From: "Roger Pau Monné" <roger.pau@citrix.com>
To: Julien Grall <julien@xen.org>
Cc: Igor Druzhinin <igor.druzhinin@citrix.com>,
Stefano Stabellini <sstabellini@kernel.org>, Wei Liu <wl@xen.org>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Ian Jackson <ian.jackson@eu.citrix.com>,
George Dunlap <george.dunlap@citrix.com>,
Jan Beulich <jbeulich@suse.com>,
xen-devel@lists.xenproject.org
Subject: Re: [PATCH] xen/spinlock: move debug helpers inside the locked regions
Date: Wed, 29 Jul 2020 15:50:45 +0200 [thread overview]
Message-ID: <20200729135045.GD7191@Air-de-Roger> (raw)
In-Reply-To: <16dd0f04-598b-8b84-8a25-6b89af9214d7@xen.org>
On Wed, Jul 29, 2020 at 02:37:44PM +0100, Julien Grall wrote:
> Hi Roger,
>
> On 29/07/2020 12:13, Roger Pau Monne wrote:
> > Debug helpers such as lock profiling or the invariant pCPU assertions
> > must strictly be performed inside the exclusive locked region, or else
> > races might happen.
> >
> > Note the issue was not strictly introduced by the pointed commit in
> > the Fixes tag, since lock stats where already incremented before the
> > barrier, but that commit made it more apparent as manipulating the cpu
> > field could happen outside of the locked regions and thus trigger the
> > BUG_ON.
>
> From the wording, it is not entirely clear which BUG_ON() you are referring
> to. I am guessing, it is the one in rel_lock(). Am I correct?
Yes, that's right. Expanding to:
"... and thus trigger the BUG_ON in rel_lock()." would be better.
> Otherwise, the change looks good to me.
Thanks.
next prev parent reply other threads:[~2020-07-29 13:51 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-29 11:13 [PATCH] xen/spinlock: move debug helpers inside the locked regions Roger Pau Monne
2020-07-29 13:37 ` Julien Grall
2020-07-29 13:50 ` Roger Pau Monné [this message]
2020-07-29 14:57 ` Julien Grall
2020-07-30 18:29 ` Julien Grall
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