| Message ID | 20220820032516.200446-1-syoshida@redhat.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | Simon Wunderlich |
| Headers | show |
| Series | batman-adv: Fix hang up with small MTU hard-interface | expand |
ping? On Sat, 20 Aug 2022 12:25:16 +0900, Shigeru Yoshida wrote: > The system hangs up when batman-adv soft-interface is created on > hard-interface with small MTU. For example, the following commands > create batman-adv soft-interface on dummy interface with zero MTU: > > # ip link add name dummy0 type dummy > # ip link set mtu 0 dev dummy0 > # ip link set up dev dummy0 > # ip link add name bat0 type batadv > # ip link set dev dummy0 master bat0 > > These commands cause the system hang up with the following messages: > > [ 90.578925][ T6689] batman_adv: bat0: Adding interface: dummy0 > [ 90.580884][ T6689] batman_adv: bat0: The MTU of interface dummy0 is too small (0) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to 1560 would solve the problem. > [ 90.586264][ T6689] batman_adv: bat0: Interface activated: dummy0 > [ 90.590061][ T6689] batman_adv: bat0: Forced to purge local tt entries to fit new maximum fragment MTU (-320) > [ 90.595517][ T6689] batman_adv: bat0: Forced to purge local tt entries to fit new maximum fragment MTU (-320) > [ 90.598499][ T6689] batman_adv: bat0: Forced to purge local tt entries to fit new maximum fragment MTU (-320) > > This patch fixes this issue by returning error when enabling > hard-interface with small MTU size. > > Signed-off-by: Shigeru Yoshida <syoshida@redhat.com> > --- > net/batman-adv/hard-interface.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c > index b8f8da7ee3de..dce5557800e9 100644 > --- a/net/batman-adv/hard-interface.c > +++ b/net/batman-adv/hard-interface.c > @@ -700,6 +700,9 @@ int batadv_hardif_enable_interface(struct batadv_hard_iface *hard_iface, > int max_header_len = batadv_max_header_len(); > int ret; > > + if (hard_iface->net_dev->mtu < ETH_MIN_MTU + max_header_len) > + return -EINVAL; > + > if (hard_iface->if_status != BATADV_IF_NOT_IN_USE) > goto out; > > -- > 2.37.2 >
On Wednesday, 7 September 2022 18:00:37 CEST Shigeru Yoshida wrote:
> ping?
This was applied a while ago:
https://git.open-mesh.org/linux-merge.git/commit/b1cb8a71f1eaec4eb77051590f7f561f25b15e32
Kind regards,
Sven
Hi Sven, On Wed, 07 Sep 2022 18:04:09 +0200,Wed, 07 Sep 2022 18:04:09 +0200, Sven Eckelmann wrote: > On Wednesday, 7 September 2022 18:00:37 CEST Shigeru Yoshida wrote: >> ping? > > This was applied a while ago: > > https://git.open-mesh.org/linux-merge.git/commit/b1cb8a71f1eaec4eb77051590f7f561f25b15e32 Sorry, I didn't notice that. Thank you so much!! Thanks, Shigeru > > Kind regards, > Sven
diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c index b8f8da7ee3de..dce5557800e9 100644 --- a/net/batman-adv/hard-interface.c +++ b/net/batman-adv/hard-interface.c @@ -700,6 +700,9 @@ int batadv_hardif_enable_interface(struct batadv_hard_iface *hard_iface, int max_header_len = batadv_max_header_len(); int ret; + if (hard_iface->net_dev->mtu < ETH_MIN_MTU + max_header_len) + return -EINVAL; + if (hard_iface->if_status != BATADV_IF_NOT_IN_USE) goto out;
The system hangs up when batman-adv soft-interface is created on hard-interface with small MTU. For example, the following commands create batman-adv soft-interface on dummy interface with zero MTU: # ip link add name dummy0 type dummy # ip link set mtu 0 dev dummy0 # ip link set up dev dummy0 # ip link add name bat0 type batadv # ip link set dev dummy0 master bat0 These commands cause the system hang up with the following messages: [ 90.578925][ T6689] batman_adv: bat0: Adding interface: dummy0 [ 90.580884][ T6689] batman_adv: bat0: The MTU of interface dummy0 is too small (0) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to 1560 would solve the problem. [ 90.586264][ T6689] batman_adv: bat0: Interface activated: dummy0 [ 90.590061][ T6689] batman_adv: bat0: Forced to purge local tt entries to fit new maximum fragment MTU (-320) [ 90.595517][ T6689] batman_adv: bat0: Forced to purge local tt entries to fit new maximum fragment MTU (-320) [ 90.598499][ T6689] batman_adv: bat0: Forced to purge local tt entries to fit new maximum fragment MTU (-320) This patch fixes this issue by returning error when enabling hard-interface with small MTU size. Signed-off-by: Shigeru Yoshida <syoshida@redhat.com> --- net/batman-adv/hard-interface.c | 3 +++ 1 file changed, 3 insertions(+)