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BUG: KASAN: use-after-free in __vb2_perform_fileio+0xce9/0xda0 drivers/media/v4l2-core/videobuf2-core.c:2390
Read of size 4 at addr ffff8880b36c831c by task syz-executor584/7995

CPU: 1 PID: 7995 Comm: syz-executor584 Not tainted 4.14.264-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+0x1b2/0x281 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:252
 kasan_report_error.cold+0x8a/0x191 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:2390
 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
 do_loop_readv_writev fs/read_write.c:695 [inline]
 do_loop_readv_writev fs/read_write.c:682 [inline]
 do_iter_read+0x3eb/0x5b0 fs/read_write.c:919
 vfs_readv+0xc8/0x120 fs/read_write.c:981
 do_preadv fs/read_write.c:1065 [inline]
 SYSC_preadv fs/read_write.c:1115 [inline]
 SyS_preadv+0x15a/0x200 fs/read_write.c:1110
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7f36c65f5439
RSP: 002b:00007fffe7ea3998 EFLAGS: 00000246 ORIG_RAX: 0000000000000127
RAX: ffffffffffffffda RBX: 00000000000f4240 RCX: 00007f36c65f5439
RDX: 0000000000000001 RSI: 0000000020000600 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f36c65b46a0
R13: 0000000000000000 R14: 00007fffe7ea39c0 R15: 00007fffe7ea39b0

Allocated by task 7990:
 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:2235
 __vb2_perform_fileio+0x993/0xda0 drivers/media/v4l2-core/videobuf2-core.c:2369
 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
 do_loop_readv_writev fs/read_write.c:695 [inline]
 do_loop_readv_writev fs/read_write.c:682 [inline]
 do_iter_read+0x3eb/0x5b0 fs/read_write.c:919
 vfs_readv+0xc8/0x120 fs/read_write.c:981
 do_preadv fs/read_write.c:1065 [inline]
 SYSC_preadv fs/read_write.c:1115 [inline]
 SyS_preadv+0x15a/0x200 fs/read_write.c:1110
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 7996:
 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:2328
 vb2_core_queue_release+0x17/0x70 drivers/media/v4l2-core/videobuf2-core.c:2051
 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/0x6c0 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
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0xa44/0x2850 kernel/exit.c:868
 do_group_exit+0x100/0x2e0 kernel/exit.c:965
 SYSC_exit_group kernel/exit.c:976 [inline]
 SyS_exit_group+0x19/0x20 kernel/exit.c:974
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

The buggy address belongs to the object at ffff8880b36c8000
 which belongs to the cache kmalloc-1024 of size 1024
The buggy address is located 796 bytes inside of
 1024-byte region [ffff8880b36c8000, ffff8880b36c8400)
The buggy address belongs to the page:
page:ffffea0002cdb200 count:1 mapcount:0 mapping:ffff8880b36c8000 index:0x0 compound_mapcount: 0
flags: 0xfff00000008100(slab|head)
raw: 00fff00000008100 ffff8880b36c8000 0000000000000000 0000000100000007
raw: ffffea0002cde820 ffffea0002ccbfa0 ffff88813fe74ac0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880b36c8200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880b36c8280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880b36c8300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff8880b36c8380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880b36c8400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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