From: Thomas Monjalon <thomas@monjalon.net>
To: Bruce Richardson <bruce.richardson@intel.com>
Cc: dev@dpdk.org, yliu@fridaylinux.org,
Maxime Coquelin <maxime.coquelin@redhat.com>
Subject: Re: [dpdk-dev] [PATCH v2] vhost: fix false-positive warning from clang 5
Date: Wed, 11 Oct 2017 14:49:23 +0200 [thread overview]
Message-ID: <188478579.ZJIaHkYeo6@xps> (raw)
In-Reply-To: <20171011112817.3357-1-bruce.richardson@intel.com>
11/10/2017 13:28, Bruce Richardson:
> When compiling with clang extra warning flags, such as used by default with
> meson, a warning is given in iotlb.c:
>
> ../lib/librte_vhost/iotlb.c:318:6: warning: variable 'socket' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
>
> This is a false positive, as the socket value will be initialized by the
> call to get_mempolicy in the case where the NUMA build-time flag is set,
> and in cases where it is not set, "if (ret)" will always be true as ret is
> initialized to -1 and never changed.
>
> However, this is not immediately obvious, and is perhaps a little fragile,
> as it will break if other code using ret is subsequently added above the
> call to get_mempolicy by someone unaware of this subtle dependency.
> Therefore, we can fix the warning and making the code more robust by
> explicitly initializing socket to zero, and moving the extra condition
> check on the return from get_mempolicy() into the #ifdef
>
> Fixes: d012d1f293f4 ("vhost: add IOTLB helper functions")
>
> CC: Maxime Coquelin <maxime.coquelin@redhat.com>
> Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Applied, thanks
prev parent reply other threads:[~2017-10-11 12:49 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-11 9:59 [dpdk-dev] [PATCH] " Bruce Richardson
2017-10-11 10:12 ` Maxime Coquelin
2017-10-11 10:51 ` [dpdk-dev] [PATCH] vhost: fix false-positive warning from clang5 Thomas Monjalon
2017-10-11 11:01 ` Bruce Richardson
2017-10-11 11:28 ` [dpdk-dev] [PATCH v2] vhost: fix false-positive warning from clang 5 Bruce Richardson
2017-10-11 12:49 ` Thomas Monjalon [this message]
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