This is a note to let you know that I've just added the patch titled media: m920x: don't use stack on USB reads to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: media-m920x-don-t-use-stack-on-usb-reads.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 259934ce7f86725fed480b7250373b6ef82474fc Author: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx> Date: Mon Dec 6 15:34:19 2021 +0100 media: m920x: don't use stack on USB reads [ Upstream commit a2ab06d7c4d6bfd0b545a768247a70463e977e27 ] Using stack-allocated pointers for USB message data don't work. This driver is almost OK with that, except for the I2C read logic. Fix it by using a temporary read buffer, just like on all other calls to m920x_read(). Link: https://lore.kernel.org/all/ccc99e48-de4f-045e-0fe4-61e3118e3f74@xxxxxxx/ Reported-by: rkardell@xxxxxxx Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/media/usb/dvb-usb/m920x.c b/drivers/media/usb/dvb-usb/m920x.c index 4bb5b82599a79..691e05833db19 100644 --- a/drivers/media/usb/dvb-usb/m920x.c +++ b/drivers/media/usb/dvb-usb/m920x.c @@ -274,6 +274,13 @@ static int m920x_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msg[], int nu /* Should check for ack here, if we knew how. */ } if (msg[i].flags & I2C_M_RD) { + char *read = kmalloc(1, GFP_KERNEL); + if (!read) { + ret = -ENOMEM; + kfree(read); + goto unlock; + } + for (j = 0; j < msg[i].len; j++) { /* Last byte of transaction? * Send STOP, otherwise send ACK. */ @@ -281,9 +288,12 @@ static int m920x_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msg[], int nu if ((ret = m920x_read(d->udev, M9206_I2C, 0x0, 0x20 | stop, - &msg[i].buf[j], 1)) != 0) + read, 1)) != 0) goto unlock; + msg[i].buf[j] = read[0]; } + + kfree(read); } else { for (j = 0; j < msg[i].len; j++) { /* Last byte of transaction? Then send STOP. */