From owner-svn-src-projects@freebsd.org Sat Aug 15 22:58:07 2020 Return-Path: Delivered-To: svn-src-projects@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id AD83A3A979A for ; Sat, 15 Aug 2020 22:58:07 +0000 (UTC) (envelope-from dim@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4BTbLl43F2z4rH6; Sat, 15 Aug 2020 22:58:07 +0000 (UTC) (envelope-from dim@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 6EBB5267AD; Sat, 15 Aug 2020 22:58:07 +0000 (UTC) (envelope-from dim@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id 07FMw7bI050962; Sat, 15 Aug 2020 22:58:07 GMT (envelope-from dim@FreeBSD.org) Received: (from dim@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id 07FMw7ob050961; Sat, 15 Aug 2020 22:58:07 GMT (envelope-from dim@FreeBSD.org) Message-Id: <202008152258.07FMw7ob050961@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: dim set sender to dim@FreeBSD.org using -f From: Dimitry Andric Date: Sat, 15 Aug 2020 22:58:07 +0000 (UTC) To: src-committers@freebsd.org, svn-src-projects@freebsd.org Subject: svn commit: r364263 - projects/clang1100-import/contrib/llvm-project/libunwind/src X-SVN-Group: projects X-SVN-Commit-Author: dim X-SVN-Commit-Paths: projects/clang1100-import/contrib/llvm-project/libunwind/src X-SVN-Commit-Revision: 364263 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-projects@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: "SVN commit messages for the src " projects" tree" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 15 Aug 2020 22:58:07 -0000 Author: dim Date: Sat Aug 15 22:58:07 2020 New Revision: 364263 URL: https://svnweb.freebsd.org/changeset/base/364263 Log: Temporarily disable libunwind's FrameHeaderCache, until there is a resolution for . The cache implementation depends on dl_iterate_phdr(3) ensuring that its callbacks are not called simultaneously for multiple threads, but that is only the case for the dl_iterate_phdr() implementation in rtld. In a statically linked executable, libc's dl_iterate_phdr() is used, which does no such locking. If multiple threads then call into the unwinder at the same time, it is possible to trigger a segfault. In particular, the statically linked lld which is built during the cross-tools stage can segfault in this way, because it starts multiple worker threads that can exit in parallel. Since our pthread_exit(3) invokes the unwinder, it will therefore call into it in parallel too. Modified: projects/clang1100-import/contrib/llvm-project/libunwind/src/AddressSpace.hpp Modified: projects/clang1100-import/contrib/llvm-project/libunwind/src/AddressSpace.hpp ============================================================================== --- projects/clang1100-import/contrib/llvm-project/libunwind/src/AddressSpace.hpp Sat Aug 15 21:40:36 2020 (r364262) +++ projects/clang1100-import/contrib/llvm-project/libunwind/src/AddressSpace.hpp Sat Aug 15 22:58:07 2020 (r364263) @@ -452,10 +452,12 @@ struct _LIBUNWIND_HIDDEN dl_iterate_cb_data { #error "_LIBUNWIND_SUPPORT_DWARF_UNWIND requires _LIBUNWIND_SUPPORT_DWARF_INDEX on this platform." #endif +#if defined(_LIBUNWIND_USE_FRAME_HEADER_CACHE) #include "FrameHeaderCache.hpp" // There should be just one of these per process. static FrameHeaderCache ProcessFrameHeaderCache; +#endif // _LIBUNWIND_USE_FRAME_HEADER_CACHE static bool checkAddrInSegment(const Elf_Phdr *phdr, size_t image_base, dl_iterate_cb_data *cbdata) { @@ -476,8 +478,10 @@ int findUnwindSectionsByPhdr(struct dl_phdr_info *pinf auto cbdata = static_cast(data); if (pinfo->dlpi_phnum == 0 || cbdata->targetAddr < pinfo->dlpi_addr) return 0; +#if defined(_LIBUNWIND_USE_FRAME_HEADER_CACHE) if (ProcessFrameHeaderCache.find(pinfo, pinfo_size, data)) return 1; +#endif // _LIBUNWIND_USE_FRAME_HEADER_CACHE Elf_Addr image_base = calculateImageBase(pinfo); bool found_obj = false; @@ -505,7 +509,9 @@ int findUnwindSectionsByPhdr(struct dl_phdr_info *pinf found_obj = checkAddrInSegment(phdr, image_base, cbdata); } if (found_obj && found_hdr) { +#if defined(_LIBUNWIND_USE_FRAME_HEADER_CACHE) ProcessFrameHeaderCache.add(cbdata->sects); +#endif // _LIBUNWIND_USE_FRAME_HEADER_CACHE return 1; } }