From mboxrd@z Thu Jan 1 00:00:00 1970 From: Al Grant Subject: Re: [PATCH] perf inject: correct event attribute sizes Date: Wed, 26 Aug 2020 14:23:59 +0100 Message-ID: <9a48bd74-42ad-4498-7f38-aed560031c4e@foss.arm.com> References: <20200826112745.GB43491@C02TD0UTHF1T.local> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20200826112745.GB43491@C02TD0UTHF1T.local> Content-Language: en-GB Sender: linux-kernel-owner@vger.kernel.org To: Mark Rutland Cc: linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, acme@redhat.com, Denis Nikitin List-Id: linux-perf-users.vger.kernel.org On 26/08/2020 12:27, Mark Rutland wrote: > On Wed, Aug 26, 2020 at 10:42:04AM +0100, Al Grant wrote: >> When perf inject reads a perf.data file from an older version of perf, >> it writes event attributes into the output with the original size field, >> but lays them out as if they had the size currently used. Readers see >> a corrupt file. Update the size field to match the layout. >> >> From: Denis Nikitin >> Signed-off-by: Al Grant > > Did Denis write this patch? Joint work - I fixed the sizes in the event attributes section, but Denis noticed that the copies in HEADER_EVENT_DESC also need fixing, so the final text is his. > If so, we need an S-o-B line from them. I have his approval to upstream this, so: Signed-off-by: Denis Nikitin Al > > Mark. > >> tools/perf/util/header.c | 8 ++++++++ >> 1 file changed, 8 insertions(+) >> >> diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c >> index 9cf4efdcbbbd..762eb94bd532 100644 >> --- a/tools/perf/util/header.c >> +++ b/tools/perf/util/header.c >> @@ -3326,6 +3326,14 @@ int perf_session__write_header(struct >> perf_session *session, >> attr_offset = lseek(ff.fd, 0, SEEK_CUR); >> >> evlist__for_each_entry(evlist, evsel) { >> + if (evsel->core.attr.size < sizeof(evsel->core.attr)) { >> + /* >> + * We are likely in "perf inject" and have read + >> * from an older file. Update attr size so that >> + * reader gets the right offset to the ids. >> + */ >> + evsel->core.attr.size = sizeof(evsel->core.attr); >> + } >> f_attr = (struct perf_file_attr){ >> .attr = evsel->core.attr, >> .ids = {