On Tue, 2013-07-23 at 17:17 -0400, Chris Metcalf wrote: > On 7/23/2013 5:00 PM, James Bottomley wrote: > > On Tue, 2013-07-23 at 16:50 -0400, Chris Metcalf wrote: > >> > The slot->response value may not be aligned, so should be read > >> > using the appropriate kernel "unaligned" accessor. > > Hm, institutional memory re-presenting the wrong patch? However, I am > > reminded to push the right one in spite of no ack from marvell. > > You may be right; the original author of that patch is not me, but someone > else here at Tilera. > > That said, the version I pushed is effectively the version we have in the tip > of our tree, so if we've ended up carrying the wrong patch, that's bad! Let > me know what the right patch is that you have - thanks.
This is what I have. James --- >From 53a983c4f8b4246f5ff00567411be55967b0350a Mon Sep 17 00:00:00 2001 From: James Bottomley <[email protected]> Date: Sun, 9 Jun 2013 09:23:16 -0700 Subject: [PATCH] [SCSI] mvsas: Fix kernel panic on tile due to unaligned data access slot->response is a 64 bit quantity (and accessed as such), but its alignment is only 32 bits. This doesn't cause a problem on x86, but apparently causes a kernel panic on Tile: Stack dump complete Kernel panic - not syncing: Kernel unalign fault running the idle task! Starting stack dump of tid 0, pid 0 (swapper) on cpu 1 at cycle 341586172541 frame 0: 0xfffffff700140ee0 dump_stack+0x0/0x20 (sp 0xfffffe43ffedf420) frame 1: 0xfffffff700283270 panic+0x150/0x3a0 (sp 0xfffffe43ffedf420) frame 2: 0xfffffff70012bff8 jit_bundle_gen+0xfd8/0x27e0 (sp 0xfffffe43ffedf4c8) frame 3: 0xfffffff7003b5b68 do_unaligned+0xc0/0x5a0 (sp 0xfffffe43ffedf710) frame 4: 0xfffffff70044ca78 handle_interrupt+0x270/0x278 (sp 0xfffffe43ffedf840) <interrupt 17 while in kernel mode> frame 5: 0xfffffff7002ac370 mvs_slot_complete+0x5f0/0x12a0 (sp 0xfffffe43ffedfa90) frame 6: 0xfffffff7002abec0 mvs_slot_complete+0x140/0x12a0 (sp 0xfffffe43ffedfa90) frame 7: 0xfffffff7005cc840 mvs_int_rx+0x140/0x2a0 (sp 0xfffffe43ffedfb00) frame 8: 0xfffffff7005bbaf0 mvs_94xx_isr+0xd8/0x2b8 (sp 0xfffffe43ffedfb68) frame 9: 0xfffffff700658ba0 mvs_tasklet+0x128/0x1f8 (sp 0xfffffe43ffedfba8) frame 10: 0xfffffff7003e8230 tasklet_action+0x178/0x2c8 (sp 0xfffffe43ffedfbe0) frame 11: 0xfffffff700103850 __do_softirq+0x210/0x398 (sp 0xfffffe43ffedfc40) frame 12: 0xfffffff700180308 do_softirq+0xc8/0x140 (sp 0xfffffe43ffedfcd8) frame 13: 0xfffffff7000bd7f0 irq_exit+0xb0/0x158 (sp 0xfffffe43ffedfcf0) frame 14: 0xfffffff70013fa58 tile_dev_intr+0x1d8/0x2f0 (sp 0xfffffe43ffedfd00) frame 15: 0xfffffff70044ca78 handle_interrupt+0x270/0x278 (sp 0xfffffe43ffedfd40) <interrupt 30 while in kernel mode> frame 16: 0xfffffff700143e68 _cpu_idle_nap+0x0/0x18 (sp 0xfffffe43ffedffb0) frame 17: 0xfffffff700482480 cpu_idle+0x310/0x428 (sp 0xfffffe43ffedffb0) Since the check is just for non-zero, split it to be two 32 bit accesses (preserving speed in the fast path) and do a get_unaligned() in the slow path. This is a modification of a wholly get_unaligned patch submitted by Paul Guo Reported-by: Paul Guo <[email protected]> Signed-off-by: James Bottomley <[email protected]> diff --git a/drivers/scsi/mvsas/mv_sas.c b/drivers/scsi/mvsas/mv_sas.c index f14665a..6b1b4e9 100644 --- a/drivers/scsi/mvsas/mv_sas.c +++ b/drivers/scsi/mvsas/mv_sas.c @@ -1857,11 +1857,16 @@ int mvs_slot_complete(struct mvs_info *mvi, u32 rx_desc, u32 flags) goto out; } - /* error info record present */ - if (unlikely((rx_desc & RXQ_ERR) && (*(u64 *) slot->response))) { + /* + * error info record present; slot->response is 32 bit aligned but may + * not be 64 bit aligned, so check for zero in two 32 bit reads + */ + if (unlikely((rx_desc & RXQ_ERR) + && (*((u32 *)slot->response) + || *(((u32 *)slot->response) + 1)))) { mv_dprintk("port %d slot %d rx_desc %X has error info" "%016llX.\n", slot->port->sas_port.id, slot_idx, - rx_desc, (u64)(*(u64 *)slot->response)); + rx_desc, get_unaligned_le64(slot->response)); tstat->stat = mvs_slot_err(mvi, task, slot_idx); tstat->resp = SAS_TASK_COMPLETE; goto out; diff --git a/drivers/scsi/mvsas/mv_sas.h b/drivers/scsi/mvsas/mv_sas.h index 60e2fb7..d6b19dc 100644 --- a/drivers/scsi/mvsas/mv_sas.h +++ b/drivers/scsi/mvsas/mv_sas.h @@ -39,6 +39,7 @@ #include <linux/irq.h> #include <linux/slab.h> #include <linux/vmalloc.h> +#include <asm/unaligned.h> #include <scsi/libsas.h> #include <scsi/scsi.h> #include <scsi/scsi_tcq.h> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
