Re: [PATCH v2 3/3] tracing/kprobes: Use APIs that matches symbols without .XXX suffix

[Steven Rostedt]

On Wed, 7 Aug 2024 19:41:11 +0000
Song Liu <songliubraving@xxxxxxxx> wrote:


> It appears there are multiple APIs that may need change. For example, on gcc
> built kernel, /sys/kernel/tracing/available_filter_functions does not show 
> the suffix: 
> 
>   [root@(none)]# grep cmos_irq_enable /proc/kallsyms
>   ffffffff81db5470 t __pfx_cmos_irq_enable.constprop.0
>   ffffffff81db5480 t cmos_irq_enable.constprop.0
>   ffffffff822dec6e t cmos_irq_enable.constprop.0.cold
> 
>   [root@(none)]# grep cmos_irq_enable /sys/kernel/tracing/available_filter_functions
>   cmos_irq_enable

Strange, I don't see that:

  ~# grep cmos_irq_enable /proc/kallsyms 
  ffffffff8f4b2500 t __pfx_cmos_irq_enable.constprop.0
  ffffffff8f4b2510 t cmos_irq_enable.constprop.0

  ~# grep cmos_irq_enable /sys/kernel/tracing/available_filter_functions
  cmos_irq_enable.constprop.0

-- Steve

> 
> perf-probe uses _text+<offset> for such cases:
> 
>   [root@(none)]# cat /sys/kernel/tracing/kprobe_events
>   p:probe/cmos_irq_enable _text+14374016 
> 
> I am not sure which APIs do we need to change here. 
> 
> Thanks,
> Song
> 
>