On Fri, 30 Nov 2012 08:28:48 +0800
Fengguang Wu <fengguang.wu@xxxxxxxxx> wrote:
> Hi Rafael,
>
> [Julia and me think that this coccinelle warning is worth reporting.]
>
> tree: git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git since-3.6
> head: 422a0f651b5cefa1b6b3ede2e1c9e540a24a6e01
> commit: 5f1da4063294480b3fabcee554f976565dec54b5 [341/499] virtio_balloon: introduce migration primitives to balloon pages
>
> + drivers/virtio/virtio_balloon.c:157:2-8: preceding lock on line 136
>
> vim +157 drivers/virtio/virtio_balloon.c
>
> 6b35e407 Rusty Russell 2008-02-04 130 {
> 5f1da406 Rafael Aquini 2012-11-09 131 struct balloon_dev_info *vb_dev_info = vb->vb_dev_info;
> 5f1da406 Rafael Aquini 2012-11-09 132
> 6b35e407 Rusty Russell 2008-02-04 133 /* We can only do one array worth at a time. */
> 6b35e407 Rusty Russell 2008-02-04 134 num = min(num, ARRAY_SIZE(vb->pfns));
> 6b35e407 Rusty Russell 2008-02-04 135
> 5f1da406 Rafael Aquini 2012-11-09 @136 mutex_lock(&vb->balloon_lock);
> 3ccc9372 Michael S. Tsirkin 2012-04-12 137 for (vb->num_pfns = 0; vb->num_pfns < num;
> 3ccc9372 Michael S. Tsirkin 2012-04-12 138 vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE) {
> 5f1da406 Rafael Aquini 2012-11-09 139 struct page *page = balloon_page_enqueue(vb_dev_info);
> 5f1da406 Rafael Aquini 2012-11-09 140
> 6b35e407 Rusty Russell 2008-02-04 141 if (!page) {
> 6b35e407 Rusty Russell 2008-02-04 142 if (printk_ratelimit())
> 6b35e407 Rusty Russell 2008-02-04 143 dev_printk(KERN_INFO, &vb->vdev->dev,
> 6b35e407 Rusty Russell 2008-02-04 144 "Out of puff! Can't get %zu pages\n",
> 5f1da406 Rafael Aquini 2012-11-09 145 VIRTIO_BALLOON_PAGES_PER_PAGE);
> 6b35e407 Rusty Russell 2008-02-04 146 /* Sleep for at least 1/5 of a second before retry. */
> 6b35e407 Rusty Russell 2008-02-04 147 msleep(200);
> 6b35e407 Rusty Russell 2008-02-04 148 break;
> 6b35e407 Rusty Russell 2008-02-04 149 }
> 3ccc9372 Michael S. Tsirkin 2012-04-12 150 set_page_pfns(vb->pfns + vb->num_pfns, page);
> 3ccc9372 Michael S. Tsirkin 2012-04-12 151 vb->num_pages += VIRTIO_BALLOON_PAGES_PER_PAGE;
> 6b35e407 Rusty Russell 2008-02-04 152 totalram_pages--;
> 6b35e407 Rusty Russell 2008-02-04 153 }
> 6b35e407 Rusty Russell 2008-02-04 154
> 6b35e407 Rusty Russell 2008-02-04 155 /* Didn't get any? Oh well. */
> 6b35e407 Rusty Russell 2008-02-04 156 if (vb->num_pfns == 0)
> 6b35e407 Rusty Russell 2008-02-04 @157 return;
> 6b35e407 Rusty Russell 2008-02-04 158
> 6b35e407 Rusty Russell 2008-02-04 159 tell_host(vb, vb->inflate_vq);
> 5f1da406 Rafael Aquini 2012-11-09 160 mutex_unlock(&vb->balloon_lock);
This bug was fixed by
virtio_balloon-introduce-migration-primitives-to-balloon-pages.patch
this one -> virtio_balloon-introduce-migration-primitives-to-balloon-pages-fix.patch
virtio_balloon-introduce-migration-primitives-to-balloon-pages-fix-fix.patch
virtio_balloon-introduce-migration-primitives-to-balloon-pages-fix-fix-fix.patch
I'm surprised this sort of thing hasn't occurred before now - I'd
assumed that your bisection system knew about the followup patches and
skipped them.
