| Message ID | 20211009091604.84141-1-mst@redhat.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 732b74d647048668f0f8dc0c848f0746c69e2e2f |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net] virtio-net: fix for skb_over_panic inside big mode | expand |
| Context | Check | Description |
|---|---|---|
| netdev/cover_letter | success | Single patches do not need cover letters |
| netdev/fixes_present | success | Fixes tag present in non-next series |
| netdev/patch_count | success | Link |
| netdev/tree_selection | success | Clearly marked for net |
| netdev/subject_prefix | success | Link |
| netdev/cc_maintainers | success | CCed 7 of 7 maintainers |
| netdev/source_inline | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Signed-off-by tag matches author and committer |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/build_32bit | success | Errors and warnings before: 0 this patch: 0 |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/verify_fixes | success | Fixes tag looks correct |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 8 lines checked |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 0 this patch: 0 |
| netdev/header_inline | success | No static functions without inline keyword in header files |
On Sat, Oct 9, 2021 at 5:18 PM Michael S. Tsirkin <mst@redhat.com> wrote: > > From: Xuan Zhuo <xuanzhuo@linux.alibaba.com> > > commit 126285651b7f ("Merge ra.kernel.org:/pub/scm/linux/kernel/git/netdev/net") > accidentally reverted the effect of > commit 1a8024239da ("virtio-net: fix for skb_over_panic inside big mode") > on drivers/net/virtio_net.c > > As a result, users of crosvm (which is using large packet mode) > are experiencing crashes with 5.14-rc1 and above that do not > occur with 5.13. > > Crash trace: > > [ 61.346677] skbuff: skb_over_panic: text:ffffffff881ae2c7 len:3762 put:3762 head:ffff8a5ec8c22000 data:ffff8a5ec8c22010 tail:0xec2 end:0xec0 dev:<NULL> > [ 61.369192] kernel BUG at net/core/skbuff.c:111! > [ 61.372840] invalid opcode: 0000 [#1] SMP PTI > [ 61.374892] CPU: 5 PID: 0 Comm: swapper/5 Not tainted 5.14.0-rc1 linux-v5.14-rc1-for-mesa-ci.tar.bz2 #1 > [ 61.376450] Hardware name: ChromiumOS crosvm, BIOS 0 > > .. > > [ 61.393635] Call Trace: > [ 61.394127] <IRQ> > [ 61.394488] skb_put.cold+0x10/0x10 > [ 61.395095] page_to_skb+0xf7/0x410 > [ 61.395689] receive_buf+0x81/0x1660 > [ 61.396228] ? netif_receive_skb_list_internal+0x1ad/0x2b0 > [ 61.397180] ? napi_gro_flush+0x97/0xe0 > [ 61.397896] ? detach_buf_split+0x67/0x120 > [ 61.398573] virtnet_poll+0x2cf/0x420 > [ 61.399197] __napi_poll+0x25/0x150 > [ 61.399764] net_rx_action+0x22f/0x280 > [ 61.400394] __do_softirq+0xba/0x257 > [ 61.401012] irq_exit_rcu+0x8e/0xb0 > [ 61.401618] common_interrupt+0x7b/0xa0 > [ 61.402270] </IRQ> > > See > https://lore.kernel.org/r/5edaa2b7c2fe4abd0347b8454b2ac032b6694e2c.camel%40collabora.com > for the report. > > Apply the original 1a8024239da ("virtio-net: fix for skb_over_panic inside big mode") > again, the original logic still holds: > > In virtio-net's large packet mode, there is a hole in the space behind > buf. > > hdr_padded_len - hdr_len > > We must take this into account when calculating tailroom. > > Cc: Greg KH <gregkh@linuxfoundation.org> > Fixes: fb32856b16ad ("virtio-net: page_to_skb() use build_skb when there's sufficient tailroom") > Fixes: 126285651b7f ("Merge ra.kernel.org:/pub/scm/linux/kernel/git/netdev/net") > Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com> > Reported-by: Corentin Noël <corentin.noel@collabora.com> > Tested-by: Corentin Noël <corentin.noel@collabora.com> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> > --- Acked-by: Jason Wang <jasowang@redhat.com> > > David, I think we need this in stable, too. > > drivers/net/virtio_net.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index 096c2ac6b7a6..6b0812f44bbf 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -406,7 +406,7 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi, > * add_recvbuf_mergeable() + get_mergeable_buf_len() > */ > truesize = headroom ? PAGE_SIZE : truesize; > - tailroom = truesize - len - headroom; > + tailroom = truesize - len - headroom - (hdr_padded_len - hdr_len); > buf = p - headroom; > > len -= hdr_len; > -- > MST >
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 096c2ac6b7a6..6b0812f44bbf 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -406,7 +406,7 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi, * add_recvbuf_mergeable() + get_mergeable_buf_len() */ truesize = headroom ? PAGE_SIZE : truesize; - tailroom = truesize - len - headroom; + tailroom = truesize - len - headroom - (hdr_padded_len - hdr_len); buf = p - headroom; len -= hdr_len;