[cmaster-next] [PATCH] bgpd: Fix multiple bgp view vnc crash

[Martin Winter]

Bad luck, this doesn’t fix it.

New traceback:

[Thread debugging using libthread_db enabled]
Using host libthread_db library 
"/lib/x86_64-linux-gnu/libthread_db.so.1".
Core was generated by `/usr/lib/quagga/bgpd -d'.
Program terminated with signal SIGABRT, Aborted.
#0  0x00007fef8cecb428 in __GI_raise (sig=sig at entry=6) at 
../sysdeps/unix/sysv/linux/raise.c:54
#0  0x00007fef8cecb428 in __GI_raise (sig=sig at entry=6) at 
../sysdeps/unix/sysv/linux/raise.c:54
#1  0x00007fef8cecd02a in __GI_abort () at abort.c:89
#2  0x00007fef8d7b52be in core_handler (signo=<optimized out>, 
siginfo=<optimized out>, context=<optimized out>) at sigevent.c:242
#3  <signal handler called>
#4  vnc_rhnck (tag=tag at entry=0x7fffad18a1a8 "vnc_import_bgp_add_route: 
enter") at rfapi/vnc_import_bgp.c:254
#5  0x00000000004b02e5 in vnc_import_bgp_add_route 
(bgp=bgp at entry=0x229dcd0, prefix=prefix at entry=0x22ba000, 
info=info at entry=0x22ba670) at rfapi/vnc_import_bgp.c:2770
#6  0x000000000044a25b in bgp_process_main (wq=<optimized out>, 
data=<optimized out>) at bgp_route.c:1974
#7  0x00007fef8d7b5dad in work_queue_run (thread=0x7fffad18c4f8) at 
workqueue.c:308
#8  0x00007fef8d79e70e in thread_call 
(thread=thread at entry=0x7fffad18c4f8) at thread.c:1442
#9  0x000000000042c586 in main (argc=2, argv=0x7fffad18c698) at 
bgp_main.c:567


Here is the relevant code (with the patch)

244:	#ifdef ENABLE_VNC_RHNCK
245:	static void
246:	vnc_rhnck (char *tag)
247:	{
248:	  struct bgp *bgp;
249:	  struct skiplist *sl;
250:	  struct skiplistnode *p;
251:
252:	  bgp = bgp_get_default ();
253:
254:	  sl = bgp->rfapi->resolve_nve_nexthop;
255:
256:	  if (!sl)
257:		return;

The issue is in line 254 - before the fix.
In this testcase we enter the function with bgp=0.

- Martin


On 30 Nov 2016, at 6:27, Donald Sharp wrote:

> When configuring multiple bgp views without a default
> bgp session, the code will crash.
>
> This code change only fixes the crash from happening.  I'm not
> entirely sure that the code will not misbehave with multiple
> bgp views and configuring vnc in this case.
>
> Signed-off-by: Donald Sharp <sharpd at cumulusnetworks.com>
> ---
>  bgpd/rfapi/vnc_import_bgp.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/bgpd/rfapi/vnc_import_bgp.c b/bgpd/rfapi/vnc_import_bgp.c
> index 4215ce2..441bdee 100644
> --- a/bgpd/rfapi/vnc_import_bgp.c
> +++ b/bgpd/rfapi/vnc_import_bgp.c
> @@ -1798,6 +1798,9 @@ vnc_import_bgp_exterior_add_route_it (
>    struct bgp *bgp_default = bgp_get_default ();
>    afi_t afi = family2afi (prefix->family);
>
> +  if (!bgp_default)
> +    return;
> +
>    h = bgp_default->rfapi;
>    hc = bgp_default->rfapi_cfg;
>
> @@ -1992,6 +1995,9 @@ vnc_import_bgp_exterior_del_route (
>    afi_t afi = family2afi (prefix->family);
>    struct bgp *bgp_default = bgp_get_default ();
>
> +  if (!bgp_default)
> +    return;
> +
>    memset (&pfx_orig_nexthop, 0, sizeof (struct prefix));        /* 
> keep valgrind happy */
>
>    h = bgp_default->rfapi;
> -- 
> 2.5.5
>
>
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