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 EAFE52E6114; Fri, 22 Aug 2025 13:07:35 +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=1755868056; cv=none; b=ZG8k5HMA8lTFN0jniKAkJ0ZU5/2X2HuWSjRBdcOfHou6NxIr9wK7el6Xnq22YtpOFUhCCeTzrGDPO+52N0kH7ndDOUZmegdBFJvM9mkdL/llTYeCE9MYkbHBPhIRpBYSGqBpK3m0OlEz3D2iNjfunbYpegInxhbryKUDWjn2ITQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755868056; c=relaxed/simple; bh=I1vnQdWoQ3da9zwNugFK9yS/sak81xz7G7nlJDyiBeo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=WJjykYA9oqpXgBG5ifcfLHnMVQ0t/JaJG+aUiQAKhbv6IORYWZZBYESnUsvpX2f4WAFrPG5+5QeA1yWX+r8VbUfvMlbt6SGQCRP/tLwGsuhBRgc5/Sc1twWD/tTNBAn+wvjij363L6bgCk7mOFMxb7U1Cqi+/LeAaGIAexOcLFc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=b1Vq6JAQ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="b1Vq6JAQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BA726C4CEED; Fri, 22 Aug 2025 13:07:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1755868055; bh=I1vnQdWoQ3da9zwNugFK9yS/sak81xz7G7nlJDyiBeo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=b1Vq6JAQuvvYPjy3NLd+Zc0cKD6v4zj7BDiT3YiYnx/jPqw/ZNUOAM7c9XqhYd/LK oqYOjigGO508K0nHIROPC7OtRhegzMoOM7xO454jJsMWtcO5yZviV2qONvrLqZMa/9 ZPxMiq1GmVKjz0q8fOrgsKvB/Ym0MSG5EEl4W+88= Date: Fri, 22 Aug 2025 15:07:32 +0200 From: Greg KH To: Sumanth Gavini Cc: rostedt@goodmis.org, mhiramat@kernel.org, tglx@linutronix.de, jstultz@google.com, clingutla@codeaurora.org, mingo@kernel.org, sashal@kernel.org, boqun.feng@gmail.com, ryotkkr98@gmail.com, kprateek.nayak@amd.com, linux-kernel@vger.kernel.org, stable@vger.kernel.org, "J . Avila" Subject: Re: [PATCH 6.1] softirq: Add trace points for tasklet entry/exit Message-ID: <2025082257-smirk-backside-6d93@gregkh> References: <20250812161755.609600-1-sumanth.gavini.ref@yahoo.com> <20250812161755.609600-1-sumanth.gavini@yahoo.com> Precedence: bulk X-Mailing-List: linux-kernel@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: <20250812161755.609600-1-sumanth.gavini@yahoo.com> On Tue, Aug 12, 2025 at 11:17:54AM -0500, Sumanth Gavini wrote: > commit f4bf3ca2e5cba655824b6e0893a98dfb33ed24e5 upstream. > > Tasklets are supposed to finish their work quickly and should not block the > current running process, but it is not guaranteed that they do so. > > Currently softirq_entry/exit can be used to analyse the total tasklets > execution time, but that's not helpful to track individual tasklets > execution time. That makes it hard to identify tasklet functions, which > take more time than expected. > > Add tasklet_entry/exit trace point support to track individual tasklet > execution. > > Trivial usage example: > # echo 1 > /sys/kernel/debug/tracing/events/irq/tasklet_entry/enable > # echo 1 > /sys/kernel/debug/tracing/events/irq/tasklet_exit/enable > # cat /sys/kernel/debug/tracing/trace > # tracer: nop > # > # entries-in-buffer/entries-written: 4/4 #P:4 > # > # _-----=> irqs-off/BH-disabled > # / _----=> need-resched > # | / _---=> hardirq/softirq > # || / _--=> preempt-depth > # ||| / _-=> migrate-disable > # |||| / delay > # TASK-PID CPU# ||||| TIMESTAMP FUNCTION > # | | | ||||| | | > -0 [003] ..s1. 314.011428: tasklet_entry: tasklet=0xffffa01ef8db2740 function=tcp_tasklet_func > -0 [003] ..s1. 314.011432: tasklet_exit: tasklet=0xffffa01ef8db2740 function=tcp_tasklet_func > -0 [003] ..s1. 314.017369: tasklet_entry: tasklet=0xffffa01ef8db2740 function=tcp_tasklet_func > -0 [003] ..s1. 314.017371: tasklet_exit: tasklet=0xffffa01ef8db2740 function=tcp_tasklet_func > > Signed-off-by: Lingutla Chandrasekhar > Signed-off-by: J. Avila > Signed-off-by: John Stultz > Signed-off-by: Thomas Gleixner > Reviewed-by: Steven Rostedt (Google) > Link: https://lore.kernel.org/r/20230407230526.1685443-1-jstultz@google.com > > [elavila: Port to android-mainline] This is not android-mainline, this is the normal stable tree. And I'm with John, this makes no sense as to why you need/want these. I think that the syzbot report is bogus, sorry. Please prove me wrong :) thanks, greg k-h