[Qemu-devel] [PATCH] dump-guest-memory.py: fix No symbol "vmcoreinfo_find"

Marc-André Lureau posted 1 patch 6 years, 3 months ago
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git fetch https://github.com/patchew-project/qemu tags/patchew/20171201113744.2313-1-marcandre.lureau@redhat.com
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scripts/dump-guest-memory.py | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
[Qemu-devel] [PATCH] dump-guest-memory.py: fix No symbol "vmcoreinfo_find"
Posted by Marc-André Lureau 6 years, 3 months ago
When qemu is compiled without debug, the dump gdb python script can fail with:

Error occurred in Python command: No symbol "vmcoreinfo_find" in current context.

Because vmcoreinfo_find() is inlined and not exported.

Use the underlying object_resolve_path_type() to get the instance instead.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 scripts/dump-guest-memory.py | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/scripts/dump-guest-memory.py b/scripts/dump-guest-memory.py
index 69dd5efadf..1af26c1a45 100644
--- a/scripts/dump-guest-memory.py
+++ b/scripts/dump-guest-memory.py
@@ -546,13 +546,15 @@ shape and this command should mostly work."""
         return None
 
     def add_vmcoreinfo(self):
-        if not gdb.parse_and_eval("vmcoreinfo_find()") \
-           or not gdb.parse_and_eval("vmcoreinfo_find()->has_vmcoreinfo"):
+        vmci = '(VMCoreInfoState *)' + \
+               'object_resolve_path_type("", "vmcoreinfo", 0)'
+        if not gdb.parse_and_eval("%s" % vmci) \
+           or not gdb.parse_and_eval("(%s)->has_vmcoreinfo" % vmci):
             return
 
-        fmt = gdb.parse_and_eval("vmcoreinfo_find()->vmcoreinfo.guest_format")
-        addr = gdb.parse_and_eval("vmcoreinfo_find()->vmcoreinfo.paddr")
-        size = gdb.parse_and_eval("vmcoreinfo_find()->vmcoreinfo.size")
+        fmt = gdb.parse_and_eval("(%s)->vmcoreinfo.guest_format" % vmci)
+        addr = gdb.parse_and_eval("(%s)->vmcoreinfo.paddr" % vmci)
+        size = gdb.parse_and_eval("(%s)->vmcoreinfo.size" % vmci)
 
         fmt = le16_to_cpu(fmt)
         addr = le64_to_cpu(addr)
-- 
2.15.0.277.ga3d2ad2c43


Re: [Qemu-devel] [PATCH] dump-guest-memory.py: fix No symbol "vmcoreinfo_find"
Posted by Laszlo Ersek 6 years, 3 months ago
On 12/01/17 12:37, Marc-André Lureau wrote:
> When qemu is compiled without debug, the dump gdb python script can fail with:
> 
> Error occurred in Python command: No symbol "vmcoreinfo_find" in current context.
> 
> Because vmcoreinfo_find() is inlined and not exported.
> 
> Use the underlying object_resolve_path_type() to get the instance instead.
> 
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> ---
>  scripts/dump-guest-memory.py | 12 +++++++-----
>  1 file changed, 7 insertions(+), 5 deletions(-)
> 
> diff --git a/scripts/dump-guest-memory.py b/scripts/dump-guest-memory.py
> index 69dd5efadf..1af26c1a45 100644
> --- a/scripts/dump-guest-memory.py
> +++ b/scripts/dump-guest-memory.py
> @@ -546,13 +546,15 @@ shape and this command should mostly work."""
>          return None
>  
>      def add_vmcoreinfo(self):
> -        if not gdb.parse_and_eval("vmcoreinfo_find()") \
> -           or not gdb.parse_and_eval("vmcoreinfo_find()->has_vmcoreinfo"):
> +        vmci = '(VMCoreInfoState *)' + \
> +               'object_resolve_path_type("", "vmcoreinfo", 0)'
> +        if not gdb.parse_and_eval("%s" % vmci) \
> +           or not gdb.parse_and_eval("(%s)->has_vmcoreinfo" % vmci):
>              return
>  
> -        fmt = gdb.parse_and_eval("vmcoreinfo_find()->vmcoreinfo.guest_format")
> -        addr = gdb.parse_and_eval("vmcoreinfo_find()->vmcoreinfo.paddr")
> -        size = gdb.parse_and_eval("vmcoreinfo_find()->vmcoreinfo.size")
> +        fmt = gdb.parse_and_eval("(%s)->vmcoreinfo.guest_format" % vmci)
> +        addr = gdb.parse_and_eval("(%s)->vmcoreinfo.paddr" % vmci)
> +        size = gdb.parse_and_eval("(%s)->vmcoreinfo.size" % vmci)
>  
>          fmt = le16_to_cpu(fmt)
>          addr = le64_to_cpu(addr)
> 

This is why I had recommended a volatile assignment back then.

http://mid.mail-archive.com/bbc74cf4-4d61-8ad3-7a33-0e6c49490892@redhat.com

http://mid.mail-archive.com/c661a649-e438-e80b-baf4-b44ee6612ca3@redhat.com

Anyway,

Reviewed-by: Laszlo Ersek <lersek@redhat.com>