syzbot has found a reproducer for the following crash on:

HEAD commit: d41217aac0a5 Merge tag 'pci-v4.20-fixes-1' of git://git.ke.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=15c136d5400000 kernel config: https://syzkaller.appspot.com/x/.config?x=4a0a89f12ca9b0f5 dashboard link: https://syzkaller.appspot.com/bug?extid=a9317fe7ad261fc76b88 compiler: gcc (GCC) 8.0.1 20180413 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16f7b6f5400000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=105a2783400000

IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+a9317fe7ad261fc76b88@syzkaller.appspotmail.com

audit: type=1400 audit(1542267352.102:36): avc: denied { map } for pid=6158 comm="syz-executor267" path="/root/syz-executor267520803" dev="sda1" ino=16483 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 WARNING: CPU: 0 PID: 6180 at drivers/dma-buf/dma-buf.c:992 dma_buf_vunmap+0x1bb/0x220 drivers/dma-buf/dma-buf.c:992 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 6180 Comm: syz-executor267 Not tainted 4.20.0-rc2+ #113 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 panic+0x2ad/0x55c kernel/panic.c:188 __warn.cold.8+0x20/0x45 kernel/panic.c:540 report_bug+0x254/0x2d0 lib/bug.c:186 fixup_bug arch/x86/kernel/traps.c:178 [inline] do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271 do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:290 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:969 RIP: 0010:dma_buf_vunmap+0x1bb/0x220 drivers/dma-buf/dma-buf.c:992 Code: 00 00 00 00 e8 56 f2 27 fd 4c 89 f7 e8 7e 1f 77 03 e8 49 f2 27 fd 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 35 f2 27 fd <0f> 0b eb e3 e8 2c f2 27 fd 0f 0b e8 25 f2 27 fd 0f 0b e8 1e f2 27 RSP: 0018:ffff8881b17cf948 EFLAGS: 00010293 RAX: ffff8881cde40040 RBX: 0000000000000000 RCX: ffffffff854cfa50 RDX: 0000000000000000 RSI: ffffffff845795ab RDI: 0000000000000000 RBP: ffff8881b17cf978 R08: ffff8881cde40040 R09: ffffed103a5dd096 R10: ffff8881b17cfad0 R11: ffff8881d2ee84b7 R12: ffffc90007465000 R13: ffff8881b100a940 R14: ffff8881b100a9a8 R15: ffff8881d965d800 vb2_vmalloc_detach_dmabuf+0x5a/0x80 drivers/media/common/videobuf2/videobuf2-vmalloc.c:406 __vb2_plane_dmabuf_put.isra.5+0x122/0x310 drivers/media/common/videobuf2/videobuf2-core.c:275 __vb2_buf_dmabuf_put drivers/media/common/videobuf2/videobuf2-core.c:291 [inline] __vb2_free_mem drivers/media/common/videobuf2/videobuf2-core.c:415 [inline] __vb2_queue_free+0x7f3/0xa30 drivers/media/common/videobuf2/videobuf2-core.c:458 vb2_core_queue_release+0x62/0x80 drivers/media/common/videobuf2/videobuf2-core.c:2231 vb2_queue_release+0x15/0x20 drivers/media/common/videobuf2/videobuf2-v4l2.c:837 v4l2_m2m_ctx_release+0x1e/0x35 drivers/media/v4l2-core/v4l2-mem2mem.c:930 vim2m_release+0xe6/0x150 drivers/media/platform/vim2m.c:977 v4l2_release+0x224/0x3a0 drivers/media/v4l2-core/v4l2-dev.c:456 __fput+0x385/0xa30 fs/file_table.c:278 ____fput+0x15/0x20 fs/file_table.c:309 task_work_run+0x1e8/0x2a0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x318/0x380 arch/x86/entry/common.c:166 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x405731 Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 94 17 00 00 c3 48 83 ec 08 e8 6a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 b3 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01 RSP: 002b:00007fff450aae60 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000405731 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 0000000000000003 RBP: 000000000000c12d R08: 00000000006dbc3c R09: 000000037ffffa00 R10: 00007fff450aae80 R11: 0000000000000293 R12: 000000000000002d R13: 20c49ba5e353f7cf R14: 0000000000000004 R15: 00000000006dbd2c Kernel Offset: disabled Rebooting in 86400 seconds..

syzbot suspects this bug was fixed by commit:

commit 62dcb4f41836bd3c44b5b651bb6df07ea4cb1551 Author: Hans Verkuil hverkuil-cisco@xs4all.nl Date: Thu Nov 8 12:23:37 2018 +0000

media: vb2: check memory model for VIDIOC_CREATE_BUFS

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=116af11c600000 start commit: d41217aa Merge tag 'pci-v4.20-fixes-1' of git://git.kernel.. git tree: upstream kernel config: https://syzkaller.appspot.com/x/.config?x=4a0a89f12ca9b0f5 dashboard link: https://syzkaller.appspot.com/bug?extid=a9317fe7ad261fc76b88 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16f7b6f5400000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=105a2783400000

If the result looks correct, please mark the bug fixed by replying with:

#syz fix: media: vb2: check memory model for VIDIOC_CREATE_BUFS

For information about bisection process see: https://goo.gl/tpsmEJ#bisection