On Sat, Sep 25, 2010 at 03:55:35PM +0200, Frederic Weisbecker wrote: > On Sat, Sep 25, 2010 at 02:29:20AM +0200, Peter Zijlstra wrote: > > On Fri, 2010-09-24 at 15:30 -0500, Jason Wessel wrote: > > > Jiri, > > > > > > Can you try this simple patch which is attached? > > > > > > > > > > > > On 09/24/2010 01:04 PM, Jiri Olsa wrote: > > > > while starting kgdb early debug on latest tip tree, > > > > I got SIGSEGV inside kernel in following location: > > > > > > > > > > > [clip] > > > > I found out it's due to foolowing commit, that's causing the init code > > > > to be called without the ctx field being defined... > > > > > > > > commit c3f00c70276d8ae82578c8b773e2db657f69a478 > > > > Author: Peter Zijlstra <[email protected]> > > > > Date: Wed Aug 18 14:37:15 2010 +0200 > > > > > > > > > > > > > > > > > > I took a look at the tip core, and the ctx parameter is no longer passed > > > into the perf_event_alloc() from perf_event_create_kernel_counter() kgdb > > > no longer gets it filled in for free. > > > > > > The reality is that kgdb never had a true context or a way to mark the > > > hw breakpoint as a kernel only context for the hw breakpoint > > > reservations. The patch is only a short term fix perhaps until on of > > > the perf guys explains the right way to use it. :-) > > > > Argh, yes, its using the ctx rather early.. we cannot have a context > > before we've initialized the event, and here it looks like hw_breakpoint > > wants to use the context to initialize the event, chick, egg, etc.. > > > > Frederic, anything we can do about that? > > > > Jason's patch is partially good, it just lacks one place to handle. > Jiri, can you test that?
it works ok feel free to add Tested-by: Jiri Olsa <[email protected]> thanks, jirka ------------------------------------------------------------------------------ Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing. http://p.sf.net/sfu/novell-sfdev2dev _______________________________________________ Kgdb-bugreport mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/kgdb-bugreport
