Re: [PATCH v2 9/9] target/ppc/kvm: Replace alloca() by g_malloc()

From: David Gibson <david@gibson.dropbear.id.au>
To: "Philippe Mathieu-Daudé" <philmd@redhat.com>
Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org, qemu-ppc@nongnu.org,
	qemu-arm@nongnu.org, "Gerd Hoffmann" <kraxel@redhat.com>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Alex Bennée" <alex.bennee@linaro.org>,
	"Greg Kurz" <groug@kaod.org>
Subject: Re: [PATCH v2 9/9] target/ppc/kvm: Replace alloca() by g_malloc()
Date: Fri, 7 May 2021 11:05:35 +1000	[thread overview]
Message-ID: <YJSSX1eUIecBpwwX@yekko> (raw)
In-Reply-To: <20210506133758.1749233-10-philmd@redhat.com>

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On Thu, May 06, 2021 at 03:37:58PM +0200, Philippe Mathieu-Daudé wrote:
> The ALLOCA(3) man-page mentions its "use is discouraged".
> 
> Replace it by a g_malloc() call.
> 
> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> ---
>  target/ppc/kvm.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
> index 104a308abb5..63c458e2211 100644
> --- a/target/ppc/kvm.c
> +++ b/target/ppc/kvm.c
> @@ -2698,11 +2698,10 @@ int kvmppc_save_htab(QEMUFile *f, int fd, size_t bufsize, int64_t max_ns)
>  int kvmppc_load_htab_chunk(QEMUFile *f, int fd, uint32_t index,
>                             uint16_t n_valid, uint16_t n_invalid, Error **errp)
>  {
> -    struct kvm_get_htab_header *buf;
>      size_t chunksize = sizeof(*buf) + n_valid * HASH_PTE_SIZE_64;
> +    g_autofree struct kvm_get_htab_header *buf = g_malloc(chunksize);

Um.. that doesn't look like it would compile, since you use
sizeof(*buf) before declaring buf.

>      ssize_t rc;
>  
> -    buf = alloca(chunksize);
>      buf->index = index;
>      buf->n_valid = n_valid;
>      buf->n_invalid = n_invalid;

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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