On Tue, 2021-03-23 at 14:04 +0100, Arnd Bergmann wrote:
From: Arnd Bergmann arnd@arndb.de
gcc warns about an sprintf() that uses the same buffer as source and destination, which is undefined behavior in C99:
drivers/gpu/drm/amd/amdgpu/amdgpu_securedisplay.c: In function 'amdgpu_securedisplay_debugfs_write': drivers/gpu/drm/amd/amdgpu/amdgpu_securedisplay.c:141:6: error: 'sprintf' argument 3 overlaps destination object 'i2c_output' [-Werror=restrict] 141 | sprintf(i2c_output, "%s 0x%X", i2c_output, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 142 | securedisplay_cmd->securedisplay_out_message.send_roi_crc.i2c_buf[i]); | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/amd/amdgpu/amdgpu_securedisplay.c:97:7: note: destination object referenced by 'restrict'-qualified argument 1 was declared here 97 | char i2c_output[256]; | ^~~~~~~~~~
Rewrite it to remember the current offset into the buffer instead.
Signed-off-by: Arnd Bergmann arnd@arndb.de
drivers/gpu/drm/amd/amdgpu/amdgpu_securedisplay.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_securedisplay.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_securedisplay.c index 834440ab9ff7..69d7f6bff5d4 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_securedisplay.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_securedisplay.c @@ -136,9 +136,10 @@ static ssize_t amdgpu_securedisplay_debugfs_write(struct file *f, const char __u ret = psp_securedisplay_invoke(psp, TA_SECUREDISPLAY_COMMAND__SEND_ROI_CRC); if (!ret) { if (securedisplay_cmd->status == TA_SECUREDISPLAY_STATUS__SUCCESS) {
int pos = 0;memset(i2c_output, 0, sizeof(i2c_output)); for (i = 0; i < TA_SECUREDISPLAY_I2C_BUFFER_SIZE; i++)
sprintf(i2c_output, "%s 0x%X", i2c_output,
pos += sprintf(i2c_output + pos, " 0x%X",securedisplay_cmd->securedisplay_out_message.send_roi_crc.i2c_buf[i]); dev_info(adev->dev, "SECUREDISPLAY: I2C buffer out put is :%s\n", i2c_output);
Perhaps use a hex output like:
--- drivers/gpu/drm/amd/amdgpu/amdgpu_securedisplay.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_securedisplay.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_securedisplay.c index 9cf856c94f94..25bb34c72d20 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_securedisplay.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_securedisplay.c @@ -97,13 +97,12 @@ static ssize_t amdgpu_securedisplay_debugfs_write(struct file *f, const char __u uint32_t op; int i; char str[64]; - char i2c_output[256]; int ret;
if (*pos || size > sizeof(str) - 1) return -EINVAL;
- memset(str, 0, sizeof(str)); + memset(str, 0, sizeof(str)); ret = copy_from_user(str, buf, size); if (ret) return -EFAULT; @@ -139,11 +138,9 @@ static ssize_t amdgpu_securedisplay_debugfs_write(struct file *f, const char __u ret = psp_securedisplay_invoke(psp, TA_SECUREDISPLAY_COMMAND__SEND_ROI_CRC); if (!ret) { if (securedisplay_cmd->status == TA_SECUREDISPLAY_STATUS__SUCCESS) { - memset(i2c_output, 0, sizeof(i2c_output)); - for (i = 0; i < TA_SECUREDISPLAY_I2C_BUFFER_SIZE; i++) - sprintf(i2c_output, "%s 0x%X", i2c_output, - securedisplay_cmd->securedisplay_out_message.send_roi_crc.i2c_buf[i]); - dev_info(adev->dev, "SECUREDISPLAY: I2C buffer out put is :%s\n", i2c_output); + dev_info(adev->dev, "SECUREDISPLAY: I2C buffer output is: %*ph\n", + (int)TA_SECUREDISPLAY_I2C_BUFFER_SIZE, + securedisplay_cmd->securedisplay_out_message.send_roi_crc.i2c_buf); } else { psp_securedisplay_parse_resp_status(psp, securedisplay_cmd->status); }