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SubjectRe: [PATCH] tracing/eprobe: Fix eprobe filter to make a filter correctly
On Sat, Nov 12, 2022 at 02:41:04PM +0900, Masami Hiramatsu (Google) wrote:
> From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
>
> Since the eprobe filter was defined based on the eprobe's trace event
> itself, it doesn't work correctly. Use the original trace event of
> the eprobe when making the filter so that the filter works correctly.
>
> Without this fix:
>
> # echo 'e syscalls/sys_enter_openat \
> flags_rename=$flags:u32 if flags < 1000' >> dynamic_events
> # echo 1 > events/eprobes/sys_enter_openat/enable
> [ 114.551550] event trace: Could not enable event sys_enter_openat
> -bash: echo: write error: Invalid argument
>
> With this fix:
> # echo 'e syscalls/sys_enter_openat \
> flags_rename=$flags:u32 if flags < 1000' >> dynamic_events
> # echo 1 > events/eprobes/sys_enter_openat/enable
> # tail trace
> cat-241 [000] ...1. 266.498449: sys_enter_openat: (syscalls.sys_enter_openat) flags_rename=0
> cat-242 [000] ...1. 266.977640: sys_enter_openat: (syscalls.sys_enter_openat) flags_rename=0
>
> Fixes: 752be5c5c910 ("tracing/eprobe: Add eprobe filter support")
> Reported-by: Rafael Mendonca <rafaelmendsr@gmail.com>
> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> ---
> kernel/trace/trace_eprobe.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)

Hi Masami,

Tested this on top of v6.1-rc5 and the event filtering seems to be
working fine now. Tested with multiple events and conditions. Thanks.

Tested-by: Rafael Mendonca <rafaelmendsr@gmail.com>

>
> diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
> index fe4833a7b7b3..1c3096ab2fe7 100644
> --- a/kernel/trace/trace_eprobe.c
> +++ b/kernel/trace/trace_eprobe.c
> @@ -643,7 +643,7 @@ new_eprobe_trigger(struct trace_eprobe *ep, struct trace_event_file *file)
> INIT_LIST_HEAD(&trigger->list);
>
> if (ep->filter_str) {
> - ret = create_event_filter(file->tr, file->event_call,
> + ret = create_event_filter(file->tr, ep->event,
> ep->filter_str, false, &filter);
> if (ret)
> goto error;
>

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