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Peter Anvin" , Jens Remus Cc: "Jason A. Donenfeld" , "Peter Zijlstra (Intel)" , Theodore Ts'o , Thomas =?ISO-8859-1?Q?Wei=DFschuh?= , Xin Li , Andrew Cooper , Andy Lutomirski , Ard Biesheuvel , Borislav Petkov , Brian Gerst , Dave Hansen , Ingo Molnar , James Morse , Jarkko Sakkinen , Josh Poimboeuf , Kees Cook , Nam Cao , Oleg Nesterov , Perry Yuan , Thomas Gleixner , Thomas Huth , Uros Bizjak , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-sgx@vger.kernel.org, x86@kernel.org, Indu Bhagat , Claudiu Zissulescu-Ianculescu , Heiko Carstens , Vasily Gorbik Date: Tue, 10 Feb 2026 11:11:25 +0800 In-Reply-To: References: <20260106211856.560186-6-hpa@zytor.com> <223707e2-3231-4037-bd1f-490ddf6aeeb6@linux.ibm.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.58.3 MIME-Version: 1.0 X-Rspam-User: X-Rspamd-Queue-Id: 348E7A0008 X-Rspamd-Server: rspam07 X-Stat-Signature: 1nk9mcw6dcgs4xqkn89jfy65kd8x6nte X-HE-Tag: 1770693103-824501 X-HE-Meta: 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 Kq9amVVt tkTcR8umcI5aRvA9Bumw0ppTvadJsImQxPOj+0Uy7rRmJzvwmoOquQPU1jI2kyzymEkeuj3rErtgoHL6Guk6Qy4M1uG9pz8Obz6ieg5rpU6pB0ZGnwhn6ueu3d5JYuw6iZ2M+r192/fC8iRj71XS6BLHBueR1oHcR+xQhogJLbuhG9LAMQBAVTecIRrD9OxYbjBbynqCXvmdkhfY7kk7nzsYT8repH1v8JmTcA1k7oq2KOXvQYvXxz/eJozkHiXx/JOid5wRSGG5GIdfVrQnrtAvBMThlVCF4QLSzmGiYsFQUOsMl+uOFC7HJbiWkjLD7Ia+Rof8DJ6MGjnMEUVVbmFV7Yv8SSdzJfEVKeiyWNd1YPjgA1Eg1VfRlAc5omnjx1QI0fmie77q9f5hKgxk2gh17VjlzY4QU/5p37vIwkqIk+z3eIP+INULjfIJ/qO5Nwa3G X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, 2026-02-02 at 19:57 -0800, H. Peter Anvin wrote: > That hack dates back from before the signal frame extension. It is no > longer necessary. Unfortunately at least it seems libgcc unwinder does not handle the signal frame extension properly. The code reads: fde =3D _Unwind_Find_FDE (context->ra + _Unwind_IsSignalFrame (context) -= 1,=20 &context->bases); if (fde =3D=3D NULL) { =20 #ifdef MD_FALLBACK_FRAME_STATE_FOR /* Couldn't find frame unwind info for this function. Try a target-specific fallback mechanism. This will necessarily not provide a personality routine or LSDA. */ return MD_FALLBACK_FRAME_STATE_FOR (context, fs);=20 #else return _URC_END_OF_STACK; #endif } =20 fs->pc =3D context->bases.func; cie =3D get_cie (fde); insn =3D extract_cie_info (cie, context, fs);=20 Thus, it indeed attempts to avoid subtracting 1 for a signal frame, but ... _Unwind_IsSignalFrame (context) actually extracts a flag in context which will only be raised up by extract_cie_info. Or am I missing something here? --=20 Xi Ruoyao