| 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
| ||
|
Message-Id: <1251472247.17617.74.camel@laptop> Date: Fri, 28 Aug 2009 17:10:47 +0200 From: Peter Zijlstra <peterz@...radead.org> To: Ingo Molnar <mingo@...e.hu>, Paul Mackerras <paulus@...ba.org> Cc: lkml <linux-kernel@...r.kernel.org> Subject: [PATCH] perf_counter: fix possible /0 bug in swcounters We have a race in the swcounter stuff where we can start counting a counter that has never been enabled, this leads to a /0 situation. The below avoids the /0 but doesn't close the race, this would need a new counter state. The race is due to perf_swcounter_is_counting() which cannot discern between disabled due to scheduled out, and disabled for any other reason. Signed-off-by: Peter Zijlstra <a.p.zijlstra@...llo.nl> --- kernel/perf_counter.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index 53abcbe..2b90d26 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -4103,6 +4103,7 @@ perf_counter_alloc(struct perf_counter_attr *attr, hwc->sample_period = attr->sample_period; if (attr->freq && attr->sample_freq) hwc->sample_period = 1; + hwc->last_period = hwc->sample_period; atomic64_set(&hwc->period_left, hwc->sample_period); -- 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