lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Sun, 21 Mar 2010 21:51:51 +0100 From: "Rafael J. Wysocki" <rjw@...k.pl> To: Linus Torvalds <torvalds@...ux-foundation.org> Cc: Peter Zijlstra <peterz@...radead.org>, pm list <linux-pm@...ts.linux-foundation.org>, LKML <linux-kernel@...r.kernel.org>, Ingo Molnar <mingo@...e.hu>, Andrew Morton <akpm@...ux-foundation.org> Subject: Re: [Regression, post-2.6.34-rc1][PATCH] x86 / perf: Fix suspend to RAM on HP nx6325 On Sunday 21 March 2010, Linus Torvalds wrote: > > On Sat, 20 Mar 2010, Rafael J. Wysocki wrote: > > > > The appended patch fixes the breakage for me too. > > Please don't use a 'goto' for something like this. > > > raw_spin_lock(&amd_nb_lock); > > > > + if (!cpuhw->amd_nb) > > + goto unlock; > > + > > if (--cpuhw->amd_nb->refcnt == 0) > > kfree(cpuhw->amd_nb); > > > > cpuhw->amd_nb = NULL; > > > > + unlock: > > raw_spin_unlock(&amd_nb_lock); > > } > > Just do > > raw_spin_lock(&amd_nb_lock); > if (cpuhw->amd_nb) { > if (!--cpuhw->amd_nb->refcnt) > kfree(cpuhw->amd_nb); > cpuhw->amd_nb = NULL; > } > raw_spin_unlock(&amd_nb_lock); > > instead. Much more readable. > > Let's keep 'goto' for cases where we have error returns that we don't want > to nest, not trivial stuff like this. OK Rafael --- From: Rafael J. Wysocki <rjw@...k.pl> Subject: x86 / perf: Fix suspend to RAM on HP nx6325 Commit 3f6da3905398826d85731247e7fbcf53400c18bd (perf: Rework and fix the arch CPU-hotplug hooks) broke suspend to RAM on my HP nx6325 (and most likely on other AMD-based boxes too) by allowing amd_pmu_cpu_offline() to be executed for CPUs that are going offline as part of the suspend process. The problem is that cpuhw->amd_nb may be NULL already, so the function should make sure it's not NULL before accessing the object pointed to by it. Signed-off-by: Rafael J. Wysocki <rjw@...k.pl> --- arch/x86/kernel/cpu/perf_event_amd.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) Index: linux-2.6/arch/x86/kernel/cpu/perf_event_amd.c =================================================================== --- linux-2.6.orig/arch/x86/kernel/cpu/perf_event_amd.c +++ linux-2.6/arch/x86/kernel/cpu/perf_event_amd.c @@ -348,10 +348,12 @@ static void amd_pmu_cpu_offline(int cpu) raw_spin_lock(&amd_nb_lock); - if (--cpuhw->amd_nb->refcnt == 0) - kfree(cpuhw->amd_nb); + if (cpuhw->amd_nb) { + if (--cpuhw->amd_nb->refcnt == 0) + kfree(cpuhw->amd_nb); - cpuhw->amd_nb = NULL; + cpuhw->amd_nb = NULL; + } raw_spin_unlock(&amd_nb_lock); } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists