From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8666C191; Mon, 12 Aug 2024 17:33:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723484011; cv=none; b=plxwjFJjckEn0XWN8ZM5gQwja1t6zlEy1fhVbeR6O1NTVaVrVtNkGiB7ywnYaFJfmFKwedsmK/LjPEtTVAkBUCrcjlEl9R8UO8ypgyjEcMqm/KEYKJRDHFSzjYvj2KvDc320AwHMo5G4MRW7+8J/b6TrQwoGc9IL8xdBzux5lLI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723484011; c=relaxed/simple; bh=+hevNowKUmPgWOv+xcjbhVWNsC7IU/ZZjoQNOBBsqis=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=C2dYgbhgtkJDaEYDTIpMtOgEOJ4fIO3SX6iszuYxZLFHSfSu0guq0/+g/thNtNFGtZJBof7XnjP3xLSYzN+kpK9jAN5qLzJfK0owRYVNR4uJTiiEuQvKFPprZX1/RC4Mday3YgmU16QSEpd8i6Nvz/TBAhk8NJeCppoDSdH9LG8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=aL5kmQKP; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="aL5kmQKP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AAF71C32782; Mon, 12 Aug 2024 17:33:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1723484011; bh=+hevNowKUmPgWOv+xcjbhVWNsC7IU/ZZjoQNOBBsqis=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=aL5kmQKP4nAB4Za0B1shM3JqHHRqygf39jTY+L+T21mY69/Sub8ohLMNvX8m4wSiH 822qNc+jhdCyrOveWwVsJdMXaeci8dPemM1XarkF2eeRGTNCRFFiJ3DNw/QQvgL4N2 nczsdsJK+Vn/p1whTrHK9PRlUlpxqIfiom27cTl+E6MWXrRWiUPN+F7w+/qxsB4umO HljApv6FSb2TYfieMnxPCVAgnjt8p1/T6UvC0tRYV4YCggINmJr1IsjliVUWiZNjlu yU9+SACFu4/oHZXl+H82RTK7fWcLX/0HYj2wzgM/2CoKA5zK2vw/xTiKfZoYIx95Ih JQMo2wd6F8Wcw== Date: Mon, 12 Aug 2024 14:33:27 -0300 From: Arnaldo Carvalho de Melo To: Namhyung Kim Cc: Ian Rogers , Kan Liang , Jiri Olsa , Adrian Hunter , Peter Zijlstra , Ingo Molnar , LKML , linux-perf-users@vger.kernel.org, Dan Carpenter Subject: Re: [PATCH v2] perf lock contention: Change stack_id type to s32 Message-ID: References: <20240812172533.2015291-1-namhyung@kernel.org> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240812172533.2015291-1-namhyung@kernel.org> On Mon, Aug 12, 2024 at 10:25:33AM -0700, Namhyung Kim wrote: > The bpf_get_stackid() helper returns a signed type to check whether it > failed to get a stacktrace or not. But it saved the result in u32 and > checked if the value is negative. > > 376 if (needs_callstack) { > 377 pelem->stack_id = bpf_get_stackid(ctx, &stacks, > 378 BPF_F_FAST_STACK_CMP | stack_skip); > --> 379 if (pelem->stack_id < 0) > > ./tools/perf/util/bpf_skel/lock_contention.bpf.c:379 contention_begin() > warn: unsigned 'pelem->stack_id' is never less than zero. > > Let's change the type to s32 instead. > > Fixes: 6d499a6b3d90 ("perf lock: Print the number of lost entries for BPF") > Reported-by: Dan Carpenter > Signed-off-by: Namhyung Kim > --- > v2) fix build error for s32 Thanks, applied to perf-tools-next, - Arnaldo > tools/perf/util/bpf_skel/lock_data.h | 4 ++-- > tools/perf/util/bpf_skel/vmlinux/vmlinux.h | 1 + > 2 files changed, 3 insertions(+), 2 deletions(-) > > diff --git a/tools/perf/util/bpf_skel/lock_data.h b/tools/perf/util/bpf_skel/lock_data.h > index 36af11faad03..de12892f992f 100644 > --- a/tools/perf/util/bpf_skel/lock_data.h > +++ b/tools/perf/util/bpf_skel/lock_data.h > @@ -7,11 +7,11 @@ struct tstamp_data { > u64 timestamp; > u64 lock; > u32 flags; > - u32 stack_id; > + s32 stack_id; > }; > > struct contention_key { > - u32 stack_id; > + s32 stack_id; > u32 pid; > u64 lock_addr_or_cgroup; > }; > diff --git a/tools/perf/util/bpf_skel/vmlinux/vmlinux.h b/tools/perf/util/bpf_skel/vmlinux/vmlinux.h > index e9028235d771..d818e30c5457 100644 > --- a/tools/perf/util/bpf_skel/vmlinux/vmlinux.h > +++ b/tools/perf/util/bpf_skel/vmlinux/vmlinux.h > @@ -15,6 +15,7 @@ > > typedef __u8 u8; > typedef __u32 u32; > +typedef __s32 s32; > typedef __u64 u64; > typedef __s64 s64; > > -- > 2.46.0.76.ge559c4bf1a-goog