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-Wsometimes-uninitialized in drivers/gpu/drm/amd/powerplay/vega20_ppt.c #425

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nathanchance opened this issue Mar 19, 2019 · 3 comments
Closed

-Wsometimes-uninitialized in drivers/gpu/drm/amd/powerplay/vega20_ppt.c #425

nathanchance opened this issue Mar 19, 2019 · 3 comments
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@nathanchance
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-Wsometimes-uninitialized [BUG] linux-next This is an issue only seen in linux-next [FIXED][LINUX] development cycle This bug was only present and fixed in a -next or -rc cycle

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@nathanchance
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drivers/gpu/drm/amd/amdgpu/../powerplay/vega20_ppt.c:456:2: warning: variable 'num_of_levels' is used uninitialized whenever '?:' condition is false [-Wsometimes-uninitialized]
@nathanchance nathanchance added [BUG] linux-next This is an issue only seen in linux-next -Wsometimes-uninitialized labels Mar 19, 2019
@nathanchance
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Patch sent: https://lore.kernel.org/lkml/20190320005842.25383-1-natechancellor@gmail.com/

@nathanchance nathanchance added the [PATCH] Submitted A patch has been submitted for review label Mar 20, 2019
@nathanchance nathanchance self-assigned this Mar 20, 2019
FireBurn pushed a commit to FireBurn/linux that referenced this issue Mar 21, 2019
@nathanchance @alexdeucher
drm/amd/powerplay: Zero initialize num_of_levels in vega20_set_single…
5ea8b47 
…_dpm_table

When building with -Wsometimes-uninitialized, Clang warns:

drivers/gpu/drm/amd/amdgpu/../powerplay/vega20_ppt.c:456:2: warning:
variable 'num_of_levels' is used uninitialized whenever '?:' condition
is false [-Wsometimes-uninitialized]
        smu_read_smc_arg(smu, &num_of_levels);
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/../powerplay/inc/amdgpu_smu.h:608:3: note:
expanded from macro 'smu_read_smc_arg'
        ((smu)->funcs->read_smc_arg? (smu)->funcs->read_smc_arg((smu), (arg)) : 0)
         ^~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/../powerplay/vega20_ppt.c:457:7: note:
uninitialized use occurs here
        if (!num_of_levels) {
             ^~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/../powerplay/vega20_ppt.c:456:2: note: remove
the '?:' if its condition is always true
        smu_read_smc_arg(smu, &num_of_levels);
        ^
drivers/gpu/drm/amd/amdgpu/../powerplay/inc/amdgpu_smu.h:608:3: note:
expanded from macro 'smu_read_smc_arg'
        ((smu)->funcs->read_smc_arg? (smu)->funcs->read_smc_arg((smu), (arg)) : 0)
         ^
drivers/gpu/drm/amd/amdgpu/../powerplay/vega20_ppt.c:446:27: note:
initialize the variable 'num_of_levels' to silence this warning
        uint32_t i, num_of_levels, clk;
                                 ^
                                  = 0
1 warning generated.

The if statement it mentions as potentially problematic is currently
always true because the read_smc_arg callback is assigned at the
bottom of this file but Clang can't tell that. If the callback were
ever to disappear, num_of_levels would never be initialized. Just
zero initialize it to ensure that the intent behind this code
remains the same.

Link: ClangBuiltLinux/linux#425
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
@nathanchance
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Patch accepted: https://cgit.freedesktop.org/~agd5f/linux/commit/?id=5ea8b4725f42c22c37b370eebb5d33b4236f5301

@nathanchance nathanchance added [PATCH] Accepted A submitted patch has been accepted upstream and removed [PATCH] Submitted A patch has been submitted for review labels Mar 21, 2019
@nathanchance
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Fixed in next-20190322: https://git.kernel.org/next/linux-next/c/5ea8b4725f42c22c37b370eebb5d33b4236f5301

@nathanchance nathanchance added [FIXED][LINUX] development cycle This bug was only present and fixed in a -next or -rc cycle and removed [PATCH] Accepted A submitted patch has been accepted upstream labels Mar 22, 2019
M-Bab pushed a commit to M-Bab/linux-kernel-amdgpu that referenced this issue Mar 26, 2019
@nathanchance @alexdeucher
drm/amd/powerplay: Zero initialize num_of_levels in vega20_set_single…
8c3fb5d 
…_dpm_table

