From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Raspl Date: Tue, 19 May 2009 06:46:57 +0000 Subject: Re: [Patch] blktrace: remove debugfs entries on bad path Message-Id: <4A1255E1.1060301@linux.vnet.ibm.com> List-Id: References: <4A115BA5.6090905@linux.vnet.ibm.com> <4A1207DE.4000409@cn.fujitsu.com> In-Reply-To: <4A1207DE.4000409@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Li Zefan Cc: linux-btrace@vger.kernel.org, Jens Axboe , linux-kernel@vger.kernel.org, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com Li Zefan wrote: > A better title: > [Patch] blktrace: remove debugfs entries on bad path > > Stefan Raspl wrote: >> debugfs directory entries for devices are not removed on bad path. > > Can you be more elaborate on how to reproduce this issue? It can happen for most bad pathes within do_blk_trace_setup(). One way to trigger is to set the Vmalloc space via the respective kernel parameter to a value that is so small that it will not suffice for the 2MB per device and cpu that is required. For instance, set vmallocM and start blktrace on a system with 2 cpus on 7 devices. Depending on how much Vmalloc space is still free, the final 2 or 3 devices will fail with a message like this: BLKTRACESETUP(2) /dev/sdu failed: 5/Input/output error Best regards, Stefan Raspl