[PATCH AUTOSEL 4.9 25/87] crypto: crypto4xx - add missing of_node_put after of_device_is_available

[PATCH AUTOSEL 4.9 25/87] crypto: crypto4xx - add missing of_node_put after of_device_is_available

[Sasha Levin]

From: Julia Lawall <Julia.Lawall@lip6.fr>

[ Upstream commit 8c2b43d2d85b48a97d2f8279278a4aac5b45f925 ]

Add an of_node_put when a tested device node is not available.

The semantic patch that fixes this problem is as follows
(http://coccinelle.lip6.fr):

// <smpl>
@@
identifier f;
local idexpression e;
expression x;
@@

e = f(...);
... when != of_node_put(e)
    when != x = e
    when != e = x
    when any
if (<+...of_device_is_available(e)...+>) {
  ... when != of_node_put(e)
(
  return e;
|
+ of_node_put(e);
  return ...;
)
}
// </smpl>

Fixes: 5343e674f32fb ("crypto4xx: integrate ppc4xx-rng into crypto4xx")
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/crypto/amcc/crypto4xx_trng.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/crypto/amcc/crypto4xx_trng.c b/drivers/crypto/amcc/crypto4xx_trng.c
index 677ca17fd223..368c5599515e 100644
--- a/drivers/crypto/amcc/crypto4xx_trng.c
+++ b/drivers/crypto/amcc/crypto4xx_trng.c
@@ -80,8 +80,10 @@ void ppc4xx_trng_probe(struct crypto4xx_core_device *core_dev)
 
 	/* Find the TRNG device node and map it */
 	trng = of_find_matching_node(NULL, ppc4xx_trng_match);
-	if (!trng || !of_device_is_available(trng))
+	if (!trng || !of_device_is_available(trng)) {
+		of_node_put(trng);
 		return;
+	}
 
 	dev->trng_base = of_iomap(trng, 0);
 	of_node_put(trng);
-- 
2.19.1

[PATCH AUTOSEL 4.9 70/87] hwrng: virtio - Avoid repeated init of completion

[Sasha Levin]

From: David Tolnay <dtolnay@gmail.com>

[ Upstream commit aef027db48da56b6f25d0e54c07c8401ada6ce21 ]

The virtio-rng driver uses a completion called have_data to wait for a
virtio read to be fulfilled by the hypervisor. The completion is reset
before placing a buffer on the virtio queue and completed by the virtio
callback once data has been written into the buffer.

Prior to this commit, the driver called init_completion on this
completion both during probe as well as when registering virtio buffers
as part of a hwrng read operation. The second of these init_completion
calls should instead be reinit_completion because the have_data
completion has already been inited by probe. As described in
Documentation/scheduler/completion.txt, "Calling init_completion() twice
on the same completion object is most likely a bug".

This bug was present in the initial implementation of virtio-rng in
f7f510ec1957 ("virtio: An entropy device, as suggested by hpa"). Back
then the have_data completion was a single static completion rather than
a member of one of potentially multiple virtrng_info structs as
implemented later by 08e53fbdb85c ("virtio-rng: support multiple
virtio-rng devices"). The original driver incorrectly used
init_completion rather than INIT_COMPLETION to reset have_data during
read.

Tested by running `head -c48 /dev/random | hexdump` within crosvm, the
Chrome OS virtual machine monitor, and confirming that the virtio-rng
driver successfully produces random bytes from the host.

Signed-off-by: David Tolnay <dtolnay@gmail.com>
Tested-by: David Tolnay <dtolnay@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/char/hw_random/virtio-rng.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c
index 3fa2f8a009b3..1c5c4314c6b5 100644
--- a/drivers/char/hw_random/virtio-rng.c
+++ b/drivers/char/hw_random/virtio-rng.c
@@ -73,7 +73,7 @@ static int virtio_read(struct hwrng *rng, void *buf, size_t size, bool wait)
 
 	if (!vi->busy) {
 		vi->busy = true;
-		init_completion(&vi->have_data);
+		reinit_completion(&vi->have_data);
 		register_buffer(vi, buf, size);
 	}
 
-- 
2.19.1