{"id":2227758,"url":"http://patchwork.ozlabs.org/api/1.1/patches/2227758/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/patch/616E96C0-F0A5-4A9E-A63B-3BC1B5F18094@gmail.com/","project":{"id":14,"url":"http://patchwork.ozlabs.org/api/1.1/projects/14/?format=json","name":"QEMU Development","link_name":"qemu-devel","list_id":"qemu-devel.nongnu.org","list_email":"qemu-devel@nongnu.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<616E96C0-F0A5-4A9E-A63B-3BC1B5F18094@gmail.com>","date":"2026-04-24T08:19:39","name":"build: prefer sigaltstack over ucontext on Linux","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"bc9c96ed233b1e3bc26be1dcaed2b30a32ef917f","submitter":{"id":93247,"url":"http://patchwork.ozlabs.org/api/1.1/people/93247/?format=json","name":"Elisey Konstantinov","email":"elisey.konstantinov@gmail.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/qemu-devel/patch/616E96C0-F0A5-4A9E-A63B-3BC1B5F18094@gmail.com/mbox/","series":[{"id":501316,"url":"http://patchwork.ozlabs.org/api/1.1/series/501316/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/list/?series=501316","date":"2026-04-24T08:19:39","name":"build: prefer sigaltstack over ucontext on Linux","version":1,"mbox":"http://patchwork.ozlabs.org/series/501316/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2227758/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2227758/checks/","tags":{},"headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256\n header.s=20251104 header.b=FG/Bj/3S;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; helo=lists1p.gnu.org;\n envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n receiver=patchwork.ozlabs.org)"],"Received":["from lists1p.gnu.org (lists1p.gnu.org [209.51.188.17])\n\t(using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4g25VY42Jqz1yDD\n\tfor ; Fri, 24 Apr 2026 18:20:05 +1000 (AEST)","from localhost ([::1] helo=lists1p.gnu.org)\n\tby lists1p.gnu.org with esmtp (Exim 4.90_1)\n\t(envelope-from )\n\tid 1wGBlW-0000MD-Tm; Fri, 24 Apr 2026 04:19:58 -0400","from eggs.gnu.org ([2001:470:142:3::10])\n by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256)\n (Exim 4.90_1) (envelope-from )\n id 1wGBlV-0000M2-9y\n for qemu-devel@nongnu.org; Fri, 24 Apr 2026 04:19:57 -0400","from mail-wr1-x42b.google.com ([2a00:1450:4864:20::42b])\n by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128)\n (Exim 4.90_1) (envelope-from )\n id 1wGBlT-0006OU-Mt\n for qemu-devel@nongnu.org; Fri, 24 Apr 2026 04:19:57 -0400","by mail-wr1-x42b.google.com with SMTP id\n ffacd0b85a97d-43fe8bda8e9so4100005f8f.1\n for ; Fri, 24 Apr 2026 01:19:54 -0700 (PDT)","from smtpclient.apple ([5.32.173.67])\n by smtp.gmail.com with ESMTPSA id\n ffacd0b85a97d-43fe4e4d6casm54940068f8f.32.2026.04.24.01.19.50\n (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128);\n Fri, 24 Apr 2026 01:19:51 -0700 (PDT)"],"DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed;\n d=gmail.com; s=20251104; t=1777018792; x=1777623592; darn=nongnu.org;\n h=to:cc:date:message-id:subject:mime-version\n :content-transfer-encoding:from:from:to:cc:subject:date:message-id\n :reply-to; bh=d77vENISFV3A65XabyMzbFCvFzAjCcNL7BdC1hwSU8k=;\n b=FG/Bj/3SQjsBWVE0n6c9RUZXKgVwPLDTwQF2/kcAV0H3k+C085ccR7LaknUJS9QeeZ\n rcKSTEdJSN841r0IAHBuvwmAcehCnm+ZEMdsGtmafYgEQ6GBARMdtZcnWdXLsT+pyk9l\n wOLl6gmWje90Nad9RCcRs9HfTafuhmEHFhOG/ILlrluTwB0yAPSYpMvuEgTlsT819DcZ\n ins/DqDb7uvAcn2JvmOAUaGI1Hhntaav4Nto3TUxqaHKqaIKH0EXTe84l5b9nA2CcY0b\n kLg1BRPvKLSYnvVYEtt2zM5JMyDFvK9rkHWDOspmaxlhpSaVDb/nw3DTrwAOB5ZMKpKX\n sLyg==","X-Google-DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed;\n d=1e100.net; s=20251104; t=1777018792; x=1777623592;\n h=to:cc:date:message-id:subject:mime-version\n :content-transfer-encoding:from:x-gm-gg:x-gm-message-state:from:to\n :cc:subject:date:message-id:reply-to;\n bh=d77vENISFV3A65XabyMzbFCvFzAjCcNL7BdC1hwSU8k=;\n b=E7SHcDl65n+R5YBGtxKfTNgt7nytpMUzFge7f3bT7f2vjDe2rs+QNSWrGeAL+8C7EQ\n HCqKGGhu0YFnXeL8JWBCBT+HfDYTZhOOUFgrjwbiF2euGJKDEPQf5EMSVSpjrWGhLG3R\n 1TlLa3GJsSci7kt6m518VMkETSqagdAkjku0TCj3Y8ZqPK/k+2cIcZPYOvrDVXEcXmND\n twfdAbJrN6h7owks9hiRX0Bx9Mo/Ht7mcgDhGxUtVeGTRy/yooKorrkmtMq4d/4BFRZD\n e4u7ah70GgQ+RSBuSU4mFArdVvI2HUJZ0lMJE/494rrueVXTx+uZ27wxN4dqegLsF64c\n HjHQ==","X-Gm-Message-State":"AOJu0YxAZ5poBA6GrR0ovCDSU8jBQaYhdK0bZZl9OYpCZQry+Er55eZX\n GdeCQjWjI9GvA4sgLGTZMQ7ojdf9aRzzi0Hzn7Hg86is1vYRp7Jz/1KniD62/67A","X-Gm-Gg":"AeBDieuZitkoRkLbstbr11bmiwZ6EVmsHevD4pAbdZkI85xEO0+JI+2grCOcRZyFerY\n egCee3g0anhvPE6w3UkkHgxqv42s5foidEsZ0AvJiPMv7IvaK7KmhhFZPkL8PWBFKCIOUMemch8\n ZO1NKCT8AS1Nzt8K+/X+ON/rU0KcSWTftnQKlib31qj2zR+A90k1yy+BwhRtsr2Jgn9peaC7m+A\n qX1KvtTwQ/CCfO2nQNND9Ua6eIIpSuPgTf7Olm4THMFUQNxVB/nxNx2/24OzY35UZtnKDkRila4\n FLUreo13cnjprREv1I6mPaADpGLP2h971ix+IZ+kb62fbcfPzcWFNvOFVtKR6Xg1EJQdAI5P/8L\n LkG0RXOkhtU9THAETb+YZfVuq7W5mHTiJgtOvhanhBBtaUPh+Wguvy24uvTxTjD7SPmp1WXupIB\n bF/oOc1aeOi1bUyqCY90qxbhFB7KEpAxaPOSi+nnXVl4CbFSgTpOVcWAMg1IT8R+u1vsaiZtYC4\n Kg=","X-Received":"by 2002:a05:6000:2289:b0:43c:f793:f1c5 with SMTP id\n ffacd0b85a97d-43fe3e0c63cmr47731903f8f.34.1777018791601;\n Fri, 24 Apr 2026 01:19:51 -0700 (PDT)","From":"Elisey Konstantinov ","Content-Type":"text/plain;\n\tcharset=us-ascii","Content-Transfer-Encoding":"quoted-printable","Mime-Version":"1.0 (Mac OS X Mail 16.0 \\(3864.500.181\\))","Subject":"[PATCH] build: prefer sigaltstack over ucontext on Linux","Message-Id":"<616E96C0-F0A5-4A9E-A63B-3BC1B5F18094@gmail.com>","Date":"Fri, 24 Apr 2026 11:19:39 +0300","Cc":"pbonzini@redhat.com, marcandre.lureau@redhat.com, berrange@redhat.com,\n philmd@linaro.org","To":"qemu-devel@nongnu.org","X-Mailer":"Apple Mail (2.3864.500.181)","Received-SPF":"pass client-ip=2a00:1450:4864:20::42b;\n envelope-from=elisey.konstantinov@gmail.com; helo=mail-wr1-x42b.google.com","X-Spam_score_int":"-20","X-Spam_score":"-2.1","X-Spam_bar":"--","X-Spam_report":"(-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1,\n DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001,\n RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001,\n SPF_PASS=-0.001 autolearn=ham autolearn_force=no","X-Spam_action":"no action","X-BeenThere":"qemu-devel@nongnu.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"qemu development ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org"},"content":"From 517099e65de1e2ad3d0f33d3c4a7a71f8728279c Mon Sep 17 00:00:00 2001\nFrom: Elisey \nDate: Mon, 23 Mar 2026 16:02:45 +0100\nSubject: [PATCH] build: prefer sigaltstack over ucontext on Linux\n\nsigaltstack coroutine backend is more stable on some Linux\nconfigurations, while ucontext causes boot failures for certain\nPPC Mac OS X guests (issue #3276).\n\nSelect sigaltstack first when available, keeping ucontext as fallback\nuntil the underlying issue is resolved.\n\nSigned-off-by: Elisey Konstantinov \n---\n meson.build | 4 +++-\n 1 file changed, 3 insertions(+), 1 deletion(-)","diff":"diff --git a/meson.build b/meson.build\nindex ab3e97eb9f..742655e007 100644\n--- a/meson.build\n+++ b/meson.build\n@@ -505,10 +505,12 @@ if host_os == 'windows'\n elif host_os == 'emscripten'\n supported_backends += ['wasm']\n else\n+ # FIXME: This is a temporary workaround!\n+ # SigAltStack is in higher priority to fix #3276\n+ supported_backends += ['sigaltstack']\n if host_os != 'darwin' and cc.links(ucontext_probe)\n supported_backends += ['ucontext']\n endif\n- supported_backends += ['sigaltstack']\n endif\n \n if coroutine_backend == 'auto'\n","prefixes":[]}