sgi-xp: incoming XPC channel messages can come in after the channel's partition struc...
Robin Holt [Tue, 26 Oct 2010 21:21:15 +0000 (14:21 -0700)]
Under some workloads, some channel messages have been observed being
delayed on the sending side past the point where the receiving side has
been able to tear down its partition structures.

This condition is already detected in xpc_handle_activate_IRQ_uv(), but
that information is not given to xpc_handle_activate_mq_msg_uv().  As a
result, xpc_handle_activate_mq_msg_uv() assumes the structures still exist
and references them, causing a NULL-pointer deref.

Signed-off-by: Robin Holt <holt@sgi.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/misc/sgi-xp/xpc_uv.c

index 1f59ee2..17bbacb 100644 (file)
@@ -417,6 +417,7 @@ xpc_process_activate_IRQ_rcvd_uv(void)
 static void
 xpc_handle_activate_mq_msg_uv(struct xpc_partition *part,
                              struct xpc_activate_mq_msghdr_uv *msg_hdr,
+                             int part_setup,
                              int *wakeup_hb_checker)
 {
        unsigned long irq_flags;
@@ -481,6 +482,9 @@ xpc_handle_activate_mq_msg_uv(struct xpc_partition *part,
        case XPC_ACTIVATE_MQ_MSG_CHCTL_CLOSEREQUEST_UV: {
                struct xpc_activate_mq_msg_chctl_closerequest_uv *msg;
 
+               if (!part_setup)
+                       break;
+
                msg = container_of(msg_hdr, struct
                                   xpc_activate_mq_msg_chctl_closerequest_uv,
                                   hdr);
@@ -497,6 +501,9 @@ xpc_handle_activate_mq_msg_uv(struct xpc_partition *part,
        case XPC_ACTIVATE_MQ_MSG_CHCTL_CLOSEREPLY_UV: {
                struct xpc_activate_mq_msg_chctl_closereply_uv *msg;
 
+               if (!part_setup)
+                       break;
+
                msg = container_of(msg_hdr, struct
                                   xpc_activate_mq_msg_chctl_closereply_uv,
                                   hdr);
@@ -511,6 +518,9 @@ xpc_handle_activate_mq_msg_uv(struct xpc_partition *part,
        case XPC_ACTIVATE_MQ_MSG_CHCTL_OPENREQUEST_UV: {
                struct xpc_activate_mq_msg_chctl_openrequest_uv *msg;
 
+               if (!part_setup)
+                       break;
+
                msg = container_of(msg_hdr, struct
                                   xpc_activate_mq_msg_chctl_openrequest_uv,
                                   hdr);
@@ -528,6 +538,9 @@ xpc_handle_activate_mq_msg_uv(struct xpc_partition *part,
        case XPC_ACTIVATE_MQ_MSG_CHCTL_OPENREPLY_UV: {
                struct xpc_activate_mq_msg_chctl_openreply_uv *msg;
 
+               if (!part_setup)
+                       break;
+
                msg = container_of(msg_hdr, struct
                                   xpc_activate_mq_msg_chctl_openreply_uv, hdr);
                args = &part->remote_openclose_args[msg->ch_number];
@@ -545,6 +558,9 @@ xpc_handle_activate_mq_msg_uv(struct xpc_partition *part,
        case XPC_ACTIVATE_MQ_MSG_CHCTL_OPENCOMPLETE_UV: {
                struct xpc_activate_mq_msg_chctl_opencomplete_uv *msg;
 
+               if (!part_setup)
+                       break;
+
                msg = container_of(msg_hdr, struct
                                xpc_activate_mq_msg_chctl_opencomplete_uv, hdr);
                spin_lock_irqsave(&part->chctl_lock, irq_flags);
@@ -621,6 +637,7 @@ xpc_handle_activate_IRQ_uv(int irq, void *dev_id)
 
                        part_referenced = xpc_part_ref(part);
                        xpc_handle_activate_mq_msg_uv(part, msg_hdr,
+                                                     part_referenced,
                                                      &wakeup_hb_checker);
                        if (part_referenced)
                                xpc_part_deref(part);