I wonder how hard this is to do. My naming scheme is pretty simple:
foo-bar-zot.patch
foo-bar-zot-[some-other-text].patch
foo-bar-zot-[some-different-other-text].patch
But those are the local-to-mm filenames. The Subject: field in the
linux-next commit is sometimes quite different from the original
filename. But I can stop doing that, and ensure that the Subject:
matches the filename for fixup patches.
That means that your are-there-any-fixup-patches logic would need to do
this:
- Look at the patch title, For example, "virtio_balloon: introduce
migration primitives to balloon pages".
- Mangle that title into an akpm patch filename. The dopey script I
use to do this is below. In this example it will yield
virtio_balloon-introduce-migration-primitives-to-balloon-pages
- Look at the Subject: field of the following patches. If they start
with virtio_balloon-introduce-migration-primitives-to-balloon-pages
then skip over them.
#!/bin/sh
. patchfns 2>/dev/null ||
. /usr/lib/patch-scripts/patchfns 2>/dev/null ||
. $PATCHSCRIPTS_LIBDIR/patchfns 2>/dev/null ||
{
echo "Impossible to find my library 'patchfns'."
echo "Check your install, or go to the right directory"
exit 1
}
line="$1"
if stripit $line 2>/dev/null > /dev/null
then
f=$(stripit $line)
if [ -e txt/$f.txt ]
then
line="$(grep "^Subject: " txt/$f.txt | head -n 1)"
line=$(echo $line | sed -e "s/^Subject: //")
fi
fi
line=$(echo "$line" | tr 'A-Z' 'a-z')
line=$(echo "$line" | sed -e 's/^subject:[ ]*//')
line=$(echo "$line" | sed -e 's/^fw:[ ]*//')
line=$(echo "$line" | sed -e 's/(fwd)//g')
line=$(echo "$line" | sed -e 's/^fwd:[ ]*//')
line=$(echo "$line" | sed -e 's/^aw:[ ]*//')
line=$(echo "$line" | sed -e 's/^re:[ ]*//')
line=$(echo "$line" | sed -e 's/^patch//')
line=$(echo "$line" | sed -e "s/['\(\)\<\>\{\}\,\.\\]//g")
line=$(echo "$line" | sed -e "s/[\#\*\&\+\^\!\~\`\|\?\;]//g")
line=$(echo "$line" | sed -e "s/[\$]//g")
line=$(echo "$line" | sed -e 's/"//g')
line=$(echo "$line" | sed -e 's/^[-]*//g')
line=$(echo "$line" | sed -e 's/\[[^]]*\]//g')
line=$(echo "$line" | sed -e 's/[ ]*\[patch\][ ]*//')
line=$(echo "$line" | sed -e 's/\[//g')
line=$(echo "$line" | sed -e 's/\]//g')
line=$(echo "$line" | sed -e 's/^[ ]*//')
line=$(echo "$line" | sed -e 's/ -/-/g')
line=$(echo "$line" | sed -e 's/@/-/g')
line=$(echo "$line" | sed -e 's/- /-/g')
line=$(echo "$line" | sed -e 's/[ ][ ]*/-/g')
line=$(echo "$line" | sed -e 's,/,-,g')
line=$(echo "$line" | sed -e 's/--/-/g')
line=$(echo "$line" | sed -e 's/-$//g')
line=$(echo "$line" | sed -e 's/^-//g')
line=$(echo "$line" | sed -e 's/:/-/g')
line=$(echo "$line" | sed -e 's/--/-/g')
line=$(echo "$line" | sed -e 's/--/-/g')
line=$(echo "$line" | sed -e 's/--/-/g')
line=$(echo "$line" | sed -e 's/^[-]//')
line=$(echo "$line" | sed -e 's/[-]$//')
line=$(echo "$line" | sed -e 's/[-]$//')
line=$(echo "$line" | sed -e 's/[-]$//')
echo "$line"
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