From: Breno Leitao <leitao@debian.org>
To: Usama Arif <usama.arif@linux.dev>
Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
mathieu.desnoyers@efficios.com, mhiramat@kernel.org,
rostedt@goodmis.org, stable@vger.kernel.org
Subject: Re: [PATCH] tracing: Fix context switch counter truncation
Date: Mon, 20 Jul 2026 02:24:35 -0700 [thread overview]
Message-ID: <al3ocaRVD0mZaDU2@gmail.com> (raw)
In-Reply-To: <20260717173252.3431565-1-usama.arif@linux.dev>
On Fri, Jul 17, 2026 at 10:32:52AM -0700, Usama Arif wrote:
> This affects long-running systems and workloads with high context-switch
> rates. A CPU switching 1,000 times per second takes about 50 days.
nr_context_switches_cpu() returns "unsigned long long"
and rq->nr_switches is u64, so the unsigned int cnt truncation is real
> Fixes: 64cf7d058a00 ("tracing: Have trace_marker use per-cpu data to read user space")
> Cc: stable@vger.kernel.org
> Reported-by: Breno Leitao <leitao@debian.org>
> Signed-off-by: Usama Arif <usama.arif@linux.dev>
Reviewed-by: Breno Leitao <leitao@debian.org>
Thanks for the investigation and fix,
--breno
prev parent reply other threads:[~2026-07-20 9:25 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-17 17:32 [PATCH] tracing: Fix context switch counter truncation Usama Arif
2026-07-17 23:45 ` Masami Hiramatsu
2026-07-20 9:24 ` Breno Leitao [this message]
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