[PATCH 1/4] drm/amdgpu: Fix a bug for input with double sscanf

[Luben Tuikov]

Remove double-sscanf to scan for %llu and 0x%llx,
as that is not going to work!

The %llu will consume the "0" in "0x" of your
input, and the hex value you think you're entering
will always be 0. That is, a valid hex value can
never be consumed.

On the other hand, just entering a hex number
without leading 0x will either be scanned as a
string and not match, for instance FAB123, or
the leading decimal portion is scanned as the
%llu, for instance 123FAB will be scanned as 123,
which is not correct.

Thus remove the first %llu scan and leave only the
%llx scan, removing the leading 0x since %llx can
scan either.

Addresses are usually always hex values, so this
suffices.

Cc: Alexander Deucher <Alexander.Deucher at amd.com>
Cc: Xinhui Pan <xinhui.pan at amd.com>
Cc: Hawking Zhang <Hawking.Zhang at amd.com>
Signed-off-by: Luben Tuikov <luben.tuikov at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
index 0541196ae1ed..9041453465f1 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
@@ -230,9 +230,8 @@ static int amdgpu_ras_debugfs_ctrl_parse_data(struct file *f,
 	if (op != -1) {
 
 		if (op == 3) {
-			if (sscanf(str, "%*s %llu", &address) != 1)
-				if (sscanf(str, "%*s 0x%llx", &address) != 1)
-					return -EINVAL;
+			if (sscanf(str, "%*s %llx", &address) != 1)
+				return -EINVAL;
 
 			data->op = op;
 			data->inject.address = address;
@@ -255,11 +254,9 @@ static int amdgpu_ras_debugfs_ctrl_parse_data(struct file *f,
 		data->op = op;
 
 		if (op == 2) {
-			if (sscanf(str, "%*s %*s %*s %u %llu %llu",
-						&sub_block, &address, &value) != 3)
-				if (sscanf(str, "%*s %*s %*s 0x%x 0x%llx 0x%llx",
-							&sub_block, &address, &value) != 3)
-					return -EINVAL;
+			if (sscanf(str, "%*s %*s %*s %x %llx %llx",
+				   &sub_block, &address, &value) != 3)
+				return -EINVAL;
 			data->head.sub_block_index = sub_block;
 			data->inject.address = address;
 			data->inject.value = value;
-- 
2.31.0.97.g1424303384