This is a note to let you know that I've just added the patch titled
staging: comedi: comedi_fops: do not call blocking ops when !TASK_RUNNING
to the 4.9-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:
staging-comedi-comedi_fops-do-not-call-blocking-ops-when-task_running.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From cef988642cdac44e910a27cb6e8166c96f86a0df Mon Sep 17 00:00:00 2001
From: Ian Abbott <abbotti@xxxxxxxxx>
Date: Fri, 28 Jul 2017 16:22:31 +0100
Subject: staging: comedi: comedi_fops: do not call blocking ops when !TASK_RUNNING
From: Ian Abbott <abbotti@xxxxxxxxx>
commit cef988642cdac44e910a27cb6e8166c96f86a0df upstream.
Comedi's read and write file operation handlers (`comedi_read()` and
`comedi_write()`) currently call `copy_to_user()` or `copy_from_user()`
whilst in the `TASK_INTERRUPTIBLE` state, which falls foul of the
`might_fault()` checks when enabled. Fix it by setting the current task
state back to `TASK_RUNNING` a bit earlier before calling these
functions.
Reported-by: Piotr Gregor <piotrgregor@xxxxxxxxxxx>
Signed-off-by: Ian Abbott <abbotti@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/comedi/comedi_fops.c | 3 +++
1 file changed, 3 insertions(+)
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -2385,6 +2385,7 @@ static ssize_t comedi_write(struct file
continue;
}
+ set_current_state(TASK_RUNNING);
wp = async->buf_write_ptr;
n1 = min(n, async->prealloc_bufsz - wp);
n2 = n - n1;
@@ -2517,6 +2518,8 @@ static ssize_t comedi_read(struct file *
}
continue;
}
+
+ set_current_state(TASK_RUNNING);
rp = async->buf_read_ptr;
n1 = min(n, async->prealloc_bufsz - rp);
n2 = n - n1;
Patches currently in stable-queue which might be from abbotti@xxxxxxxxx are
queue-4.9/staging-comedi-comedi_fops-do-not-call-blocking-ops-when-task_running.patch