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=1793827084; b=I21vGPDWityPwwfC8f/FcpVB4pkNsW5cCqSiIZj2wwxEF55yJtiYpAUXbOKsh3yHsNZo sJhJcr0MRyxXELWnPNzm/3HD8ciMne72uyAGF3aEMTg0E0iWeUDTBuP/p/JPwZ3Orr1j8 p82O54hCsmRCMv4xY/qp+WEIyUfXKdsCnjrSAF+1iOeF9Ts1sDwfoEfMwI0EFA/qRjQa+ Nml3B35mc9Q9leknmQ6HjBLl+biKIYjY19OkMDl/R8PsUEl2c7t13/OM5fFwIlhNZQ+2M UllLrOST7JsR39XvrvyFiZ8wool6vKnQWZj5Ffy14sko3gBkAPZ8Y3NXqY5PbQMqOzQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793827084; 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=UqdNdxS/g/GxjUCDYgrM2QjQHbmSqYytfuSCKgKZcso=; b=wr8xuMHEi1e1W/vo3L4Dg4wMFEydYVu1o0MCh48jRWmXnIvURswQZx3tRWjLa9ZS/U2a 1jO4b6ZHeAhKLs/o1uDOz4U3RXLZYysN9SggbzeYKGGqLg2jIxxcS9i19/t8+xIo4VrnW qRYSwBYemBBf5P8HPLbci9hAVs1RxDBnClIVp13zdopK3+hh35xbiNeH+Z8iAzsncUeze aOhjwFDyqKjEvEgI7Kaq6A08uSrLa40205Eox6LBCiZ51K4HIQwAVMOMLHexKC2/7FR2Z JSrNeHx0uUtUgpLeienuRgyDT3767G7LLz+x3Y8c+uI0BCyNfyjf2VmU/rCj0CT4FXA== 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=ELA1SM9B; 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 7D4FC606A86D; Wed, 4 Nov 2026 21:18:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=ELA1SM9B Received: by smtp.kernel.org (Postfix) with ESMTPSA id 026711F000C1; Wed, 4 Nov 2026 21:18:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793827084; bh=UqdNdxS/g/GxjUCDYgrM2QjQHbmSqYytfuSCKgKZcso=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ELA1SM9BEmHkfYPUSUNYGeRZuvf6lJcB7b+Pf3gcckkQhpajc7jeNJfz2sf3vmINY huE2US1fmFDksn9sLA7h3z1ZciH2Bi+uPxG1li5we46tVnKP/WEvq1TW6cC5lYRYoC jo6sqRwbd7magvCoqjFxr/Fbcuv2jzMcnzzM2Q3I= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Heiko Carstens Subject: [PATCH 7.3 178/547] s390/signal: Fix incorrect return address in signal frame Date: Wed, 4 Nov 2026 16:06:02 -0500 Message-ID: <20261104211043.204014388@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261104211038.406938024@linuxfoundation.org> References: <20261104211038.406938024@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.3-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 @@ -131,6 +131,12 @@ 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; @@ -168,12 +174,6 @@ int copy_thread(struct task_struct *p, c p->thread.acrs[0] = (unsigned int)(tls >> 32); 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 @@ -475,7 +475,11 @@ 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); handle_signal(&ksig, oldset, regs); return;