| Message ID | 168657113778.3038017.12245893750241701312.stgit@mhiramat.roam.corp.google.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 53431798f4bb60d214ae1ec4a79eefdd414f577b |
| Headers | show |
| Series | tracing/probes: Fix tracepoint event with $arg* to fetch correct argument | expand |
On 6/12/23 04:58, Masami Hiramatsu (Google) wrote: > From: Masami Hiramatsu (Google) <mhiramat@kernel.org> > > To hide the first dummy 'data' argument on the tracepoint probe events, > the BTF argument array was modified (skip the first argument for tracepoint), > but the '$arg*' meta argument parser missed that. > > Fix to increment the argument index if it is tracepoint probe. And decrement > the index when searching the type of the argument. > > Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> > --- > kernel/trace/trace_probe.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c > index 473e1c43bc57..643aa3a51d5a 100644 > --- a/kernel/trace/trace_probe.c > +++ b/kernel/trace/trace_probe.c > @@ -456,7 +456,10 @@ static int parse_btf_arg(const char *varname, struct fetch_insn *code, > > if (name && !strcmp(name, varname)) { > code->op = FETCH_OP_ARG; > - code->param = i; > + if (ctx->flags & TPARG_FL_TPOINT) > + code->param = i + 1; > + else > + code->param = i; > return 0; > } > } > @@ -470,8 +473,11 @@ static const struct fetch_type *parse_btf_arg_type(int arg_idx, > struct btf *btf = traceprobe_get_btf(); > const char *typestr = NULL; > > - if (btf && ctx->params) > + if (btf && ctx->params) { > + if (ctx->flags & TPARG_FL_TPOINT) > + arg_idx--; > typestr = type_from_btf_id(btf, ctx->params[arg_idx].type); > + } > > return find_fetch_type(typestr, ctx->flags); > } > > I failed to apply this patch. Would you mind to rebase this patch?
On Mon, 12 Jun 2023 20:58:57 +0900 "Masami Hiramatsu (Google)" <mhiramat@kernel.org> wrote: > From: Masami Hiramatsu (Google) <mhiramat@kernel.org> > > To hide the first dummy 'data' argument on the tracepoint probe events, > the BTF argument array was modified (skip the first argument for tracepoint), > but the '$arg*' meta argument parser missed that. > > Fix to increment the argument index if it is tracepoint probe. And decrement > the index when searching the type of the argument. I'm curious. What if we want a variable that points to that data argument? ;-) Probably just add a new type I guess. Anyway, Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> -- Steve > > Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> > --- > kernel/trace/trace_probe.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c > index 473e1c43bc57..643aa3a51d5a 100644 > --- a/kernel/trace/trace_probe.c > +++ b/kernel/trace/trace_probe.c > @@ -456,7 +456,10 @@ static int parse_btf_arg(const char *varname, struct fetch_insn *code, > > if (name && !strcmp(name, varname)) { > code->op = FETCH_OP_ARG; > - code->param = i; > + if (ctx->flags & TPARG_FL_TPOINT) > + code->param = i + 1; > + else > + code->param = i; > return 0; > } > } > @@ -470,8 +473,11 @@ static const struct fetch_type *parse_btf_arg_type(int arg_idx, > struct btf *btf = traceprobe_get_btf(); > const char *typestr = NULL; > > - if (btf && ctx->params) > + if (btf && ctx->params) { > + if (ctx->flags & TPARG_FL_TPOINT) > + arg_idx--; > typestr = type_from_btf_id(btf, ctx->params[arg_idx].type); > + } > > return find_fetch_type(typestr, ctx->flags); > }
On Wed, 14 Jun 2023 12:50:34 -0700 Kui-Feng Lee <sinquersw@gmail.com> wrote: > > > On 6/12/23 04:58, Masami Hiramatsu (Google) wrote: > > From: Masami Hiramatsu (Google) <mhiramat@kernel.org> > > > > To hide the first dummy 'data' argument on the tracepoint probe events, > > the BTF argument array was modified (skip the first argument for tracepoint), > > but the '$arg*' meta argument parser missed that. > > > > Fix to increment the argument index if it is tracepoint probe. And decrement > > the index when searching the type of the argument. > > > > Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> > > --- > > kernel/trace/trace_probe.c | 10 ++++++++-- > > 1 file changed, 8 