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Re: [Qemu-devel] [PATCH] qemu-iotests: Fix core dump suppression in test
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-devel] [PATCH] qemu-iotests: Fix core dump suppression in test 039 |
Date: |
Wed, 14 May 2014 13:42:38 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
Am 14.05.2014 um 13:16 hat Markus Armbruster geschrieben:
> 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?
Fine with me in _filter_qemu_io. We may later need it elsewhere too,
but we can still move it then.
Kevin