When building with -Wsometimes-uninitialized, Clang warns:

drivers/gpu/drm/amd/amdgpu/../powerplay/vega20_ppt.c:456:2: warning:
variable 'num_of_levels' is used uninitialized whenever '?:' condition
is false [-Wsometimes-uninitialized]
        smu_read_smc_arg(smu, &num_of_levels);
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/../powerplay/inc/amdgpu_smu.h:608:3: note:
expanded from macro 'smu_read_smc_arg'
        ((smu)->funcs->read_smc_arg? (smu)->funcs->read_smc_arg((smu), (arg)) : 0)
         ^~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/../powerplay/vega20_ppt.c:457:7: note:
uninitialized use occurs here
        if (!num_of_levels) {
             ^~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/../powerplay/vega20_ppt.c:456:2: note: remove
the '?:' if its condition is always true
        smu_read_smc_arg(smu, &num_of_levels);
        ^
drivers/gpu/drm/amd/amdgpu/../powerplay/inc/amdgpu_smu.h:608:3: note:
expanded from macro 'smu_read_smc_arg'
        ((smu)->funcs->read_smc_arg? (smu)->funcs->read_smc_arg((smu), (arg)) : 0)
         ^
drivers/gpu/drm/amd/amdgpu/../powerplay/vega20_ppt.c:446:27: note:
initialize the variable 'num_of_levels' to silence this warning
        uint32_t i, num_of_levels, clk;
                                 ^
                                  = 0
1 warning generated.

The if statement it mentions as potentially problematic is currently
always true because the read_smc_arg callback is assigned at the
bottom of this file but Clang can't tell that. If the callback were
ever to disappear, num_of_levels would never be initialized. Just
zero initialize it to ensure that the intent behind this code
remains the same.

Fixes: 870b996f955f ("drm/amd/powerplay: set defalut dpm table for smu")
Link: ClangBuiltLinux/linux#425
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
evadot pushed a commit to freebsd/drm-kmod that referenced this issue May 10, 2020
@nathanchance @evadot
drm/amd/powerplay: Zero initialize num_of_levels in vega20_set_single…
639f466 
…_dpm_table

When building with -Wsometimes-uninitialized, Clang warns:

drivers/gpu/drm/amd/amdgpu/../powerplay/vega20_ppt.c:456:2: warning:
variable 'num_of_levels' is used uninitialized whenever '?:' condition
is false [-Wsometimes-uninitialized]
        smu_read_smc_arg(smu, &num_of_levels);
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/../powerplay/inc/amdgpu_smu.h:608:3: note:
expanded from macro 'smu_read_smc_arg'
        ((smu)->funcs->read_smc_arg? (smu)->funcs->read_smc_arg((smu), (arg)) : 0)
         ^~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/../powerplay/vega20_ppt.c:457:7: note:
uninitialized use occurs here
        if (!num_of_levels) {
             ^~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/../powerplay/vega20_ppt.c:456:2: note: remove
the '?:' if its condition is always true
        smu_read_smc_arg(smu, &num_of_levels);
        ^
drivers/gpu/drm/amd/amdgpu/../powerplay/inc/amdgpu_smu.h:608:3: note:
expanded from macro 'smu_read_smc_arg'
        ((smu)->funcs->read_smc_arg? (smu)->funcs->read_smc_arg((smu), (arg)) : 0)
         ^
drivers/gpu/drm/amd/amdgpu/../powerplay/vega20_ppt.c:446:27: note:
initialize the variable 'num_of_levels' to silence this warning
        uint32_t i, num_of_levels, clk;
                                 ^
                                  = 0
1 warning generated.

The if statement it mentions as potentially problematic is currently
always true because the read_smc_arg callback is assigned at the
bottom of this file but Clang can't tell that. If the callback were
ever to disappear, num_of_levels would never be initialized. Just
zero initialize it to ensure that the intent behind this code
remains the same.

