From nobody Thu Oct 31 23:43:51 2024 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1694677498330106.58675779463351; Thu, 14 Sep 2023 00:44:58 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qgh12-00015Q-2B; Thu, 14 Sep 2023 03:43:56 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qgh0w-0000zW-P8 for qemu-devel@nongnu.org; Thu, 14 Sep 2023 03:43:50 -0400 Received: from isrv.corpit.ru ([86.62.121.231]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qgh0u-0007nW-Dj for qemu-devel@nongnu.org; Thu, 14 Sep 2023 03:43:49 -0400 Received: from tsrv.corpit.ru (tsrv.tls.msk.ru [192.168.177.2]) by isrv.corpit.ru (Postfix) with ESMTP id A62CB21C33 for ; Thu, 14 Sep 2023 10:43:51 +0300 (MSK) Received: from tls.msk.ru (mjt.wg.tls.msk.ru [192.168.177.130]) by tsrv.corpit.ru (Postfix) with SMTP id 3666B27F69; Thu, 14 Sep 2023 10:43:44 +0300 (MSK) Received: (nullmailer pid 149922 invoked by uid 1000); Thu, 14 Sep 2023 07:43:44 -0000 From: Michael Tokarev To: qemu-devel@nongnu.org Cc: Michael Tokarev Subject: [PATCH v3 1/3] linux-user/syscall.c: do_ppoll: simplify time64 host<=>target conversion expressions Date: Thu, 14 Sep 2023 10:43:35 +0300 Message-Id: <20230914074337.149897-2-mjt@tls.msk.ru> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230914074337.149897-1-mjt@tls.msk.ru> References: <20230914074337.149897-1-mjt@tls.msk.ru> 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=86.62.121.231; envelope-from=mjt@tls.msk.ru; helo=isrv.corpit.ru X-Spam_score_int: -68 X-Spam_score: -6.9 X-Spam_bar: ------ X-Spam_report: (-6.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_HI=-5, 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: 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-ZM-MESSAGEID: 1694677500500100001 Content-Type: text/plain; charset="utf-8" replace if (time64) { time64-expr } else { time32-expr } expressions which are difficult to read with a much shorter and easier to read arithmetic-if constructs. Signed-off-by: Michael Tokarev --- linux-user/syscall.c | 27 +++++++++------------------ 1 file changed, 9 insertions(+), 18 deletions(-) diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 3521a2d70b..33bf84c205 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -1516,16 +1516,11 @@ static abi_long do_ppoll(abi_long arg1, abi_long ar= g2, abi_long arg3, sigset_t *set =3D NULL; =20 if (arg3) { - if (time64) { - if (target_to_host_timespec64(timeout_ts, arg3)) { - unlock_user(target_pfd, arg1, 0); - return -TARGET_EFAULT; - } - } else { - if (target_to_host_timespec(timeout_ts, arg3)) { - unlock_user(target_pfd, arg1, 0); - return -TARGET_EFAULT; - } + if (time64 + ? target_to_host_timespec64(timeout_ts, arg3) + : target_to_host_timespec(timeout_ts, arg3)) { + unlock_user(target_pfd, arg1, 0); + return -TARGET_EFAULT; } } else { timeout_ts =3D NULL; @@ -1546,14 +1541,10 @@ static abi_long do_ppoll(abi_long arg1, abi_long ar= g2, abi_long arg3, finish_sigsuspend_mask(ret); } if (!is_error(ret) && arg3) { - if (time64) { - if (host_to_target_timespec64(arg3, timeout_ts)) { - return -TARGET_EFAULT; - } - } else { - if (host_to_target_timespec(arg3, timeout_ts)) { - return -TARGET_EFAULT; - } + if (time64 + ? host_to_target_timespec64(arg3, timeout_ts) + : host_to_target_timespec(arg3, timeout_ts)) { + return -TARGET_EFAULT; } } } else { --=20 2.39.2 From nobody Thu Oct 31 23:43:51 2024 