lkml.org 
[lkml]   [2022]   [Dec]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 1/2] tracing: Add a way to filter function addresses to function names
On Mon, Dec 19, 2022 at 01:31:07PM -0500, Steven Rostedt wrote:
> From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
>
> There's been several times where an event records a function address in
> its field and I needed to filter on that address for a specific function
> name. It required looking up the function in kallsyms, finding its size,
> and doing a compare of "field >= function_start && field < function_end".
>
> But this would change from boot to boot and is unreliable in scripts.
> Also, it is useful to have this at boot up, where the addresses will not
> be known. For example, on the boot command line:
>
> trace_trigger="initcall_finish.traceoff if func.function == acpi_init"
>
> To implement this, add a ".function" prefix, that will check that the
> field is of size long, and the only operations allowed (so far) are "=="
> and "!=".
>
> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Reviewed-by: Ross Zwisler <zwisler@google.com>

\
 
 \ /
  Last update: 2023-03-26 23:15    [W:0.055 / U:0.172 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site