Re: [Qemu-devel] [PATCH] qemu-iotests: Fix core dump suppression in test 039

[Markus Armbruster]

Markus Armbruster <address@hidden> writes:

> Kevin Wolf <address@hidden> writes:
>
>> Am 13.05.2014 um 19:44 hat Markus Armbruster geschrieben:
>>> Fam Zheng <address@hidden> writes:
>>> 
>>> > On Tue, 05/13 10:46, Markus Armbruster wrote:
>>> >> The shell script attempts to suppress core dumps like this:
>>> >> 
>>> >>     old_ulimit=$(ulimit -c)
>>> >>     ulimit -c 0
>>> >>     $QEMU_IO arg...
>>> >>     ulimit -c "$old_ulimit"
>>> >> 
>>> >> This breaks the test hard unless the limit was zero to begin with!
>>> >> ulimit sets both hard and soft limit by default, and (re-)raising the
>>> >> hard limit requires privileges.  Broken since it was added in commit
>>> >> dc68afe.
>>> >> 
>>> >> Could be fixed by adding -S to set only the soft limit, but I'm not
>>> >> sure how portable that is in practice.  Simply do it in a subshell
>>> >> instead, like this:
>>> >> 
>>> >>     (ulimit -c 0; exec $QEMU_IO arg...)
>>> >> 
>>> >> Signed-off-by: Markus Armbruster <address@hidden>
>>> >> ---
>>> >>  tests/qemu-iotests/039 | 18 ++++++------------
>>> >>  1 file changed, 6 insertions(+), 12 deletions(-)
>>> >> 
>>> >> diff --git a/tests/qemu-iotests/039 b/tests/qemu-iotests/039
>>> >> index b9cbe99..182b0f0 100755
>>> >> --- a/tests/qemu-iotests/039
>>> >> +++ b/tests/qemu-iotests/039
>>> >> @@ -67,10 +67,8 @@ echo "== Creating a dirty image file =="
>>> >>  IMGOPTS="compat=1.1,lazy_refcounts=on"
>>> >>  _make_test_img $size
>>> >>  
>>> >> -old_ulimit=$(ulimit -c)
>>> >> -ulimit -c 0 # do not produce a core dump on abort(3)
>>> >> -$QEMU_IO -c "write -P 0x5a 0 512" -c "abort" "$TEST_IMG" | 
>>> >> _filter_qemu_io
>>> >> -ulimit -c "$old_ulimit"
>>> >> +(ulimit -c 0 # do not produce a core dump on abort(3)
>>> >> +exec $QEMU_IO -c "write -P 0x5a 0 512" -c "abort" "$TEST_IMG") | 
>>> >> _filter_qemu_io
>>> >
>>> > This works well.
>>> >
>>> > But when I try to put this in a function to avoid repeating:
>>> >
>>> >     function _no_dump_exec()
>>> >     {
>>> >         (ulimit -c 0; exec "$@")
>>> >     }
>>> >
>>> >     _no_dump_exec $QEMU_IO -c "write -P 0x5a 0 512" -c "abort" 
>>> > "$TEST_IMG") | _filter_qemu_io
>>> >
>>> > it doesn't work:
>>> >
>>> >     039 1s ... - output mismatch (see 039.out.bad)
>>> >     --- 039.out     2014-05-13 12:10:39.248866480 +0800
>>> >     +++ 039.out.bad 2014-05-13 17:19:46.161986618 +0800
>>> >     @@ -9,6 +9,7 @@
>>> >
>>> >      == Creating a dirty image file ==
>>> >      Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=134217728
>>> >     +./039: line 51: 10517 Aborted                 "$@"
>>> >      wrote 512/512 bytes at offset 0
>>> >      512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
>>> >      incompatible_features     0x1
>>> >
>>> > Any idea what the difference is here?
>>> 
>>> This is qemu-io aborting, as instructed.  The command is
>>> 
>>>     qemu-io --cache writeback --cache writethrough -c 'write -P 0x5a
>>> 0 512' -c abort scratch/t.qcow2
>>> 
>>> [...]
>>> 
>>> The additional "Aborted" line appears as soon as I put pass the qemu-io
>>> command to a function that runs it using "$@".  I don't need a subshell,
>>> exec or anything:
>>
>> So that looks fine, I'd even consider it a feature to have the abort
>> recorded explicitly.  Let's just update the reference output. Another
>> reason why qemu-iotests is bash-only, but we already have the same kind
>> of output in other test cases, so this is not setting a precedence.
>
> Okay, I'll respin it that way.

The message printed by the shell looks like:

./039: line <LINENR>:  <PID> Aborted <LINETEXT>

Need to filter out the PID.  Okay to add that to the sed script in
_filter_qemu_io, or would you like to have it elsewhere?