| Message ID | 20241219132644.725161-1-yuyanghuang@google.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net-next] netlink: correct nlmsg size for multicast notifications | expand |
On Thu, Dec 19, 2024 at 2:27 PM Yuyang Huang <yuyanghuang@google.com> wrote: > > Corrected the netlink message size calculation for multicast group > join/leave notifications. The previous calculation did not account for > the inclusion of both IPv4/IPv6 addresses and ifa_cacheinfo in the > payload. This fix ensures that the allocated message size is > sufficient to hold all necessary information. > > Fixes: 2c2b61d2138f ("netlink: add IGMP/MLD join/leave notifications") > Cc: Maciej Żenczykowski <maze@google.com> > Cc: Lorenzo Colitti <lorenzo@google.com> > Signed-off-by: Yuyang Huang <yuyanghuang@google.com> > --- > net/ipv4/igmp.c | 4 +++- > net/ipv6/mcast.c | 4 +++- > 2 files changed, 6 insertions(+), 2 deletions(-) > > diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c > index 8a370ef37d3f..4e2f1497f320 100644 > --- a/net/ipv4/igmp.c > +++ b/net/ipv4/igmp.c > @@ -1473,7 +1473,9 @@ static void inet_ifmcaddr_notify(struct net_device *dev, > int err = -ENOMEM; > > skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) + > - nla_total_size(sizeof(__be32)), GFP_ATOMIC); > + nla_total_size(sizeof(__be32)) + > + nla_total_size(sizeof(struct ifa_cacheinfo)), > + GFP_ATOMIC); > if (!skb) > goto error; > > diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c > index 587831c148de..b7430f15d1fc 100644 > --- a/net/ipv6/mcast.c > +++ b/net/ipv6/mcast.c > @@ -920,7 +920,9 @@ static void inet6_ifmcaddr_notify(struct net_device *dev, > int err = -ENOMEM; > > skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) + > - nla_total_size(16), GFP_ATOMIC); > + nla_total_size(16) + While we are at it , can you use nla_total_size(sizeof(struct in6_addr)) inet6_fill_ifmcaddr() got an EXPORT_SYMBOL() for no good reason, please remove it. Squash the following in v2, thanks ! diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 2e2684886953d55140cd3d4a1e024b5218331a49..4da409bc45777f60fd37bdee541c61165a51d22c 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -5239,7 +5239,6 @@ int inet6_fill_ifmcaddr(struct sk_buff *skb, nlmsg_end(skb, nlh); return 0; } -EXPORT_SYMBOL(inet6_fill_ifmcaddr); static int inet6_fill_ifacaddr(struct sk_buff *skb, const struct ifacaddr6 *ifaca,
On Thu, Dec 19, 2024 at 2:42 PM Eric Dumazet <edumazet@google.com> wrote: > > On Thu, Dec 19, 2024 at 2:27 PM Yuyang Huang <yuyanghuang@google.com> wrote: > > > > Corrected the netlink message size calculation for multicast group > > join/leave notifications. The previous calculation did not account for > > the inclusion of both IPv4/IPv6 addresses and ifa_cacheinfo in the > > payload. This fix ensures that the allocated message size is > > sufficient to hold all necessary information. > > > > Fixes: 2c2b61d2138f ("netlink: add IGMP/MLD join/leave notifications") > > Cc: Maciej Żenczykowski <maze@google.com> > > Cc: Lorenzo Colitti <lorenzo@google.com> > > Signed-off-by: Yuyang Huang <yuyanghuang@google.com> > > --- > > net/ipv4/igmp.c | 4 +++- > > net/ipv6/mcast.c | 4 +++- > > 2 files changed, 6 insertions(+), 2 deletions(-) > > > > diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c > > index 8a370ef37d3f..4e2f1497f320 100644 > > --- a/net/ipv4/igmp.c > > +++ b/net/ipv4/igmp.c > > @@ -1473,7 +1473,9 @@ static void inet_ifmcaddr_notify(struct net_device *dev, > > int err = -ENOMEM; > > > > skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) + > > - nla_total_size(sizeof(__be32)), GFP_ATOMIC); > > + nla_total_size(sizeof(__be32)) + > > + nla_total_size(sizeof(struct ifa_cacheinfo)), > > + GFP_ATOMIC); > > if (!skb) > > goto error; > > > > diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c > > index 587831c148de..b7430f15d1fc 100644 > > --- a/net/ipv6/mcast.c > > +++ b/net/ipv6/mcast.c > > @@ -920,7 +920,9 @@ static void inet6_ifmcaddr_notify(struct net_device *dev, > > int err = -ENOMEM; > > > > skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) + > > - nla_total_size(16), GFP_ATOMIC); > > + nla_total_size(16) + > > While we are at it , can you use nla_total_size(sizeof(struct in6_addr)) > > inet6_fill_ifmcaddr() got an EXPORT_SYMBOL() for no good reason, > please remove it. > Squash the following in v2, thanks ! > > diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c > index 2e2684886953d55140cd3d4a1e024b5218331a49..4da409bc45777f60fd37bdee541c61165a51d22c > 100644 > --- a/net/ipv6/addrconf.c > +++ b/net/ipv6/addrconf.c > @@ -5239,7 +5239,6 @@ int inet6_fill_ifmcaddr(struct sk_buff *skb, > nlmsg_end(skb, nlh); > return 0; > } > -EXPORT_SYMBOL(inet6_fill_ifmcaddr); > > static int inet6_fill_ifacaddr(struct sk_buff *skb, > const struct ifacaddr6 *ifaca, Also GFP_ATOMIC should probably be replaced by GFP_KERNEL. All inet6_ifmcaddr_notify() callers are in process context, hold RTNL, thus can sleep under memory pressure. Same remark for inet_ifmcaddr_notify()
Hi Eric Thanks for the prompt review feedback. I will adjust all the comments in the v2 patch. >inet6_fill_ifmcaddr() got an EXPORT_SYMBOL() for no good reason, please remove it. I made the same mistake in Link: https://lore.kernel.org/netdev/20241218090057.76899-1-yuyanghuang@google.com/T/ I will fix that patch as well. Thanks, Yuyang Thanks, Yuyang On Thu, Dec 19, 2024 at 10:47 PM Eric Dumazet <edumazet@google.com> wrote: > > On Thu, Dec 19, 2024 at 2:42 PM Eric Dumazet <edumazet@google.com> wrote: > > > > On Thu, Dec 19, 2024 at 2:27 PM Yuyang Huang <yuyanghuang@google.com> wrote: > > > > > > Corrected the netlink message size calculation for multicast group > > > join/leave notifications. The previous calculation did not account for > > > the inclusion of both IPv4/IPv6 addresses and ifa_cacheinfo in the > > > payload. This fix ensures that the allocated message size is > > > sufficient to hold all necessary information. > > > > > > Fixes: 2c2b61d2138f ("netlink: add IGMP/MLD join/leave notifications") > > > Cc: Maciej Żenczykowski <maze@google.com> > > > Cc: Lorenzo Colitti <lorenzo@google.com> > > > Signed-off-by: Yuyang Huang <yuyanghuang@google.com> > > > --- > > > net/ipv4/igmp.c | 4 +++- > > > net/ipv6/mcast.c | 4 +++- > > > 2 files changed, 6 insertions(+), 2 deletions(-) > > > > > > diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c > > > index 8a370ef37d3f..4e2f1497f320 100644 > > > --- a/net/ipv4/igmp.c > > > +++ b/net/ipv4/igmp.c > > > @@ -1473,7 +1473,9 @@ static void inet_ifmcaddr_notify(struct net_device *dev, > > > int err = -ENOMEM; > > > > > > skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) + > > > - nla_total_size(sizeof(__be32)), GFP_ATOMIC); > > > + nla_total_size(sizeof(__be32)) + > > > + nla_total_size(sizeof(struct ifa_cacheinfo)), > > > + GFP_ATOMIC); > > > if (!skb) > > > goto error; > > > > > > diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c > > > index 587831c148de..b7430f15d1fc 100644 > > > --- a/net/ipv6/mcast.c > > > +++ b/net/ipv6/mcast.c > > > @@ -920,7 +920,9 @@ static void inet6_ifmcaddr_notify(struct net_device *dev, > > > int err = -ENOMEM; > > > > > > skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) + > > > - nla_total_size(16), GFP_ATOMIC); > > > + nla_total_size(16) + > > > > While we are at it , can you use nla_total_size(sizeof(struct in6_addr)) > > > > inet6_fill_ifmcaddr() got an EXPORT_SYMBOL() for no good reason, > > please remove it. > > Squash the following in v2, thanks ! > > > > diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c > > index 2e2684886953d55140cd3d4a1e024b5218331a49..4da409bc45777f60fd37bdee541c61165a51d22c > > 100644 > > --- a/net/ipv6/addrconf.c > > +++ b/net/ipv6/addrconf.c > > @@ -5239,7 +5239,6 @@ int inet6_fill_ifmcaddr(struct sk_buff *skb, > > nlmsg_end(skb, nlh); > > return 0; > > } > > -EXPORT_SYMBOL(inet6_fill_ifmcaddr); > > > > static int inet6_fill_ifacaddr(struct sk_buff *skb, > > const struct ifacaddr6 *ifaca, > > Also GFP_ATOMIC should probably be replaced by GFP_KERNEL. > > All inet6_ifmcaddr_notify() callers are in process context, hold RTNL, > thus can sleep under memory pressure. > > Same remark for inet_ifmcaddr_notify()
>Also GFP_ATOMIC should probably be replaced by GFP_KERNEL. >All inet6_ifmcaddr_notify() callers are in process context, hold RTNL, >thus can sleep under memory pressure. I might not have enough background knowledge here, but why does holding RTNL imply that the callers are in process context? Link: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/tree/net/ipv6/addrconf.c#n2241 In addrconf.c, the logic joins the solicited-node multicast group and calls into mcast.c logic, which eventually triggers the notification. I guess this code path is not in process context when the kernel does SLAAC? Thanks, Yuyang On Thu, Dec 19, 2024 at 11:31 PM Yuyang Huang <yuyanghuang@google.com> wrote: > > Hi Eric > > Thanks for the prompt review feedback. I will adjust all the comments > in the v2 patch. > > >inet6_fill_ifmcaddr() got an EXPORT_SYMBOL() for no good reason, > please remove it. > > I made the same mistake in Link: > https://lore.kernel.org/netdev/20241218090057.76899-1-yuyanghuang@google.com/T/ > > I will fix that patch as well. > > Thanks, > Yuyang > > Thanks, > Yuyang > > > On Thu, Dec 19, 2024 at 10:47 PM Eric Dumazet <edumazet@google.com> wrote: > > > > On Thu, Dec 19, 2024 at 2:42 PM Eric Dumazet <edumazet@google.com> wrote: > > > > > > On Thu, Dec 19, 2024 at 2:27 PM Yuyang Huang <yuyanghuang@google.com> wrote: > > > > > > > > Corrected the netlink message size calculation for multicast group > > > > join/leave notifications. The previous calculation did not account for > > > > the inclusion of both IPv4/IPv6 addresses and ifa_cacheinfo in the > > > > payload. This fix ensures that the allocated message size is > > > > sufficient to hold all necessary information. > > > > > > > > Fixes: 2c2b61d2138f ("netlink: add IGMP/MLD join/leave notifications") > > > > Cc: Maciej Żenczykowski <maze@google.com> > > > > Cc: Lorenzo Colitti <lorenzo@google.com> > > > > Signed-off-by: Yuyang Huang <yuyanghuang@google.com> > > > > --- > > > > net/ipv4/igmp.c | 4 +++- > > > > net/ipv6/mcast.c | 4 +++- > > > > 2 files changed, 6 insertions(+), 2 deletions(-) > > > > > > > > diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c > > > > index 8a370ef37d3f..4e2f1497f320 