Commit 09358972 authored by Robin Holt's avatar Robin Holt Committed by Linus Torvalds
Browse files

sgi-xp: incoming XPC channel messages can come in after the channel's... 


sgi-xp: incoming XPC channel messages can come in after the channel's partition structures have been torn down

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: default avatarRobin Holt <holt@sgi.com>
Cc: <stable@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 482db6df

drivers/misc/sgi-xp/xpc_uv.c

+17 −0
Original line number Diff line number Diff line
@@ -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);

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