From patchwork Fri Aug 16 04:39:14 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Neeraj Upadhyay X-Patchwork-Id: 13765435 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 3B36177111; Fri, 16 Aug 2024 04:39:56 +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=1723783198; cv=none; b=kCNixKUREk88vpQJVuC4jr800P6zby/UyHiP+O7FyamlD8rnaAHaBJL7jXv6sObNWUMLTELRFaM+GjdP+f8tQYjTdHEVgMTXv8vsFVwzDAPF3XIRzLtzV2O7j5YNmGhMla/4CpYgowMkUYBvZrAANKlyGvdYjFFDj4I6qeJvUsI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723783198; c=relaxed/simple; bh=EQ7mddlc0hf+YaM1u17yUZvNq42jgh8Dic8l77MpinI=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=jB90XMA4HOA+VVAuMTpq4+cjFdvPY5DmvOybYqjyl2B40Kws3TmJdCh3/pOnQMwOzQto4YxN7yyyU6U/I2PPvOy5UOEZvnEVzzm5tWCkRXaFcbHN/0NjlaC7RQiWOBiGiAS425rof4GY2H28zp1SIshTuzw3wVxEJR1qeIgl9pI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=A4VWccQx; 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="A4VWccQx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 012DAC32782; Fri, 16 Aug 2024 04:39:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1723783196; bh=EQ7mddlc0hf+YaM1u17yUZvNq42jgh8Dic8l77MpinI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=A4VWccQxvsZoXHT7JlT10k6GxP55bWAnR5Uf0t0vDxdMUWltkNnkDEL2akWGX+HSn KnGIuLkxUFa1k3Y1GxJ3WVLd/sK/2qbXhiYmy0+cpmnAuxAOGl9CjvG1VyXtRVN5BY HUCo1XXN3HAtVBfy5l9hTUhWR+7D6YG8X8Ayc+BnXaweFa+BwM9Pys7ztwWiHJ69UJ 7/n+dtuxbeIe5BiYVUxjK2+2YNukcgPYgIUE+zkkPivRPlhubp0esth4r0UjgbeiFU xWnReSUXlDipjyoHmBRPJTRsky8luwpmX7nuRcZ1XMkKOhFtXLOhPmOzRDzbgSYVfJ 6WLVh+D9hYpEg== From: neeraj.upadhyay@kernel.org To: rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com, rostedt@goodmis.org, paulmck@kernel.org, neeraj.upadhyay@kernel.org, neeraj.upadhyay@amd.com, boqun.feng@gmail.com, joel@joelfernandes.org, urezki@gmail.com, frederic@kernel.org, mingo@kernel.org, peterz@infradead.org, leobras@redhat.com, imran.f.khan@oracle.com, riel@surriel.com, tglx@linutronix.de Subject: [PATCH rcu 1/4] locking/csd_lock: Print large numbers as negatives Date: Fri, 16 Aug 2024 10:09:14 +0530 Message-Id: <20240816043917.26537-1-neeraj.upadhyay@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20240816043600.GA25206@neeraj.linux> References: <20240816043600.GA25206@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 Reviewed-by: Rik van Riel Signed-off-by: Neeraj Upadhyay --- kernel/smp.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/smp.c b/kernel/smp.c index aaffecdad319..e87953729230 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -249,8 +249,8 @@ 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