[syzbot] WARNING in __dma_map_sg_attrs

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: c5c17547b778 Merge tag 'net-5.16-rc3' of git://git.kernel...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13a73609b00000
kernel config: https://syzkaller.appspot.com/x/.config?x=bf85c53718a1e697
dashboard link: https://syzkaller.appspot.com/bug?extid=10e27961f4da37c443b2
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+10e279...@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 2 PID: 17169 at kernel/dma/mapping.c:188 __dma_map_sg_attrs+0x181/0x1f0 kernel/dma/mapping.c:188
Modules linked in:
CPU: 0 PID: 17169 Comm: syz-executor.3 Not tainted 5.16.0-rc2-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
RIP: 0010:__dma_map_sg_attrs+0x181/0x1f0 kernel/dma/mapping.c:188
Code: 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 71 4c 8b 3d 70 6d b1 0d e9 db fe ff ff e8 86 ff 12 00 0f 0b e8 7f ff 12 00 <0f> 0b 45 31 e4 e9 54 ff ff ff e8 70 ff 12 00 49 8d 7f 50 48 b8 00
RSP: 0018:ffffc90002c0fb20 EFLAGS: 00010216
RAX: 0000000000013018 RBX: 0000000000000020 RCX: ffffc900037d4000
RDX: 0000000000040000 RSI: ffffffff8163d361 RDI: ffff8880182ae4d0
RBP: ffff8880182ae088 R08: 0000000000000002 R09: ffff888017ba054f
R10: ffffffff8163d242 R11: 000000000008808a R12: 0000000000000000
R13: ffff888024ca5700 R14: 0000000000000001 R15: 0000000000000000
FS: 00007fa269e34700(0000) GS:ffff88802cb00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000040c120 CR3: 000000006c77c000 CR4: 0000000000150ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
dma_map_sgtable+0x70/0xf0 kernel/dma/mapping.c:264
drm_gem_map_dma_buf+0x12a/0x1e0 drivers/gpu/drm/drm_prime.c:633
__map_dma_buf drivers/dma-buf/dma-buf.c:675 [inline]
dma_buf_map_attachment+0x39a/0x5b0 drivers/dma-buf/dma-buf.c:954
drm_gem_prime_import_dev.part.0+0x85/0x220 drivers/gpu/drm/drm_prime.c:939
drm_gem_prime_import_dev drivers/gpu/drm/drm_prime.c:982 [inline]
drm_gem_prime_import+0xc8/0x200 drivers/gpu/drm/drm_prime.c:982
virtgpu_gem_prime_import+0x49/0x150 drivers/gpu/drm/virtio/virtgpu_prime.c:166
drm_gem_prime_fd_to_handle+0x21d/0x550 drivers/gpu/drm/drm_prime.c:318
drm_prime_fd_to_handle_ioctl+0x9b/0xd0 drivers/gpu/drm/drm_prime.c:374
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: 0033:0x7fa26c8beae9
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:00007fa269e34188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fa26c9d1f60 RCX: 00007fa26c8beae9
RDX: 00000000200004c0 RSI: 00000000c00c642e RDI: 0000000000000005
RBP: 00007fa26c918f6d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc0019c51f R14: 00007fa269e34300 R15: 0000000000022000
</TASK>


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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[Christoph Hellwig]

This means the virtgpu driver uses dma mapping helpers but has not set up
a DMA mask (which most likely suggests it is some kind of virtual device).

---end quoted text---

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 0457e5153e0e Merge tag 'for-linus' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11b2637c700000
kernel config: https://syzkaller.appspot.com/x/.config?x=6f043113811433a5

dashboard link: https://syzkaller.appspot.com/bug?extid=10e27961f4da37c443b2
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11c65542700000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1163f480700000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+10e279...@syzkaller.appspotmail.com

------------[ cut here ]------------

WARNING: CPU: 1 PID: 3595 at kernel/dma/mapping.c:188 __dma_map_sg_attrs+0x181/0x1f0 kernel/dma/mapping.c:188
Modules linked in:
CPU: 0 PID: 3595 Comm: syz-executor249 Not tainted 5.17.0-rc2-syzkaller-00316-g0457e5153e0e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