100644 > > > > --- a/net/ipv4/igmp.c > > > > +++ b/net/ipv4/igmp.c > > > > @@ -1473,7 +1473,9 @@ static void inet_ifmcaddr_notify(struct net_device *dev, > > > > int err = -ENOMEM; > > > > > > > > skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) + > > > > - nla_total_size(sizeof(__be32)), GFP_ATOMIC); > > > > + nla_total_size(sizeof(__be32)) + > > > > + nla_total_size(sizeof(struct ifa_cacheinfo)), > > > > + GFP_ATOMIC); > > > > if (!skb) > > > > goto error; > > > > > > > > diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c > > > > index 587831c148de..b7430f15d1fc 100644 > > > > --- a/net/ipv6/mcast.c > > > > +++ b/net/ipv6/mcast.c > > > > @@ -920,7 +920,9 @@ static void inet6_ifmcaddr_notify(struct net_device *dev, > > > > int err = -ENOMEM; > > > > > > > > skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) + > > > > - nla_total_size(16), GFP_ATOMIC); > > > > + nla_total_size(16) + > > > > > > While we are at it , can you use nla_total_size(sizeof(struct in6_addr)) > > > > > > inet6_fill_ifmcaddr() got an EXPORT_SYMBOL() for no good reason, > > > please remove it. > > > Squash the following in v2, thanks ! > > > > > > diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c > > > index 2e2684886953d55140cd3d4a1e024b5218331a49..4da409bc45777f60fd37bdee541c61165a51d22c > > > 100644 > > > --- a/net/ipv6/addrconf.c > > > +++ b/net/ipv6/addrconf.c > > > @@ -5239,7 +5239,6 @@ int inet6_fill_ifmcaddr(struct sk_buff *skb, > > > nlmsg_end(skb, nlh); > > > return 0; > > > } > > > -EXPORT_SYMBOL(inet6_fill_ifmcaddr); > > > > > > static int inet6_fill_ifacaddr(struct sk_buff *skb, > > > const struct ifacaddr6 *ifaca, > > > > Also GFP_ATOMIC should probably be replaced by GFP_KERNEL. > > > > All inet6_ifmcaddr_notify() callers are in process context, hold RTNL, > > thus can sleep under memory pressure. > > > > Same remark for inet_ifmcaddr_notify()
>Same remark for inet_ifmcaddr_notify() Moreover, for both IPv4 and IPv6, when a device is up, the kernel joins the all-hosts multicast addresses (224.0.0.1/ff02::1). I guess this logic also does not run in process context? Thanks, Yuyang On Fri, Dec 20, 2024 at 12:27 AM Yuyang Huang <yuyanghuang@google.com> wrote: > > >Also GFP_ATOMIC should probably be replaced by GFP_KERNEL. > > >All inet6_ifmcaddr_notify() callers are in process context, hold RTNL, > >thus can sleep under memory pressure. > > I might not have enough background knowledge here, but why does > holding RTNL imply that the callers are in process context? > > Link: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/tree/net/ipv6/addrconf.c#n2241 > > In addrconf.c, the logic joins the solicited-node multicast group and > calls into mcast.c logic, which eventually triggers the notification. > I guess this code path is not in process context when the kernel does > SLAAC? > > Thanks, > Yuyang > > On Thu, Dec 19, 2024 at 11:31 PM Yuyang Huang <yuyanghuang@google.com> wrote: > > > > Hi Eric > > > > Thanks for the prompt review feedback. I will adjust all the comments > > in the v2 patch. > > > > >inet6_fill_ifmcaddr() got an EXPORT_SYMBOL() for no good reason, > > please remove it. > > > > I made the same mistake in Link: > > https://lore.kernel.org/netdev/20241218090057.76899-1-yuyanghuang@google.com/T/ > > > > I will fix that patch as well. > > > > Thanks, > > Yuyang > > > > Thanks, > > Yuyang > > > > > > On Thu, Dec 19, 2024 at 10:47 PM Eric Dumazet <edumazet@google.com> wrote: > > > > > > On