Re: [PATCH v2.1 1/2] check: detect and preserve all coredumps made by a test

["Darrick J. Wong" <djwong@kernel.org>]

On Thu, Oct 13, 2022 at 09:27:08AM -0700, Darrick J. Wong wrote:
> On Fri, Oct 14, 2022 at 12:03:26AM +0800, Zorro Lang wrote:
> > On Thu, Oct 13, 2022 at 08:48:41AM -0700, Darrick J. Wong wrote:
> > > On Thu, Oct 13, 2022 at 07:44:46PM +0800, Zorro Lang wrote:
> > > > On Wed, Oct 12, 2022 at 05:19:50PM -0700, Darrick J. Wong wrote:
> > > > > From: Darrick J. Wong <djwong@kernel.org>
> > > > > 
> > > > > If someone sets kernel.core_uses_pid (or kernel.core_pattern), any
> > > > > coredumps generated by fstests might have names that are longer than
> > > > > just "core".  Since the pid isn't all that useful by itself, let's
> > > > > record the coredumps by hash when we save them, so that we don't waste
> > > > > space storing identical crash dumps.
> > > > > 
> > > > > Signed-off-by: Darrick J. Wong <djwong@kernel.org>
> > > > > ---
> > > > > v2.1: use REPORT_DIR per maintainer suggestion
> > > > > ---
> > > > 
> > > > This version looks good to me,
> > > > Reviewed-by: Zorro Lang <zlang@redhat.com>
> > > 
> > > It occurred to me overnight that ./check doesn't export REPORT_DIR, so
> > > I'll push out a v2.2 that adds that.  Currently the lack of an export
> > > doesn't affect anyone, but as soon as any tests want to call
> > > _save_coredump they're going to run into that issue.
> > 
> > Hmm... the RESULT_DIR is exported, you can use it, or use $seqres directly due
> > to it's defined in common/preamble (although is not exported).
> > 
> > ./common/preamble:42:   seqres=$RESULT_DIR/$seq
> > 
> > What do you think?
> 
> seqres is defined differently in check than in common/preamble, but I
> guess RESULT_DIR will work.

Nope, it won't, because RESULT_DIR ends up getting set to something
like /var/tmp/fstests/xfs_moocow/xfs, seqnum gets set to xfs/350, and
then you end up with garbage paths like:

/var/tmp/fstests/xfs_moocow/xfs/xfs/350.core.XXX

Soooo you were right, I should have used seqres from the start.  The
multiple definitions are confusing, but they end up resolving to the
same pathnames(!) so it's all good.

--D

> --D
> 
> > Thanks,
> > Zorro
> > 
> > > 
> > > (...and yes, I do have future fuzz tests that will call it from a test
> > > in between fuzz field cycles.)
> > > 
> > > --D
> > > 
> > > > >  check     |   26 ++++++++++++++++++++++----
> > > > >  common/rc |   16 ++++++++++++++++
> > > > >  2 files changed, 38 insertions(+), 4 deletions(-)
> > > > > 
> > > > > diff --git a/check b/check
> > > > > index d587a70546..29303db1c8 100755
> > > > > --- a/check
> > > > > +++ b/check
> > > > > @@ -923,11 +923,19 @@ function run_section()
> > > > >  			sts=$?
> > > > >  		fi
> > > > >  
> > > > > -		if [ -f core ]; then
> > > > > -			_dump_err_cont "[dumped core]"
> > > > > -			mv core $RESULT_BASE/$seqnum.core
> > > > > +		# If someone sets kernel.core_pattern or kernel.core_uses_pid,
> > > > > +		# coredumps generated by fstests might have a longer name than
> > > > > +		# just "core".  Use globbing to find the most common patterns,
> > > > > +		# assuming there are no other coredump capture packages set up.
> > > > > +		local cores=0
> > > > > +		for i in core core.*; do
> > > > > +			test -f "$i" || continue
> > > > > +			if ((cores++ == 0)); then
> > > > > +				_dump_err_cont "[dumped core]"
> > > > > +			fi
> > > > > +			_save_coredump "$i"
> > > > >  			tc_status="fail"
> > > > > -		fi
> > > > > +		done
> > > > >  
> > > > >  		if [ -f $seqres.notrun ]; then
> > > > >  			$timestamp && _timestamp
> > > > > @@ -960,6 +968,16 @@ function run_section()
> > > > >  			# of the check script itself.
> > > > >  			(_adjust_oom_score 250; _check_filesystems) || tc_status="fail"
> > > > >  			_check_dmesg || tc_status="fail"
> > > > > +
> > > > > +			# Save any coredumps from the post-test fs checks
> > > > > +			for i in core core.*; do
> > > > > +				test -f "$i" || continue
> > > > > +				if ((cores++ == 0)); then
> > > > > +					_dump_err_cont "[dumped core]"
> > > > > +				fi
> > > > > +				_save_coredump "$i"
> > > > > +				tc_status="fail"
> > > > > +			done
> > > > >  		fi
> > > > >  
> > > > >  		# Reload the module after each test to check for leaks or
> > > > > diff --git a/common/rc b/common/rc
> > > > > index d877ac77a0..2e1891180a 100644
> > > > > --- a/common/rc
> > > > > +++ b/common/rc
> > > > > @@ -4949,6 +4949,22 @@ _create_file_sized()
> > > > >  	return $ret
> > > > >  }
> > > > >  
> > > > > +_save_coredump()
> > > > > +{
> > > > > +	local path="$1"
> > > > > +
> > > > > +	local core_hash="$(_md5_checksum "$path")"
> > > > > +	local out_file="$REPORT_DIR/$seqnum.core.$core_hash"
> > > > > +
> > > > > +	if [ -s "$out_file" ]; then
> > > > > +		rm -f "$path"
> > > > > +		return
> > > > > +	fi
> > > > > +	rm -f "$out_file"
> > > > > +
> > > > > +	mv "$path" "$out_file"
> > > > > +}
> > > > > +
> > > > >  init_rc
> > > > >  
> > > > >  ################################################################################
> > > > > 
> > > > 
> > > 
> >