From patchwork Tue May 5 19:06:52 2026 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Adhemerval Zanella Netto X-Patchwork-Id: 2233154 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=linaro.org header.i=@linaro.org header.a=rsa-sha256 header.s=google header.b=AMFu/y49; dkim-atps=neutral Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=sourceware.org (client-ip=38.145.34.32; helo=vm01.sourceware.org; envelope-from=libc-alpha-bounces~incoming=patchwork.ozlabs.org@sourceware.org; receiver=patchwork.ozlabs.org) Received: from vm01.sourceware.org (vm01.sourceware.org [38.145.34.32]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519 server-signature ECDSA (secp384r1) server-digest SHA384) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4g97Nc0QCjz1yJx for ; Wed, 06 May 2026 05:08:59 +1000 (AEST) Received: from vm01.sourceware.org (localhost [127.0.0.1]) by sourceware.org (Postfix) with ESMTP id 27FF84BAD142 for ; Tue, 5 May 2026 19:08:58 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 27FF84BAD142 Authentication-Results: sourceware.org; dkim=pass (2048-bit key, unprotected) header.d=linaro.org header.i=@linaro.org header.a=rsa-sha256 header.s=google header.b=AMFu/y49 X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from mail-vs1-xe2b.google.com (mail-vs1-xe2b.google.com [IPv6:2607:f8b0:4864:20::e2b]) by sourceware.org (Postfix) with ESMTPS id 5E9E74BA79A2 for ; Tue, 5 May 2026 19:08:26 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 5E9E74BA79A2 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=linaro.org Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=linaro.org ARC-Filter: OpenARC Filter v1.0.0 sourceware.org 5E9E74BA79A2 Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=2607:f8b0:4864:20::e2b ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1778008106; cv=none; b=dVJYK8BKXSkPK4kyQb0jnarin35M0V6cKwpFmsBdsTgrWhwhDnlape9LCqdCezbauGgwj9A1sAE3p3X73QOAhzo6OQbwYodUZLygwrG5I1AeTd5UW6rlqWZgcl2z9YOPbegnuMGKAKB3d19mRLmrYhZkxJMWJ+tn+xZCN99zI+4= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1778008106; c=relaxed/simple; bh=L3pZ5rrC4x2yTQdRKpOevEtZJizWu1R5GAEmoIUUrFo=; h=DKIM-Signature:From:To:Subject:Date:Message-ID:MIME-Version; b=FTR99biuxUvJ/NtiCe0L2zitXtKzC8nloRIpOkxHxyR4af3pT5a6+McCC1D/h0LhC7f0u56DHM+LGFpF4aJYruUriCSzwms/H1Xlwp7O9JZKjjkzXF51JZhuu7g+zKuWQvcIsAhudjT768q5l1BU1HQMWjPHaQ2a99HO6F36Xc8= ARC-Authentication-Results: i=1; server2.sourceware.org DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 5E9E74BA79A2 Received: by mail-vs1-xe2b.google.com with SMTP id ada2fe7eead31-62f390b8df7so1606684137.1 for ; Tue, 05 May 2026 12:08:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1778008105; x=1778612905; darn=sourceware.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=jxFmbu9+XBXAKdKF0W4t5VOJl29THVzXXkcLcNbj4Ss=; b=AMFu/y49PzX1z6nfB0l9IE/2A1aAOeRDyV7pz3vReF0/0DyjDUIzgOUPohw8DYvPBL mqdgEf0DQN1kteKhUTE/kaoDYYJSAkyGBBK3GTxXqbNhNvcNAGhwiNHBQNZgvTJcpJKM RmeY0JF3GlAvnF8FpPgZ45oS4e31kGmqlDtX+MTVZn6q5E+EgI9vqkcAczKGPGjF22SI T8Zi9+pjmc4/g+cTUJ9UiSb8+xeMVufPBGLEE9UmVaZQanTAxQA/k2eV6K2wpWlXUAYg klRvp9DO4b/IPlveJxzb79Jka2uTQq41a/9Dn9rAg5FF7QtIz7AGMMt5dG1LsT4MqIhq FWdw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1778008105; x=1778612905; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=jxFmbu9+XBXAKdKF0W4t5VOJl29THVzXXkcLcNbj4Ss=; b=s9/rG3HV4P1l1k3pwzdQjOV/9+ZLybuz8iWJoc/rLRLzIJN7adLzQ6Q9XzutjcMvX2 