Displaying 4 results from an estimated 4 matches for "p9_client_zc_rpc".
2013 Dec 06
1
[PATCH] 9p/trans_virtio.c: Fix broken zero-copy on vmalloc() buffers
...page(data);
>> - pages[index++] = kmap_to_page(data);
>> + if (is_vmalloc_or_module_addr(data))
>
> Can this really end up being a module address?
Yes. Here is the stacktrace to prove it:
[<ffffffff814878ce>] p9_virtio_zc_request+0x45e/0x510
[<ffffffff814814ed>] p9_client_zc_rpc.constprop.16+0xfd/0x4f0
[<ffffffff814839dd>] p9_client_read+0x15d/0x240
[<ffffffff811c8440>] v9fs_fid_readn+0x50/0xa0
[<ffffffff811c84a0>] v9fs_file_readn+0x10/0x20
[<ffffffff811c84e7>] v9fs_file_read+0x37/0x70
[<ffffffff8114e3fb>] vfs_read+0x9b/0x160
[<ffffffff8115...
2013 Dec 06
1
[PATCH] 9p/trans_virtio.c: Fix broken zero-copy on vmalloc() buffers
...page(data);
>> - pages[index++] = kmap_to_page(data);
>> + if (is_vmalloc_or_module_addr(data))
>
> Can this really end up being a module address?
Yes. Here is the stacktrace to prove it:
[<ffffffff814878ce>] p9_virtio_zc_request+0x45e/0x510
[<ffffffff814814ed>] p9_client_zc_rpc.constprop.16+0xfd/0x4f0
[<ffffffff814839dd>] p9_client_read+0x15d/0x240
[<ffffffff811c8440>] v9fs_fid_readn+0x50/0xa0
[<ffffffff811c84a0>] v9fs_file_readn+0x10/0x20
[<ffffffff811c84e7>] v9fs_file_read+0x37/0x70
[<ffffffff8114e3fb>] vfs_read+0x9b/0x160
[<ffffffff8115...
2013 Dec 04
3
[PATCH] 9p/trans_virtio.c: Fix broken zero-copy on vmalloc() buffers
The 9p-virtio transport does zero copy on things larger than 1024 bytes
in size. It accomplishes this by returning the physical addresses of
pages to the virtio-pci device. At present, the translation is usually a
bit shift.
However, that approach produces an invalid page address when we
read/write to vmalloc buffers, such as those used for Linux kernle
modules. This causes QEMU to die printing:
2013 Dec 04
3
[PATCH] 9p/trans_virtio.c: Fix broken zero-copy on vmalloc() buffers
The 9p-virtio transport does zero copy on things larger than 1024 bytes
in size. It accomplishes this by returning the physical addresses of
pages to the virtio-pci device. At present, the translation is usually a
bit shift.
However, that approach produces an invalid page address when we
read/write to vmalloc buffers, such as those used for Linux kernle
modules. This causes QEMU to die printing: