The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x acb3dac2805d3342ded7dbbd164add32bbfdf21c # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025061707-conceded-outwit-2f2f@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From acb3dac2805d3342ded7dbbd164add32bbfdf21c Mon Sep 17 00:00:00 2001 From: Dave Penkler dpenkler@gmail.com Date: Wed, 21 May 2025 14:16:55 +0200 Subject: [PATCH] usb: usbtmc: Fix read_stb function and get_stb ioctl

The usbtmc488_ioctl_read_stb function relied on a positive return from usbtmc_get_stb to reset the srq condition in the driver. The USBTMC_IOCTL_GET_STB case tested for a positive return to return the stb to the user.

Commit: <cac01bd178d6> ("usb: usbtmc: Fix erroneous get_stb ioctl error returns") changed the return value of usbtmc_get_stb to 0 on success instead of returning the value of usb_control_msg which is positive in the normal case. This change caused the function usbtmc488_ioctl_read_stb and the USBTMC_IOCTL_GET_STB ioctl to no longer function correctly.

Change the test in usbtmc488_ioctl_read_stb to test for failure first and return the failure code immediately. Change the test for the USBTMC_IOCTL_GET_STB ioctl to test for 0 instead of a positive value.

Fixes: cac01bd178d6 ("usb: usbtmc: Fix erroneous get_stb ioctl error returns") Cc: stable@vger.kernel.org Signed-off-by: Dave Penkler dpenkler@gmail.com Link: https://lore.kernel.org/r/20250521121656.18174-3-dpenkler@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c index 740d2d2b19fb..08511442a27f 100644 --- a/drivers/usb/class/usbtmc.c +++ b/drivers/usb/class/usbtmc.c @@ -563,14 +563,15 @@ static int usbtmc488_ioctl_read_stb(struct usbtmc_file_data *file_data,

rv = usbtmc_get_stb(file_data, &stb);

- if (rv > 0) { - srq_asserted = atomic_xchg(&file_data->srq_asserted, - srq_asserted); - if (srq_asserted) - stb |= 0x40; /* Set RQS bit */ + if (rv < 0) + return rv; + + srq_asserted = atomic_xchg(&file_data->srq_asserted, srq_asserted); + if (srq_asserted) + stb |= 0x40; /* Set RQS bit */ + + rv = put_user(stb, (__u8 __user *)arg);

- rv = put_user(stb, (__u8 __user *)arg); - } return rv;

} @@ -2199,7 +2200,7 @@ static long usbtmc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)

case USBTMC_IOCTL_GET_STB: retval = usbtmc_get_stb(file_data, &tmp_byte); - if (retval > 0) + if (!retval) retval = put_user(tmp_byte, (__u8 __user *)arg); break;