On Fri, Apr 10, 2020 at 10:16:47AM -0400, David Hill wrote:
> On a April 9, 2020 cvs built machine:
>
> An splassert shows when I add or delete vlan0 on bridge0
>
> # ifconfig bridge0 add vlan0
> splassert: vlan_ioctl: want 2 have 0
> Starting stack trace...
> vlan_ioctl(ffff800000936800,80206910,ffff80003316f318) at vlan_ioctl+0x65
> ifpromisc(ffff800000936800,1) at ifpromisc+0xbb
> bridge_ioctl(ffff8000009da000,8060693c,ffff80003316f520) at
> bridge_ioctl+0x8c8
> ifioctl(fffffd811e7e5e40,8060693c,ffff80003316f520,ffff800032fd49e8) at
> ifioctl+0xa03
> soo_ioctl(fffffd81015768e8,8060693c,ffff80003316f520,ffff800032fd49e8) at
> soo_ioctl+0x171
> sys_ioctl(ffff800032fd49e8,ffff80003316f630,ffff80003316f690) at
> sys_ioctl+0x2df
> syscall(ffff80003316f700) at syscall+0x389
> Xsyscall() at Xsyscall+0x128
> end of kernel
> end trace frame: 0x7f7ffffdcef0, count: 249
> End of stack trace.
>
> # ifconfig bridge0 del vlan0
> splassert: vlan_ioctl: want 2 have 0
> Starting stack trace...
> vlan_ioctl(ffff800000936800,80206910,ffff80003316ee78) at vlan_ioctl+0x65
> ifpromisc(ffff800000936800,0) at ifpromisc+0xbb
> bridge_ifremove(ffff8000009ed900) at bridge_ifremove+0xa4
> bridge_ioctl(ffff8000009da000,8060693d,ffff80003316f0c0) at
> bridge_ioctl+0x91e
> ifioctl(fffffd811e7e5e40,8060693d,ffff80003316f0c0,ffff800032fd49e8) at
> ifioctl+0xa03
> soo_ioctl(fffffd81015768e8,8060693d,ffff80003316f0c0,ffff800032fd49e8) at
> soo_ioctl+0x171
> sys_ioctl(ffff800032fd49e8,ffff80003316f1d0,ffff80003316f230) at
> sys_ioctl+0x2df
> syscall(ffff80003316f2a0) at syscall+0x389
> Xsyscall() at Xsyscall+0x128
> end of kernel
> end trace frame: 0x7f7fffff6a20, count: 248
Acquiring NET_LOCK() when calling ifpromisc() seems to help.
This is similar to what bpf(4) does.
It looks that besides bridge(4), there are other places in the kernel
where ifpromisc() is called without NET_LOCK().
Index: net/if_bridge.c
===================================================================
RCS file: src/sys/net/if_bridge.c,v
retrieving revision 1.338
diff -u -p -r1.338 if_bridge.c
--- net/if_bridge.c 6 Nov 2019 03:51:26 -0000 1.338
+++ net/if_bridge.c 10 Apr 2020 19:05:05 -0000
@@ -313,7 +313,9 @@ bridge_ioctl(struct ifnet *ifp, u_long c
break;
}
+ NET_LOCK();
error = ifpromisc(ifs, 1);
+ NET_UNLOCK();
if (error != 0) {
free(bif, M_DEVBUF, sizeof(*bif));
break;
@@ -558,7 +560,9 @@ bridge_ifremove(struct bridge_iflist *bi
}
bif->ifp->if_bridgeidx = 0;
+ NET_LOCK();
error = ifpromisc(bif->ifp, 0);
+ NET_UNLOCK();
bridge_rtdelete(sc, bif->ifp, 0);
bridge_flushrule(bif);
