| Message ID | 20200522174355.GA4406@embeddedor (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/[radeon|amdgpu]: Replace one-element array and use struct_size() helper | expand |
On Fri, May 22, 2020 at 1:39 PM Gustavo A. R. Silva <gustavoars@kernel.org> wrote: > > 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 SISLANDS_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@kernel.org> Applied. Thanks! Alex > --- > drivers/gpu/drm/amd/amdgpu/si_dpm.c | 5 ++--- > drivers/gpu/drm/amd/amdgpu/sislands_smc.h | 2 +- > drivers/gpu/drm/radeon/si_dpm.c | 5 ++--- > 3 files changed, 5 insertions(+), 7 deletions(-) > > diff --git a/drivers/gpu/drm/amd/amdgpu/si_dpm.c b/drivers/gpu/drm/amd/amdgpu/si_dpm.c > index c00ba4b23c9a6..0fc56c5bac080 100644 > --- a/drivers/gpu/drm/amd/amdgpu/si_dpm.c > +++ b/drivers/gpu/drm/amd/amdgpu/si_dpm.c > @@ -5715,10 +5715,9 @@ static int si_upload_sw_state(struct amdgpu_device *adev, > int ret; > u32 address = si_pi->state_table_start + > offsetof(SISLANDS_SMC_STATETABLE, driverState); > - u32 state_size = sizeof(SISLANDS_SMC_SWSTATE) + > - ((new_state->performance_level_count - 1) * > - sizeof(SISLANDS_SMC_HW_PERFORMANCE_LEVEL)); > SISLANDS_SMC_SWSTATE *smc_state = &si_pi->smc_statetable.driverState; > + size_t state_size = struct_size(smc_state, levels, > + new_state->performance_level_count); > > memset(smc_state, 0, state_size); > > diff --git a/drivers/gpu/drm/amd/amdgpu/sislands_smc.h b/drivers/gpu/drm/amd/amdgpu/sislands_smc.h > index d2930eceaf3c8..a089dbf8f7a93 100644 > --- a/drivers/gpu/drm/amd/amdgpu/sislands_smc.h > +++ b/drivers/gpu/drm/amd/amdgpu/sislands_smc.h > @@ -186,7 +186,7 @@ struct SISLANDS_SMC_SWSTATE > uint8_t levelCount; > uint8_t padding2; > uint8_t padding3; > - SISLANDS_SMC_HW_PERFORMANCE_LEVEL levels[1]; > + SISLANDS_SMC_HW_PERFORMANCE_LEVEL levels[]; > }; > > typedef struct SISLANDS_SMC_SWSTATE SISLANDS_SMC_SWSTATE; > diff --git a/drivers/gpu/drm/radeon/si_dpm.c b/drivers/gpu/drm/radeon/si_dpm.c > index a167e1c36d243..bab01ca864c63 100644 > --- a/drivers/gpu/drm/radeon/si_dpm.c > +++ b/drivers/gpu/drm/radeon/si_dpm.c > @@ -5253,10 +5253,9 @@ static int si_upload_sw_state(struct radeon_device *rdev, > int ret; > u32 address = si_pi->state_table_start + > offsetof(SISLANDS_SMC_STATETABLE, driverState); > - u32 state_size = sizeof(SISLANDS_SMC_SWSTATE) + > - ((new_state->performance_level_count - 1) * > - sizeof(SISLANDS_SMC_HW_PERFORMANCE_LEVEL)); > SISLANDS_SMC_SWSTATE *smc_state = &si_pi->smc_statetable.driverState; > + size_t state_size = struct_size(smc_state, levels, > + new_state->performance_level_count); > > memset(smc_state, 0, state_size); > > -- > 2.26.2 > > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel
diff --git a/drivers/gpu/drm/amd/amdgpu/si_dpm.c b/drivers/gpu/drm/amd/amdgpu/si_dpm.c index c00ba4b23c9a6..0fc56c5bac080 100644 --- a/drivers/gpu/drm/amd/amdgpu/si_dpm.c +++ b/drivers/gpu/drm/amd/amdgpu/si_dpm.c @@ -5715,10 +5715,9 @@ static int si_upload_sw_state(struct amdgpu_device *adev, int ret; u32 address = si_pi->state_table_start + offsetof(SISLANDS_SMC_STATETABLE, driverState); - u32 state_size = sizeof(SISLANDS_SMC_SWSTATE) + - ((new_state->performance_level_count - 1) * - sizeof(SISLANDS_SMC_HW_PERFORMANCE_LEVEL)); SISLANDS_SMC_SWSTATE *smc_state = &si_pi->smc_statetable.driverState; + size_t state_size = struct_size(smc_state, levels, + new_state->performance_level_count); memset(smc_state, 0, state_size); diff --git a/drivers/gpu/drm/amd/amdgpu/sislands_smc.h b/drivers/gpu/drm/amd/amdgpu/sislands_smc.h index d2930eceaf3c8..a089dbf8f7a93 100644 --- a/drivers/gpu/drm/amd/amdgpu/sislands_smc.h +++ b/drivers/gpu/drm/amd/amdgpu/sislands_smc.h @@ -186,7 +186,7 @@ struct SISLANDS_SMC_SWSTATE uint8_t levelCount; uint8_t padding2; uint8_t padding3; - SISLANDS_SMC_HW_PERFORMANCE_LEVEL levels[1]; + SISLANDS_SMC_HW_PERFORMANCE_LEVEL levels[]; }; typedef struct SISLANDS_SMC_SWSTATE SISLANDS_SMC_SWSTATE; diff --git a/drivers/gpu/drm/radeon/si_dpm.c b/drivers/gpu/drm/radeon/si_dpm.c index a167e1c36d243..bab01ca864c63 100644 --- a/drivers/gpu/drm/radeon/si_dpm.c +++ b/drivers/gpu/drm/radeon/si_dpm.c @@ -5253,10 +5253,9 @@ static int si_upload_sw_state(struct radeon_device *rdev, int ret; u32 address = si_pi->state_table_start + offsetof(SISLANDS_SMC_STATETABLE, driverState); - u32 state_size = sizeof(SISLANDS_SMC_SWSTATE) + - ((new_state->performance_level_count - 1) * - sizeof(SISLANDS_SMC_HW_PERFORMANCE_LEVEL)); SISLANDS_SMC_SWSTATE *smc_state = &si_pi->smc_statetable.driverState; + size_t state_size = struct_size(smc_state, levels, + new_state->performance_level_count); memset(smc_state, 0, state_size);
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 SISLANDS_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@kernel.org> --- drivers/gpu/drm/amd/amdgpu/si_dpm.c | 5 ++--- drivers/gpu/drm/amd/amdgpu/sislands_smc.h | 2 +- drivers/gpu/drm/radeon/si_dpm.c | 5 ++--- 3 files changed, 5 insertions(+), 7 deletions(-)