Linus, You can hold off on pulling this if you want. I just received a patch that fixes a "use after free" bug that was introduced in this merge window. I've added that patch after this commit, and I'm starting my tests now. I should have another pull request later today if all goes well. -- Steve On Thu, 8 May 2014 07:13:27 -0400 Steven Rostedt <rostedt@xxxxxxxxxxx> wrote: > > Linus, > > This is a long standing bug that causes bogus data to show up > in the refcnt field of the module_refcnt tracepoint. It was > introduced by a merge conflict resolution back in 2.6.35-rc days. > > The result should be refcnt = incs - decs, but instead it did > refcnt = incs + decs. > > Please pull the latest trace-fixes-v3.15-rc4 tree, which can be found at: > > > git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git > trace-fixes-v3.15-rc4 > > Tag SHA1: df839af2f97c5761d24b7a1c80f5ac8c4fa63dfe > Head SHA1: 098507ae3ec2331476fb52e85d4040c1cc6d0ef4 > > > Romain Izard (1): > trace: module: Maintain a valid user count > > ---- > include/trace/events/module.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > --------------------------- > commit 098507ae3ec2331476fb52e85d4040c1cc6d0ef4 > Author: Romain Izard <romain.izard.pro@xxxxxxxxx> > Date: Tue Mar 4 10:09:39 2014 +0100 > > trace: module: Maintain a valid user count > > The replacement of the 'count' variable by two variables 'incs' and > 'decs' to resolve some race conditions during module unloading was done > in parallel with some cleanup in the trace subsystem, and was integrated > as a merge. > > Unfortunately, the formula for this replacement was wrong in the tracing > code, and the refcount in the traces was not usable as a result. > > Use 'count = incs - decs' to compute the user count. > > Link: http://lkml.kernel.org/p/1393924179-9147-1-git-send-email-romain.izard.pro@xxxxxxxxx > > Acked-by: Ingo Molnar <mingo@xxxxxxxxxx> > Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx> > Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx> > Cc: stable@xxxxxxxxxxxxxxx # 2.6.35 > Fixes: c1ab9cab7509 "merge conflict resolution" > Signed-off-by: Romain Izard <romain.izard.pro@xxxxxxxxx> > Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx> > > diff --git a/include/trace/events/module.h b/include/trace/events/module.h > index 11fd51b..daa60c7 100644 > --- a/include/trace/events/module.h > +++ b/include/trace/events/module.h > @@ -80,7 +80,7 @@ DECLARE_EVENT_CLASS(module_refcnt, > > TP_fast_assign( > __entry->ip = ip; > - __entry->refcnt = __this_cpu_read(mod->refptr->incs) + __this_cpu_read(mod->refptr->decs); > + __entry->refcnt = __this_cpu_read(mod->refptr->incs) - __this_cpu_read(mod->refptr->decs); > __assign_str(name, mod->name); > ), > -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html