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Subject[syzbot] general protection fault in virtio_gpu_array_put_free
From
Hello,

syzbot found the following issue on:

HEAD commit: d58071a8a76d Linux 5.16-rc3
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11f773f6b00000
kernel config: https://syzkaller.appspot.com/x/.config?x=171728a464c05f2b
dashboard link: https://syzkaller.appspot.com/bug?extid=e9072e90624a31dfa85f
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e9072e90624a31dfa85f@syzkaller.appspotmail.com

</TASK>
general protection fault, probably for non-canonical address 0xdffffc000000000e: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000070-0x0000000000000077]
CPU: 0 PID: 20114 Comm: syz-executor.3 Not tainted 5.16.0-rc3-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
RIP: 0010:virtio_gpu_array_put_free+0x2f/0x190 drivers/gpu/drm/virtio/virtgpu_gem.c:251
Code: 55 49 89 fd 41 54 55 53 48 83 ec 08 e8 5a dd 09 fd 49 8d 45 70 48 89 c2 48 89 04 24 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 21 01 00 00 41 8b 5d 70 31 ff
RSP: 0018:ffffc90005a9fa90 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc900262ce000
RDX: 000000000000000e RSI: ffffffff846cf6e6 RDI: 0000000000000000
RBP: ffff88801882b800 R08: 0000000000000000 R09: ffffc90005a9f9ef
R10: ffffffff846dcc29 R11: 0000000000000000 R12: ffffc90005a9fbd0
R13: 0000000000000000 R14: ffff888045f60000 R15: 00000000fffffff4
FS: 00007f4ad9393700(0000) GS:ffff88802ca00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f561e680558 CR3: 0000000050bde000 CR4: 0000000000150ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
<TASK>
virtio_gpu_object_create+0x5c7/0xd90 drivers/gpu/drm/virtio/virtgpu_object.c:251
virtio_gpu_gem_create drivers/gpu/drm/virtio/virtgpu_gem.c:42 [inline]
virtio_gpu_mode_dumb_create+0x319/0x5c0 drivers/gpu/drm/virtio/virtgpu_gem.c:90
drm_mode_create_dumb+0x26c/0x2f0 drivers/gpu/drm/drm_dumb_buffers.c:96
drm_ioctl_kernel+0x27d/0x4e0 drivers/gpu/drm/drm_ioctl.c:782
drm_ioctl+0x51e/0x9d0 drivers/gpu/drm/drm_ioctl.c:885
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl fs/ioctl.c:860 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f4adbe1dae9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4ad9393188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f4adbf30f60 RCX: 00007f4adbe1dae9
RDX: 0000000020000040 RSI: 00000000c02064b2 RDI: 0000000000000003
RBP: 00007f4ad93931d0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002
R13: 00007ffccb96db4f R14: 00007f4ad9393300 R15: 0000000000022000
</TASK>
Modules linked in:
---[ end trace 8191b5e5ff4f69ef ]---
RIP: 0010:virtio_gpu_array_put_free+0x2f/0x190 drivers/gpu/drm/virtio/virtgpu_gem.c:251
Code: 55 49 89 fd 41 54 55 53 48 83 ec 08 e8 5a dd 09 fd 49 8d 45 70 48 89 c2 48 89 04 24 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 21 01 00 00 41 8b 5d 70 31 ff
RSP: 0018:ffffc90005a9fa90 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc900262ce000
RDX: 000000000000000e RSI: ffffffff846cf6e6 RDI: 0000000000000000
RBP: ffff88801882b800 R08: 0000000000000000 R09: ffffc90005a9f9ef
R10: ffffffff846dcc29 R11: 0000000000000000 R12: ffffc90005a9fbd0
R13: 0000000000000000 R14: ffff888045f60000 R15: 00000000fffffff4
FS: 00007f4ad9393700(0000) GS:ffff88802cb00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000065f4d7 CR3: 0000000050bde000 CR4: 0000000000150ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 55 push %rbp
1: 49 89 fd mov %rdi,%r13
4: 41 54 push %r12
6: 55 push %rbp
7: 53 push %rbx
8: 48 83 ec 08 sub $0x8,%rsp
c: e8 5a dd 09 fd callq 0xfd09dd6b
11: 49 8d 45 70 lea 0x70(%r13),%rax
15: 48 89 c2 mov %rax,%rdx
18: 48 89 04 24 mov %rax,(%rsp)
1c: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
23: fc ff df
26: 48 c1 ea 03 shr $0x3,%rdx
* 2a: 0f b6 04 02 movzbl (%rdx,%rax,1),%eax <-- trapping instruction
2e: 84 c0 test %al,%al
30: 74 08 je 0x3a
32: 3c 03 cmp $0x3,%al
34: 0f 8e 21 01 00 00 jle 0x15b
3a: 41 8b 5d 70 mov 0x70(%r13),%ebx
3e: 31 ff xor %edi,%edi


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

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