On Fri, Dec 06, 2013 at 02:38:28PM +0000, Richard Yao wrote:
> On 12/06/2013 06:14 AM, Will Deacon wrote:
> > On Wed, Dec 04, 2013 at 08:43:18PM +0000, Richard Yao wrote:
> >> diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
> >> index 9c5a1aa..5d1d04b 100644
> >> --- a/net/9p/trans_virtio.c
> >> +++ b/net/9p/trans_virtio.c
> >> @@ -340,7 +340,10 @@ static int p9_get_mapped_pages(struct virtio_chan *chan,
> >> int count = nr_pages;
> >> while (nr_pages) {
> >> s = rest_of_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
> [<ffffffff81153571>] kernel_read+0x41/0x60
> [<ffffffff810c83ab>] copy_module_from_fd.isra.34+0xfb/0x180
> [<ffffffff810cc420>] SyS_finit_module+0x70/0xd0
> [<ffffffff814a08fd>] system_call_fastpath+0x1a/0x1f
> [<ffffffffffffffff>] 0xffffffffffffffff
>
> This is easily reproducible by trying to load a module off virtfs. QEMU
> will print the message that I cited in the commit message and then kill
> itself.
Ok, thanks for confirming!
In which case, this patch looks fine to me:
Reviewed-by: Will Deacon <will.deacon@xxxxxxx>
Will
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