Tejun Heo <tj@xxxxxxxxxx> wrote: > James Bottomley wrote: > > On Sun, 2008-10-26 at 18:46 +0900, Tejun Heo wrote: > >> Hello, Jens. > >> > >> Commit 242f9dcb8ba6f68fcd217a119a7648a4f69290e9 introduces a strange > >> regression for libata. The second timeout gives puts different > >> pointer from the issued command onto eh_cmd_q breaking libata EH > >> command matching which triggers WARN_ON() in ata_eh_finish() and hangs > >> command processing or causes oops later depending on circumstances. > >> > >> Here are logs with induced timeouts (patch attached). In commit > >> 242f9dcb8, the XXX messages for the second timeout shows different > >> scsi_cmd pointers for eh_cmd_q and qc->scmd which is initialized by > >> ata_scsi_qc_new() during command translation. > > > > I can't see a way we could be getting a different command passed in from > > the actual one, since the only way to lose the command from the request > > is to go through the command completion routines which free it (and end > > the request). > > I have no idea either. It's something in the timeout logic because on > the issue path the scmd pointer is identical but on tiemout pointer > for another scmd is queued on eh_cmd_q, which doesn't make much sense. > I was trying to recreate this error using ata_ram wth v2.6.28-rc2. Currently I am not able to see this error on timeout recovery using this setup. Does IO load (or other factors) effect the error being seen? -andmike -- Michael Anderson andmike@xxxxxxxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
