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dump-guest-memory: more descriptive lookup_type failure

PATCH Superseded Andrew Jones 4 participants 4 messages Mar 14, 2018 – Mar 15, 2018

v1 of 2 Superseded Latest is v2 →

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Andrew Jones

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#0 lore raw

PATCH 1/1 dump-guest-memory: more descriptive lookup_type failure

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.

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 <[email protected]>
---
 scripts/dump-guest-memory.py | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
scripts/dump-guest-memory.py +5 -1
index 51acfcd0c053..e56fff6d7e82 100644
@@ -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
Signature · 1 line
2.13.6
Acked-by on v1 1/1
#1 lore raw
Quoted 7 lines · Andrew Jones

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 <[email protected]>
Quoted 28 lines

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 <[email protected]>
---
 scripts/dump-guest-memory.py | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
scripts/dump-guest-memory.py +5 -1
index 51acfcd0c053..e56fff6d7e82 100644
@@ -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
bot
#2 lore raw
In reply to Andrew Jones
This series seems to have some coding style problems. See output below for more information:

Hi,

This series seems to have some coding style problems. See output below for more information:

Type: series
Message-id: [email protected]
Subject: [Qemu-devel] [PATCH] dump-guest-memory: more descriptive lookup_type failure

=== TEST SCRIPT BEGIN ===
#!/bin/bash

BASE=base
n=1
total=$(git log --oneline $BASE.. | wc -l)
failed=0

git config --local diff.renamelimit 0
git config --local diff.renames True
git config --local diff.algorithm histogram

commits="$(git log --format=%H --reverse $BASE..)" for c in $commits; do

    echo "Checking PATCH $n/$total: $(git log -n 1 --format=%s $c)..."
    if ! git show $c --format=email | ./scripts/checkpatch.pl --mailback -; then
        failed=1
        echo
    fi
    n=$((n+1))

done

exit $failed
=== TEST SCRIPT END ===

Updating 3c8cf5a9c21ff8782164d1def7f44bd888713384
From https://github.com/patchew-project/qemu
* [new tag] patchew/[email protected] -> patchew/[email protected]
Switched to a new branch 'test'
8dba220694 dump-guest-memory: more descriptive lookup_type failure

=== OUTPUT BEGIN ===
Checking PATCH 1/1: dump-guest-memory: more descriptive lookup_type failure...
WARNING: line over 80 characters
#34: FILE: scripts/dump-guest-memory.py:22:
+ raise gdb.GdbError("Symbols must be loaded prior to sourcing dump-guest-memory.\n"

ERROR: line over 90 characters
#35: FILE: scripts/dump-guest-memory.py:23:
+ "Symbols may be loaded by first 'attach'ing a QEMU process id or by 'load'ing a QEMU binary.")

total: 1 errors, 1 warnings, 12 lines checked

Your patch has style problems, please review. If any of these errors are false positives report them to the maintainer, see CHECKPATCH in MAINTAINERS.

=== OUTPUT END ===

Test command exited with code: 1

---
Email generated automatically by Patchew [http://patchew.org/].
Please send your feedback to [email protected]

Reviewed-by
#3 lore raw
Quoted 10 lines · On 03/14/18 15:24, [email protected] wrote:

Checking PATCH 1/1: dump-guest-memory: more descriptive lookup_type failure...
WARNING: line over 80 characters
#34: FILE: scripts/dump-guest-memory.py:22:
+ raise gdb.GdbError("Symbols must be loaded prior to sourcing dump-guest-memory.\n"

ERROR: line over 90 characters
#35: FILE: scripts/dump-guest-memory.py:23:
+ "Symbols may be loaded by first 'attach'ing a QEMU process id or by 'load'ing a QEMU binary.")

total: 1 errors, 1 warnings, 12 lines checked

The current "width" of the script is currently:

$ wc -L scripts/dump-guest-memory.py
81 scripts/dump-guest-memory.py

I think it would be good to stick with 80 chars in this patch. (While adhering to whatever Python idioms are considered necessary -- I think Janosch and Marc-André can help with that.)

Once that's fixed, please add my:

Reviewed-by Laszlo Ersek <[email protected]>

(And, I agree, this error message has been reported several times to me as well.)

Thanks!
Laszlo