vRiwKoAFGhhlGzBF3qz0gQI7FWc7JecFX1ZZ6tgEaMoxnBHhJTlm/549UPrtZsD9XCJR yq+tS5JV4BJabVuw8I2OciJwyn1ipTJmSyDEHV80sEsO3eBdt9Zrof15IiZbwt8IoT+N nnXehISBFsrn6/aYQ+fo9OlB7y91Y2twLSSeD4oDPVgBabg4Vc9Xi6YMwF9u22gjsCTw IS33ulvhLeYwwtYPCQAW+GH68SZhPyweYb5w7OZYiQ6gk1agQZPjjn/MwH/Tk2tI5Ez5 xwXg== X-Gm-Message-State: AOJu0Yw6xPaXNtiMlREfhD6FANXVTnb7KKSTpQrUyC14mhHRJIhkdcQ/ NN5RAy+utO+cSJRMKtFMCmRAcmcLsSobAx08zH7KIF22gETv0cIBcS2Di+XHGL60ZFZV1dT4cMA DAGEc X-Gm-Gg: AeBDieseoYIbU1romLIXF+HLbw/G4iBsMnIWGCKlg/EsHeiEACSXnAd0f7Q7hfj2bnV e7Olw8bItrzFd9GWtBQi0DOM6gmxvNIH2gr0fXY7/TdJqYfOktL4zg2ASSaFArit+3sxKX31uyh xr2MfM7kj4xJGZQ9P6B/css43Ld43zaMQYhlUb1tPSoJ1X/ugpCP79Kzv60PH9L0R0/ZF/Cyc9K Ywg4mKtvW967O/vWATeVx0ne+sF3gGtESiQ4LEFGC1zP3jGBaE3qLwngJVTxchdrXNqBXhtnaW6 isZWqkBFZB1DtIcre9WoNm5T6WX6BoXl/z0ghxjI/K9DaCDDG9qA8MugVvHxqVOCGVeMhWoupeq 9K+BAOx9bcP115tseE4iqJyW9RDdVjCzhLEpHz9j0Kk8JhoVAh3ieVN52vQw5UFSgbdST7WDh3T AQ1sG31ZD/jPsiHPrnj+zVLeHYDSKlAfp8MmYozPNP8Ac= X-Received: by 2002:a05:6102:802a:b0:618:3503:5659 with SMTP id ada2fe7eead31-62f591dbcfemr3622245137.14.1778008104395; Tue, 05 May 2026 12:08:24 -0700 (PDT) Received: from mandiga.. ([2804:1b3:a7c1:364:abee:44ff:b045:5a7]) by smtp.gmail.com with ESMTPSA id a1e0cc1a2514c-95ce08f4a7asm7504046241.5.2026.05.05.12.08.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 05 May 2026 12:08:23 -0700 (PDT) From: Adhemerval Zanella To: libc-alpha@sourceware.org Cc: Florian Weimer Subject: [PATCH v2 3/3] nptl: Only initialize robust list at mutex usage Date: Tue, 5 May 2026 16:06:52 -0300 Message-ID: <20260505190809.3898686-4-adhemerval.zanella@linaro.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260505190809.3898686-1-adhemerval.zanella@linaro.org> References: <20260505190809.3898686-1-adhemerval.zanella@linaro.org> MIME-Version: 1.0 X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.30 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: libc-alpha-bounces~incoming=patchwork.ozlabs.org@sourceware.org The set_robust_list syscall is currently called unconditionally at process startup (__tls_init_tp) and on every thread creation (pthread_create), even in programs that never use robust mutexes. This patch defers the call to the first time a robust mutex is actually locked or initialized with PTHREAD_PROCESS_SHARED. The new helper robust_list_setup() performs the deferred registration and is called from pthread_mutex_init (for pshared+robust), pthread_mutex_lock, pthread_mutex_trylock, and pthread_mutex_timedlock. The field robust_head.futex_offset serves as a sentinel: zero means the list has not been registered with the kernel; non-zero means it has. robust_list_setup() sets futex_offset to its correct value before calling set_robust_list, so the kernel always reads a valid offset when it walks the list on thread death. On syscall failure futex_offset is reset to zero. _Fork is updated to re-register the list with the kernel only when the parent had already initialized it (futex_offset != 0). If the parent never used robust mutexes, the child's first robust mutex lock calls robust_list_setup() itself. The __nptl_set_robust_list_avail variable moves from ld.so to libc.so, since it no longer needs to be set during pthread startup. Checked on x86_64-linux-gnu and aarch64-linux-gnu. --- nptl/Makefile | 2 + nptl/Versions | 1 - nptl/allocatestack.c | 9 +--- nptl/descr.h | 31 ++++++++++++ nptl/nptl_robust_setup.c | 38 +++++++++++++++ nptl/pthread_create.c | 8 --- nptl/pthread_mutex_init.c | 2 +- nptl/pthread_mutex_lock.c | 2 + nptl/pthread_mutex_timedlock.c | 2 + nptl/pthread_mutex_trylock.c | 2 + nptl/tst-robust-pshared.c | 89 ++++++++++++++++++++++++++++++++++ sysdeps/nptl/_Fork.c | 24 ++++----- sysdeps/nptl/dl-tls_init_tp.c | 17 +------ sysdeps/nptl/pthreadP.h | 6 +-- 14 files changed, 183 insertions(+), 50 deletions(-) create mode 100644 nptl/nptl_robust_setup.c create mode 100644 nptl/tst-robust-pshared.c diff --git a/nptl/Makefile b/nptl/Makefile index 02862d1c04b..c9c7fc00f55 100644 --- a/nptl/Makefile +++ b/nptl/Makefile @@ -50,6 +50,7 @@ routines = \ nptl_deallocate_tsd \ nptl_free_tcb \ nptl_nthreads \ + nptl_robust_setup \ nptl_setxid \ nptlfreeres \ old_pthread_cond_broadcast \ @@ -326,6 +327,7 @@ tests = \ tst-pthread_exit-nothreads-static \ tst-pthread_gettid_np \ tst-robust-fork \ + tst-robust-pshared \ tst-robustpi1 \ tst-robustpi2 \ tst-robustpi3 \ diff --git a/nptl/Versions b/nptl/Versions index b813b675b91..94a567bd609 100644 --- a/nptl/Versions +++ b/nptl/Versions @@ -535,6 +535,5 @@ libpthread { ld { GLIBC_PRIVATE { __nptl_initial_report_events; - __nptl_set_robust_list_avail; } } diff --git a/nptl/allocatestack.c b/nptl/allocatestack.c index b2ecb001136..fcccc75ddb8 100644 --- a/nptl/allocatestack.c +++ b/nptl/allocatestack.c @@ -631,14 +631,7 @@ allocate_stack (const struct pthread_attr *attr, struct pthread **pdp, /* The robust mutex lists also need to be initialized unconditionally because the cleanup for the previous stack owner might have happened in the kernel. */ - pd->robust_head.futex_offset = (offsetof (pthread_mutex_t, __data.__lock) - - offsetof (pthread_mutex_t, - __data.__list.__next)); - pd->robust_head.list_op_pending = NULL; -#if __PTHREAD_MUTEX_HAVE_PREV - pd->robust_prev = &pd->robust_head; -#endif - pd->robust_head.list = &pd->robust_head; + robust_list_init (pd); /* We place the thread descriptor at the end of the stack. */ *pdp = pd; diff --git a/nptl/descr.h b/nptl/descr.h index 627cc3980f0..308100c0c30 100644 --- a/nptl/descr.h +++ b/nptl/descr.h @@ -458,6 +458,37 @@ cancel_enabled_and_canceled_and_async (int value) == (CANCELTYPE_BITMASK | CANCELED_BITMASK); } +static inline void +robust_list_init (struct pthread *pd) +{ + pd->robust_head.list_op_pending = NULL; +#if __PTHREAD_MUTEX_HAVE_PREV + pd->robust_prev = &pd->robust_head; +#endif + pd->robust_head.list = &pd->robust_head; + pd->robust_head.futex_offset = 0; +} + +extern bool __nptl_robust_setup (struct robust_list_head *robust_head) + attribute_hidden; + +static inline bool +robust_list_setup (struct pthread *pd) +{ + /* The current thread was already initialized. */ + if (pd->robust_head.futex_offset != 0) + return true; + + pd->robust_head.futex_offset = (offsetof (pthread_mutex_t, __data.__lock) + - offsetof (pthread_mutex_t, + __data.__list.__next)); + if (__nptl_robust_setup (&pd->robust_head)) + return true; + + pd->robust_head.futex_offset = 0; + return false; +} + /* This yields the pointer that TLS support code calls the thread pointer. */ #if TLS_TCB_AT_TP # define TLS_TPADJ(pd) (pd) diff --git a/nptl/nptl_robust_setup.c b/nptl/nptl_robust_setup.c new file mode 100644 index 00000000000..0b95de22009 --- /dev/null +++ b/nptl/nptl_robust_setup.c @@ -0,0 +1,38 @@ +/* Linux robust mutex setup. + Copyright (C) 2025 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include +#include +#include + +int __nptl_set_robust_list_avail = 1; + +bool +__nptl_robust_setup (struct robust_list_head *robust_head) +{ + if (atomic_load_relaxed (&__nptl_set_robust_list_avail)) + { + int res = INTERNAL_SYSCALL_CALL (set_robust_list, robust_head, + sizeof (struct robust_list_head)); + if (!INTERNAL_SYSCALL_ERROR_P (res)) + return true; + + atomic_store_relaxed (&__nptl_set_robust_list_avail, 0); + } + return false; +} diff --git a/nptl/pthread_create.c b/nptl/pthread_create.c index 72f77d1914e..d7aed06efda 100644 --- a/nptl/pthread_create.c +++ b/nptl/pthread_create.c @@ -386,14 +386,6 @@ start_thread (void *arg) __libc_fatal ("Fatal glibc error: rseq registration failed\n"); } - if (__nptl_set_robust_list_avail) - { - /* This call should never fail because the initial call in init.c - succeeded. */ - INTERNAL_SYSCALL_CALL (set_robust_list, &pd->robust_head, - sizeof (struct robust_list_head)); - } - /* This is where the try/finally block should be created. For compilers without that support we do use setjmp. */ struct pthread_unwind_buf unwind_buf; diff --git a/nptl/pthread_mutex_init.c b/nptl/pthread_mutex_init.c index 9be08332f1f..2f0bb84c557 100644 --- a/nptl/pthread_mutex_init.c +++ b/nptl/pthread_mutex_init.c @@ -94,7 +94,7 @@ ___pthread_mutex_init (pthread_mutex_t *mutex, if ((imutexattr->mutexkind & PTHREAD_MUTEXATTR_FLAG_ROBUST) != 0) { if ((imutexattr->mutexkind & PTHREAD_MUTEXATTR_FLAG_PSHARED) != 0 - && !__nptl_set_robust_list_avail) + && !robust_list_setup (THREAD_SELF)) return ENOTSUP; mutex_kind |= PTHREAD_MUTEX_ROBUST_NORMAL_NP; } diff --git a/nptl/pthread_mutex_lock.c b/nptl/pthread_mutex_lock.c index a697f2b6ca8..f649036d954 100644 --- a/nptl/pthread_mutex_lock.c +++ b/nptl/pthread_mutex_lock.c @@ -177,6 +177,7 @@ __pthread_mutex_lock_full (pthread_mutex_t *mutex) case PTHREAD_MUTEX_ROBUST_ERRORCHECK_NP: case PTHREAD_MUTEX_ROBUST_NORMAL_NP: case PTHREAD_MUTEX_ROBUST_ADAPTIVE_NP: + robust_list_setup (THREAD_SELF); THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, &mutex->__data.__list.__next); /* We need to set op_pending before starting the operation. Also @@ -361,6 +362,7 @@ __pthread_mutex_lock_full (pthread_mutex_t *mutex) if (robust) { + robust_list_setup (THREAD_SELF); /* Note: robust PI futexes are signaled by setting bit 0. */ THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, (void *) (((uintptr_t) &mutex->__data.__list.__next) diff --git a/nptl/pthread_mutex_timedlock.c b/nptl/pthread_mutex_timedlock.c index 9efca2c7791..a52ed795df0 100644 --- a/nptl/pthread_mutex_timedlock.c +++ b/nptl/pthread_mutex_timedlock.c @@ -111,6 +111,7 @@ __pthread_mutex_clocklock_common (pthread_mutex_t *mutex, case PTHREAD_MUTEX_ROBUST_ERRORCHECK_NP: case PTHREAD_MUTEX_ROBUST_NORMAL_NP: case PTHREAD_MUTEX_ROBUST_ADAPTIVE_NP: + robust_list_setup (THREAD_SELF); THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, &mutex->__data.__list.__next); /* We need to set op_pending before starting the operation. Also @@ -295,6 +296,7 @@ __pthread_mutex_clocklock_common (pthread_mutex_t *mutex, if (robust) { + robust_list_setup (THREAD_SELF); /* Note: robust PI futexes are signaled by setting bit 0. */ THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, (void *) (((uintptr_t) &mutex->__data.__list.