The current codebase makes use of one-element arrays in the following form: struct something { int length; u8 data[1]; }; struct something *instance; instance = kmalloc(sizeof(*instance) + size, GFP_KERNEL); instance->length = size; memcpy(instance->data, source, size); but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. So, replace the one-element array with a flexible-array member. Also, make use of the new struct_size() helper to properly calculate the size of struct NISLANDS_SMC_SWSTATE. This issue was found with the help of Coccinelle and, audited and fixed _manually_. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx> --- drivers/gpu/drm/amd/amdgpu/si_dpm.h | 2 +- drivers/gpu/drm/radeon/ni_dpm.c | 7 ++++--- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/si_dpm.h b/drivers/gpu/drm/amd/amdgpu/si_dpm.h index 6b7d292b919f3..bc0be6818e218 100644 --- a/drivers/gpu/drm/amd/amdgpu/si_dpm.h +++ b/drivers/gpu/drm/amd/amdgpu/si_dpm.h @@ -781,7 +781,7 @@ struct NISLANDS_SMC_SWSTATE uint8_t levelCount; uint8_t padding2; uint8_t padding3; - NISLANDS_SMC_HW_PERFORMANCE_LEVEL levels[1]; + NISLANDS_SMC_HW_PERFORMANCE_LEVEL levels[]; }; typedef struct NISLANDS_SMC_SWSTATE NISLANDS_SMC_SWSTATE; diff --git a/drivers/gpu/drm/radeon/ni_dpm.c b/drivers/gpu/drm/radeon/ni_dpm.c index b57c37ddd164c..7d81dde509dc9 100644 --- a/drivers/gpu/drm/radeon/ni_dpm.c +++ b/drivers/gpu/drm/radeon/ni_dpm.c @@ -2685,11 +2685,12 @@ static int ni_upload_sw_state(struct radeon_device *rdev, struct rv7xx_power_info *pi = rv770_get_pi(rdev); u16 address = pi->state_table_start + offsetof(NISLANDS_SMC_STATETABLE, driverState); - u16 state_size = sizeof(NISLANDS_SMC_SWSTATE) + - ((NISLANDS_MAX_SMC_PERFORMANCE_LEVELS_PER_SWSTATE - 1) * sizeof(NISLANDS_SMC_HW_PERFORMANCE_LEVEL)); + NISLANDS_SMC_SWSTATE *smc_state; + u16 state_size = struct_size(smc_state, levels, + NISLANDS_MAX_SMC_PERFORMANCE_LEVELS_PER_SWSTATE); int ret; - NISLANDS_SMC_SWSTATE *smc_state = kzalloc(state_size, GFP_KERNEL); + smc_state = kzalloc(state_size, GFP_KERNEL); if (smc_state == NULL) return -ENOMEM; -- 2.26.2 _______________________________________________ amd-gfx mailing list amd-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/amd-gfx