[v3] hmp: fix "dump-quest-memory" segfault

[Qemu-devel] [PATCH v3 2/3] hmp: fix "dump-quest-memory" segfault (arm)

Posted by Laurent Vivier 8 years, 4 months ago

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
-- 
2.13.5

Re: [Qemu-devel] [PATCH v3 2/3] hmp: fix "dump-quest-memory" segfault (arm)

Posted by Thomas Huth 8 years, 4 months ago

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>

Re: [Qemu-devel] [PATCH v3 2/3] hmp: fix "dump-quest-memory" segfault (arm)

Posted by Greg Kurz 8 years, 4 months ago

On Tue, 12 Sep 2017 16:01:48 +0200
Laurent Vivier <lvivier@redhat.com> 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>
> ---

Reviewed-by: Greg Kurz <groug@kaod.org>

>  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