[PATCH 3/3] nfc: trf7970a: Prevent repeated polling from crashing the kernel
From: Geoff Lansberry <hidden>
Date: 2016-12-20 16:17:38
Also in:
linux-devicetree, lkml, netdev
Subsystem:
nfc subsystem, the rest, ti trf7970a nfc driver · Maintainers:
David Heidelberg, Linus Torvalds, Mark Greer
From: Jaret Cantu <redacted> Repeated polling attempts cause a NULL dereference error to occur. This is because the state of the trf7970a is currently reading but another request has been made to send a command before it has finished. The solution is to properly kill the waiting reading (workqueue) before failing on the send. --- drivers/nfc/trf7970a.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/drivers/nfc/trf7970a.c b/drivers/nfc/trf7970a.c
index 8a88195..5916737 100644
--- a/drivers/nfc/trf7970a.c
+++ b/drivers/nfc/trf7970a.c@@ -1496,6 +1496,10 @@ static int trf7970a_send_cmd(struct nfc_digital_dev *ddev, (trf->state != TRF7970A_ST_IDLE_RX_BLOCKED)) { dev_err(trf->dev, "%s - Bogus state: %d\n", __func__, trf->state); + if (trf->state == TRF7970A_ST_WAIT_FOR_RX_DATA || + trf->state == TRF7970A_ST_WAIT_FOR_RX_DATA_CONT) + trf->ignore_timeout = + !cancel_delayed_work(&trf->timeout_work); ret = -EIO; goto out_err; }
--
Signed-off-by: Geoff Lansberry <geoff@kuvee.com>