[PATCH 6.0 090/157] drm/vmwgfx: Fix race issue calling pin_user_pages

Greg Kroah-Hartman
2022-12-12T13:43:30Z

From: Dawei Li <set_pte_at@outlook.com>

[ Upstream commit ed14d225cc7c842f6d4d5a3009f71a44f5852d09 ]

pin_user_pages() is unsafe without protection of mmap_lock,
fix it by calling pin_user_pages_fast().

Fixes: 7a7a933edd6c ("drm/vmwgfx: Introduce VMware mks-guest-stats")
Signed-off-by: Dawei Li <set_pte_at@outlook.com>
Reviewed-by: Martin Krastev <krastevm@vmware.com>
Signed-off-by: Zack Rusin <zackr@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/TYWP286MB23193621CB443E1E1959A00BCA3E9@TYWP286MB2319.JPNP286.PROD.OUTLOOK.COM
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/vmwgfx/vmwgfx_msg.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_msg.c b/drivers/gpu/drm/vmwgfx/vmwgfx_msg.c
index 089046fa21be..50fa3df0bc0c 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_msg.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_msg.c
@@ -1085,21 +1085,21 @@ int vmw_mksstat_add_ioctl(struct drm_device *dev, void *data,
reset_ppn_array(pdesc->strsPPNs, ARRAY_SIZE(pdesc->strsPPNs));

/* Pin mksGuestStat user pages and store those in the instance descriptor */
- nr_pinned_stat = pin_user_pages(arg->stat, num_pages_stat, FOLL_LONGTERM, pages_stat, NULL);
+ nr_pinned_stat = pin_user_pages_fast(arg->stat, num_pages_stat, FOLL_LONGTERM, pages_stat);
if (num_pages_stat != nr_pinned_stat)
goto err_pin_stat;

for (i = 0; i < num_pages_stat; ++i)
pdesc->statPPNs[i] = page_to_pfn(pages_stat[i]);

- nr_pinned_info = pin_user_pages(arg->info, num_pages_info, FOLL_LONGTERM, pages_info, NULL);
+ nr_pinned_info = pin_user_pages_fast(arg->info, num_pages_info, FOLL_LONGTERM, pages_info);
if (num_pages_info != nr_pinned_info)
goto err_pin_info;

for (i = 0; i < num_pages_info; ++i)
pdesc->infoPPNs[i] = page_to_pfn(pages_info[i]);

- nr_pinned_strs = pin_user_pages(arg->strs, num_pages_strs, FOLL_LONGTERM, pages_strs, NULL);
+ nr_pinned_strs = pin_user_pages_fast(arg->strs, num_pages_strs, FOLL_LONGTERM, pages_strs);
if (num_pages_strs != nr_pinned_strs)
goto err_pin_strs;

--
2.35.1