[RESEND PATCH] cxl: Fix leaking pid refs in some error paths
Vaibhav Jain
vaibhav at linux.vnet.ibm.com
Fri Oct 21 20:23:53 AEDT 2016
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: 7b8ad495("cxl: Fix DSI misses when the context owning task exits")
Cc: stable at vger.kernel.org
Reviewed-by: Andrew Donnellan <andrew.donnellan at au1.ibm.com>
Reported-by: Frederic Barrat <fbarrat at linux.vnet.ibm.com>
Signed-off-by: Vaibhav Jain <vaibhav at linux.vnet.ibm.com>
---
This patch is based on earlier patch "cxl: Prevent adapter reset
if an active context exists" at
https://patchwork.ozlabs.org/patch/682187/
Changelog:
RESEND -> * Marked the patch for stable tree.
* Moved the patch dependency text under '---' area
* Added Andrew Donnellan's review sign-off
---
drivers/misc/cxl/api.c | 2 ++
drivers/misc/cxl/file.c | 22 +++++++++++++---------
2 files changed, 15 insertions(+), 9 deletions(-)
diff --git a/drivers/misc/cxl/api.c b/drivers/misc/cxl/api.c
index af23d7d..2e5233b 100644
--- 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 d0b421f..77080cc 100644
--- a/drivers/misc/cxl/file.c
+++ b/drivers/misc/cxl/file.c
@@ -194,6 +194,16 @@ 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
* 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 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;
}
--
2.7.4
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