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From: Peter Maydell <peter.maydell@linaro.org>
To: Miroslav Rezanina <mrezanin@redhat.com>
Cc: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>,
	QEMU Developers <qemu-devel@nongnu.org>,
	Qemu-block <qemu-block@nongnu.org>
Subject: Re: Prevent compiler warning on block.c
Date: Wed, 5 May 2021 11:43:44 +0100	[thread overview]
Message-ID: <CAFEAcA9mZfuSYsEK-TcERB+8yTnq_Qhn7HwRGvCnE7_DMfAXyQ@mail.gmail.com> (raw)
In-Reply-To: <1162368493.17178530.1620201543649.JavaMail.zimbra@redhat.com>

On Wed, 5 May 2021 at 09:06, Miroslav Rezanina <mrezanin@redhat.com> wrote:
>
> Commit 3108a15cf (block: introduce bdrv_drop_filter()) introduced uninitialized
> variable to_cow_parent in bdrv_replace_node_common function that is used only when
> detach_subchain is true. It is used in two places. First if block properly initialize
> the variable and second block use it.
>
> However, compiler treats this two blocks as two independent cases so it thinks first
> block can fail test and second one pass (although both use same condition). This cause
> warning that variable can be uninitialized in second block.
>
> To prevent this warning, initialize the variable with NULL.

If fixing compiler warnings, please quote the compiler name/version
in the commit message. (This helps with understanding whether the issue
is because of an older and not-smart-enough compiler or a new bleeding-edge
compiler with extra checking.)

thanks
-- PMM


  parent reply	other threads:[~2021-05-05 10:46 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <603798381.17174916.1620200426349.JavaMail.zimbra@redhat.com>
2021-05-05  7:59 ` Prevent compiler warning on block.c Miroslav Rezanina
2021-05-05  8:05   ` Vladimir Sementsov-Ogievskiy
2021-05-05 10:03     ` Paolo Bonzini
2021-05-05 10:32       ` Vladimir Sementsov-Ogievskiy
2021-06-09  7:12     ` Thomas Huth
2021-06-09  9:04       ` Kevin Wolf
2021-05-05 10:43   ` Peter Maydell [this message]
2021-05-05 11:12     ` Miroslav Rezanina

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