Patch "cxl: Fix leaking pid refs in some error paths" has been added to the 4.8-stable tree

Patch "cxl: Fix leaking pid refs in some error paths" has been added to the 4.8-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    cxl: Fix leaking pid refs in some error paths

to the 4.8-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     cxl-fix-leaking-pid-refs-in-some-error-paths.patch
and it can be found in the queue-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From a05b82d5149dfeef05254a11c3636a89a854520a Mon Sep 17 00:00:00 2001
From: Vaibhav Jain <vaibhav@linux.vnet.ibm.com>
Date: Fri, 21 Oct 2016 14:53:53 +0530
Subject: cxl: Fix leaking pid refs in some error paths

From: Vaibhav Jain <vaibhav@linux.vnet.ibm.com>

commit a05b82d5149dfeef05254a11c3636a89a854520a upstream.

In some error paths in functions cxl_start_context and
afu_ioctl_start_work pid references to the current & group-leader tasks
can leak after they are taken. This patch fixes these error paths to
release these pid references before exiting the error path.

Fixes: 7b8ad495d592 ("cxl: Fix DSI misses when the context owning task exits")
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Reported-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com>
Acked-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/misc/cxl/api.c  |    2 ++
 drivers/misc/cxl/file.c |   22 +++++++++++++---------
 2 files changed, 15 insertions(+), 9 deletions(-)

--- a/drivers/misc/cxl/api.c
+++ b/drivers/misc/cxl/api.c
@@ -247,7 +247,9 @@ int cxl_start_context(struct cxl_context
 	cxl_ctx_get();
 
 	if ((rc = cxl_ops->attach_process(ctx, kernel, wed, 0))) {
+		put_pid(ctx->glpid);
 		put_pid(ctx->pid);
+		ctx->glpid = ctx->pid = NULL;
 		cxl_adapter_context_put(ctx->afu->adapter);
 		cxl_ctx_put();
 		goto out;
--- a/drivers/misc/cxl/file.c
+++ b/drivers/misc/cxl/file.c
@@ -194,6 +194,16 @@ static long afu_ioctl_start_work(struct
 	ctx->mmio_err_ff = !!(work.flags & CXL_START_WORK_ERR_FF);
 
 	/*
+	 * Increment the mapped context count for adapter. This also checks
+	 * if adapter_context_lock is taken.
+	 */
+	rc = cxl_adapter_context_get(ctx->afu->adapter);
+	if (rc) {
+		afu_release_irqs(ctx, ctx);
+		goto out;
+	}
+
+	/*
 	 * We grab the PID here and not in the file open to allow for the case
 	 * where a process (master, some daemon, etc) has opened the chardev on
 	 * behalf of another process, so the AFU's mm gets bound to the process
@@ -205,15 +215,6 @@ static long afu_ioctl_start_work(struct
 	ctx->pid = get_task_pid(current, PIDTYPE_PID);
 	ctx->glpid = get_task_pid(current->group_leader, PIDTYPE_PID);
 
-	/*
-	 * Increment the mapped context count for adapter. This also checks
-	 * if adapter_context_lock is taken.
-	 */
-	rc = cxl_adapter_context_get(ctx->afu->adapter);
-	if (rc) {
-		afu_release_irqs(ctx, ctx);
-		goto out;
-	}
 
 	trace_cxl_attach(ctx, work.work_element_descriptor, work.num_interrupts, amr);
 
@@ -221,6 +222,9 @@ static long afu_ioctl_start_work(struct
 							amr))) {
 		afu_release_irqs(ctx, ctx);
 		cxl_adapter_context_put(ctx->afu->adapter);
+		put_pid(ctx->glpid);
+		put_pid(ctx->pid);
+		ctx->glpid = ctx->pid = NULL;
 		goto out;
 	}
 


Patches currently in stable-queue which might be from vaibhav@linux.vnet.ibm.com are

queue-4.8/cxl-fix-leaking-pid-refs-in-some-error-paths.patch