Messages in this thread Patch in this message | | | Subject | Re: [PATCH] kmemleak: Fix scheduling-while-atomic bug | From | Catalin Marinas <> | Date | Wed, 01 Jul 2009 10:18:57 +0100 |
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On Wed, 2009-07-01 at 09:53 +0200, Ingo Molnar wrote: > * Linux Kernel Mailing List <linux-kernel@vger.kernel.org> wrote: > > > Gitweb: http://git.kernel.org/linus/acf4968ec9dea49387ca8b3d36dfaa0850bdb2d5 > > Commit: acf4968ec9dea49387ca8b3d36dfaa0850bdb2d5 > > Parent: 4698c1f2bbe44ce852ef1a6716973c1f5401a4c4 > > Author: Catalin Marinas <catalin.marinas@arm.com> > > AuthorDate: Fri Jun 26 17:38:29 2009 +0100 > > Committer: Catalin Marinas <catalin.marinas@arm.com> > > CommitDate: Fri Jun 26 17:38:29 2009 +0100 > > > > kmemleak: Slightly change the policy on newly allocated objects > > I think one of the kmemleak fixes that went upstream yesterday > caused the following scheduling-while-holding-the-tasklist-lock > regression/crash on x86:
Thanks for the patch. The bug was always there, only that the task stack scanning is now enabled by default (and I probably have a small number of tasks that the rescheduling didn't happen during stack scanning).
> The minimal fix below removes scan_yield() and adds a cond_resched() > to the outmost (safe) place of the scanning thread. This solves the > regression.
With CONFIG_PREEMPT disabled it won't reschedule during the bss scanning but I don't see this as a real issue (task stacks scanning probably takes longer anyway).
> The background scanning thread could probably also be reniced > to +10.
diff --git a/mm/kmemleak.c b/mm/kmemleak.c index e766e1d..6006553 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -1039,6 +1039,7 @@ static int kmemleak_scan_thread(void *arg) static int first_run = 1; pr_info("Automatic memory scanning thread started\n"); + set_user_nice(current, 10); /* * Wait before the first scan to allow the system to fully initialize. -- Catalin
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