Similar to the handle_userfault() case, also make sure to never
attempt to send any event past the PF_EXITING point of no return.
This is purely a robustness check.
Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
---
fs/userfaultfd.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 52733a7..3d7c248 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -529,8 +529,13 @@ int handle_userfault(struct vm_fault *vmf, unsigned long reason)
static int userfaultfd_event_wait_completion(struct userfaultfd_ctx *ctx,
struct userfaultfd_wait_queue *ewq)
{
- int ret = 0;
+ int ret;
+
+ ret = -1;
+ if (WARN_ON_ONCE(current->flags & PF_EXITING))
+ goto out;
+ ret = 0;
ewq->ctx = ctx;
init_waitqueue_entry(&ewq->wq, current);
@@ -565,7 +570,7 @@ static int userfaultfd_event_wait_completion(struct userfaultfd_ctx *ctx,
* ctx may go away after this if the userfault pseudo fd is
* already released.
*/
-
+out:
userfaultfd_ctx_put(ctx);
return ret;
}
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