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1694677499349852.1745838359665; Thu, 14 Sep 2023 00:44:59 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qgh12-00018k-T8; Thu, 14 Sep 2023 03:43:57 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qgh0y-00010Q-5w for qemu-devel@nongnu.org; Thu, 14 Sep 2023 03:43:52 -0400 Received: from isrv.corpit.ru ([86.62.121.231]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qgh0w-0007om-HQ for qemu-devel@nongnu.org; Thu, 14 Sep 2023 03:43:51 -0400 Received: from tsrv.corpit.ru (tsrv.tls.msk.ru [192.168.177.2]) by isrv.corpit.ru (Postfix) with ESMTP id C8CA021C34 for ; Thu, 14 Sep 2023 10:43:52 +0300 (MSK) Received: from tls.msk.ru (mjt.wg.tls.msk.ru [192.168.177.130]) by tsrv.corpit.ru (Postfix) with SMTP id 5AD0927F6A; Thu, 14 Sep 2023 10:43:45 +0300 (MSK) Received: (nullmailer pid 149926 invoked by uid 1000); Thu, 14 Sep 2023 07:43:45 -0000 From: Michael Tokarev To: qemu-devel@nongnu.org Cc: Michael Tokarev Subject: [PATCH v3 2/3] linux-user/syscall.c: do_ppoll: consolidate and fix the forgotten unlock_user Date: Thu, 14 Sep 2023 10:43:36 +0300 Message-Id: <20230914074337.149897-3-mjt@tls.msk.ru> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230914074337.149897-1-mjt@tls.msk.ru> References: <20230914074337.149897-1-mjt@tls.msk.ru> 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=86.62.121.231; envelope-from=mjt@tls.msk.ru; helo=isrv.corpit.ru X-Spam_score_int: -68 X-Spam_score: -6.9 X-Spam_bar: ------ X-Spam_report: (-6.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_HI=-5, 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: 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-ZM-MESSAGEID: 1694677500508100002 Content-Type: text/plain; charset="utf-8" in do_ppoll we've one place where unlock_user isn't done at all, while other places use 0 for the size of the area being unlocked instead of the actual size. Instead of open-coding calls to unlock_user(), jump to the end of this function and do a single call to unlock there. Note: original code calls unlock_user() with target_pfd being NULL in one case (when nfds =3D=3D 0). Move initializers to variable declarations, - I wondered a few times if target_pfd isn't being initialized at all for unlock_user. Signed-off-by: Michael Tokarev --- linux-user/syscall.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 33bf84c205..eabdf50abc 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -1487,14 +1487,12 @@ static abi_long do_pselect6(abi_long arg1, abi_long= arg2, abi_long arg3, static abi_long do_ppoll(abi_long arg1, abi_long arg2, abi_long arg3, abi_long arg4, abi_long arg5, bool ppoll, bool ti= me64) { - struct target_pollfd *target_pfd; + struct target_pollfd *target_pfd =3D NULL; unsigned int nfds =3D arg2; - struct pollfd *pfd; + struct pollfd *pfd =3D NULL; unsigned int i; abi_long ret; =20 - pfd =3D NULL; - target_pfd =3D NULL; if (nfds) { if (nfds > (INT_MAX / sizeof(struct target_pollfd))) { return -TARGET_EINVAL; @@ -1519,8 +1517,8 @@ static abi_long do_ppoll(abi_long arg1, abi_long arg2= , abi_long arg3, if (time64 ? target_to_host_timespec64(timeout_ts, arg3) : target_to_host_timespec(timeout_ts, arg3)) { - unlock_user(target_pfd, arg1, 0); - return -TARGET_EFAULT; + ret =3D -TARGET_EFAULT; + goto out; } } else { timeout_ts =3D NULL; @@ -1529,8 +1527,7 @@ static abi_long do_ppoll(abi_long arg1, abi_long arg2= , abi_long arg3, if (arg4) { ret =3D process_sigsuspend_mask(&set, arg4, arg5); if (ret !