From patchwork Sat Jul 13 16:58:44 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Neeraj Upadhyay X-Patchwork-Id: 13732454 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 3070513B287; Sat, 13 Jul 2024 16:59:29 +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=1720889970; cv=none; b=ODyCFYn9qhdtTmUNmKVaUqSDD2YNumlwCgGpR+M+iLHT8yhuNjnbECYpEp+5X5A6GHEfcdKr7xGHuVXrhTLCW15j5Lyd7lIKs3Oxcg3GaDRel5sxUm4jfplyaSWD+oMpIzpPgMEPoaDwLGUuk3L8h/K6PcP0KGl9itkqhkIok+E= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720889970; c=relaxed/simple; bh=KYBad74cZVInqYWF85EGV9C9g4LucoMsE/dNGXtFggU=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=tAbv4iLS/TnftM/3AYyV+P3TsrUPCeC5cpplkFeVKqp3dVTOlgsdOrxSr9rM4pDVGhAOCY/ULwWoLNRUF4OpixBAv2hpg6h01l75e0zjYq9qx/AR43E1gbdVHJLg+KAJSlMS/jp2Lgx9zwkU8whBwsJBuEXJjTxCLMkcusa3Hrw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ivG7ua0f; 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="ivG7ua0f" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 95F9BC32781; Sat, 13 Jul 2024 16:59:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720889969; bh=KYBad74cZVInqYWF85EGV9C9g4LucoMsE/dNGXtFggU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ivG7ua0fflJ90aOgBFrUgWD74Fli9Tt2UpLfAAa5BmG38tcX1yzE5dT0+R8fu2o8Q v7wM+vzKoqBt0Gix3uFgjZ7aOkTpjzY2SADh+SlSjjo/H76d+rBGCib/FS4tigubCM WjRwsOBipxMb78kh8kTzJDo43CN+CRuHfh1uT5tWY/nVC5mbl/vzPVL2/k9HC+okQI 5Kp4jqK99HflrmHzA4iowWdyzZmgEP3lt9rzq0Iss775MaR2/nfT2qEAtss45A3Z29 XHOefIVdkUHIN2fry/uTVYjbq693nsIr8HSmctvU+oT4umRVeY6uyjZBHCwlImIXG5 PSJWPtxTsZwgw== From: neeraj.upadhyay@kernel.org To: linux-kernel@vger.kernel.org Cc: rcu@vger.kernel.org, kernel-team@meta.com, rostedt@goodmis.org, mingo@kernel.org, peterz@infradead.org, paulmck@kernel.org, leobras@redhat.com, imran.f.khan@oracle.com, riel@surriel.com, neeraj.upadhyay@kernel.org Subject: [PATCH 1/3] locking/csd_lock: Print large numbers as negatives Date: Sat, 13 Jul 2024 22:28:44 +0530 Message-Id: <20240713165846.216174-1-neeraj.upadhyay@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20240713165642.GA215331@neeraj.linux> References: <20240713165642.GA215331@neeraj.linux> Precedence: bulk X-Mailing-List: rcu@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: "Paul E. McKenney" The CSD-lock-hold diagnostics from CONFIG_CSD_LOCK_WAIT_DEBUG are printed in nanoseconds as unsigned long longs, which is a bit obtuse for human readers when timing bugs result in negative CSD-lock hold times. Yes, there are some people to whom it is immediately obvious that 18446744073709551615 is really -1, but for the rest of us... Therefore, print these numbers as signed long longs, making the negative hold times immediately apparent. Reported-by: Rik van Riel Signed-off-by: Paul E. McKenney Cc: Imran Khan Cc: Ingo Molnar Cc: Leonardo Bras Cc: "Peter Zijlstra (Intel)" Cc: Rik van Riel Signed-off-by: Neeraj Upadhyay Reviewed-by: Rik van Riel --- kernel/smp.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/smp.c b/kernel/smp.c index f085ebcdf9e7..81f7083a53e2 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -248,8 +248,8 @@ static bool csd_lock_wait_toolong(call_single_data_t *csd, u64 ts0, u64 *ts1, in cpu_cur_csd = smp_load_acquire(&per_cpu(cur_csd, cpux)); /* Before func and info. */ /* How long since this CSD lock was stuck. */ ts_delta = ts2 - ts0; - pr_alert("csd: %s non-responsive CSD lock (#%d) on CPU#%d, waiting %llu ns for CPU#%02d %pS(%ps).\n", - firsttime ? "Detected" : "Continued", *bug_id, raw_smp_processor_id(), ts_delta, + pr_alert("csd: %s non-responsive CSD lock (#%d) on CPU#%d, waiting %lld ns for CPU#%02d %pS(%ps).\n", + firsttime ? "Detected" : "Continued", *bug_id, raw_smp_processor_id(), (s64)ts_delta, cpu, csd->func, csd->info); /* * If the CSD lock is still stuck after 5 minutes, it is unlikely