Sometimes when I remove SD card I can notice that when I reinsert it - it doesn't mount by itself. Also I've notice that umount process is stalled and I cannot kill it (not even with -9). I use Ubuntu 14.04.

Any idea what I do wrong?


First: get out from that directory in terminal :) Jocking.. but not so much, thinking how many times I run umount and it gives me an error because I'm actually inside the folder. I would go in terminal and try lsof | grep ssdDirectory, to see what it tells is using that dir.

Example output of lsof | grep /mnt/share, where share is mounted.

COMMAND     PID  TID    USER   FD      TYPE             DEVICE  SIZE/OFF       NODE NAME
lsof      11930         root  cwd       DIR              253,2        15     213678 /mnt/share

This is telling that lsof is executing exactly from /mnt/share with FD (File Descriptor) cwd, the current working directory. If you see the same.. get out from that directory ;))

  • Can this be related to copying a file onto that SD card and removing the card without sync'ing? – lewiatan Nov 13 '15 at 8:35
  • What you mean by sync'ing? Is the sd configured to be synced in some program? If the sd mount directory and related files/services are free, you should be able to unmount and mount it again. Try findmnt, it should tell you where exactly is the sd mounted, and then use lsof | grep sdmountpoint to find out what actually is using it. – nnsense Nov 13 '15 at 14:31
  • I meant that I used "cp" instruction earlier and later "sync" in the terminal. Unfortunately I resolved the issue with hard reset but I'm sure it will come back and then I'll post the output of findmnt, lsof and iostat. – lewiatan Nov 13 '15 at 17:52

umount process is stuck in system call and kernel waiting for something - perhaps it's a bad driver issue, because normally USB drivers correctly handle such situations and let userspace processes go on to exit, instead of hanging them into kernel mode, when user suddenly pulls out USB stick or SD card from reader.

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