From: Nam Cao <namcao@linutronix.de>
To: Gabriele Monaco <gmonaco@redhat.com>,
linux-kernel@vger.kernel.org,
Steven Rostedt <rostedt@goodmis.org>,
Gabriele Monaco <gmonaco@redhat.com>,
linux-trace-kernel@vger.kernel.org
Cc: Wen Yang <wen.yang@linux.dev>
Subject: Re: [PATCH v2 04/12] rv: Prevent task migration while handling per-CPU events
Date: Thu, 28 May 2026 10:56:50 +0200 [thread overview]
Message-ID: <87fr3boqst.fsf@yellow.woof> (raw)
In-Reply-To: <20260527062313.39908-5-gmonaco@redhat.com>
Gabriele Monaco <gmonaco@redhat.com> writes:
> Tracepoint handlers are now fully preemptible.
Would be nice to mention the commit that did this:
a46023d5616e ("tracing: Guard __DECLARE_TRACE() use of __DO_TRACE_CALL() with SRCU-fast")
> When a per-CPU monitor
> handles an event, it retrieves the monitor state using a per-CPU
> pointer. If the event itself doesn't disable preemption, the task can
> migrate to a different CPU and we risk updating the wrong monitor.
>
> Mitigate this by explicitly disabling task migration before acquiring
> the monitor pointer. This cannot guarantee the monitor runs on the
> correct CPU but reduces the race condition window and prevents warnings.
>
> Reviewed-by: Wen Yang <wen.yang@linux.dev>
> Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
Reviewed-by: Nam Cao <namcao@linutronix.de>
next prev parent reply other threads:[~2026-05-28 8:56 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-27 6:23 [PATCH v2 00/12] rv: Fixes on Deterministic and Hybrid Automata Gabriele Monaco
2026-05-27 6:23 ` [PATCH v2 01/12] rv: Fix __user specifier usage in extract_params() Gabriele Monaco
2026-05-28 8:38 ` Nam Cao
2026-05-27 6:23 ` [PATCH v2 02/12] rv: Fix read_lock scope in per-task DA cleanup Gabriele Monaco
2026-05-28 8:43 ` Nam Cao
2026-05-27 6:23 ` [PATCH v2 03/12] rv: Reset per-task DA monitors before releasing the slot Gabriele Monaco
2026-05-28 8:48 ` Nam Cao
2026-05-27 6:23 ` [PATCH v2 04/12] rv: Prevent task migration while handling per-CPU events Gabriele Monaco
2026-05-28 8:56 ` Nam Cao [this message]
2026-05-27 6:23 ` [PATCH v2 05/12] rv: Prevent in-flight per-task handlers from using invalid slots Gabriele Monaco
2026-05-28 8:59 ` Nam Cao
2026-05-27 6:23 ` [PATCH v2 06/12] rv: Ensure all pending probes terminate on per-obj monitor destroy Gabriele Monaco
2026-05-28 9:01 ` Nam Cao
2026-05-27 6:23 ` [PATCH v2 07/12] rv: Fix monitor start ordering and memory ordering for monitoring flag Gabriele Monaco
2026-05-28 9:09 ` Nam Cao
2026-05-27 6:23 ` [PATCH v2 08/12] rv: Ensure synchronous cleanup for HA monitors Gabriele Monaco
2026-05-27 6:23 ` [PATCH v2 09/12] rv: Do not rely on clean monitor when initialising HA Gabriele Monaco
2026-05-27 6:23 ` [PATCH v2 10/12] rv: Add automatic cleanup handlers for per-task HA monitors Gabriele Monaco
2026-05-27 6:23 ` [PATCH v2 11/12] verification/rvgen: Generate cleanup hook for per-obj monitor Gabriele Monaco
2026-05-27 6:23 ` [PATCH v2 12/12] verification/rvgen: Fix suffix strip in dot2k Gabriele Monaco
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