__next) diff --git a/nptl/pthread_mutex_trylock.c b/nptl/pthread_mutex_trylock.c index 236b3228ddb..09c5dc983b2 100644 --- a/nptl/pthread_mutex_trylock.c +++ b/nptl/pthread_mutex_trylock.c @@ -77,6 +77,7 @@ ___pthread_mutex_trylock (pthread_mutex_t *mutex) case PTHREAD_MUTEX_ROBUST_ERRORCHECK_NP: case PTHREAD_MUTEX_ROBUST_NORMAL_NP: case PTHREAD_MUTEX_ROBUST_ADAPTIVE_NP: + robust_list_setup (THREAD_SELF); THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, &mutex->__data.__list.__next); /* We need to set op_pending before starting the operation. Also @@ -219,6 +220,7 @@ ___pthread_mutex_trylock (pthread_mutex_t *mutex) if (robust) { + robust_list_setup (THREAD_SELF); /* Note: robust PI futexes are signaled by setting bit 0. */ THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, (void *) (((uintptr_t) &mutex->__data.__list.__next) diff --git a/nptl/tst-robust-pshared.c b/nptl/tst-robust-pshared.c new file mode 100644 index 00000000000..4074ffa494b --- /dev/null +++ b/nptl/tst-robust-pshared.c @@ -0,0 +1,89 @@ +/* Test process-shared robust mutex support and lazy initialization (BZ 33225). + Copyright (C) 2025 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +/* Verify that pthread_mutex_init returns ENOTSUP for a process-shared robust + mutex when the set_robust_list syscall is not available (e.g., qemu-user), + and that the lazy robust list initialization works correctly when the + syscall is available. */ + +#include +#include +#include +#include +#include +#include +#include + +/* Lock the mutex and exit without unlocking to trigger EOWNERDEAD. */ +static void * +owner_thread (void *arg) +{ + pthread_mutex_t *mutex = arg; + TEST_COMPARE (pthread_mutex_lock (mutex), 0); + /* Thread exits here without unlocking. The kernel walks the robust + list registered via set_robust_list and marks the mutex owner-dead. + This verifies that lazy robust_list_setup correctly set futex_offset + and called set_robust_list before the first lock. */ + return NULL; +} + +static int +do_test (void) +{ + bool robust_support = support_process_shared_robust_mutex (); + if (test_verbose) + printf ("info: process-shared robust mutex support: %d\n", robust_support); + + pthread_mutexattr_t attr; + TEST_COMPARE (pthread_mutexattr_init (&attr), 0); + TEST_COMPARE (pthread_mutexattr_setpshared (&attr, PTHREAD_PROCESS_SHARED), + 0); + TEST_COMPARE (pthread_mutexattr_setrobust (&attr, PTHREAD_MUTEX_ROBUST), 0); + + pthread_mutex_t mutex; + int ret = pthread_mutex_init (&mutex, &attr); + TEST_COMPARE (pthread_mutexattr_destroy (&attr), 0); + + if (!robust_support) + { + /* When set_robust_list is unavailable, pshared+robust mutex init + must fail with ENOTSUP rather than silently succeeding. */ + TEST_COMPARE (ret, ENOTSUP); + return 0; + } + + TEST_COMPARE (ret, 0); + + /* Have a thread lock the mutex and exit without unlocking. + This exercises the lazy robust_list_setup path in + pthread_mutex_lock: futex_offset must be set before set_robust_list + is called so the kernel can correctly compute the lock address on + thread death. */ + pthread_t thread; + TEST_COMPARE (pthread_create (&thread, NULL, owner_thread, &mutex), 0); + TEST_COMPARE (pthread_join (thread, NULL), 0); + + TEST_COMPARE (pthread_mutex_lock (&mutex), EOWNERDEAD); + TEST_COMPARE (pthread_mutex_consistent (&mutex), 0); + TEST_COMPARE (pthread_mutex_unlock (&mutex), 0); + TEST_COMPARE (pthread_mutex_destroy (&mutex), 0); + + return 0; +} + +#include diff --git a/sysdeps/nptl/_Fork.c b/sysdeps/nptl/_Fork.c index 907b3fef876..ba6912aa346 100644 --- a/sysdeps/nptl/_Fork.c +++ b/sysdeps/nptl/_Fork.c @@ -35,22 +35,22 @@ _Fork (void) { struct pthread *self = THREAD_SELF; - /* Initialize the robust mutex list setting in the kernel which has - been reset during the fork. We do not check for errors because if - it fails here, it must have failed at process startup as well and - nobody could have used robust mutexes. - Before we do that, we have to clear the list of robust mutexes - because we do not inherit ownership of mutexes from the parent. - We do not have to set self->robust_head.futex_offset since we do - inherit the correct value from the parent. We do not need to clear - the pending operation because it must have been zero when fork was - called. */ + /* Clear the list of robust mutexes because we do not inherit ownership + of mutexes from the parent. We do not need to clear the pending + operation because it must have been zero when fork was called. + futex_offset is inherited from the parent unchanged. */ #if __PTHREAD_MUTEX_HAVE_PREV self->robust_prev = &self->robust_head; #endif self->robust_head.list = &self->robust_head; - INTERNAL_SYSCALL_CALL (set_robust_list, &self->robust_head, - sizeof (struct robust_list_head)); + /* Re-register the robust list with the kernel only if the parent had + already initialized it. futex_offset is the sentinel: zero means + lazy initialization has not happened yet, so there is nothing to + re-register and the first robust mutex lock in the child will call + set_robust_list itself. */ + if (self->robust_head.futex_offset != 0) + INTERNAL_SYSCALL_CALL (set_robust_list, &self->robust_head, + sizeof (struct robust_list_head)); call_function_static_weak (__getrandom_fork_subprocess); } diff --git a/sysdeps/nptl/dl-tls_init_tp.c b/sysdeps/nptl/dl-tls_init_tp.c index 75e3712a6d8..77f2e341822 100644 --- a/sysdeps/nptl/dl-tls_init_tp.c +++ b/sysdeps/nptl/dl-tls_init_tp.c @@ -28,9 +28,6 @@ #define TUNABLE_NAMESPACE pthread #include -bool __nptl_set_robust_list_avail; -rtld_hidden_data_def (__nptl_set_robust_list_avail) - bool __nptl_initial_report_events; rtld_hidden_def (__nptl_initial_report_events) @@ -82,19 +79,7 @@ __tls_init_tp (void) THREAD_SETMEM (pd, report_events, __nptl_initial_report_events); /* Initialize the robust mutex data. */ - { -#if __PTHREAD_MUTEX_HAVE_PREV - pd->robust_prev = &pd->robust_head; -#endif - pd->robust_head.list = &pd->robust_head; - pd->robust_head.futex_offset = (offsetof (pthread_mutex_t, __data.__lock) - - offsetof (pthread_mutex_t, - __data.__list.__next)); - int res = INTERNAL_SYSCALL_CALL (set_robust_list, &pd->robust_head, - sizeof (struct robust_list_head)); - if (!INTERNAL_SYSCALL_ERROR_P (res)) - __nptl_set_robust_list_avail = true; - } + robust_list_init (pd); { /* If the registration fails or is disabled by tunable, the public diff --git a/sysdeps/nptl/pthreadP.h b/sysdeps/nptl/pthreadP.h index c62c8982905..38a1383c3fe 100644 --- a/sysdeps/nptl/pthreadP.h +++ b/sysdeps/nptl/pthreadP.h @@ -192,10 +192,8 @@ libc_hidden_proto (__pthread_keys) extern unsigned int __nptl_nthreads; libc_hidden_proto (__nptl_nthreads) -/* True if the set_robust_list system call works. Initialized in - __tls_init_tp. */ -extern bool __nptl_set_robust_list_avail; -rtld_hidden_proto (__nptl_set_robust_list_avail) +/* Set if the set_robust_list system call works. */ +extern int __nptl_set_robust_list_avail attribute_hidden; /* Thread Priority Protection. */ extern int __sched_fifo_min_prio;