On Wed, 23 Jul 2025 12:52:32 -0400
Steven Rostedt [off-list ref] wrote:

On Wed, 23 Jul 2025 12:42:02 -0400
Steven Rostedt [off-list ref] wrote:

quoted

 [
   Create an eprobe called "sys" and attach it to sys_enter.
   Read the id of the system call and the second argument
 ]
 # echo 'e:sys raw_syscalls.sys_enter nr=$id:u32 arg2+8($args):u64' >> /sys/kernel/tracing/dynamic_events

The above has a typo. I originally had it as "filename=+8($args):u64"
but decided to change it to "arg2" as its attached to the generic raw
syscall. But in the process, I accidentally deleted the "=". So the
above should be:

 # echo 'e:sys raw_syscalls.sys_enter nr=$id:u32 arg2=+8($args):u64' >> /sys/kernel/tracing/dynamic_events

Yeah, it should be :)

quoted

 [
   Create a synthetic event "path" that will hold the address of the
   sys_openat filename. This is on a 64bit machine, so make it 64 bits
 ]
 # echo 's:path u64 file;' >> /sys/kernel/tracing/dynamic_events

 [
   Add a histogram to the eprobe/sys which tiggers if the "nr" field is
   257 (sys_openat), and save the filename in the "file" variable.
 ]
 # echo 'hist:keys=common_pid:file=filename if nr == 257' > /sys/kernel/tracing/events/eprobes/sys/trigger

And I forgot to update this, as it's not "filename" any more, but
"arg2". So this needs to be:

 # echo 'hist:keys=common_pid:file=arg2 if nr == 257' > /sys/kernel/tracing/events/eprobes/sys/trigger

OK, let me fix when I pick this.

The code looks good to me.

Thanks!

-- Steve

-- 
Masami Hiramatsu (Google) [off-list ref]