cxl: Fix leaking pid refs in some error paths

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")
Cc: stable@vger.kernel.org # v4.5+
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>

diff --git a/drivers/misc/cxl/api.c b/drivers/misc/cxl/api.c
index af23d7dfe752037dbea1bdbd4878c2cbbc39119a..2e5233b6097110e72ae147f21ed15cf259b0a5a9 100644 (file)
--- a/drivers/misc/cxl/api.c
+++ b/drivers/misc/cxl/api.c
@@ -247,7 +247,9 @@ int cxl_start_context(struct cxl_context *ctx, u64 wed,
        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;

diff --git a/drivers/misc/cxl/file.c b/drivers/misc/cxl/file.c
index d0b421f49b3976180be65c5beb4c60d17c0e32fb..77080cc5fa0aa4cdbc476729e4cdabcac8afae7b 100644 (file)
--- a/drivers/misc/cxl/file.c
+++ b/drivers/misc/cxl/file.c
@@ -193,6 +193,16 @@ static long afu_ioctl_start_work(struct cxl_context *ctx,
 
        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
@@ -205,15 +215,6 @@ static long afu_ioctl_start_work(struct cxl_context *ctx,
        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 cxl_context *ctx,
                                                        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;
        }