insertions(+), 2 deletions(-) > > > > diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c > > index 473e1c43bc57..643aa3a51d5a 100644 > > --- a/kernel/trace/trace_probe.c > > +++ b/kernel/trace/trace_probe.c > > @@ -456,7 +456,10 @@ static int parse_btf_arg(const char *varname, struct fetch_insn *code, > > > > if (name && !strcmp(name, varname)) { > > code->op = FETCH_OP_ARG; > > - code->param = i; > > + if (ctx->flags & TPARG_FL_TPOINT) > > + code->param = i + 1; > > + else > > + code->param = i; > > return 0; > > } > > } > > @@ -470,8 +473,11 @@ static const struct fetch_type *parse_btf_arg_type(int arg_idx, > > struct btf *btf = traceprobe_get_btf(); > > const char *typestr = NULL; > > > > - if (btf && ctx->params) > > + if (btf && ctx->params) { > > + if (ctx->flags & TPARG_FL_TPOINT) > > + arg_idx--; > > typestr = type_from_btf_id(btf, ctx->params[arg_idx].type); > > + } > > > > return find_fetch_type(typestr, ctx->flags); > > } > > > > > > I failed to apply this patch. > Would you mind to rebase this patch? Ah, this is against for the probes/for-next branch on git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git Thanks, >
On Wed, 21 Jun 2023 19:03:37 -0400 Steven Rostedt <rostedt@goodmis.org> wrote: > On Mon, 12 Jun 2023 20:58:57 +0900 > "Masami Hiramatsu (Google)" <mhiramat@kernel.org> wrote: > > > From: Masami Hiramatsu (Google) <mhiramat@kernel.org> > > > > To hide the first dummy 'data' argument on the tracepoint probe events, > > the BTF argument array was modified (skip the first argument for tracepoint), > > but the '$arg*' meta argument parser missed that. > > > > Fix to increment the argument index if it is tracepoint probe. And decrement > > the index when searching the type of the argument. > > I'm curious. What if we want a variable that points to that data argument? ;-) That is a dummy parameter which is passed when registering the callback, so it is passed from trace_fprobe.c. Currently trace_fprobe.c passed NULL to the data argument. > > Probably just add a new type I guess. Yeah, if we get any idea to use it, it will be accessed by a new $-variable. > > Anyway, > > Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> Thank you! > > -- Steve > > > > > Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> > > --- > > kernel/trace/trace_probe.c | 10 ++++++++-- > > 1 file changed, 8 insertions(+), 2 deletions(-) > > > > diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c > > index 473e1c43bc57..643aa3a51d5a 100644 > > --- a/kernel/trace/trace_probe.c > > +++ b/kernel/trace/trace_probe.c > > @@ -456,7 +456,10 @@ static int parse_btf_arg(const char *varname, struct fetch_insn *code, > > > > if (name && !strcmp(name, varname)) { > > code->op = FETCH_OP_ARG; > > - code->param = i; > > + if (ctx->flags & TPARG_FL_TPOINT) > > + code->param = i + 1; > > + else > > + code->param = i; > > return 0; > > } > > } > > @@ -470,8 +473,11 @@ static const struct fetch_type *parse_btf_arg_type(int arg_idx, > > struct btf *btf = traceprobe_get_btf(); > > const char *typestr = NULL; > > > > - if (btf && ctx->params) > > + if (btf && ctx->params) { > > + if (ctx->flags & TPARG_FL_TPOINT) > > + arg_idx--; > > typestr = type_from_btf_id(btf, ctx->params[arg_idx].type); > > + } > > > > return find_fetch_type(typestr, ctx->flags); > > } >
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index 473e1c43bc57..643aa3a51d5a 100644 --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -456,7 +456,10 @@ static int parse_btf_arg(const char *varname, struct fetch_insn *code, if (name && !strcmp(name, varname)) { code->op = FETCH_OP_ARG; - code->param = i; + if (ctx->flags & TPARG_FL_TPOINT) + code->param = i + 1; + else + code->param = i; return 0; } } @@ -470,8 +473,11 @@ static const struct fetch_type *parse_btf_arg_type(int arg_idx, struct btf *btf = traceprobe_get_btf(); const char *typestr = NULL; - if (btf && ctx->params) + if (btf && ctx->params) { + if (ctx->flags & TPARG_FL_TPOINT) + arg_idx--; typestr = type_from_btf_id(btf, ctx->params[arg_idx].type); + } return find_fetch_type(typestr, ctx->flags); }