On Mon, Sep 25, 2023 at 09:15:15PM +0900, Masami Hiramatsu wrote: > Hi Jiri, > > On Mon, 25 Sep 2023 12:41:59 +0200 > Jiri Olsa <olsajiri@xxxxxxxxx> wrote: > > > On Sun, Sep 24, 2023 at 10:36:36PM +0900, Masami Hiramatsu (Google) wrote: > > > From: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx> > > > > > > This allows fprobes to be available with CONFIG_DYNAMIC_FTRACE_WITH_ARGS > > > instead of CONFIG_DYNAMIC_FTRACE_WITH_REGS, then we can enable fprobe > > > on arm64. > > > > > > Signed-off-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx> > > > Acked-by: Florent Revest <revest@xxxxxxxxxxxx> > > > > I was getting bpf selftests failures with this patchset and when > > bisecting I'm getting crash when running on top of this change > > Thanks for bisecting! > > > > > looks like it's missing some of the regs NULL checks added later? > > yeah, if the RIP (arch_rethook_prepare+0x0/0x30) is correct, > > void arch_rethook_prepare(struct rethook_node *rh, struct ftrace_regs *fregs, bool mcount) > > RSI (the 2nd argument) is NULL. This means fregs == NULL and caused the crash. > I think ftrace_get_regs(fregs) for the entry handler may return NULL. > > Ah, > > @@ -182,7 +182,7 @@ static void fprobe_init(struct fprobe *fp) > fp->ops.func = fprobe_kprobe_handler; > else > fp->ops.func = fprobe_handler; > - fp->ops.flags |= FTRACE_OPS_FL_SAVE_REGS; > + fp->ops.flags |= FTRACE_OPS_FL_SAVE_ARGS; > } > > static int fprobe_init_rethook(struct fprobe *fp, int num) > > This may cause the issue, it should keep REGS at this point (this must be done in > [9/12]). But after applying [9/12], it shouldn't be a problem... > > Let me check it again. that helped with the crash, I'll continue bisecting to find out where it breaks the tests thanks, jirka
