The buffer size is determined by the declaration char fw_name[30]; This
means fw_name can hold up to 30 characters, including the null character
that marks the end of the string.
The string to be written is "amdgpu/%s_mec.bin" or "amdgpu/%s_rlc.bin",
where %s will be replaced by the value of chip_name.
The length of the string "amdgpu/%s_mec.bin" or "amdgpu/%s_rlc.bin"
without the %s is 16 characters.
The warning message is saying that the chip_name could be up to 29
characters long. If we add the 16 characters from the string
"amdgpu/%s_mec.bin" or "amdgpu/%s_rlc.bin", we get a total of 45
characters.
This is potentially longer than the buffer size of 30 characters.
if chip_name is longer than 14 characters (30 buffer size - 16
characters from the string), the resulting string will not fit into the
fw_name buffer, Thus increasing fw_name buffer size to 50
Fixes the below with gcc W=1:
drivers/gpu/drm/amd/amdgpu/gfx_v9_4_3.c: In function ‘gfx_v9_4_3_early_init’:
drivers/gpu/drm/amd/amdgpu/gfx_v9_4_3.c:379:52: warning: ‘%s’ directive output may be truncated writing up to 29 bytes into a region of size 23 [-Wformat-truncation=]
379 | snprintf(fw_name, sizeof(fw_name), "amdgpu/%s_rlc.bin", chip_name);
| ^~
......
439 | r = gfx_v9_4_3_init_rlc_microcode(adev, ucode_prefix);
| ~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/gfx_v9_4_3.c:379:9: note: ‘snprintf’ output between 16 and 45 bytes into a destination of size 30
379 | snprintf(fw_name, sizeof(fw_name), "amdgpu/%s_rlc.bin", chip_name);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/gfx_v9_4_3.c:413:52: warning: ‘%s’ directive output may be truncated writing up to 29 bytes into a region of size 23 [-Wformat-truncation=]
413 | snprintf(fw_name, sizeof(fw_name), "amdgpu/%s_mec.bin", chip_name);
| ^~
......
443 | r = gfx_v9_4_3_init_cp_compute_microcode(adev, ucode_prefix);
| ~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/gfx_v9_4_3.c:413:9: note: ‘snprintf’ output between 16 and 45 bytes into a destination of size 30
413 | snprintf(fw_name, sizeof(fw_name), "amdgpu/%s_mec.bin", chip_name);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Fixes: 86301129698b ("drm/amdgpu: split gc v9_4_3 functionality from gc v9_0")
Cc: Hawking Zhang <Hawking.Zhang@xxxxxxx>
Cc: Christian König <christian.koenig@xxxxxxx>
Cc: Alex Deucher <alexander.deucher@xxxxxxx>
Cc: Lijo Lazar <lijo.lazar@xxxxxxx>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@xxxxxxx>
---
drivers/gpu/drm/amd/amdgpu/gfx_v9_4_3.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v9_4_3.c b/drivers/gpu/drm/amd/amdgpu/gfx_v9_4_3.c
index 0e429b7ed036..1c46d5f6677f 100644
--- a/drivers/gpu/drm/amd/amdgpu/gfx_v9_4_3.c
+++ b/drivers/gpu/drm/amd/amdgpu/gfx_v9_4_3.c
@@ -370,7 +370,7 @@ static void gfx_v9_4_3_free_microcode(struct amdgpu_device *adev)
static int gfx_v9_4_3_init_rlc_microcode(struct amdgpu_device *adev,
const char *chip_name)
{
- char fw_name[30];
+ char fw_name[50];
int err;
const struct rlc_firmware_header_v2_0 *rlc_hdr;
uint16_t version_major;
@@ -407,7 +407,7 @@ static void gfx_v9_4_3_check_if_need_gfxoff(struct amdgpu_device *adev)
static int gfx_v9_4_3_init_cp_compute_microcode(struct amdgpu_device *adev,
const char *chip_name)
{
- char fw_name[30];
+ char fw_name[50];
int err;
snprintf(fw_name, sizeof(fw_name), "amdgpu/%s_mec.bin", chip_name);
--
2.34.1
