Re: [Qemu-devel] [PATCH] dump-guest-memory: more descriptive lookup_type failure

From: Janosch Frank <frankja@linux.vnet.ibm.com>
To: Andrew Jones <drjones@redhat.com>, qemu-devel@nongnu.org
Cc: marcandre.lureau@redhat.com, lersek@redhat.com
Subject: Re: [Qemu-devel] [PATCH] dump-guest-memory: more descriptive lookup_type failure
Date: Wed, 14 Mar 2018 16:12:21 +0100	[thread overview]
Message-ID: <203683e2-773b-d23c-423b-598ea98a98d5@linux.vnet.ibm.com> (raw)
In-Reply-To: <20180314142133.14166-1-drjones@redhat.com>

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On 14.03.2018 15:21, Andrew Jones wrote:
> We've seen a few reports of
> 
>  (gdb) source /usr/share/qemu-kvm/dump-guest-memory.py
>  Traceback (most recent call last):
>    File "/usr/share/qemu-kvm/dump-guest-memory.py", line 19, in <module>
>      UINTPTR_T = gdb.lookup_type("uintptr_t")
>  gdb.error: No type named uintptr_t.

Oh yeah, I remember that particular error.
Acked-by: Janosch Frank <frankja@linux.vnet.ibm.com>

> 
> This occurs when symbols haven't been loaded first, i.e. neither a
> QEMU binary was loaded nor a QEMU process was attached first. Let's
> better inform the user of how to fix the issue themselves in order
> to avoid more reports.
> 
> Signed-off-by: Andrew Jones <drjones@redhat.com>
> ---
>  scripts/dump-guest-memory.py | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/scripts/dump-guest-memory.py b/scripts/dump-guest-memory.py
> index 51acfcd0c053..e56fff6d7e82 100644
> --- a/scripts/dump-guest-memory.py
> +++ b/scripts/dump-guest-memory.py
> @@ -16,7 +16,11 @@ the COPYING file in the top-level directory.
>  import ctypes
>  import struct
> 
> -UINTPTR_T = gdb.lookup_type("uintptr_t")
> +try:
> +    UINTPTR_T = gdb.lookup_type("uintptr_t")
> +except Exception as inst:
> +    raise gdb.GdbError("Symbols must be loaded prior to sourcing dump-guest-memory.\n"
> +                       "Symbols may be loaded by first 'attach'ing a QEMU process id or by 'load'ing a QEMU binary.")>
>  TARGET_PAGE_SIZE = 0x1000
>  TARGET_PAGE_MASK = 0xFFFFFFFFFFFFF000
> 

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