RIP: 0010:__dma_map_sg_attrs+0x181/0x1f0 kernel/dma/mapping.c:188

Code: 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 71 4c 8b 3d c0 83 b5 0d e9 db fe ff ff e8 b6 0f 13 00 0f 0b e8 af 0f 13 00 <0f> 0b 45 31 e4 e9 54 ff ff ff e8 a0 0f 13 00 49 8d 7f 50 48 b8 00
RSP: 0018:ffffc90002a07d68 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff88807e25e2c0 RSI: ffffffff81649e91 RDI: ffff88801b848408
RBP: ffff88801b848000 R08: 0000000000000002 R09: ffff88801d86c74f
R10: ffffffff81649d72 R11: 0000000000000001 R12: 0000000000000002
R13: ffff88801d86c680 R14: 0000000000000001 R15: 0000000000000000
FS: 0000555556e30300(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00000000200000cc CR3: 000000001d74a000 CR4: 00000000003506e0

DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
dma_map_sgtable+0x70/0xf0 kernel/dma/mapping.c:264

get_sg_table.isra.0+0xe0/0x160 drivers/dma-buf/udmabuf.c:72
begin_cpu_udmabuf+0x130/0x1d0 drivers/dma-buf/udmabuf.c:126
dma_buf_begin_cpu_access+0xfd/0x1d0 drivers/dma-buf/dma-buf.c:1164
dma_buf_ioctl+0x259/0x2b0 drivers/dma-buf/dma-buf.c:363

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: 0033:0x7f62fcf530f9
Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 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 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe3edab9b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f62fcf530f9
RDX: 0000000020000200 RSI: 0000000040086200 RDI: 0000000000000006
RBP: 00007f62fcf170e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f62fcf17170
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
</TASK>

[Daniel Vetter]

On Sat, Feb 05, 2022 at 12:18:23PM -0800, syzbot wrote:
> syzbot has found a reproducer for the following issue on:
>
> HEAD commit: 0457e5153e0e Merge tag 'for-linus' of git://git.kernel.org..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=11b2637c700000
> kernel config: https://syzkaller.appspot.com/x/.config?x=6f043113811433a5
> dashboard link: https://syzkaller.appspot.com/bug?extid=10e27961f4da37c443b2
> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11c65542700000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1163f480700000
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+10e279...@syzkaller.appspotmail.com

Adding Gerd, since this seems to blow up in udmabuf.

I wonder why syzbot didn't figure this out, since it seems to have
correctly added both dma-api and dma-buf people. Just not the maintainer
for the begin_cpu_udmabuf function in the middle of the backtrace?
-Daniel

--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

[Dmitry Vyukov]

On Tue, 8 Feb 2022 at 13:26, Daniel Vetter <dan...@ffwll.ch> wrote:
>
> On Sat, Feb 05, 2022 at 12:18:23PM -0800, syzbot wrote:
> > syzbot has found a reproducer for the following issue on:
> >
> > HEAD commit: 0457e5153e0e Merge tag 'for-linus' of git://git.kernel.org..
> > git tree: upstream
> > console output: https://syzkaller.appspot.com/x/log.txt?x=11b2637c700000
> > kernel config: https://syzkaller.appspot.com/x/.config?x=6f043113811433a5
> > dashboard link: https://syzkaller.appspot.com/bug?extid=10e27961f4da37c443b2
> > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11c65542700000
> > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1163f480700000
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: syzbot+10e279...@syzkaller.appspotmail.com
>
> Adding Gerd, since this seems to blow up in udmabuf.
>
> I wonder why syzbot didn't figure this out, since it seems to have
> correctly added both dma-api and dma-buf people. Just not the maintainer
> for the begin_cpu_udmabuf function in the middle of the backtrace?

Hi Daniel,

syzbot selects only 1 file to get maintainers.
Do you suggest using all files in the stack trace? I think it may lead
to too many developers CCed since there can be something like 20 files
including something from scheduler, arch, fs, etc.

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