|Summary:||Hitting WARN_ON in hw_breakpoint code|
|Product:||Platform Specific/Hardware||Reporter:||Maciej Rutecki (maciej.rutecki)|
|Component:||PPC-64||Assignee:||Anton Blanchard (anton)|
|Severity:||normal||CC:||maciej.rutecki, paulus, rjw|
|Bug Depends on:|
Description Maciej Rutecki 2010-06-24 15:33:13 UTC
Subject : Hitting WARN_ON in hw_breakpoint code Submitter : Paul Mackerras <firstname.lastname@example.org> Date : 2010-06-23 12:57 Message-ID : 20100623125740.GA3368@brick.ozlabs.ibm.com References : http://marc.info/?l=linux-kernel&m=127729789113432&w=2 This entry is being used for tracking a regression from 2.6.34. Please don't close it until the problem is fixed in the mainline.
Comment 1 Rafael J. Wysocki 2010-07-09 21:38:14 UTC
On Friday, July 09, 2010, Frederic Weisbecker wrote: > On Thu, Jul 08, 2010 at 06:34:25PM -0700, Linus Torvalds wrote: > > On Thu, Jul 8, 2010 at 4:33 PM, Rafael J. Wysocki <email@example.com> wrote: > > > Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=16284 > > > Subject : Hitting WARN_ON in hw_breakpoint code > > > Submitter : Paul Mackerras <firstname.lastname@example.org> > > > Date : 2010-06-23 12:57 (16 days old) > > > > This has "I have a fix, will post it very soon." in the thread from > > Frederic, but I'm not seeing anything else. Frederic? > > > > Right. In fact it wasn't a regression. The per task breakpoint reservation > design was broken from the beginning and this warning has revealed the > problem. This only touched perf, and it did since perf support breakpoints. > Fortunately ptrace wasn't concerned by this problem, even not by side effects > of this. > > The fix is invasive as it's a rewrite of a (little) part of the breakpoint > reservation. And since the symptom is only a warning and also breakpoints > never released from the constraint table (just a counter, no memory leak), > the fix is headed for 2.6.36. > > It is ready in tip:/perf/core: > > > http://git.kernel.org/?p=linux/kernel/git/tip/linux-2.6-tip.git;a=commitdiff;h=45a73372efe4a63f44aa2e1125d4a777c2fdc8d8 > > I think this ticket can be safely closed.