Thu, Dec 19, 2024 at 2:42 PM Eric Dumazet <edumazet@google.com> wrote: > > > > > > > > On Thu, Dec 19, 2024 at 2:27 PM Yuyang Huang <yuyanghuang@google.com> wrote: > > > > > > > > > > Corrected the netlink message size calculation for multicast group > > > > > join/leave notifications. The previous calculation did not account for > > > > > the inclusion of both IPv4/IPv6 addresses and ifa_cacheinfo in the > > > > > payload. This fix ensures that the allocated message size is > > > > > sufficient to hold all necessary information. > > > > > > > > > > Fixes: 2c2b61d2138f ("netlink: add IGMP/MLD join/leave notifications") > > > > > Cc: Maciej Żenczykowski <maze@google.com> > > > > > Cc: Lorenzo Colitti <lorenzo@google.com> > > > > > Signed-off-by: Yuyang Huang <yuyanghuang@google.com> > > > > > --- > > > > > net/ipv4/igmp.c | 4 +++- > > > > > net/ipv6/mcast.c | 4 +++- > > > > > 2 files changed, 6 insertions(+), 2 deletions(-) > > > > > > > > > > diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c > > > > > index 8a370ef37d3f..4e2f1497f320 100644 > > > > > --- a/net/ipv4/igmp.c > > > > > +++ b/net/ipv4/igmp.c > > > > > @@ -1473,7 +1473,9 @@ static void inet_ifmcaddr_notify(struct net_device *dev, > > > > > int err = -ENOMEM; > > > > > > > > > > skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) + > > > > > - nla_total_size(sizeof(__be32)), GFP_ATOMIC); > > > > > + nla_total_size(sizeof(__be32)) + > > > > > + nla_total_size(sizeof(struct ifa_cacheinfo)), > > > > > + GFP_ATOMIC); > > > > > if (!skb) > > > > > goto error; > > > > > > > > > > diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c > > > > > index 587831c148de..b7430f15d1fc 100644 > > > > > --- a/net/ipv6/mcast.c > > > > > +++ b/net/ipv6/mcast.c > > > > > @@ -920,7 +920,9 @@ static void inet6_ifmcaddr_notify(struct net_device *dev, > > > > > int err = -ENOMEM; > > > > > > > > > > skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) + > > > > > - nla_total_size(16), GFP_ATOMIC); > > > > > + nla_total_size(16) + > > > > > > > > While we are at it , can you use nla_total_size(sizeof(struct in6_addr)) > > > > > > > > inet6_fill_ifmcaddr() got an EXPORT_SYMBOL() for no good reason, > > > > please remove it. > > > > Squash the following in v2, thanks ! > > > > > > > > diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c > > > > index 2e2684886953d55140cd3d4a1e024b5218331a49..4da409bc45777f60fd37bdee541c61165a51d22c > > > > 100644 > > > > --- a/net/ipv6/addrconf.c > > > > +++ b/net/ipv6/addrconf.c > > > > @@ -5239,7 +5239,6 @@ int inet6_fill_ifmcaddr(struct sk_buff *skb, > > > > nlmsg_end(skb, nlh); > > > > return 0; > > > > } > > > > -EXPORT_SYMBOL(inet6_fill_ifmcaddr); > > > > > > > > static int inet6_fill_ifacaddr(struct sk_buff *skb, > > > > const struct ifacaddr6 *ifaca, > > > > > > Also GFP_ATOMIC should probably be replaced by GFP_KERNEL. > > > > > > All inet6_ifmcaddr_notify() callers are in process context, hold RTNL, > > > thus can sleep under memory pressure. > > > > > > Same remark for inet_ifmcaddr_notify()
