From nobody Mon Feb 9 15:06:56 2026 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 01E36D51E for ; Fri, 2 Aug 2024 00:30:48 +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=1722558649; cv=none; b=RT/r55/GzNZTn7co2RI5415ARY4Qty5D/s00hV3zmCcHrrG4GVulZ+ryAwFp6G3UiNdPZoGPPGSoPSevNA+SvUfiMyVcSnz9YrTQkK9JYyOPHZS3Ccq1cy6kt1BkDw+cUzvfPPqOQh0EW40CjE3MzGmqjSn0F+C5gX56RaIlJbM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722558649; c=relaxed/simple; bh=GOsLE2H2kxozZGmGGy11M/q8AzvicOB0v4IKkxs553w=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=PCHTwJ5F7u583/Mq98SgvQci+3H7d3WiCIBadOAGJPw89D1+VRy0BX5HgPp7nFQ9mW2Cf/DkJ4L7cdcAd7L51EuIBiaiw9t+y4VhMx/gIEXy1zU1OyC8hmFZTOCk64SErSyH/wyyweqoR2fCe4ZbDrF+g1d5+Un+2XkrTrMX1WI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HbFfDc3k; 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="HbFfDc3k" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 869ADC4AF0A; Fri, 2 Aug 2024 00:30:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1722558648; bh=GOsLE2H2kxozZGmGGy11M/q8AzvicOB0v4IKkxs553w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HbFfDc3kU+sa5h4LiyXBiMNWMS/ohMRjT0qVpeRS1HGbH4DsBaHK+Q58j6MtAVUuf ehwjpQaAJ37bvNLN9EssSjDq/2Tp7lwRseE/1Mih41o7PRgiTQ6saSkKq0/TvA7nHA SHn3DPQ0PnzzlV3s3/vjMyMBZq0fZVTApAdSOqoiZduHqNDtm+tRaRoINt2L0dlKjW SR6+cV4tXAMJovXSmAB/TUlCAoIEJ6vnTCixPqD1lez0r72nqA+aEUPA9Y4u6j4b7q jwqwYwboTBK7U0Mwcc/lTVwRqVxasIlUU5nnyW51wrZ1y0Ie348UynyTT5yLn8GWss dxXq7O4M7WqOQ== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id 2F230CE0A01; Thu, 1 Aug 2024 17:30:48 -0700 (PDT) From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: Tejun Heo , Lai Jiangshan , Breno Leitao , Rik van Riel , Anhad Jai Singh , Oleg Nesterov , Jens Axboe , Christian Brauner , Andrew Morton , "Matthew Wilcox (Oracle)" , Chris Mason , "Paul E. McKenney" Subject: [PATCH misc 2/2] exit: Sleep at TASK_IDLE when waiting for application core dump Date: Thu, 1 Aug 2024 17:30:46 -0700 Message-Id: <20240802003046.4134043-2-paulmck@kernel.org> X-Mailer: git-send-email 2.40.1 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-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Currently, the coredump_task_exit() function sets the task state to TASK_UNINTERRUPTIBLE|TASK_FREEZABLE, which usually works well. But a combination of large memory and slow (and/or highly contended) mass storage can cause application core dumps to take more than two minutes, which can cause check_hung_task(), which is invoked by check_hung_uninterruptible_tasks(), to produce task-blocked splats. There does not seem to be any reasonable benefit to getting these splats. Furthermore, as Oleg Nesterov points out, TASK_UNINTERRUPTIBLE could be misleading because the task sleeping in coredump_task_exit() really is killable, albeit indirectly. See the check of signal->core_state in prepare_signal() and the check of fatal_signal_pending() in dump_interrupted(), which bypass the normal unkillability of TASK_UNINTERRUPTIBLE, resulting in coredump_finish() invoking wake_up_process() on any threads sleeping in coredump_task_exit(). Therefore, change that TASK_UNINTERRUPTIBLE to TASK_IDLE. Reported-by: Anhad Jai Singh Signed-off-by: Paul E. McKenney Acked-by: Oleg Nesterov Cc: Jens Axboe Cc: Christian Brauner Cc: Andrew Morton Cc: "Matthew Wilcox (Oracle)" Cc: Chris Mason Cc: Rik van Riel --- kernel/exit.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/exit.c b/kernel/exit.c index 7430852a85712..0d62a53605dfc 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -428,7 +428,7 @@ static void coredump_task_exit(struct task_struct *tsk) complete(&core_state->startup); =20 for (;;) { - set_current_state(TASK_UNINTERRUPTIBLE|TASK_FREEZABLE); + set_current_state(TASK_IDLE|TASK_FREEZABLE); if (!self.task) /* see coredump_finish() */ break; schedule(); --=20 2.40.1