On Wed, 13 Aug 2025 01:21:01 +0900 Ryan Chung <[email protected]> wrote:
> Resolve TODO in `__register_trace_fprobe()`: > parse `tf->symbol` robustly (support `sym!filter` and comma-separated lists), > trim tokens, ignore empties, deduplicate symbols, use bulk registration for > lists, return `-EEXIST` if already registered, and preserve > lockdown/tracepoint deferral semantics. Hi Ryan, Please read the Submitting Patches document to have proper format. https://docs.kernel.org/process/submitting-patches.html For example, the change long should have a max column of 74 (with the exception of cut and paste commands or output) > > Please note that this was my personal interpretation of what TODO > required here. Welcoming any feedback. > > Signed-off-by: Ryan Chung <[email protected]> > --- > kernel/trace/trace_fprobe.c | 102 +++++++++++++++++++++++++++++++++++- > 1 file changed, 100 insertions(+), 2 deletions(-) > > diff --git a/kernel/trace/trace_fprobe.c b/kernel/trace/trace_fprobe.c > index b40fa59159ac..37d4260b9012 100644 > --- a/kernel/trace/trace_fprobe.c > +++ b/kernel/trace/trace_fprobe.c > @@ -12,6 +12,8 @@ > #include <linux/security.h> > #include <linux/tracepoint.h> > #include <linux/uaccess.h> > +#include <linux/string.h> > +#include <linux/slab.h> > > #include "trace_dynevent.h" > #include "trace_probe.h" > @@ -762,8 +764,104 @@ static int __register_trace_fprobe(struct trace_fprobe > *tf) > return __regsiter_tracepoint_fprobe(tf); > } > > - /* TODO: handle filter, nofilter or symbol list */ > - return register_fprobe(&tf->fp, tf->symbol, NULL); > + /* Parse tf->symbol */ > + { Code does not add random blocks. > + char *spec, *bang, *p; > + int n = 0, w = 0, j, rc; Indentation is always 8 byte tabs (not spaces). > + char **syms = NULL; > + > + spec = kstrdup(tf->symbol, GFP_KERNEL); Why did you declare spec as "char **" when you use it as "char *"? > + if (!spec) > + return -ENOMEM; > + > + /* If a '!' exists, treat it as single symbol + filter */ > + bang = strchr(spec, '!'); > + if (bang) { > + char *sym, *flt; > + > + *bang = '\0'; > + sym = strim(spec); > + flt = strim(bang + 1); > + > + if (!*sym || !*flt) { > + kfree(spec); > + return -EINVAL; /* reject empty symbol/filter */ > + } > + > + rc = register_fprobe(&tf->fp, sym, flt); > + kfree(spec); > + return rc; > + } > + > + /* Comma list (or single symbol without '!') */ > + /* First pass: count non-empty tokens */ Strange comments. Did you use AI to help you write this? -- Steve > + p = spec; > + while (p) { > + char *tok = strsep(&p, ","); > + if (tok && *strim(tok)) > + n++; > + } > + > + if (n == 0){ > + kfree(spec); > + return -EINVAL; > + } > + > + /* Allocate array for pointers into spec (callee copies/consumes) */ > + syms = kcalloc(n, sizeof(*syms), GFP_KERNEL); > + if (!syms) { > + kfree(spec); > + return -ENOMEM; > + } > + > + /* Second pass: fill, skipping empties */ > + p = spec; > + while (p) { > + char *tok = strsep(&p, ","); > + char *s; > + > + if (!tok) > + break; > + s = strim(tok); > + if (!*s) > + continue; > + syms[w++] = s; > + } > + > + /* Dedup in-place */ > + for (i = 0; i < w; i++){ > + if (!syms[i]) > + continue; > + for (j = i + 1; j < w; j++) { > + if (syms[j] && !strcmp(syms[i], syms[j])) > + syms[j] = NULL; > + } > + } > + > + /* Compact */ > + for (i = 0, j = 0; i < w; i++) { > + if (syms[i]) > + syms[j++] = syms[i]; > + } > + w = j; > + > + /* After dedup, ensure we still have at least one symbol */ > + if (w == 0){ > + kfree(syms); > + kfree(spec); > + return -EINVAL; > + } > + > + /* Register list or single symbol, using the existing bulk API */ > + if (w == 1) > + rc = register_fprobe(&tf->fp, syms[0], NULL); > + else > + rc = register_fprobe_syms(&tf->fp, (const char **)syms, w); > + > + kfree(syms); > + kfree(spec); > + return rc; > + } > } > > /* Internal unregister function - just handle fprobe and flags */
