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charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, Mar 18, 2025 at 10:39=E2=80=AFPM Josh Poimboeuf wrote: > > On Tue, Mar 18, 2025 at 08:58:52PM -0700, Song Liu wrote: > > On a closer look, I think we also need some logic in unwind_find_stack(= ) > > so that we can see when the unwinder hits the exception boundary. For > > this reason, we may still need unwind_state.unreliable. I will look int= o > > fixing this and send v2. > > Isn't that what FRAME_META_TYPE_PT_REGS is for? > > Maybe it can just tell kunwind_stack_walk() to set a bit in > kunwind_state which tells kunwind_next_frame_record_meta() to quit the > unwind early for the FRAME_META_TYPE_PT_REGS case. =C2=A0That also has th= e > benefit of stopping the unwind as soon as the exception is encounterd. > After reviewing the code flow, it seems like we should treat all -EINVALID cases or `FRAME_META_TYPE_PT_REGS` cases as unreliable unwinds. Would a simplification like the one below work? Or we can return a special value for success cases in kunwind_next_regs_pc(= )=20 ``` diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.= c index 69d0567a0c38..0eb69fa6161a 100644 --- a/arch/arm64/kernel/stacktrace.c +++ b/arch/arm64/kernel/stacktrace.c @@ -296,7 +296,8 @@ do_kunwind(struct kunwind_state *state, kunwind_consume= _fn consume_state, if (!consume_state(state, cookie)) break; ret =3D kunwind_next(state); - if (ret < 0) + if (ret < 0 || state->source =3D=3D KUNWIND_SOURCE_REGS_PC) + state->common.unreliable =3D true; break; } } ``` -- Weinan