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References: <20170912140149.7692-1-lvivier@redhat.com>
	<20170912140149.7692-3-lvivier@redhat.com>
From: Thomas Huth <thuth@redhat.com>
Message-ID: <13c0f923-dbaa-e458-0544-59cd8e05a7e6@redhat.com>
Date: Tue, 12 Sep 2017 16:11:17 +0200
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Subject: Re: [Qemu-devel] [PATCH v3 2/3] hmp: fix "dump-quest-memory"
 segfault (arm)
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To: Laurent Vivier <lvivier@redhat.com>, qemu-devel@nongnu.org
Cc: "Daniel P . Berrange" <berrange@redhat.com>, Cornelia Huck <cohuck@redhat.com>, David Gibson <david@gibson.dropbear.id.au>, qemu-arm@nongnu.org, qemu-ppc@nongnu.org, Peter Maydell <peter.maydell@linaro.org>, "Dr . David Alan Gilbert" <dgilbert@redhat.com>, Greg Kurz <groug@kaod.org>

On 12.09.2017 16:01, Laurent Vivier wrote:
> Running QEMU with
>     qemu-system-aarch64 -M none -nographic -m 256
> and executing
>     dump-guest-memory /dev/null 0 8192
> results in segfault
> 
> Fix by checking if we have CPU, and exit with
> error if there is no CPU:
> 
>     (qemu) dump-guest-memory /dev/null
>     this feature or command is not currently supported
> 
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
> ---
>  target/arm/arch_dump.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/target/arm/arch_dump.c b/target/arm/arch_dump.c
> index 1a9861f69b..9e5b2fb31c 100644
> --- a/target/arm/arch_dump.c
> +++ b/target/arm/arch_dump.c
> @@ -273,11 +273,18 @@ int arm_cpu_write_elf32_note(WriteCoreDumpFunction f, CPUState *cs,
>  int cpu_get_dump_info(ArchDumpInfo *info,
>                        const GuestPhysBlockList *guest_phys_blocks)
>  {
> -    ARMCPU *cpu = ARM_CPU(first_cpu);
> -    CPUARMState *env = &cpu->env;
> +    ARMCPU *cpu;
> +    CPUARMState *env;
>      GuestPhysBlock *block;
>      hwaddr lowest_addr = ULLONG_MAX;
>  
> +    if (first_cpu == NULL) {
> +        return -1;
> +    }
> +
> +    cpu = ARM_CPU(first_cpu);
> +    env = &cpu->env;
> +
>      /* Take a best guess at the phys_base. If we get it wrong then crash
>       * will need '--machdep phys_offset=<phys-offset>' added to its command
>       * line, which isn't any worse than assuming we can use zero, but being
> 

Reviewed-by: Thomas Huth <thuth@redhat.com>