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[103.95.112.190]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2b08354bce3sm66285675ad.32.2026.03.21.06.56.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 21 Mar 2026 06:56:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1774101411; x=1774706211; darn=nongnu.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=33bK0g5AvUfHWijJiI0bLgMdG2DgEQ/sawsGLjJgXd8=; b=kAmUAsG2ATmIheurfLDKt++ncy3ogCjJe/0rylLEd2wytRyq0ecfMMxPg8oNjpvoMu oR+Ai5U4yR8TqStVWexZ5nWpHv01jE7GcC9FG7//yFl/TrpNVRl7Nvkw4I/4Vc2oXzcD ymxNuMSwhtKw+BnzlE7u9ZX+pMz5LIG7z7UkGPUe4TnuJHS55dXxwECSYouOcfKRI5Zm N3GMgLy9aUsPReQlO9N3xn2nu8Uqo6qbV1XscFXeBBwxfwAA/gmopHJzkWCgZ31ZHaS7 QYvhePoEcb1XzRqtBoLZwJHK5+/Baqtpf1YOPRiqv6JfZGFfu1sGoeFMtdrdJFJG76R3 TpbA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1774101411; x=1774706211; 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=33bK0g5AvUfHWijJiI0bLgMdG2DgEQ/sawsGLjJgXd8=; b=prmYnK8zjXeJX39BUVBjC5eLPzer+49TMRqTkczpKdXNdG39RPc/Fv0DbsSLtUC1jW 3eXSDORQJvZKVHNhMOLLvBwUGbEpPRZjLLe6Zat4zgQAgZijrgVsCyacgNEUNkCT+IUL TaQtwRJ7TzXBiTevo0ixuT6k9GNcPTn33bAnDNuqV5MYRRdOADAm1IvihKm3XEnzmQLf 3n1eYB7SseNlmNW5UwxYeLIq6J6IZkGjV+FMIkVHqsV33lBnjsUXT0gFumcroSSEQanv chDXeUjR4oP+SJGOBA6qPBEsg8N+A5J582rPxQZKQRGK1KqfbAcNNtX/dVxvN4T1mRWB 6yAw== X-Gm-Message-State: AOJu0YzPYeQG71C5DgEfPNEkvO8qnWU2Y9/b9Icd3lnHQXwzwa4DOW// MDfFrU61qX1nHNi5ZcDbedrGZM5Ok5EIoD3iDUi0GuCpUFWOz+oEvwauuufdZg== X-Gm-Gg: ATEYQzxBXNAWtaV/cWxMChMeJNVQ+x1zK7KjQXsbYLHuRB0mm8YNSoxo3GkRzy2HXSA IfOqVGQBvvnR7/su0uYThAKGWCzbFsf7R1lzXAVcCM/6GgW3e9rcmU/DihQ+rHJGXXBF9z3vFKT uJy84wGd+YHUT/fAxV6focwiRSWM1sX4MU9F+UGBJIqJ4IE3LsDXzPH+WlnER14msO/2AEGTfRg deVLPfEALXF63LfG6Z93UQpHULDcep8CLrbltSJtDouzwymzWn0zZ58WO0u6BvKk4XPazYc2lTD w4OhfWVkFNxgCQd1Bc40v2Z7jBK8wgBJnUGNECyrsUy6erHIPp7Z+Dc9uGvgpkke/ypVMWoXz7L 00Aw71IGdE3i5IdXPgmX1p/bBCZvACo8u0Xl5TVxvfettoMQMKGj7fOe1Jr8mrmV4WgQf0IpCak dteFqpa23QngYMgf7oJh46mtECYB4lkyeLBExKQf2SiPLmJVxXEX+JPZPcP1zWAQ9jI/Luf+40M PZ+7r0= X-Received: by 2002:a17:902:ccd2:b0:2b0:5682:6973 with SMTP id d9443c01a7336-2b08273d0d4mr58134035ad.19.1774101411065; Sat, 21 Mar 2026 06:56:51 -0700 (PDT) From: Nicholas Piggin To: qemu-devel@nongnu.org Cc: Nicholas Piggin , Warner Losh , Kyle Evans , Laurent Vivier , Pierrick Bouvier , =?UTF-8?q?Alex=20Benn=C3=A9e?= , Peter Maydell Subject: [PATCH 2/3] bsd-user, linux-user: signal: recursive signal delivery fix Date: Sat, 21 Mar 2026 23:56:22 +1000 Message-ID: <20260321135624.581398-3-npiggin@gmail.com> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260321135624.581398-1-npiggin@gmail.com> References: <20260321135624.581398-1-npiggin@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2607:f8b0:4864:20::62d; envelope-from=npiggin@gmail.com; helo=mail-pl1-x62d.