From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794061594; b=Md+M0PveIWm/I6lwUy9w7sfvMdUNJ8rL5HmQZ4omG3XUT+hjuO5+GSjDUqSa9WSdBIIH zB8LceyXdCqI1i2/pVwCNEjA+VjUOgRJrRjL1ZypbNRXjcKToySW3vrNQIfaGSVgf1IXT R1NEPS/V4+kWVWFEpQS5u/j5RYpkx5BCb874AZhPSWwtZZRy6emVfGxLGzQCs0Gy4YtZz NWhfhJvn4xxIAYT9uP/eIShr9vdgb2o6ng9r3k5iqvQWMrEeIYf934lUW9l2t47EMWTYW 796WDS2CqeQ0PZH2zf7mCs/9rRtaRehv09oyuAmoXlAMpwnEV6JI3G2Zw+jo/yBaMEQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794061594; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=Ffk9wnZ1YQn1vdhOVF/HvPRTnEPlPa0WGky46k+zkdw=; b=Wgd5w3DLn8aw8c1CKDdmquSrk1F8UUCN1AFQgQ8NcVb26/ANrVb99+06NxR3onapA59y rcZawny1vvjoOyaSdhsJvNg4pStbnekQ9LZYYayn1Yd9UgzW0t1ZelpZ0PlUyi88qW1LB ybbbGS9dYXv8l2fclbuetTSytI0TLhMmlR94NO3gxhnTgkOr15jrI45pgKgfZiBrkClAA 5igLkEuQ7X3DQwtG0ObK4rYb7ItbQSWj0ZdPQ3rJLrecF30v5jjXUx8CdXmFwFcyNdxYb BwX35pd2TPpic7I7mom8BqzSYWQoylluNLqV70UgcF/zOv1TKZrUVG09+1dvCFUts1Q== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=Aj4srcI3; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D62F3606A32D; Sat, 7 Nov 2026 14:26:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=Aj4srcI3 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4027B1F0089F; Sat, 7 Nov 2026 14:26:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794061593; bh=Ffk9wnZ1YQn1vdhOVF/HvPRTnEPlPa0WGky46k+zkdw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Aj4srcI3MIP42ZJYtsprKrZQeAO4knf1Xf43sktnhsKY+fa7VeP6HcnT/tOPRsxJf gY8f3daAcdbOrBcC70nPoA63LhYs6t3pHlOtG33PPdy4fbn1hpZdAUzNy0OWqmcztw SR3yp90SG8TkDLfVrAUHXIS7Mz5xPSubYxYuwF88= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Heiko Carstens Subject: [PATCH 6.12 0619/1536] s390/signal: Fix incorrect return address in signal frame Date: Sat, 7 Nov 2026 08:43:55 -0500 Message-ID: <20261107135014.920122240@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134957.653319350@linuxfoundation.org> References: <20261107134957.653319350@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Heiko Carstens commit adc9e872f7350e3ac29c1818d8c68b0760b4ba23 upstream. exit_to_user_mode_loop() can call arch_do_signal_or_restart() multiple times when signals are pending. If the first call set up a vDSO system call restart by saving the real user return address and adjusting psw.addr so it points to the vDSO stub, a second call builds the signal frame with the wrong return address. Restore psw.addr from arch_data, and set the return code to -EINTR before building the signal frame. This requires restart_block.arch_data to be properly initialized for all tasks. Move the initialization in copy_thread() in front of the kernel thread check, so that it also covers kernel threads and their children (PID 1, usermode helpers). Only PID 0 is left uninitialized, since it never returns to user space. Fixes: df29a7440c4b ("s390/signal: switch to using vdso for sigreturn and syscall restart") Cc: stable@vger.kernel.org Signed-off-by: Heiko Carstens Signed-off-by: Greg Kroah-Hartman --- arch/s390/kernel/process.c | 12 ++++++------ arch/s390/kernel/signal.c | 6 +++++- 2 files changed, 11 insertions(+), 7 deletions(-) --- a/arch/s390/kernel/process.c +++ b/arch/s390/kernel/process.c @@ -133,6 +133,12 @@ int copy_thread(struct task_struct *p, c p->thread.hardirq_timer = 0; p->thread.softirq_timer = 0; p->thread.last_break = 1; + /* + * s390 stores the svc return address in arch_data when calling + * sigreturn()/restart_syscall() via vdso. 1 means no valid address + * stored. + */ + p->restart_block.arch_data = 1; frame->sf.back_chain = 0; frame->sf.gprs[11 - 6] = (unsigned long)&frame->childregs; @@ -174,12 +180,6 @@ int copy_thread(struct task_struct *p, c p->thread.acrs[1] = (unsigned int)tls; } } - /* - * s390 stores the svc return address in arch_data when calling - * sigreturn()/restart_syscall() via vdso. 1 means no valid address - * stored. - */ - p->restart_block.arch_data = 1; return 0; } --- a/arch/s390/kernel/signal.c +++ b/arch/s390/kernel/signal.c @@ -488,7 +488,11 @@ void arch_do_signal_or_restart(struct pt } /* No longer in a system call */ clear_pt_regs_flag(regs, PIF_SYSCALL); - + if (!(current->restart_block.arch_data & 1)) { + regs->psw.addr = current->restart_block.arch_data; + current->restart_block.arch_data = 1; + regs->gprs[2] = -EINTR; + } rseq_signal_deliver(&ksig, regs); if (is_compat_task()) handle_signal32(&ksig, oldset, regs);