On Thu, Jun 07, 2012 at 02:23:36PM +1000, Stephen Rothwell wrote: > Package: linux-2.6 > Version: 3.2.19-1 > Severity: normal > > Dear Maintainer, > *** Please consider answering these questions, where appropriate *** > > * What led up to the situation? > > I tried to mount a partition on an external USB drive using "pmount > /dev/sdb1 backups". > > * What exactly did you do (or not do) that was effective (or > ineffective)? > > I can CTR-C the pmount, but it leave a mount process which looks like > it is spinning in the kernel. I cannot kill the mount process (even > with kill -9). I need to reboot to recover. Any process that does a > "sync" end up in D state but with no WCHAN listed, so, in particular, > the shutdown does not finish correctly. > > ps -axlw shows: > > 4 0 8021 1 20 0 4168 772 - R pts/6 49:41 > /bin/mount -t udf -o > nosuid,nodev,user,async,atime,noexec,uid=1000,gid=1000,umask=000,iocharset=utf8 > /dev/mapper/_dev_sdb1 /media/backups > 0 1000 9205 10570 20 0 3332 252 - D pts/2 0:00 sync > > so mount is trying to mount the partiation as a udf file system (it is > ext4) (this is a LUKS encrypted file system). mount is doing what it is told. pmount now uses libblkid to do filesystem type detection (and so does mount itself if you use -t auto).
[...] > [113218.197892] xhci_hcd 0000:0f:00.0: WARN: Stalled endpoint > [113218.198628] sd 7:0:0:0: [sdb] Write Protect is off > [113218.198636] sd 7:0:0:0: [sdb] Mode Sense: 23 00 00 00 > [113218.198801] xhci_hcd 0000:0f:00.0: WARN: Stalled endpoint > [113218.199423] sd 7:0:0:0: [sdb] No Caching mode page present > [113218.199430] sd 7:0:0:0: [sdb] Assuming drive cache: write through > [113218.200502] xhci_hcd 0000:0f:00.0: WARN: Stalled endpoint > [113218.201318] xhci_hcd 0000:0f:00.0: WARN: Stalled endpoint > [113218.201944] sd 7:0:0:0: [sdb] No Caching mode page present > [113218.201951] sd 7:0:0:0: [sdb] Assuming drive cache: write through > [113218.238410] sdb: sdb1 > [113218.239476] xhci_hcd 0000:0f:00.0: WARN: Stalled endpoint > [113218.240270] xhci_hcd 0000:0f:00.0: WARN: Stalled endpoint > [113218.240911] sd 7:0:0:0: [sdb] No Caching mode page present > [113218.240918] sd 7:0:0:0: [sdb] Assuming drive cache: write through > [113218.240924] sd 7:0:0:0: [sdb] Attached SCSI disk > [113218.245679] xhci_hcd 0000:0f:00.0: WARN: Stalled endpoint > [113218.251565] xhci_hcd 0000:0f:00.0: WARN: Stalled endpoint > [113218.252659] xhci_hcd 0000:0f:00.0: WARN: Stalled endpoint > [113218.445767] xhci_hcd 0000:0f:00.0: WARN: Stalled endpoint > [113248.733637] xhci_hcd 0000:0f:00.0: WARN: Stalled endpoint > [113248.734725] xhci_hcd 0000:0f:00.0: WARN: Stalled endpoint > [113248.775204] xhci_hcd 0000:0f:00.0: WARN: Stalled endpoint > [113248.809657] xhci_hcd 0000:0f:00.0: WARN: Stalled endpoint > [113248.841803] xhci_hcd 0000:0f:00.0: WARN: Stalled endpoint [...] All this suggests that the mount attempt is hanging due to problems with the USB connection. Based on a quick look through the UDF functions in the call stack: [168534.534210] [<ffffffffa1108c3c>] ? udf_read_tagged+0x29/0x113 [udf] [168534.534218] [<ffffffffa1107422>] ? udf_check_anchor_block+0x6e/0xf5 [udf] [168534.534225] [<ffffffffa11075a2>] ? udf_scan_anchors+0xf9/0x158 [udf] [168534.534233] [<ffffffffa110781c>] ? udf_load_vrs+0x21b/0x2b9 [udf] [168534.534240] [<ffffffffa11078ba>] ? udf_load_vrs+0x2b9/0x2b9 [udf] [168534.534247] [<ffffffffa1107a8a>] ? udf_fill_super+0x1d0/0x4d6 [udf] it appears that the filesystem code loops over a finite number of different places where the superblock might be. So I don't think the filesystem code has got confused by the mis-detected filesystem and entered an infinite loop. Instead, single block reads are hanging or taking a very long time to fail. If this is reproducible on Linux 3.4 then I think the people to report this to would be the xhci maintainers. If not then I'll have a look for fixes between 3.2 and 3.4. Ben. -- Ben Hutchings We get into the habit of living before acquiring the habit of thinking. - Albert Camus
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