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Commit 62c32704 authored by Souptick Joarder's avatar Souptick Joarder Committed by Greg Kroah-Hartman
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misc: mic: scif: Fix error handling path 



[ Upstream commit a81072a9c0ae734b7889929b0bc070fe3f353f0e ]

Inside __scif_pin_pages(), when map_flags != SCIF_MAP_KERNEL it
will call pin_user_pages_fast() to map nr_pages. However,
pin_user_pages_fast() might fail with a return value -ERRNO.

The return value is stored in pinned_pages->nr_pages. which in
turn is passed to unpin_user_pages(), which expects
pinned_pages->nr_pages >=0, else disaster.

Fix this by assigning pinned_pages->nr_pages to 0 if
pin_user_pages_fast() returns -ERRNO.

Fixes: ba612aa8 ("misc: mic: SCIF memory registration and unregistration")
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: default avatarJohn Hubbard <jhubbard@nvidia.com>
Signed-off-by: default avatarSouptick Joarder <jrdr.linux@gmail.com>
Link: https://lore.kernel.org/r/1600570295-29546-1-git-send-email-jrdr.linux@gmail.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 1c4a2e9a

drivers/misc/mic/scif/scif_rma.c

+2 −2
Original line number Diff line number Diff line
@@ -1403,6 +1403,8 @@ int __scif_pin_pages(void *addr, size_t len, int *out_prot, 
				NULL);

		up_write(&mm->mmap_sem);

		if (nr_pages != pinned_pages->nr_pages) {

			if (pinned_pages->nr_pages < 0)

				pinned_pages->nr_pages = 0;

			if (try_upgrade) {

				if (ulimit)

					__scif_dec_pinned_vm_lock(mm,
@@ -1423,7 +1425,6 @@ int __scif_pin_pages(void *addr, size_t len, int *out_prot, 


	if (pinned_pages->nr_pages < nr_pages) {

		err = -EFAULT;

		pinned_pages->nr_pages = nr_pages;

		goto dec_pinned;

	}
@@ -1436,7 +1437,6 @@ int __scif_pin_pages(void *addr, size_t len, int *out_prot, 
		__scif_dec_pinned_vm_lock(mm, nr_pages, 0);

	/* Something went wrong! Rollback */

error_unmap:

	pinned_pages->nr_pages = nr_pages;

	scif_destroy_pinned_pages(pinned_pages);

	*pages = NULL;

	dev_dbg(scif_info.mdev.this_device,