| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.12 36/65] staging: comedi: comedi_fops: do not call blocking ops when !TASK_RUNNING | Date | Mon, 14 Aug 2017 18:19:27 -0700 |
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4.12-stable review patch. If anyone has any objections, please let me know.
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From: Ian Abbott <abbotti@mev.co.uk>
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@rsyncme.org> Signed-off-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- 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 @@ -2396,6 +2396,7 @@ 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; @@ -2528,6 +2529,8 @@ 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;
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