vmlinux.o: warning: objtool: mtk_timer_probe+0x23: no-cfi indirect call!

vmlinux.o: warning: objtool: mtk_timer_probe+0x23: no-cfi indirect call!

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   65ba8f34ec886ec72b2c07ddc8cf3d815c32869d
commit: 7a097aba725501c399b5e93d0199aa3a2f6e9c88 clocksource/drivers/timer-mediatek: Convert to OF probing
date:   2 weeks ago
config: x86_64-buildonly-randconfig-1001-20261028 (https://download.01.org/0day-ci/archive/20261029/202610290223.iOEGeDs2-lkp@intel.com/config)
compiler: clang version 22.1.8 (https://github.com/llvm/llvm-project ca7933e47d3a3451d81e72ac174dcb5aa28b59d1)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20261029/202610290223.iOEGeDs2-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Fixes: 7a097aba7255 ("clocksource/drivers/timer-mediatek: Convert to OF probing")
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202610290223.iOEGeDs2-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> vmlinux.o: warning: objtool: mtk_timer_probe+0x23: no-cfi indirect call!

Kconfig warnings: (for reference only)
   WARNING: unmet direct dependencies detected for PM_GENERIC_DOMAINS_OF
   Depends on [n]: PM_GENERIC_DOMAINS [=y] && OF [=n]
   Selected by [m]:
   - COMMON_CLK_MT8173_MFGTOP [=m] && COMMON_CLK [=y] && (ARCH_MEDIATEK || COMPILE_TEST [=y]) && COMMON_CLK_MT8173 [=m] && PM [=y]

--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: vmlinux.o: warning: objtool: mtk_timer_probe+0x23: no-cfi indirect call!

[Nathan Chancellor]

On Thu, Oct 29, 2026 at 03:10:30AM +0800, kernel test robot wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   65ba8f34ec886ec72b2c07ddc8cf3d815c32869d
> commit: 7a097aba725501c399b5e93d0199aa3a2f6e9c88 clocksource/drivers/timer-mediatek: Convert to OF probing
> date:   2 weeks ago
> config: x86_64-buildonly-randconfig-1001-20261028 (https://download.01.org/0day-ci/archive/20261029/202610290223.iOEGeDs2-lkp@intel.com/config)
> compiler: clang version 22.1.8 (https://github.com/llvm/llvm-project ca7933e47d3a3451d81e72ac174dcb5aa28b59d1)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20261029/202610290223.iOEGeDs2-lkp@intel.com/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Fixes: 7a097aba7255 ("clocksource/drivers/timer-mediatek: Convert to OF probing")
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202610290223.iOEGeDs2-lkp@intel.com/
> 
> All warnings (new ones prefixed by >>):
> 
> >> vmlinux.o: warning: objtool: mtk_timer_probe+0x23: no-cfi indirect call!

This warning occurs as a result of the above change because
of_device_get_match_data() returns NULL when CONFIG_OF is disabled,
which results in LLVM dropping the kCFI setup since it knows that there
is no valid target for this call. Adding a check for a NULL timer_init
avoids the warning, which would probably be more robust anyways since
of_device_get_match_data() could return NULL even with CONFIG_OF=y?

diff --git a/drivers/clocksource/timer-mediatek.c b/drivers/clocksource/timer-mediatek.c
index 842d6ee4259e..33bf4c97bb77 100644
--- a/drivers/clocksource/timer-mediatek.c
+++ b/drivers/clocksource/timer-mediatek.c
@@ -353,6 +353,8 @@ static int mtk_timer_probe(struct platform_device *pdev)
 	int (*timer_init)(struct platform_device *pdev);
 
 	timer_init = of_device_get_match_data(&pdev->dev);
+	if (!timer_init)
+		return -ENODEV;
 	return timer_init(pdev);
 }
 
-- 
Cheers,
Nathan

Re: vmlinux.o: warning: objtool: mtk_timer_probe+0x23: no-cfi indirect call!

[Luca Leonardo Scorcia]

Thank you Nathan for the analysis and suggested fix. I agree your
patch would be useful even if the warning wasn't there, to make the
device probe more robust.

Being a new contributor I'm not quite sure what the process is now -
should I send out a patch with the correction, just as I did for the
initial contribution? Or is it going to be fixed by the maintainers
autonomously? (Obviously adding a Suggested-by tag with the rest of
the bots' tags).

Thank you for your help
-- 
Luca

Re: vmlinux.o: warning: objtool: mtk_timer_probe+0x23: no-cfi indirect call!

[Daniel Lezcano]

Hi Luca,

On 10/29/26 19:54, Luca Leonardo Scorcia wrote:
> Thank you Nathan for the analysis and suggested fix. I agree your
> patch would be useful even if the warning wasn't there, to make the
> device probe more robust.
> 
> Being a new contributor I'm not quite sure what the process is now -
> should I send out a patch with the correction, just as I did for the
> initial contribution? 

If you can send a fix that would be nice

> Or is it going to be fixed by the maintainers
> autonomously? (Obviously adding a Suggested-by tag with the rest of
> the bots' tags).
> 
> Thank you for your help