Patch Detail
get:
Show a patch.
patch:
Update a patch.
put:
Update a patch.
GET /api/patches/2224132/?format=api
{ "id": 2224132, "url": "http://patchwork.ozlabs.org/api/patches/2224132/?format=api", "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20260416182527.3862296-1-mattst88@gmail.com/", "project": { "id": 14, "url": "http://patchwork.ozlabs.org/api/projects/14/?format=api", "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": "", "list_archive_url": "", "list_archive_url_format": "", "commit_url_format": "" }, "msgid": "<20260416182527.3862296-1-mattst88@gmail.com>", "list_archive_url": null, "date": "2026-04-16T18:25:27", "name": "linux-user/ppc: Fix ppc64 rt_sigframe stack offset", "commit_ref": null, "pull_url": null, "state": "new", "archived": false, "hash": "2d21272ea9d5c0b0abab7e9167fc412e43da566c", "submitter": { "id": 7917, "url": "http://patchwork.ozlabs.org/api/people/7917/?format=api", "name": "Matt Turner", "email": "mattst88@gmail.com" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20260416182527.3862296-1-mattst88@gmail.com/mbox/", "series": [ { "id": 500211, "url": "http://patchwork.ozlabs.org/api/series/500211/?format=api", "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/list/?series=500211", "date": "2026-04-16T18:25:27", "name": "linux-user/ppc: Fix ppc64 rt_sigframe stack offset", "version": 1, "mbox": "http://patchwork.ozlabs.org/series/500211/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/2224132/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/2224132/checks/", "tags": {}, "related": [], "headers": { "Return-Path": "<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>", "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=mrrPaxQx;\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 4fxXwl18Ctz1yCv\n\tfor <incoming@patchwork.ozlabs.org>; Fri, 17 Apr 2026 08:38:31 +1000 (AEST)", "from localhost ([::1] helo=lists1p.gnu.org)\n\tby lists1p.gnu.org with esmtp (Exim 4.90_1)\n\t(envelope-from <qemu-devel-bounces@nongnu.org>)\n\tid 1wDVLR-0007gk-AI; Thu, 16 Apr 2026 18:37:57 -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 <mattst88@gmail.com>)\n id 1wDRPG-0001H0-7q\n for qemu-devel@nongnu.org; Thu, 16 Apr 2026 14:25:38 -0400", "from mail-yw1-x112d.google.com ([2607:f8b0:4864:20::112d])\n by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128)\n (Exim 4.90_1) (envelope-from <mattst88@gmail.com>)\n id 1wDRPC-0004rr-T7\n for qemu-devel@nongnu.org; Thu, 16 Apr 2026 14:25:37 -0400", "by mail-yw1-x112d.google.com with SMTP id\n 00721157ae682-7a469383e0bso66574797b3.2\n for <qemu-devel@nongnu.org>; Thu, 16 Apr 2026 11:25:33 -0700 (PDT)", "from localhost (107-220-129-194.lightspeed.chrlnc.sbcglobal.net.\n [107.220.129.194]) by smtp.gmail.com with UTF8SMTPSA id\n 00721157ae682-7b7667f96f5sm26500827b3.18.2026.04.16.11.25.31\n (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256);\n Thu, 16 Apr 2026 11:25:31 -0700 (PDT)" ], "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/relaxed;\n d=gmail.com; s=20251104; t=1776363932; x=1776968732; darn=nongnu.org;\n h=content-transfer-encoding:mime-version:references:in-reply-to\n :message-id:date:subject:cc:to:from:from:to:cc:subject:date\n :message-id:reply-to;\n bh=tsmzOeoP7uNAK2BdhTFC+4QKbukVOAW6xDOyhAheOzs=;\n