[src/trunk]: src/sys/arch/arm/sunxi Avoid a race between interruption and rea...

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/eb8201eab378
branches:  trunk
changeset: 847083:eb8201eab378
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Mon Dec 09 14:56:30 2019 +0000

description:
Avoid a race between interruption and reacquisition of lock.

Otherwise, we would have leaked the memory in this case.

diffstat:

 sys/arch/arm/sunxi/sun8i_crypto.c |  18 ++++++++++++------
 1 files changed, 12 insertions(+), 6 deletions(-)

diffs (54 lines):

diff -r bc8dbb25572c -r eb8201eab378 sys/arch/arm/sunxi/sun8i_crypto.c
--- a/sys/arch/arm/sunxi/sun8i_crypto.c Mon Dec 09 14:56:18 2019 +0000
+++ b/sys/arch/arm/sunxi/sun8i_crypto.c Mon Dec 09 14:56:30 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: sun8i_crypto.c,v 1.4 2019/12/09 14:56:18 riastradh Exp $       */
+/*     $NetBSD: sun8i_crypto.c,v 1.5 2019/12/09 14:56:30 riastradh Exp $       */
 
 /*-
  * Copyright (c) 2019 The NetBSD Foundation, Inc.
@@ -43,7 +43,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(1, "$NetBSD: sun8i_crypto.c,v 1.4 2019/12/09 14:56:18 riastradh Exp $");
+__KERNEL_RCSID(1, "$NetBSD: sun8i_crypto.c,v 1.5 2019/12/09 14:56:30 riastradh Exp $");
 
 #include <sys/types.h>
 #include <sys/param.h>
@@ -1244,10 +1244,15 @@
                error = cv_wait_sig(&req->cu_cv, &req->cu_lock);
                if (error) {
                        /*
-                        * Never mind -- notify the callback that it
-                        * has to clean up after itself.
+                        * If we finished while waiting to acquire the
+                        * lock, ignore the error and just return now.
+                        * Otherwise, notify the callback that it has
+                        * to clean up after us.
                         */
-                       req->cu_cancel = true;
+                       if (req->cu_done)
+                               error = 0;
+                       else
+                               req->cu_cancel = true;
                        break;
                }
        }
@@ -1277,6 +1282,7 @@
        /* Clear the buffer.  */
        explicit_memset(req->cu_buf.cb_kva, 0, size);
 
+       /* Clean up.  */
 out2:  sun8i_crypto_task_put(sc, req->cu_task);
 out1:  sun8i_crypto_freebuf(sc, req->cu_size, &req->cu_buf);
 out0:  cv_destroy(&req->cu_cv);
@@ -1309,7 +1315,7 @@
        if (!cancel)
                return;
 
-       /* Clean up.  */
+       /* Clean up after the main thread cancelled.  */
        sun8i_crypto_task_put(sc, req->cu_task);
        sun8i_crypto_freebuf(sc, req->cu_size, &req->cu_buf);
        cv_destroy(&req->cu_cv);