On Thu, Dec 19, 2024 at 4:28 PM Yuyang Huang <yuyanghuang@google.com> wrote: > > >Also GFP_ATOMIC should probably be replaced by GFP_KERNEL. > > >All inet6_ifmcaddr_notify() callers are in process context, hold RTNL, > >thus can sleep under memory pressure. > > I might not have enough background knowledge here, but why does > holding RTNL imply that the callers are in process context? RTNL is a mutex. Acquiring a mutex might sleep. By looking at the code flow, you can see we do not hold a spinlock, or block interrupts at this point, or are in rcu_read_lock() section. > > Link: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/tree/net/ipv6/addrconf.c#n2241 > > In addrconf.c, the logic joins the solicited-node multicast group and > calls into mcast.c logic, which eventually triggers the notification. > I guess this code path is not in process context when the kernel does > SLAAC? All these paths must be from process context. Note that debug kernels have CONFIG_DEBUG_ATOMIC_SLEEP=y and would complain. > > Thanks, > Yuyang > > On Thu, Dec 19, 2024 at 11:31 PM Yuyang Huang <yuyanghuang@google.com> wrote: > > > > Hi Eric > > > > Thanks for the prompt review feedback. I will adjust all the comments > > in the v2 patch. > > > > >inet6_fill_ifmcaddr() got an EXPORT_SYMBOL() for no good reason, > > please remove it. > > > > I made the same mistake in Link: > > https://lore.kernel.org/netdev/20241218090057.76899-1-yuyanghuang@google.com/T/ > > > > I will fix that patch as well. > > > > Thanks, > > Yuyang > > > > Thanks, > > Yuyang > > > > > > On Thu, Dec 19, 2024 at 10:47 PM Eric Dumazet <edumazet@google.com> wrote: > > > > > > On Thu, Dec 19, 2024 at 2:42 PM Eric Dumazet <edumazet@google.com> wrote: > > > > > > > > On Thu, Dec 19, 2024 at 2:27 PM Yuyang Huang <yuyanghuang@google.com> wrote: > > > > > > > > > > Corrected the netlink message size calculation for multicast group > > > > > join/leave notifications. The previous calculation did not account for > > > > > the inclusion of both IPv4/IPv6 addresses and ifa_cacheinfo in the > > > > > payload. This fix ensures that the allocated message size is > > > > > sufficient to hold all necessary information. > > > > > > > > > > Fixes: 2c2b61d2138f ("netlink: add IGMP/MLD join/leave notifications") > > > > > Cc: Maciej Żenczykowski <maze@google.com> > > > > > Cc: Lorenzo Colitti <lorenzo@google.com> > > > > > Signed-off-by: Yuyang Huang <yuyanghuang@google.com> > > > > > --- > > > > > net/ipv4/igmp.c | 4 +++- > > > > > net/ipv6/mcast.c | 4 +++- > > > > > 2 files changed, 6 insertions(+), 2 deletions(-) > > > > > > > > > > diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c > > > > > index 8a370ef37d3f..4e2f1497f320 100644 > > > > > --- a/net/ipv4/igmp.c > > > > > +++ b/net/ipv4/igmp.c > > > > > @@ -1473,7 +1473,9 @@ static void inet_ifmcaddr_notify(struct net_device *dev, > > > > > int err = -ENOMEM; > > > > > > > > > > skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) + > > > > > - nla_total_size(sizeof(__be32)), GFP_ATOMIC); > > > > > + nla_total_size(sizeof(__be32)) + > > > > > + nla_total_size(sizeof(struct ifa_cacheinfo)), > > > > > + GFP_ATOMIC); > > > > > if (!skb) > > > > > goto error; > > > > > > > > > > diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c > > > > > index 587831c148de..b7430f15d1fc 100644 > > > > > --- a/net/ipv6/mcast.c > > > > > +++ b/net/ipv6/mcast.c > > > > > @@ -920,7 +920,9 @@ static void inet6_ifmcaddr_notify(struct net_device *dev, > > > > > int err = -ENOMEM; > > > > > > > > > > skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) + > > > > > - nla_total_size(16), GFP_ATOMIC); > > > > > + nla_total_size(16) + > > > > > > > > While we are at it , can you use nla_total_size(sizeof(struct in6_addr)) > > > > > > > > inet6_fill_ifmcaddr() got an EXPORT_SYMBOL() for no good reason, > > > > please remove it. > > > > Squash the following in v2, thanks ! > > > > > > > > diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c > > > > index 2e2684886953d55140cd3d4a1e024b5218331a49..4da409bc45777f60fd37bdee541c61165a51d22c > > > > 100644 > > > > --- a/net/ipv6/addrconf.c > > > > +++ b/net/ipv6/addrconf.c > > > > @@ -5239,7 +5239,6 @@ int inet6_fill_ifmcaddr(struct sk_buff *skb, > > > > nlmsg_end(skb, nlh); > > > > return 0; > > > > } > > > > -EXPORT_SYMBOL(inet6_fill_ifmcaddr); > > > > > > > > static int inet6_fill_ifacaddr(struct sk_buff *skb, > > > > const struct ifacaddr6 *ifaca, > > > > > > Also GFP_ATOMIC should probably be replaced by GFP_KERNEL. > > > > > > All inet6_ifmcaddr_notify() callers are in process context, hold RTNL, > > > thus can sleep under memory pressure. > > > > > > Same remark for inet_ifmcaddr_notify()
On Thu, Dec 19, 2024 at 4:35 PM Yuyang Huang <yuyanghuang@google.com> wrote: > > >Same remark for inet_ifmcaddr_notify() > > Moreover, for both IPv4 and IPv6, when a device is up, the kernel > joins the all-hosts multicast addresses (224.0.0.1/ff02::1). I guess > this logic also does not run in process context? > Hopefully all these paths are stressed in kselftest. A wrong gfp would trigger issues when you run the selftests before submission, or in netdev CI.
Thank you very much for the detailed explanation. I will change GFP_ATOMIC to GFP_KERNEL in the v2 patch. Thanks, Yuyang On Fri, Dec 20, 2024 at 12:53 AM Eric Dumazet <edumazet@google.com> wrote: > > On Thu, Dec 19, 2024 at 4:35 PM Yuyang Huang <yuyanghuang@google.com> wrote: > > > > >Same remark for inet_ifmcaddr_notify() > > > > Moreover, for both IPv4 and IPv6, when a device is up, the kernel > > joins the all-hosts multicast addresses (224.0.0.1/ff02::1). I guess > > this logic also does not run in process context? > > > > Hopefully all these paths are stressed in kselftest. > > A wrong gfp would trigger issues when you run the selftests before > submission, or in netdev CI.
diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c index 8a370ef37d3f..4e2f1497f320 100644 --- a/net/ipv4/igmp.c +++ b/net/ipv4/igmp.c @@ -1473,7 +1473,9 @@ static void inet_ifmcaddr_notify(struct net_device *dev, int err = -ENOMEM; skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) + - nla_total_size(sizeof(__be32)), GFP_ATOMIC); + nla_total_size(sizeof(__be32)) + + nla_total_size(sizeof(struct ifa_cacheinfo)), + GFP_ATOMIC); if (!skb) goto error; diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c index 587831c148de..b7430f15d1fc 100644 --- a/net/ipv6/mcast.c +++ b/net/ipv6/mcast.c @@ -920,7 +920,9 @@ static void inet6_ifmcaddr_notify(struct net_device *dev, int err = -ENOMEM; skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) + - nla_total_size(16), GFP_ATOMIC); + nla_total_size(16) + + nla_total_size(sizeof(struct ifa_cacheinfo)), + GFP_ATOMIC); if (!skb) goto error;
Corrected the netlink message size calculation for multicast group join/leave notifications. The previous calculation did not account for the inclusion of both IPv4/IPv6 addresses and ifa_cacheinfo in the payload. This fix ensures that the allocated message size is sufficient to hold all necessary information. Fixes: 2c2b61d2138f ("netlink: add IGMP/MLD join/leave notifications") Cc: Maciej Żenczykowski <maze@google.com> Cc: Lorenzo Colitti <lorenzo@google.com> Signed-off-by: Yuyang Huang <yuyanghuang@google.com> --- net/ipv4/igmp.c | 4 +++- net/ipv6/mcast.c | 4 +++- 2 files changed, 6 insertions(+), 2 deletions(-)