Re: [Linaro-mm-sig] [syzbot] WARNING in __dma_map_sg_attrs - Linaro-mm-sig

2 Dec 2021


      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).
On Wed, Dec 01, 2021 at 10:18:21AM -0800, syzbot wrote:
...
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+10e27961f4da37c443b2@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>

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