When the cxl driver creates a context, it stores the pid of the
calling task, and mistakenly increments the reference count of the
struct pid twice, once through get_task_pid(), once through
get_pid(). The reference count is only decremented once on detach. As
a result, a struct pid is leaked and it reduces the number of
processes that can run simultaneously by one.
The fix is to simply remove the call to get_pid().
There is a separate patch for the kernel API, since it goes to
different kernel versions.
Signed-off-by: Frederic Barrat <fbar...@linux.vnet.ibm.com>
Cc: <sta...@vger.kernel.org> # 3.18+
---
drivers/misc/cxl/file.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/misc/cxl/file.c b/drivers/misc/cxl/file.c
index 7ccd299..97003ee 100644
--- a/drivers/misc/cxl/file.c
+++ b/drivers/misc/cxl/file.c
@@ -199,7 +199,7 @@ static long afu_ioctl_start_work(struct cxl_context *ctx,
* behalf of another process, so the AFU's mm gets bound to the process
* that performs this ioctl and not the process that opened the file.
*/
- ctx->pid = get_pid(get_task_pid(current, PIDTYPE_PID));
+ ctx->pid = get_task_pid(current, PIDTYPE_PID);
trace_cxl_attach(ctx, work.work_element_descriptor,
work.num_interrupts, amr);
--
1.9.1
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