| Message ID | 20130623141903.GA21029@redhat.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
Hello. On 23-06-2013 18:19, Michael S. Tsirkin wrote: > get user pages might fail partially in tun zero copy > mode. To recover we need to put all pages that we got, > but code used a wrong index resulting in double-free > errors. > Reported-by: Brad Hubbard <bhubbard@redhat.com> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> > --- > I haven't figured out why do we get failures, > but recovery is clearly wrong. > This is also -stable material. > drivers/net/tun.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > diff --git a/drivers/net/tun.c b/drivers/net/tun.c > index bfa9bb4..c098b1e 100644 > --- a/drivers/net/tun.c > +++ b/drivers/net/tun.c > @@ -1010,8 +1010,9 @@ static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from, > return -EMSGSIZE; > num_pages = get_user_pages_fast(base, size, 0, &page[i]); > if (num_pages != size) { > - for (i = 0; i < num_pages; i++) > - put_page(page[i]); > + int j; Empty line wouldn't hurt here, after declaration. > + for (j = 0; j < num_pages; j++) > + put_page(page[i + j]); -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 06/23/2013 10:19 PM, Michael S. Tsirkin wrote: > get user pages might fail partially in tun zero copy > mode. To recover we need to put all pages that we got, > but code used a wrong index resulting in double-free > errors. > > Reported-by: Brad Hubbard <bhubbard@redhat.com> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> > --- > > I haven't figured out why do we get failures, > but recovery is clearly wrong. > > This is also -stable material. Acked-by: Jason Wang <jasowang@redhat.com> > drivers/net/tun.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/tun.c b/drivers/net/tun.c > index bfa9bb4..c098b1e 100644 > --- a/drivers/net/tun.c > +++ b/drivers/net/tun.c > @@ -1010,8 +1010,9 @@ static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from, > return -EMSGSIZE; > num_pages = get_user_pages_fast(base, size, 0, &page[i]); > if (num_pages != size) { > - for (i = 0; i < num_pages; i++) > - put_page(page[i]); > + int j; > + for (j = 0; j < num_pages; j++) > + put_page(page[i + j]); > return -EFAULT; > } > truesize = size * PAGE_SIZE; -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Sun, Jun 23, 2013 at 05:19:03PM +0300, Michael S. Tsirkin wrote: > get user pages might fail partially in tun zero copy > mode. To recover we need to put all pages that we got, > but code used a wrong index resulting in double-free > errors. > > Reported-by: Brad Hubbard <bhubbard@redhat.com> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> > --- > > I haven't figured out why do we get failures, > but recovery is clearly wrong. > > This is also -stable material. > > drivers/net/tun.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > Acked-by: Neil Horman <nhorman@tuxdriver.com> -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Sun, Jun 23, 2013 at 07:36:21PM +0400, Sergei Shtylyov wrote: > Hello. > > On 23-06-2013 18:19, Michael S. Tsirkin wrote: > > >get user pages might fail partially in tun zero copy > >mode. To recover we need to put all pages that we got, > >but code used a wrong index resulting in double-free > >errors. > > >Reported-by: Brad Hubbard <bhubbard@redhat.com> > >Signed-off-by: Michael S. Tsirkin <mst@redhat.com> > >--- > > >I haven't figured out why do we get failures, > >but recovery is clearly wrong. > > >This is also -stable material. > > > drivers/net/tun.c | 5 +++-- > > 1 file changed, 3 insertions(+), 2 deletions(-) > > >diff --git a/drivers/net/tun.c b/drivers/net/tun.c > >index bfa9bb4..c098b1e 100644 > >--- a/drivers/net/tun.c > >+++ b/drivers/net/tun.c > >@@ -1010,8 +1010,9 @@ static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from, > > return -EMSGSIZE; > > num_pages = get_user_pages_fast(base, size, 0, &page[i]); > > if (num_pages != size) { > >- for (i = 0; i < num_pages; i++) > >- put_page(page[i]); > >+ int j; > > Empty line wouldn't hurt here, after declaration. > > >+ for (j = 0; j < num_pages; j++) > >+ put_page(page[i + j]); I think it's clearer without: this is the only code within this block, declaration is really part of the loop that comes after it. An empty line would break it up visually. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: "Michael S. Tsirkin" <mst@redhat.com> Date: Mon, 24 Jun 2013 15:54:12 +0300 > On Sun, Jun 23, 2013 at 07:36:21PM +0400, Sergei Shtylyov wrote: >> Hello. >> >> On 23-06-2013 18:19, Michael S. Tsirkin wrote: >> >> >get user pages might fail partially in tun zero copy >> >mode. To recover we need to put all pages that we got, >> >but code used a wrong index resulting in double-free >> >errors. >> >> >Reported-by: Brad Hubbard <bhubbard@redhat.com> >> >Signed-off-by: Michael S. Tsirkin <mst@redhat.com> >> >--- >> >> >I haven't figured out why do we get failures, >> >but recovery is clearly wrong. >> >> >This is also -stable material. >> >> > drivers/net/tun.c | 5 +++-- >> > 1 file changed, 3 insertions(+), 2 deletions(-) >> >> >diff --git a/drivers/net/tun.c b/drivers/net/tun.c >> >index bfa9bb4..c098b1e 100644 >> >--- a/drivers/net/tun.c >> >+++ b/drivers/net/tun.c >> >@@ -1010,8 +1010,9 @@ static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from, >> > return -EMSGSIZE; >> > num_pages = get_user_pages_fast(base, size, 0, &page[i]); >> > if (num_pages != size) { >> >- for (i = 0; i < num_pages; i++) >> >- put_page(page[i]); >> >+ int j; >> >> Empty line wouldn't hurt here, after declaration. >> >> >+ for (j = 0; j < num_pages; j++) >> >+ put_page(page[i + j]); > > I think it's clearer without: this is the only code > within this block, declaration is really part of > the loop that comes after it. > An empty line would break it up visually. No, really, an empty line after local variable declarations please. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Jason Wang <jasowang@redhat.com> Date: Mon, 24 Jun 2013 11:22:52 +0800 > On 06/23/2013 10:19 PM, Michael S. Tsirkin wrote: >> get user pages might fail partially in tun zero copy >> mode. To recover we need to put all pages that we got, >> but code used a wrong index resulting in double-free >> errors. >> >> Reported-by: Brad Hubbard <bhubbard@redhat.com> >> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> >> --- >> >> I haven't figured out why do we get failures, >> but recovery is clearly wrong. >> >> This is also -stable material. > > Acked-by: Jason Wang <jasowang@redhat.com> Applied with the missing empty line added, I was tired of waiting for Michael to take care of this himself. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index bfa9bb4..c098b1e 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1010,8 +1010,9 @@ static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from, return -EMSGSIZE; num_pages = get_user_pages_fast(base, size, 0, &page[i]); if (num_pages != size) { - for (i = 0; i < num_pages; i++) - put_page(page[i]); + int j; + for (j = 0; j < num_pages; j++) + put_page(page[i + j]); return -EFAULT; } truesize = size * PAGE_SIZE;
get user pages might fail partially in tun zero copy mode. To recover we need to put all pages that we got, but code used a wrong index resulting in double-free errors. Reported-by: Brad Hubbard <bhubbard@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> --- I haven't figured out why do we get failures, but recovery is clearly wrong. This is also -stable material. drivers/net/tun.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)