The change was the addition of rq->flags = 0; the memset isn't mine. Sorry about the whitespace -- I'm still a bit new at this. As to why it's necessary, I've had boot-time oopses on two completely different hosts -- one iSCSI, one FC -- which both resolved to exactly the same code; bizarre values in rq->flags. The source seems to OR the desired values in but never actually initializes rq->flags (the memset initializes the CDB, not the flags variable), so I added the line to do so. After testing the old module to confirm the oops still occurred regularly, I installed the new code and have since (in over 100 reboots) been unable to reproduce the oops. Jerry -----Original Message----- From: James Bottomley [mailto:James.Bottomley@xxxxxxxxxxxxxxxxxxxxx] Sent: Fri 10/17/2008 1:34 PM To: Levy, Jerome Cc: linux-scsi@xxxxxxxxxxxxxxx Subject: Re: [PATCH 1/1] scsi_dh: fix boot oops with EMC Clariion On Mon, 2008-10-13 at 13:41 -0400, Levy_Jerome@xxxxxxx wrote: > Patch to fix intermittent but frequent oops occurring with multiple > paths to Clariion at boot. > Cause is uninitialized rq->flags variable which presents garbage from > clariion_activate. There are several syntactic problems with the patch: It's against a pretty old kernel (cmd has been a pointer for a while, so the memset went away). It's also whitespace damaged (all tabs have become spaces). However, I also don't quite understand why this is necessary. All calls to blk_get_request() ultimately end up in blk_rq_init() which does a memset(rq, 0, sizeof(*rq)) which should clear flags. How is it getting bogus data? James > Signed-off-by: Jerry Levy <levy_jerome@xxxxxxx> > --------------------- > --- drivers/scsi/device_handler/scsi_dh_emc.orig 2008-10-13 > 13:33:35.000000000 -0400 > +++ drivers/scsi/device_handler/scsi_dh_emc.c 2008-10-09 > 16:20:15.000000000 -0400 > @@ -283,6 +283,7 @@ > memset(rq->cmd, 0, BLK_MAX_CDB); > rq->cmd[0] = cmd; > rq->cmd_len = COMMAND_SIZE(cmd); > + rq->flags = 0; > > switch (cmd) { > case MODE_SELECT: > -- > To unsubscribe from this list: send the line "unsubscribe linux-scsi" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
