On Wed, 24 Sep 2025 17:42:18 +0200 Jiri Olsa <[email protected]> wrote:
> On Wed, Sep 24, 2025 at 02:25:36PM +0800, Feng Yang wrote: > > SNIP > > > > Hmm, can you also dump the regs and insert pr_info() to find > > > which function fails? > > > > > > Thanks, > > > > > > > After testing, it was found that the stack could not be obtained because > > user_mode(regs) returned 1. > > Referring to the arch_ftrace_fill_perf_regs function in your email > > (https://lore.kernel.org/all/173518997908.391279.15910334347345106424.stgit@devnote2/), > > > > I made the following modification: by setting the value of pstate, the > > stack can now be obtained successfully. > > > > diff --git a/arch/arm64/include/asm/ftrace.h > > b/arch/arm64/include/asm/ftrace.h > > index 058a99aa44bd..f2814175e958 100644 > > --- a/arch/arm64/include/asm/ftrace.h > > +++ b/arch/arm64/include/asm/ftrace.h > > @@ -159,11 +159,13 @@ ftrace_partial_regs(const struct ftrace_regs *fregs, > > struct pt_regs *regs) > > { > > struct __arch_ftrace_regs *afregs = arch_ftrace_regs(fregs); > > > > memcpy(regs->regs, afregs->regs, sizeof(afregs->regs)); > > regs->sp = afregs->sp; > > regs->pc = afregs->pc; > > regs->regs[29] = afregs->fp; > > regs->regs[30] = afregs->lr; > > + regs->pstate = PSR_MODE_EL1h; > > return regs; > > } > > However, I'm not sure if there will be any other impacts... > > nice, the test works for me with this change.. could you please send > formal patch? I can polish and send out the test [1] Yeah, and Cc to arm64 maintainers, also Closes: to this thread. Thanks, > > thanks, > jirka > > > [1] > https://github.com/kernel-patches/bpf/pull/9845/commits/11b31cd465a83b8719cb06331c8e81794cca40fa -- Masami Hiramatsu (Google) <[email protected]>
