Commit fa63f083 authored by Souptick Joarder's avatar Souptick Joarder Committed by Linus Torvalds

rapidio: fix error handling path

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: e8de3701 ("rapidio: add mport char device driver")
Signed-off-by: default avatarSouptick Joarder <jrdr.linux@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: default avatarIra Weiny <ira.weiny@intel.com>
Reviewed-by: default avatarJohn 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.comSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 64ead520
...@@ -871,15 +871,16 @@ rio_dma_transfer(struct file *filp, u32 transfer_mode, ...@@ -871,15 +871,16 @@ rio_dma_transfer(struct file *filp, u32 transfer_mode,
rmcd_error("pin_user_pages_fast err=%ld", rmcd_error("pin_user_pages_fast err=%ld",
pinned); pinned);
nr_pages = 0; nr_pages = 0;
} else } else {
rmcd_error("pinned %ld out of %ld pages", rmcd_error("pinned %ld out of %ld pages",
pinned, nr_pages); pinned, nr_pages);
ret = -EFAULT;
/* /*
* Set nr_pages up to mean "how many pages to unpin, in * Set nr_pages up to mean "how many pages to unpin, in
* the error handler: * the error handler:
*/ */
nr_pages = pinned; nr_pages = pinned;
}
ret = -EFAULT;
goto err_pg; goto err_pg;
} }
......
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