b=mrrPaxQxf0zlusfGc8OwZf8bKXtuerUs+XyLPtlH+q4VgbpbmMVL5x55Ip3S1blpdh\n SRLHrlbubSqdDxIhxWn4u65lQaMWGJ1uyoPtxwlk1QMiIabluXXtKqhO1+8d9pdcSkif\n CV+R+RNO76RJ60qeRR6Z+BrPkKl+udZNe8qwqRKiqIDFVgO4Utpqw0y5VLuqARWHxzAL\n X4aZlBeppuvAFkqTJOYrDnsihXK9FszhpG6izSnSM5i62cAjM8i67vnP23K6UzEIe8eN\n PGIjKTQhG4jzX2XgO8HL7fc8F9zNGbmLiTuYRMlq2KruQzIQyuGQhFB6cV7ZPVTXTLdt\n SaWA==", "X-Google-DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/relaxed;\n d=1e100.net; s=20251104; t=1776363932; x=1776968732;\n h=content-transfer-encoding:mime-version:references:in-reply-to\n :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from\n :to:cc:subject:date:message-id:reply-to;\n bh=tsmzOeoP7uNAK2BdhTFC+4QKbukVOAW6xDOyhAheOzs=;\n b=sGzMe6vZh8VH+W5uKx2xSfRQL8hgQjHC0aw4cGMGnBtBrSbBTh/i5wbfPfKHRpfw9s\n JODEEEwCIG6n0BLsZeSaS6iLxYN3hAs+W+nn3tta14wCzOnnGfOvNprOUv7IQq7XppyA\n uw4zO4RsZs+uJigYo7tMSGP77jee1lVwFUXWotWQPcchouL/Fz43RAA/GDiRHcE22IAF\n 8GyczaN0qPIE7WrVT0HDjr9tiUmEDGbRiF7WHTSk6TM0oDrxKQV+Fsj8zrSGGOgzAdte\n Z6SQ4HDYFo1TfaM6QYCqENgyfyNItjJonBcmcqon5WwTpTRCRnHXs3NRs7hWtb7/f7ie\n wgsw==", "X-Gm-Message-State": "AOJu0YyQDEpWm6KEjjQv3zigxe8xsHw/mdfsX+uSqJoKVzBIqJ7TovfV\n RpqpeLodMAY3lJRZ9Y+pRDi4FjiAJE4LrpJkHFc1GL4XQjz1dOoq5ags", "X-Gm-Gg": "AeBDievYIimxooyWqzsDB/BfLdxO+mp8PEinFSPoMXuLyAHWGU9qsNsfAKb6AhuHoAU\n k1v6rwnvRCORBYkcIJzSMP38vlpaqjTzcWG3xjY9b+vRvag9osM1mUy6Fc08fb+EOAJ/TxWCggw\n QrL9NneXVUF3BWlC9Zgns7Qy3sPO3b8qHfm1l3flyUGnMiD1e3iPdILkyeb2vWTxZkYOga+JoR3\n bNcn0n9Z8qKvZSA0I8jBySDAvDjqthNSpFguaWF2GehUmisgldLuimsdLMMcv8Sg9JWtAsiPkQv\n +reL8SF8ICI7Ch1OGZE3yu196DA0oADLqD/eq4MTb8Al4XlfFivWRs4IQtgEoWgtyCuqsTps2Pp\n Qzl9KSjxONUHYDo9Bzh733FoIj+4NnN0ik1IZd6U0LGfVo7th/22U0b5sQaRCzDxWqi7R/1z9Rh\n 9TwFtnnFfXD5xvcHqCWZjLD+zuEmuxhtQTTuIRU8/1paXBnYa2SXz7sFhMiSeghFqrFiDTrS5fx\n DDsgwjOxKtjtg==", "X-Received": "by 2002:a05:690c:660c:b0:7b8:b3:58fa with SMTP id\n 00721157ae682-7b9e3084368mr2202967b3.31.1776363932360;\n Thu, 16 Apr 2026 11:25:32 -0700 (PDT)", "From": "Matt Turner <mattst88@gmail.com>", "To": "Laurent Vivier <laurent@vivier.eu>", "Cc": "qemu-devel@nongnu.org, Peter Maydell <peter.maydell@linaro.org>,\n Matt Turner <mattst88@gmail.com>", "Subject": "[PATCH] linux-user/ppc: Fix ppc64 rt_sigframe stack offset", "Date": "Thu, 16 Apr 2026 14:25:27 -0400", "Message-ID": "<20260416182527.3862296-1-mattst88@gmail.com>", "X-Mailer": "git-send-email 2.52.0", "In-Reply-To": "<20260414025335.2847358-1-mattst88@gmail.com>", "References": "<20260414025335.2847358-1-mattst88@gmail.com>", "MIME-Version": "1.0", "Content-Transfer-Encoding": "8bit", "Received-SPF": "pass client-ip=2607:f8b0:4864:20::112d;\n envelope-from=mattst88@gmail.com; helo=mail-yw1-x112d.google.com", "X-Spam_score_int": "-17", "X-Spam_score": "-1.8", "X-Spam_bar": "-", "X-Spam_report": "(-1.8 / 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,\n FREEMAIL_ENVFROM_END_DIGIT=0.25, 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-Mailman-Approved-At": "Thu, 16 Apr 2026 18:37:49 -0400", "X-BeenThere": "qemu-devel@nongnu.org", "X-Mailman-Version": "2.1.29", "Precedence": "list", "List-Id": "qemu development <qemu-devel.nongnu.org>", "List-Unsubscribe": "<https://lists.nongnu.org/mailman/options/qemu-devel>,\n <mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>", "List-Archive": "<https://lists.nongnu.org/archive/html/qemu-devel>", "List-Post": "<mailto:qemu-devel@nongnu.org>", "List-Help": "<mailto:qemu-devel-request@nongnu.org?subject=help>", "List-Subscribe": "<https://lists.nongnu.org/mailman/listinfo/qemu-devel>,\n <mailto:qemu-devel-request@nongnu.org?subject=subscribe>", "Errors-To": "qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org", "Sender": "qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org" }, "content": "The kernel's 64-bit signal delivery (signal_64.c) uses:\n\n newsp = frame - __SIGNAL_FRAMESIZE\n\nwhile the 32-bit path (signal_32.c) uses:\n\n newsp = frame - (__SIGNAL_FRAMESIZE + 16)\n\nThe extra 16 bytes in the 32-bit case is to place siginfo and ucontext\nat the same offsets as older kernels (see the comment in signal_32.c).\nThe 64-bit rt_sigframe starts with ucontext directly and does not need\nthis adjustment.\n\nQEMU's setup_rt_frame() unconditionally used (SIGNAL_FRAMESIZE + 16)\nfor both 32-bit and 64-bit, placing the handler's SP 16 bytes too low\non ppc64. Signal delivery and return still worked because do_rt_sigreturn\nhad the matching wrong offset, but the vDSO DWARF unwind info encodes\nthe correct kernel offset. This caused any DWARF unwinder (libunwind,\nlibgcc, etc.) to compute a CFA that is 16 bytes off, reading garbage\nregister values from the signal frame.\n\nDefine RT_SIGFRAME_ADJUST (0 on ppc64, 16 on ppc32) and use it in both\nsetup_rt_frame and do_rt_sigreturn to match the kernel.\n\nThis was verified by A/B testing with libunwind's test suite:\n\n ppc64le: Gtest-bt, Ltest-bt, Gtest-concurrent, Ltest-concurrent,\n and Ltest-sig-context all change from FAIL to PASS.\n ppc64be: Gtest-bt, Ltest-bt, and Ltest-sig-context all change\n from FAIL to PASS.\n\nSigned-off-by: Matt Turner <mattst88@gmail.com>\n---\n linux-user/ppc/signal.c | 16 ++++++++++++++--\n 1 file changed, 14 insertions(+), 2 deletions(-)", "diff": "diff --git ./linux-user/ppc/signal.c ./linux-user/ppc/signal.c\nindex 24e5a02a78..a9c10e0987 100644\n--- ./linux-user/ppc/signal.c\n+++ ./linux-user/ppc/signal.c\n@@ -210,6 +210,18 @@ QEMU_BUILD_BUG_ON(offsetof(struct target_rt_sigframe, uc.tuc_mcontext)\n \n #endif\n \n+#ifdef TARGET_PPC64\n+#define RT_SIGFRAME_ADJUST 0\n+#else\n+/*\n+ * For 32-bit rt sigframes we have an extra 16 bytes of gap\n+ * on top of __SIGNAL_FRAMESIZE; this is to get the siginfo\n+ * and ucontext in the same positions as in older kernels.\n+ * See Linux's arch/powerpc/kernel/signal_32.c.\n+ */\n+#define RT_SIGFRAME_ADJUST 16\n+#endif\n+\n #if defined(TARGET_PPC64)\n \n struct target_func_ptr {\n@@ -525,7 +537,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,\n env->fpscr = 0;\n \n /* Create a stack frame for the caller of the handler. */\n- newsp = rt_sf_addr - (SIGNAL_FRAMESIZE + 16);\n+ newsp = rt_sf_addr - (SIGNAL_FRAMESIZE + RT_SIGFRAME_ADJUST);\n err |= put_user(env->gpr[1], newsp, target_ulong);\n \n if (err)\n@@ -641,7 +653,7 @@ long do_rt_sigreturn(CPUPPCState *env)\n struct target_rt_sigframe *rt_sf = NULL;\n target_ulong rt_sf_addr;\n \n- rt_sf_addr = env->gpr[1] + SIGNAL_FRAMESIZE + 16;\n+ rt_sf_addr = env->gpr[1] + SIGNAL_FRAMESIZE + RT_SIGFRAME_ADJUST;\n if (!lock_user_struct(VERIFY_READ, rt_sf, rt_sf_addr, 1))\n goto sigsegv;\n \n", "prefixes": [] }