_noabort+0x68/0x70 mm/kasan/report.c:429
 __vb2_perform_fileio+0xce9/0xda0 drivers/media/v4l2-core/videobuf2-core.c:2379
 vb2_fop_read+0x1ef/0x3d0 drivers/media/v4l2-core/videobuf2-v4l2.c:895
 v4l2_read+0x19a/0x200 drivers/media/v4l2-core/v4l2-dev.c:309
 __vfs_read+0xe4/0x620 fs/read_write.c:411
 vfs_read+0x139/0x340 fs/read_write.c:447
 SYSC_read fs/read_write.c:574 [inline]
 SyS_read+0xf2/0x210 fs/read_write.c:567
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x45e219
RSP: 002b:00007fd7ebe1ec68 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045e219
RDX: 000000000000007f RSI: 0000000020000100 RDI: 0000000000000004
RBP: 000000000119bfc0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000119bf8c
R13: 00007ffc018ffd9f R14: 00007fd7ebe1f9c0 R15: 000000000119bf8c

Allocated by task 12023:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:551
 kmem_cache_alloc_trace+0x131/0x3d0 mm/slab.c:3618
 kmalloc include/linux/slab.h:488 [inline]
 kzalloc include/linux/slab.h:661 [inline]
 __vb2_init_fileio+0x17f/0xa90 drivers/media/v4l2-core/videobuf2-core.c:2224
 __vb2_perform_fileio+0x993/0xda0 drivers/media/v4l2-core/videobuf2-core.c:2358
 vb2_fop_read+0x1ef/0x3d0 drivers/media/v4l2-core/videobuf2-v4l2.c:895
 v4l2_read+0x19a/0x200 drivers/media/v4l2-core/v4l2-dev.c:309
 __vfs_read+0xe4/0x620 fs/read_write.c:411
 vfs_read+0x139/0x340 fs/read_write.c:447
 SYSC_read fs/read_write.c:574 [inline]
 SyS_read+0xf2/0x210 fs/read_write.c:567
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 12023:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xc3/0x1a0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xc9/0x250 mm/slab.c:3815
 __vb2_cleanup_fileio+0xf5/0x150 drivers/media/v4l2-core/videobuf2-core.c:2317
 vb2_core_queue_release+0x17/0x70 drivers/media/v4l2-core/videobuf2-core.c:2040
 vb2_queue_release drivers/media/v4l2-core/videobuf2-v4l2.c:669 [inline]
 _vb2_fop_release+0x1c1/0x280 drivers/media/v4l2-core/videobuf2-v4l2.c:840
 vivid_fop_release+0x17d/0x6b6 drivers/media/platform/vivid/vivid-core.c:486
 v4l2_release+0xf4/0x190 drivers/media/v4l2-core/v4l2-dev.c:446
 __fput+0x25f/0x7a0 fs/file_table.c:210
 task_work_run+0x11f/0x190 kernel/task_work.c:113
 get_signal+0x18a3/0x1ca0 kernel/signal.c:2234
 do_signal+0x7c/0x1550 arch/x86/kernel/signal.c:814
 exit_to_usermode_loop+0x160/0x200 arch/x86/entry/common.c:160
 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+0x46/0xbb

The buggy address belongs to the object at ffff88808db676c0
 which belongs to the cache kmalloc-1024 of size 1024
The buggy address is located 796 bytes inside of
 1024-byte region [ffff88808db676c0, ffff88808db67ac0)
The buggy address belongs to the page:
page:ffffea000236d980 count:1 mapcount:0 mapping:ffff88808db66040 index:0x0 compound_mapcount: 0
flags: 0xfff00000008100(slab|head)
raw: 00fff00000008100 ffff88808db66040 0000000000000000 0000000100000007
raw: ffffea0002480a20 ffffea00027eb9a0 ffff88813fe80ac0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88808db67880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88808db67900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88808db67980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                    ^
 ffff88808db67a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88808db67a80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
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