On Wed, Mar 24, 2021 at 10:40:58AM +0900, Masami Hiramatsu wrote: > On Tue, 23 Mar 2021 23:30:07 +0100 > Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > > > On Mon, Mar 22, 2021 at 03:41:40PM +0900, Masami Hiramatsu wrote: > > > ".global kretprobe_trampoline\n" > > > ".type kretprobe_trampoline, @function\n" > > > "kretprobe_trampoline:\n" > > > #ifdef CONFIG_X86_64 > > > > So what happens if we get an NMI here? That is, after the RET but before > > the push? Then our IP points into the trampoline but we've not done that > > push yet. > > Not only NMI, but also interrupts can happen. There is no cli/sti here. > > Anyway, thanks for pointing! > I think in UNWIND_HINT_TYPE_REGS and UNWIND_HINT_TYPE_REGS_PARTIAL cases > ORC unwinder also has to check the state->ip and if it is kretprobe_trampoline, > it should be recovered. > What about this? 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()? -- Josh
