From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-171.mta1.migadu.com (out-171.mta1.migadu.com [95.215.58.171]) (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 5A53F386453 for ; Wed, 22 Jul 2026 02:10:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.171 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784686243; cv=none; b=BZOCyUtibBLpzyq57CA/JyED2x2UshKPnddf4qkeKoBmBm3lXfGvoC2vbaRn9QFymaCo0lS9RrUTGJrlG2ko3b7plNl92Yh5U3DF2Unu24j1dZSvluzD14gvTqOGB11XoE3miVfPPqiYu6m5ZnT6oBGPBCG3+Dwl/1sGfuld9Lo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784686243; c=relaxed/simple; bh=BIXyqiI2YKULwkUryrEG2qyuxw33mJqq/29VwBpyqTQ=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=fKKHzk/O4XPBTxzIqrBteoDMzfpxB05IBTTEFGYu0o4lUKbcfWM+O9JVYEutF0H/HAJJ7jVh3juCTBvy3MGgfei52aR7byH3p9hlk6P3/OvnmEa/xG7jFWkNjzC+m9n3eFL6LEV5oF6Plqs7lcNfrLAPvDCRmzyHiAi0IeGhAiQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=IL60oVb/; arc=none smtp.client-ip=95.215.58.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="IL60oVb/" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1784686239; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=+VqplA63ICF8JYaXkNQfQKK1YwmTBbmr8Qj64IshWxY=; b=IL60oVb/HIjrLKVZdVgitSfF64zorJ7dQGxuk9Dald0XKqx3qCVrJfemq0ft7sszo/pZnV QBIR7aSiVMkGv7+uH95WOTgaF1IOCiV0BKOnM06el9ULHRYS927fEZVPlFWs8OyPURCIxB sTyYXmgdUgC+qkPCmfFT96geITnMGK0= From: Lance Yang To: atomlin@atomlin.com, pmladek@suse.com Cc: lance.yang@linux.dev, akpm@linux-foundation.org, mhiramat@kernel.org, linux-kernel@vger.kernel.org, david.laight.linux@gmail.com, neelx@suse.com, sean@ashe.io, chjohnst@gmail.com, steve@abita.co, mproche@gmail.com, nick.lange@gmail.com Subject: Re: [PATCH v6] hung_task: Deduplicate identical hang reports using explicit blocker tracking Date: Wed, 22 Jul 2026 10:10:18 +0800 Message-Id: <20260722021018.85583-1-lance.yang@linux.dev> In-Reply-To: References: 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=UTF-8 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT On Tue, Jul 21, 2026 at 01:30:34PM -0400, Aaron Tomlin wrote: >On Tue, Jul 21, 2026 at 03:28:48PM +0200, Petr Mladek wrote: [...] > >> 3. We could prevent printing the same process again and again >> by adding "hung_task_reported" into struct task_struct. >> >> But then we should print some summary about how many hung tasks >> were found in the last round at least. So that we know that >> the problem persists. >> >> This should still be rather easy. But I am not sure if it is >> worth it. >> >> 4. We could add the filtering of the duplicated backtraces. But >> it has to be handled by some helper function. >> >> It looks like to most complicated part. I would personally skip >> it for now. We could always add it later when the above proposed >> changes are not enough to tune the kernel.hung_task_warnings >> value in the real life. > >I do think this is worth doing to prevent the single-line spam if a task >remains hung for hours, no? Nope. TBH, if a task is still stuck hours later, something is already gone sideways. Seen that play out plenty of times: hung task, soft/hard lockup, panic, reboot. Hard to call that one-liner spam :) So yeah, I still think v7 should just go with Petr's two patches. That should take care of the problems we're trying to solve ;) @Aaron mind taking those, testing them out, and spinning a v7? Cheers, Lance