Link: ClangBuiltLinux/linux#425
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
evadot pushed a commit to freebsd/drm-kmod that referenced this issue May 11, 2020
@nathanchance @evadot
drm/amd/powerplay: Zero initialize num_of_levels in vega20_set_single…
1c5f5d8 
…_dpm_table

When building with -Wsometimes-uninitialized, Clang warns:

drivers/gpu/drm/amd/amdgpu/../powerplay/vega20_ppt.c:456:2: warning:
variable 'num_of_levels' is used uninitialized whenever '?:' condition
is false [-Wsometimes-uninitialized]
        smu_read_smc_arg(smu, &num_of_levels);
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/../powerplay/inc/amdgpu_smu.h:608:3: note:
expanded from macro 'smu_read_smc_arg'
        ((smu)->funcs->read_smc_arg? (smu)->funcs->read_smc_arg((smu), (arg)) : 0)
         ^~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/../powerplay/vega20_ppt.c:457:7: note:
uninitialized use occurs here
        if (!num_of_levels) {
             ^~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/../powerplay/vega20_ppt.c:456:2: note: remove
the '?:' if its condition is always true
        smu_read_smc_arg(smu, &num_of_levels);
        ^
drivers/gpu/drm/amd/amdgpu/../powerplay/inc/amdgpu_smu.h:608:3: note:
expanded from macro 'smu_read_smc_arg'
        ((smu)->funcs->read_smc_arg? (smu)->funcs->read_smc_arg((smu), (arg)) : 0)
         ^
drivers/gpu/drm/amd/amdgpu/../powerplay/vega20_ppt.c:446:27: note:
initialize the variable 'num_of_levels' to silence this warning
        uint32_t i, num_of_levels, clk;
                                 ^
                                  = 0
1 warning generated.

The if statement it mentions as potentially problematic is currently
always true because the read_smc_arg callback is assigned at the
bottom of this file but Clang can't tell that. If the callback were
ever to disappear, num_of_levels would never be initialized. Just
zero initialize it to ensure that the intent behind this code
remains the same.

Link: ClangBuiltLinux/linux#425
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
evadot pushed a commit to freebsd/drm-kmod that referenced this issue May 13, 2020
@nathanchance @evadot
drm/amd/powerplay: Zero initialize num_of_levels in vega20_set_single…
9f18d43 
…_dpm_table

When building with -Wsometimes-uninitialized, Clang warns:

drivers/gpu/drm/amd/amdgpu/../powerplay/vega20_ppt.c:456:2: warning:
variable 'num_of_levels' is used uninitialized whenever '?:' condition
is false [-Wsometimes-uninitialized]
        smu_read_smc_arg(smu, &num_of_levels);
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/../powerplay/inc/amdgpu_smu.h:608:3: note:
expanded from macro 'smu_read_smc_arg'
        ((smu)->funcs->read_smc_arg? (smu)->funcs->read_smc_arg((smu), (arg)) : 0)
         ^~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/../powerplay/vega20_ppt.c:457:7: note:
uninitialized use occurs here
        if (!num_of_levels) {
             ^~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/../powerplay/vega20_ppt.c:456:2: note: remove
the '?:' if its condition is always true
        smu_read_smc_arg(smu, &num_of_levels);
        ^
drivers/gpu/drm/amd/amdgpu/../powerplay/inc/amdgpu_smu.h:608:3: note:
expanded from macro 'smu_read_smc_arg'
        ((smu)->funcs->read_smc_arg? (smu)->funcs->read_smc_arg((smu), (arg)) : 0)
         ^
drivers/gpu/drm/amd/amdgpu/../powerplay/vega20_ppt.c:446:27: note:
initialize the variable 'num_of_levels' to silence this warning
        uint32_t i, num_of_levels, clk;
                                 ^
                                  = 0
1 warning generated.

The if statement it mentions as potentially problematic is currently
always true because the read_smc_arg callback is assigned at the
bottom of this file but Clang can't tell that. If the callback were
ever to disappear, num_of_levels would never be initialized. Just
zero initialize it to ensure that the intent behind this code
remains the same.

Link: ClangBuiltLinux/linux#425
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
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-Wsometimes-uninitialized [BUG] linux-next This is an issue only seen in linux-next [FIXED][LINUX] development cycle This bug was only present and fixed in a -next or -rc cycle
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