From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 D659312F383; Fri, 19 Apr 2024 15:34:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713540889; cv=none; b=jZgK1/dztnISph3zhGjtsSFmyin6bcjxHFEWr3taKCIjGF3tcDltIyvxxfdb/9eWfWYxzDnwQbQfMRwLxkkavet42iEceii7PbRnMsxF4P/R8UlBCD0DoGMZ6z3+KWjorXEGLb4dmNKsl3mzYTpcoVLRQqqP6yT0lcEqYRxaDao= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713540889; c=relaxed/simple; bh=xk5RxQLjpLMTXtkOveIqefrfeV0w3inQhOLjLQcNQ+Q=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=fysrO3FPQEdkfiq0lNg15lyCwyLHMLVcsB32/JAgkKetXwyktjEs3BUkTclN644XhMTsN9NCZfRYAO+JVfwNbutihykLYXmeuVSCvhRHlNmcj7HsR5PMMGeeza+t2FFIDn0BAx4MMs1m26TssrZf7wYWxkDTBUd2VSc25U5LGPw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=Oie4/xg4; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=uMfNdSWL; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="Oie4/xg4"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="uMfNdSWL" Date: Fri, 19 Apr 2024 17:34:43 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1713540885; 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=9LjR+hMgOOIviyFlXVxnmansGbWA8tKdpCQ1OTyis+o=; b=Oie4/xg4HuGv2p1jKYMGBlvAjOUtDmS6cZohLywg7zad9+ccXByGV/dkkHVRyvlZW/6pPm U6Lqq9ZgpmmJWUV8KhXVuXX+2XvErS5cdMGlnQwadvDav3SCt7nnBtAFC1xbNeKMv4yuQq t3NGAKZioxyqtwJF/1y26QEpdbs762HJIeVTuJkSM5ZMlHOoBK8WrDy6hTLrZSwdIp/F/s gGtuGTJLlsdSlW6xbssdRclfI1tcLeYjRn+a5p7doXraiP3vpEr/nbaR7eNDYUSlarwr8E /tbQ5lfN4vlGcHKNVsmpN9X8y7qWeHd1RXhoy90rK3LCkn0TGuKCrQGciYa9Cg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1713540885; 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=9LjR+hMgOOIviyFlXVxnmansGbWA8tKdpCQ1OTyis+o=; b=uMfNdSWLan27BfBWRRXv+xSmDwICEfuBA3xX+rten5acv3HYwS3l2yJsq8RwiBlqhXCV6y FQoFWnfSfNsByYAA== From: Nam Cao To: Patrik Jakobsson Cc: Takashi Iwai , Harshit Mogalapalli , Helge Deller , Thomas Zimmermann , Daniel Vetter , linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, bigeasy@linutronix.de, LKML , Vegard Nossum , George Kennedy , Darren Kenny , chuansheng.liu@intel.com Subject: Re: [bug-report] task info hung problem in fb_deferred_io_work() Message-ID: <20240419173443.6c49706e@namcao> In-Reply-To: References: <271372d6-e665-4e7f-b088-dee5f4ab341a@oracle.com> <20240418160652.68df1a86@namcao> <87ttjywxv5.wl-tiwai@suse.de> <878r19voks.wl-tiwai@suse.de> <5febb249-1d4d-4ea7-b031-1df4d14620d2@oracle.com> <8734rhvlr2.wl-tiwai@suse.de> 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-Transfer-Encoding: 7bit On 2024-04-19 Patrik Jakobsson wrote: > Neither cancel_delayed_work_sync() or flush_delayed_work() prevent new > work from being scheduled after they return. flush_delayed_work() is called during device closing. And because no writes are performed after the device has been closed, no new work should be queued after flush_delayed_work(). > But > cancel_delayed_work_sync() at least makes sure the queue is empty so > the problem becomes less apparent. > > Could this explain what we're seeing? I suspect that cancel_delayed_work_sync() is only treating the symptoms by preventing the deferred work from running. The real bug is "someone" giving fb_deferred_io_work() invalid pages to work with. But that's just a blind guess. Best regards, Nam