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  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Mon, 28 Jul 2014 05:36:29 +0200
From:	Andi Kleen <>
To:	"Yan, Zheng" <>
Cc:	Peter Zijlstra <>,,,,,
Subject: Re: [PATCH v3 6/9] perf, x86: handle multiple records in PEBS

> I don't think this method works for interrupt threshold > 1 case. When collision
> happens, the hardware only create one PEBS record. The status in next record has
> nothing to do with the collision record.
Not even for the threshold == 1 case, because the same could happen with
a different PEBS event. Of course in any case it's very unlikely ...

> > So typically we'd have one event set and no problem, but in case there's
> > more we can reconstruct with such a backwards pass from a known good
> > state.
> > 
> > But when in doubt, we should drop the record, its the safest choice.
> The problem is that, in some cases, each PEBS record has more than one events
> set, so we will drop all records.

Just dropping is fine imho, this should be rare.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

Powered by blists - more mailing lists