Re: [syzbot] WARNING in dma_map_sgtable

[Christoph Hellwig]

This means the DMA API is called on a not DMA capable device.  This
needs fixing in the caller.

On Thu, Jan 20, 2022 at 04:18:21AM -0800, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    e3a8b6a1e70c Merge tag 'slab-for-5.17-part2' of git://git...
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=1507e01fb00000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=73c17fd2d4a060fe
> dashboard link: https://syzkaller.appspot.com/bug?extid=d03b64357793677f0080
> compiler:       Debian clang version 11.0.1-2, 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+d03b64357793677f0080@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
> ------------[ cut here ]------------
> WARNING: CPU: 1 PID: 21150 at kernel/dma/mapping.c:188 __dma_map_sg_attrs kernel/dma/mapping.c:188 [inline]
> WARNING: CPU: 1 PID: 21150 at kernel/dma/mapping.c:188 dma_map_sgtable+0x203/0x260 kernel/dma/mapping.c:264
> Modules linked in:
> CPU: 1 PID: 21150 Comm: syz-executor.5 Not tainted 5.16.0-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> RIP: 0010:__dma_map_sg_attrs kernel/dma/mapping.c:188 [inline]
> RIP: 0010:dma_map_sgtable+0x203/0x260 kernel/dma/mapping.c:264
> Code: 75 15 e8 50 b2 13 00 eb cb e8 49 b2 13 00 eb c4 e8 42 b2 13 00 eb bd e8 3b b2 13 00 0f 0b bd fb ff ff ff eb af e8 2d b2 13 00 <0f> 0b 31 ed 48 bb 00 00 00 00 00 fc ff df e9 7b ff ff ff 89 e9 80
> RSP: 0018:ffffc9000969fd20 EFLAGS: 00010287
> RAX: ffffffff8171ee13 RBX: dffffc0000000000 RCX: 0000000000040000
> RDX: ffffc900056f9000 RSI: 000000000000079b RDI: 000000000000079c
> RBP: ffff888147437408 R08: ffffffff8171ece3 R09: ffffed100d4e6956
> R10: ffffed100d4e6956 R11: 0000000000000000 R12: ffff888147437000
> R13: ffff88806a734aa0 R14: 0000000000000000 R15: 0000000000000002
> FS:  00007f009bbc7700(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 000055555641b108 CR3: 000000001901b000 CR4: 00000000003506e0
> DR0: 0000000020000100 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
> Call Trace:
>  <TASK>
>  get_sg_table+0xfc/0x150 drivers/dma-buf/udmabuf.c:72
>  begin_cpu_udmabuf+0xf5/0x160 drivers/dma-buf/udmabuf.c:126
>  dma_buf_begin_cpu_access+0xd8/0x170 drivers/dma-buf/dma-buf.c:1164
>  dma_buf_ioctl+0x2a0/0x2f0 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+0xfb/0x170 fs/ioctl.c:860
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x44/0xae
> RIP: 0033:0x7f009d251fe9
> 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:00007f009bbc7168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> RAX: ffffffffffffffda RBX: 00007f009d364f60 RCX: 00007f009d251fe9
> RDX: 0000000020000040 RSI: 0000000040086200 RDI: 000000000000000b
> RBP: 00007f009d2ac08d R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007ffc7751fd4f R14: 00007f009bbc7300 R15: 0000000000022000
>  </TASK>
> 
> 
> ---
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> 
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