-----Original Message-----
From: Sergei Trofimovich [mailto:[email protected]]
Subject: [PATCH] hpsa: fix boot on ia64 (atomic_t alignment)
The failure initially observed as boot failure on rx3600 ia64 machine with RAID
bus controller: Hewlett-Packard Company Smart Array P600:
kernel unaligned access to 0xe000000105dd8b95, ip=0xa000000100b87551
kernel unaligned access to 0xe000000105dd8e95, ip=0xa000000100b87551
hpsa 0000:14:01.0: Controller reports max supported commands of 0 Using 16
instead. Ensure that firmware is up to date.
swapper/0[1]: error during unaligned kernel access
Here unaligned access comes from 'struct CommandList' that happens to be
packed. The change f749d8b7a ("scsi: hpsa: Correct dev cmds outstanding for
retried cmds") introduced unexpected padding and un-aligned atomic_t from
natural alignment to something else.
This change does not remove packing annotation from struct but only restores
alignment of atomic variable.
The change is tested on the same rx3600 machine.
CC: [email protected]
CC: [email protected]
CC: [email protected]
CC: Joe Szczypek <[email protected]>
CC: Scott Benesh <[email protected]>
CC: Scott Teel <[email protected]>
CC: Tomas Henzl <[email protected]>
CC: "Martin K. Petersen" <[email protected]>
CC: Don Brace <[email protected]>
Reported-by: John Paul Adrian Glaubitz <[email protected]>
Suggested-by: Don Brace <[email protected]>
Fixes: f749d8b7a "scsi: hpsa: Correct dev cmds outstanding for retried cmds"
Signed-off-by: Sergei Trofimovich <[email protected]>
---
drivers/scsi/hpsa_cmd.h | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/hpsa_cmd.h b/drivers/scsi/hpsa_cmd.h index
d126bb877250..617bdae9a7de 100644
--- a/drivers/scsi/hpsa_cmd.h
+++ b/drivers/scsi/hpsa_cmd.h
@@ -20,6 +20,9 @@
#ifndef HPSA_CMD_H
#define HPSA_CMD_H
+#include <linux/build_bug.h> /* static_assert */ #include
+<linux/stddef.h> /* offsetof */
+
/* general boundary defintions */
#define SENSEINFOBYTES 32 /* may vary between hbas */
#define SG_ENTRIES_IN_CMD 32 /* Max SG entries excluding chain blocks */
@@ -448,11 +451,20 @@ struct CommandList {
*/
struct hpsa_scsi_dev_t *phys_disk;
- bool retry_pending;
+ int retry_pending;
struct hpsa_scsi_dev_t *device;
atomic_t refcount; /* Must be last to avoid memset in hpsa_cmd_init()
*/ } __aligned(COMMANDLIST_ALIGNMENT);
+/*
+ * Make sure our embedded atomic variable is aligned. Otherwise we
+break atomic
+ * operations on architectures that don't support unaligned atomics like IA64.
+ *
+ * Ideally this header should be cleaned up to only mark individual
+structs as
+ * packed.
+ */
+static_assert(offsetof(struct CommandList, refcount) %
+__alignof__(atomic_t) == 0);
+
/* Max S/G elements in I/O accelerator command */
#define IOACCEL1_MAXSGENTRIES 24
#define IOACCEL2_MAXSGENTRIES 28
--
2.30.2
Acked-by: Don Brace <[email protected]>
Thanks for your patch and extra effort.
