From mboxrd@z Thu Jan 1 00:00:00 1970 From: Masami Hiramatsu Date: Thu, 25 Mar 2021 03:25:24 +0000 Subject: Re: [PATCH -tip v4 10/12] x86/kprobes: Push a fake return address at kretprobe_trampoline Message-Id: <20210325122524.91bca1233c0c254fdc0678fc@kernel.org> List-Id: References: <161639518354.895304.15627519393073806809.stgit@devnote2> <161639530062.895304.16962383429668412873.stgit@devnote2> <20210323223007.GG4746@worktop.programming.kicks-ass.net> <20210324104058.7c06aaeb0408e24db6ba46f8@kernel.org> <20210324160143.wd43zribpeop2czn@treble> <20210325084741.74bdb2b1d2ed00fe68840cea@kernel.org> <20210324202613.7cad6f4f@oasis.local.home> In-Reply-To: <20210324202613.7cad6f4f@oasis.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Steven Rostedt Cc: Josh Poimboeuf , Peter Zijlstra , Ingo Molnar , X86 ML , Daniel Xu , linux-kernel@vger.kernel.org, bpf@vger.kernel.org, kuba@kernel.org, mingo@redhat.com, ast@kernel.org, tglx@linutronix.de, kernel-team@fb.com, yhs@fb.com, linux-ia64@vger.kernel.org, Abhishek Sagar On Wed, 24 Mar 2021 20:26:13 -0400 Steven Rostedt wrote: > On Thu, 25 Mar 2021 08:47:41 +0900 > Masami Hiramatsu wrote: > > > > I think the REGS and REGS_PARTIAL cases can also be affected by function > > > graph tracing. So should they use the generic unwind_recover_ret_addr() > > > instead of unwind_recover_kretprobe()? > > > > Yes, but I'm not sure this parameter can be applied. > > For example, it passed "state->sp - sizeof(unsigned long)" as where the > > return address stored address. Is that same on ftrace graph too? > > Stack traces on the return side of function graph tracer has never > worked. It's on my todo list, because that's one of the requirements to > get right if we every manage to combine kretprobe and function graph > tracers together. OK, then at this point let's just fix the kretprobe side. Thanks, > > -- Steve -- Masami Hiramatsu