From: Souptick Joarder <[email protected]> [ Upstream commit fa63f083b3492b5ed5332b8d7c90b03b5ef24a1d ]
rio_dma_transfer() attempts to clamp the return value of pin_user_pages_fast() to be >= 0. However, the attempt fails because nr_pages is overridden a few lines later, and restored to the undesirable -ERRNO value. The return value is ultimately stored in nr_pages, which in turn is passed to unpin_user_pages(), which expects nr_pages >= 0, else, disaster. Fix this by fixing the nesting of the assignment to nr_pages: nr_pages should be clamped to zero if pin_user_pages_fast() returns -ERRNO, or set to the return value of pin_user_pages_fast(), otherwise. [[email protected]: new changelog] Fixes: e8de370188d09 ("rapidio: add mport char device driver") Signed-off-by: Souptick Joarder <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Reviewed-by: Ira Weiny <[email protected]> Reviewed-by: John Hubbard <[email protected]> Cc: Matthew Wilcox <[email protected]> Cc: Matt Porter <[email protected]> Cc: Alexandre Bounine <[email protected]> Cc: Gustavo A. R. Silva <[email protected]> Cc: Madhuparna Bhowmik <[email protected]> Cc: Dan Carpenter <[email protected]> Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Sasha Levin <[email protected]> --- drivers/rapidio/devices/rio_mport_cdev.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/drivers/rapidio/devices/rio_mport_cdev.c b/drivers/rapidio/devices/rio_mport_cdev.c index 451608e960a18..438cbf994c57f 100644 --- a/drivers/rapidio/devices/rio_mport_cdev.c +++ b/drivers/rapidio/devices/rio_mport_cdev.c @@ -871,15 +871,16 @@ rio_dma_transfer(struct file *filp, u32 transfer_mode, rmcd_error("pin_user_pages_fast err=%ld", pinned); nr_pages = 0; - } else + } else { rmcd_error("pinned %ld out of %ld pages", pinned, nr_pages); + /* + * Set nr_pages up to mean "how many pages to unpin, in + * the error handler: + */ + nr_pages = pinned; + } ret = -EFAULT; - /* - * Set nr_pages up to mean "how many pages to unpin, in - * the error handler: - */ - nr_pages = pinned; goto err_pg; } -- 2.25.1
