From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lukasz Majewski Date: Wed, 12 Nov 2014 15:29:49 +0100 Subject: [U-Boot] [PATCH v2] test: ums: Add sleep before unmount directory In-Reply-To: <20141107230307.791553833CD@gemini.denx.de> References: <1415269420-6528-1-git-send-email-l.majewski@samsung.com> <1415365555-9790-1-git-send-email-l.majewski@samsung.com> <20141107215404.3580138334A@gemini.denx.de> <545D40E1.2030700@wwwdotorg.org> <20141107230307.791553833CD@gemini.denx.de> Message-ID: <20141112152949.1fe6ce3c@amdc2363> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hi Wolfgang, > Dear Stephen, > > In message <545D40E1.2030700@wwwdotorg.org> you wrote: > > > > > My gut feeling is that there might be some USB driver error > > > involved here. > > > > Where I've seen this is writing to an SD card in a USB-based SD > > card reader. > > > > I have a fairly regular amd64 machine running Ubuntu. I put the > > loop above into my own scripts that mount an SD card, copy new data > > to it, and then immediately unmount it for the same reason that > > Lukasz made this patch; umount doesn't always unmount. I did this > > so long ago that I don't recall which Ubuntu version I had at the > > time, nor the kernel version. It was *probably* Ubuntu 10.04 or > > 12.10 though. Now I'm on 14.04, but have no idea if I still need > > the loop since it's already in place:-) > > But this is a bug. Papering over is not a good idea. It should be > analyzed, reported, and finally fixed. > I've debugged the script with strace. The problem is with umount() syscall: [pid 23296] umount("/mnt/tmp-ums-test", 0) = -1 EBUSY (Device or resource busy) It is somehow strange, because with strace attached I occasionally see correct behaviour: [pid 23776] umount("/mnt/tmp-ums-test", 0) = 0 I need to debug the syscall in the kernel. Information about my system: x86_64: Linux 3.12.0 #2 SMP PREEMPT Wed Nov 27 10:26:22 CET 2013 x86_64 GNU/Linux Debian 7.4. > Best regards, > > Wolfgang Denk > -- Best regards, Lukasz Majewski Samsung R&D Institute Poland (SRPOL) | Linux Platform Group