From: Dan Carpenter <dan.carpen...@oracle.com>

[ Upstream commit c915ef890d5dc79f483e1ca3b3a5b5f1a170690c ]

If the user passes a "level" value which is higher than 31 then that
leads to shift wrapping.  The undefined behavior will lead to a
syzkaller stack dump.

Fixes: 5632708f4452 ("drm/amd/powerplay: add dpm force multiple levels on 
cz/tonga/fiji/polaris (v2)")
Signed-off-by: Dan Carpenter <dan.carpen...@oracle.com>
Signed-off-by: Alex Deucher <alexander.deuc...@amd.com>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 drivers/gpu/drm/amd/pm/amdgpu_pm.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/pm/amdgpu_pm.c 
b/drivers/gpu/drm/amd/pm/amdgpu_pm.c
index 529816637c731..9f383b9041d28 100644
--- a/drivers/gpu/drm/amd/pm/amdgpu_pm.c
+++ b/drivers/gpu/drm/amd/pm/amdgpu_pm.c
@@ -1070,7 +1070,7 @@ static ssize_t amdgpu_get_pp_dpm_sclk(struct device *dev,
 static ssize_t amdgpu_read_mask(const char *buf, size_t count, uint32_t *mask)
 {
        int ret;
-       long level;
+       unsigned long level;
        char *sub_str = NULL;
        char *tmp;
        char buf_cpy[AMDGPU_MASK_BUF_MAX + 1];
@@ -1086,8 +1086,8 @@ static ssize_t amdgpu_read_mask(const char *buf, size_t 
count, uint32_t *mask)
        while (tmp[0]) {
                sub_str = strsep(&tmp, delimiter);
                if (strlen(sub_str)) {
-                       ret = kstrtol(sub_str, 0, &level);
-                       if (ret)
+                       ret = kstrtoul(sub_str, 0, &level);
+                       if (ret || level > 31)
                                return -EINVAL;
                        *mask |= 1 << level;
                } else
-- 
2.27.0



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