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drivers/virt/fsl_hypervisor: Fix error handling path 

First, when memory allocation for sg_list_unaligned failed, there
is a bug of calling put_pages() as we haven't pinned any pages.

Second, if get_user_pages_fast() failed we should unpin num_pinned
pages.

This will address both.

As part of these changes, minor update in documentation.

Fixes: 6db7199407 ("drivers/virt: introduce Freescale hypervisor management driver")
Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Link: https://lore.kernel.org/r/1598995271-6755-1-git-send-email-jrdr.linux@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Souptick Joarder 2020-09-02 02:51:11 +05:30 committed by Greg Kroah-Hartman
parent 9f30eb29c5
commit 7f360bec37
1 changed files with 8 additions and 9 deletions
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17
drivers/virt/fsl_hypervisor.c
View File

@ -157,7 +157,7 @@ static long ioctl_memcpy(struct fsl_hv_ioctl_memcpy __user *p)
unsigned int i;
long ret = 0;
int num_pinned; /* return value from get_user_pages() */
int num_pinned = 0; /* return value from get_user_pages_fast() */
phys_addr_t remote_paddr; /* The next address in the remote buffer */
uint32_t count; /* The number of bytes left to copy */
@ -174,7 +174,7 @@ static long ioctl_memcpy(struct fsl_hv_ioctl_memcpy __user *p)
return -EINVAL;
/*
* The array of pages returned by get_user_pages() covers only
* The array of pages returned by get_user_pages_fast() covers only
* page-aligned memory. Since the user buffer is probably not
* page-aligned, we need to handle the discrepancy.
*
@ -224,7 +224,7 @@ static long ioctl_memcpy(struct fsl_hv_ioctl_memcpy __user *p)
/*
* 'pages' is an array of struct page pointers that's initialized by
* get_user_pages().
* get_user_pages_fast().
*/
pages = kcalloc(num_pages, sizeof(struct page *), GFP_KERNEL);
if (!pages) {
@ -241,7 +241,7 @@ static long ioctl_memcpy(struct fsl_hv_ioctl_memcpy __user *p)
if (!sg_list_unaligned) {
pr_debug("fsl-hv: could not allocate S/G list\n");
ret = -ENOMEM;
goto exit;
goto free_pages;
}
sg_list = PTR_ALIGN(sg_list_unaligned, sizeof(struct fh_sg_list));
@ -250,7 +250,6 @@ static long ioctl_memcpy(struct fsl_hv_ioctl_memcpy __user *p)
num_pages, param.source != -1 ? FOLL_WRITE : 0, pages);
if (num_pinned != num_pages) {
/* get_user_pages() failed */
pr_debug("fsl-hv: could not lock source buffer\n");
ret = (num_pinned < 0) ? num_pinned : -EFAULT;
goto exit;
@ -292,13 +291,13 @@ static long ioctl_memcpy(struct fsl_hv_ioctl_memcpy __user *p)
virt_to_phys(sg_list), num_pages);
exit:
if (pages) {
for (i = 0; i < num_pages; i++)
if (pages[i])
put_page(pages[i]);
if (pages && (num_pinned > 0)) {
for (i = 0; i < num_pinned; i++)
put_page(pages[i]);
}
kfree(sg_list_unaligned);
free_pages:
kfree(pages);
if (!ret)