From mboxrd@z Thu Jan 1 00:00:00 1970 From: ghaskins@novell.com (Gregory Haskins) Date: Fri, 27 Mar 2009 13:13:20 -0400 Subject: [ltt-dev] [PATCH] lttng: fix net events to check for null n->dev Message-ID: <20090327170721.16456.25463.stgit@dev.haskins.net> Hi Mathieu, LTT devs, I found that I needed this patch to allow LTT 0.116 to play nice with v2.6.29. I am not 100% sure that I am not papering over a legitimate issue w.r.t napi->dev being legally NULL. But FWIW, this patch allowed me to get 0.116 up and running. Note that I saw the same issue in 0.110 against 29-rc8, but I didnt persue since the newer trees were available. I suspect the same patch would fix things there as well. FWIW: The devices in question seemed to be the built-in skb-queues that are used as a psuedo device when you use netif_rx(). In these cases dev == NULL (not sure if this is by design). However, since this path is probably not that common unless you are using something like tuntap, I suspect it might be that this has just been a latent bug in LTT. Regards, -Greg ------------------- lttng: fix net events to check for null n->dev Applies to 29-v0.116 Certain napi structures may have a NULL device, and thus will crash when the net-tracer'er is installed. Signed-off-by: Gregory Haskins --- ltt/probes/net-trace.c | 6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-) diff --git a/ltt/probes/net-trace.c b/ltt/probes/net-trace.c index 80254bb..80d3d9c 100644 --- a/ltt/probes/net-trace.c +++ b/ltt/probes/net-trace.c @@ -260,7 +260,7 @@ notrace void probe_net_napi_schedule(struct napi_struct *n) data.f1 = (unsigned long)n; data_len += sizeof(data.f1); /* No need to align for strings */ - strcpy(data.f2, n->dev->name); + strcpy(data.f2, n->dev ? n->dev->name : ""); data_len += strlen(data.f2) + 1; marker = &GET_MARKER(net, napi_schedule); @@ -283,7 +283,7 @@ notrace void probe_net_napi_poll(struct napi_struct *n) data.f1 = (unsigned long)n; data_len += sizeof(data.f1); /* No need to align for strings */ - strcpy(data.f2, n->dev->name); + strcpy(data.f2, n->dev ? n->dev->name : ""); data_len += strlen(data.f2) + 1; marker = &GET_MARKER(net, napi_poll); @@ -306,7 +306,7 @@ notrace void probe_net_napi_complete(struct napi_struct *n) data.f1 = (unsigned long)n; data_len += sizeof(data.f1); /* No need to align for strings */ - strcpy(data.f2, n->dev->name); + strcpy(data.f2, n->dev ? n->dev->name : ""); data_len += strlen(data.f2) + 1; marker = &GET_MARKER(net, napi_complete);