From: Souptick Joarder jrdr.linux@gmail.com
[ 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.
[jhubbard@nvidia.com: new changelog]
Fixes: e8de370188d09 ("rapidio: add mport char device driver") Signed-off-by: Souptick Joarder jrdr.linux@gmail.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Reviewed-by: Ira Weiny ira.weiny@intel.com Reviewed-by: John Hubbard jhubbard@nvidia.com Cc: Matthew Wilcox willy@infradead.org Cc: Matt Porter mporter@kernel.crashing.org Cc: Alexandre Bounine alex.bou9@gmail.com Cc: Gustavo A. R. Silva gustavoars@kernel.org Cc: Madhuparna Bhowmik madhuparnabhowmik10@gmail.com Cc: Dan Carpenter dan.carpenter@oracle.com Link: https://lkml.kernel.org/r/1600227737-20785-1-git-send-email-jrdr.linux@gmail... Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 f207f8725993c..171d6bcad5bc5 100644 --- a/drivers/rapidio/devices/rio_mport_cdev.c +++ b/drivers/rapidio/devices/rio_mport_cdev.c @@ -900,15 +900,16 @@ rio_dma_transfer(struct file *filp, u32 transfer_mode, rmcd_error("get_user_pages_unlocked 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; }