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, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, 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: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @gmail.com) X-ZM-MESSAGEID: 1774101472848154100 Content-Type: text/plain; charset="utf-8" Synchronous signals must accommodate a synchronous signal being raised during delivery, as asynchronous ones do. For example badframe errors during delivery will cause SIGSEGV to be raised. Without this fix, cpu_loop() runs process_pending_signals() which delivers the first synchronous signal (e.g., SIGILL) which fails to set the handler and forces SIGSEGV, but that is not picked up. process_pending_signals() returns. Then cpu_loop() runs cpu_exec() again, which attempts to execute the same instruction, another SIGILL. Signed-off-by: Nicholas Piggin Reviewed-by: Warner Losh --- bsd-user/signal.c | 10 ++++++---- linux-user/signal.c | 9 ++++++--- 2 files changed, 12 insertions(+), 7 deletions(-) diff --git a/bsd-user/signal.c b/bsd-user/signal.c index dadcc037dc..3e5e41e1b1 100644 --- a/bsd-user/signal.c +++ b/bsd-user/signal.c @@ -998,7 +998,12 @@ void process_pending_signals(CPUArchState *env) sigdelset(&ts->signal_mask, target_to_host_signal(sig)); sigact_table[sig - 1]._sa_handler =3D TARGET_SIG_DFL; } + /* + * Restart scan from the beginning, as handle_pending_signal + * might have resulted in a new synchronous signal (eg SIGSEGV= ). + */ handle_pending_signal(env, sig, &ts->sync_signal); + goto restart_scan; } =20 k =3D ts->sigtab; @@ -1008,10 +1013,7 @@ void process_pending_signals(CPUArchState *env) if (k->pending && !sigismember(blocked_set, target_to_host_signal(sig))) { handle_pending_signal(env, sig, k); - /* - * Restart scan from the beginning, as handle_pending_sign= al - * might have resulted in a new synchronous signal (eg SIG= SEGV). - */ + /* Restart scan, explained above. */ goto restart_scan; } } diff --git a/linux-user/signal.c b/linux-user/signal.c index e4b8b28bfe..9d43e080ce 100644 --- a/linux-user/signal.c +++ b/linux-user/signal.c @@ -1385,6 +1385,11 @@ void process_pending_signals(CPUArchState *cpu_env) } =20 handle_pending_signal(cpu_env, sig, &ts->sync_signal); + /* + * Restart scan from the beginning, as handle_pending_signal + * might have resulted in a new synchronous signal (eg SIGSEGV= ). + */ + goto restart_scan; } =20 for (sig =3D 1; sig <=3D TARGET_NSIG; sig++) { @@ -1395,9 +1400,7 @@ void process_pending_signals(CPUArchState *cpu_env) (!sigismember(blocked_set, target_to_host_signal_table[sig]))) { handle_pending_signal(cpu_env, sig, &ts->sigtab[sig - 1]); - /* Restart scan from the beginning, as handle_pending_sign= al - * might have resulted in a new synchronous signal (eg SIG= SEGV). - */ + /* Restart scan, explained above. */ goto restart_scan; } } --=20 2.51.0