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{ "id": 2233152, "url": "http://patchwork.ozlabs.org/api/1.2/covers/2233152/?format=api", "web_url": "http://patchwork.ozlabs.org/project/glibc/cover/20260505190809.3898686-1-adhemerval.zanella@linaro.org/", "project": { "id": 41, "url": "http://patchwork.ozlabs.org/api/1.2/projects/41/?format=api", "name": "GNU C Library", "link_name": "glibc", "list_id": "libc-alpha.sourceware.org", "list_email": "libc-alpha@sourceware.org", "web_url": "", "scm_url": "", "webscm_url": "", "list_archive_url": "", "list_archive_url_format": "", "commit_url_format": "" }, "msgid": "<20260505190809.3898686-1-adhemerval.zanella@linaro.org>", "list_archive_url": null, "date": "2026-05-05T19:06:49", "name": "[v2,0/3] nptl: Fix robust mutex support detection and defer robust list initialization", "submitter": { "id": 66065, "url": "http://patchwork.ozlabs.org/api/1.2/people/66065/?format=api", "name": "Adhemerval Zanella Netto", "email": "adhemerval.zanella@linaro.org" }, "mbox": "http://patchwork.ozlabs.org/project/glibc/cover/20260505190809.3898686-1-adhemerval.zanella@linaro.org/mbox/", "series": [ { "id": 502884, "url": "http://patchwork.ozlabs.org/api/1.2/series/502884/?format=api", "web_url": "http://patchwork.ozlabs.org/project/glibc/list/?series=502884", "date": "2026-05-05T19:06:49", "name": "nptl: Fix robust mutex support detection and defer robust list initialization", "version": 2, "mbox": "http://patchwork.ozlabs.org/series/502884/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/covers/2233152/comments/", "headers": { "Return-Path": "<libc-alpha-bounces~incoming=patchwork.ozlabs.org@sourceware.org>", "X-Original-To": [ "incoming@patchwork.ozlabs.org", "libc-alpha@sourceware.org" ], "Delivered-To": [ "patchwork-incoming@legolas.ozlabs.org", "libc-alpha@sourceware.org" ], "Authentication-Results": [ "legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=linaro.org header.i=@linaro.org header.a=rsa-sha256\n header.s=google header.b=s0OrrT6B;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=sourceware.org\n (client-ip=2620:52:6:3111::32; helo=vm01.sourceware.org;\n envelope-from=libc-alpha-bounces~incoming=patchwork.ozlabs.org@sourceware.org;\n receiver=patchwork.ozlabs.org)", "sourceware.org;\n\tdkim=pass (2048-bit key,\n unprotected) header.d=linaro.org header.i=@linaro.org header.a=rsa-sha256\n header.s=google header.b=s0OrrT6B", "sourceware.org;\n dmarc=pass (p=none dis=none) header.from=linaro.org", "sourceware.org; spf=pass smtp.mailfrom=linaro.org", "server2.sourceware.org;\n arc=none smtp.remote-ip=2607:f8b0:4864:20::e33" ], "Received": [ "from vm01.sourceware.org (vm01.sourceware.org\n [IPv6:2620:52:6:3111::32])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519 server-signature ECDSA (secp384r1) server-digest SHA384)\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4g97ND3Dkxz1yJx\n\tfor <incoming@patchwork.ozlabs.org>; Wed, 06 May 2026 05:08:59 +1000 (AEST)", "from vm01.sourceware.org (localhost [127.0.0.1])\n\tby sourceware.org (Postfix) with ESMTP id 3FF3A4BABF30\n\tfor <incoming@patchwork.ozlabs.org>; Tue, 5 May 2026 19:08:57 +0000 (GMT)", "from mail-vs1-xe33.google.com (mail-vs1-xe33.google.com\n [IPv6:2607:f8b0:4864:20::e33])\n by sourceware.org (Postfix) with ESMTPS id E171B4BA799B\n for <libc-alpha@sourceware.org>; Tue, 5 May 2026 19:08:16 +0000 (GMT)", "by mail-vs1-xe33.google.com with SMTP id\n ada2fe7eead31-60fee2fa3b8so1985861137.2\n for <libc-alpha@sourceware.org>; Tue, 05 May 2026 12:08:16 -0700 (PDT)", "from mandiga.. 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On architectures without __ASSUME_SET_ROBUST_LIST\n(e.g. riscv64), glibc probes the syscall at startup and correctly\npropagates the failure: pthread_mutex_init returns ENOTSUP for\nprocess-shared robust mutexes. On architectures with\n__ASSUME_SET_ROBUST_LIST (e.g. x86_64, aarch64), the runtime probe is\nskipped entirely, so the missing syscall goes undetected and\npthread_mutex_init silently returns success (BZ 33225).\n\nThe fix removes __ASSUME_SET_ROBUST_LIST and always probes for\nset_robust_list availability at runtime. As an additional improvement,\nthe probe is moved out of process/thread startup and deferred to the\nfirst actual robust mutex operation (pthread_mutex_init for\nprocess-shared+robust, or the first lock of any robust mutex). This\navoids the syscall altogether for programs that never use robust mutexes.\n\n[1] https://gitlab.com/qemu-project/qemu/-/issues/3044\nReported-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>\n\nAdhemerval Zanella (3):\n support: Add support_process_shared_robust_mutex\n nptl: Do not always assume set_robust_list availability (BZ 33225)\n nptl: Only initialize robust list at mutex usage\n\n nptl/Makefile | 2 +\n nptl/Versions | 1 -\n nptl/allocatestack.c | 9 +-\n nptl/descr.h | 31 +++++++\n nptl/nptl_robust_setup.c | 38 ++++++++\n nptl/pthread_create.c | 12 ---\n nptl/pthread_mutex_init.c | 5 +-\n nptl/pthread_mutex_lock.c | 2 +\n nptl/pthread_mutex_timedlock.c | 2 +\n nptl/pthread_mutex_trylock.c | 2 +\n nptl/tst-mutexpi10.c | 4 +-\n nptl/tst-robust-fork.c | 21 +++++\n nptl/tst-robust-pshared.c | 89 +++++++++++++++++++\n support/Makefile | 1 +\n support/support_mutex_robust.c | 34 +++++++\n support/xthread.h | 3 +\n sysdeps/nptl/_Fork.c | 24 ++---\n sysdeps/nptl/dl-tls_init_tp.c | 23 +----\n sysdeps/nptl/pthreadP.h | 8 +-\n sysdeps/pthread/tst-robust7.c | 1 -\n sysdeps/pthread/tst-robust8.c | 6 ++\n sysdeps/pthread/tst-robust9.c | 1 -\n sysdeps/unix/sysv/linux/arm/kernel-features.h | 7 --\n .../unix/sysv/linux/hppa/kernel-features.h | 3 -\n sysdeps/unix/sysv/linux/kernel-features.h | 5 --\n .../unix/sysv/linux/m68k/kernel-features.h | 5 --\n .../unix/sysv/linux/mips/kernel-features.h | 6 --\n .../unix/sysv/linux/riscv/kernel-features.h | 5 --\n .../unix/sysv/linux/sparc/kernel-features.h | 6 --\n 29 files changed, 251 insertions(+), 105 deletions(-)\n create mode 100644 nptl/nptl_robust_setup.c\n create mode 100644 nptl/tst-robust-pshared.c\n create mode 100644 support/support_mutex_robust.c" }