=3D 0) { - unlock_user(target_pfd, arg1, 0); - return ret; + goto out; } } =20 @@ -1544,7 +1541,8 @@ static abi_long do_ppoll(abi_long arg1, abi_long arg2= , abi_long arg3, if (time64 ? host_to_target_timespec64(arg3, timeout_ts) : host_to_target_timespec(arg3, timeout_ts)) { - return -TARGET_EFAULT; + ret =3D -TARGET_EFAULT; + goto out; } } } else { @@ -1567,6 +1565,8 @@ static abi_long do_ppoll(abi_long arg1, abi_long arg2= , abi_long arg3, target_pfd[i].revents =3D tswap16(pfd[i].revents); } } + +out: unlock_user(target_pfd, arg1, sizeof(struct target_pollfd) * nfds); return ret; } --=20 2.39.2 From nobody Thu Oct 31 23:43:51 2024 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1694677463340741.1921170184376; Thu, 14 Sep 2023 00:44:23 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qgh14-0001JE-Ut; Thu, 14 Sep 2023 03:43:59 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qgh10-00014L-8F for qemu-devel@nongnu.org; Thu, 14 Sep 2023 03:43:54 -0400 Received: from isrv.corpit.ru ([86.62.121.231]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qgh0x-0007pf-Qv for qemu-devel@nongnu.org; Thu, 14 Sep 2023 03:43:53 -0400 Received: from tsrv.corpit.ru (tsrv.tls.msk.ru [192.168.177.2]) by isrv.corpit.ru (Postfix) with ESMTP id B068121C35 for ; Thu, 14 Sep 2023 10:43:53 +0300 (MSK) Received: from tls.msk.ru (mjt.wg.tls.msk.ru [192.168.177.130]) by tsrv.corpit.ru (Postfix) with SMTP id 4217427F6B; Thu, 14 Sep 2023 10:43:46 +0300 (MSK) Received: (nullmailer pid 149930 invoked by uid 1000); Thu, 14 Sep 2023 07:43:46 -0000 From: Michael Tokarev To: qemu-devel@nongnu.org Cc: Michael Tokarev Subject: [PATCH v3 3/3] linux-user/syscall.c: do_ppoll: eliminate large alloca Date: Thu, 14 Sep 2023 10:43:37 +0300 Message-Id: <20230914074337.149897-4-mjt@tls.msk.ru> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230914074337.149897-1-mjt@tls.msk.ru> References: <20230914074337.149897-1-mjt@tls.msk.ru> 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=86.62.121.231; envelope-from=mjt@tls.msk.ru; helo=isrv.corpit.ru X-Spam_score_int: -68 X-Spam_score: -6.9 X-Spam_bar: ------ X-Spam_report: (-6.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_HI=-5, 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: 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-ZM-MESSAGEID: 1694677471324100001 Content-Type: text/plain; charset="utf-8" do_ppoll() in linux-user/syscall.c uses alloca() to allocate an array of struct pullfds on the stack. The only upper boundary for number of entries for this array is so that whole thing fits in INT_MAX. This is definitely too much for stack allocation. Use heap allocation when large number of entries is requested (currently 32, arbitrary), and continue to use alloca() for smaller allocations, to optimize small operations for small sizes. The code for this optimization is small, I see no reason for dropping it. This eliminates last large user-controlled on-stack allocation from syscall.c. Signed-off-by: Michael Tokarev --- linux-user/syscall.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/linux-user/syscall.c b/linux-user/syscall.c index eabdf50abc..1dbe28eba4 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -1489,7 +1489,7 @@ static abi_long do_ppoll(abi_long arg1, abi_long arg2= , abi_long arg3, { struct target_pollfd *target_pfd =3D NULL; unsigned int nfds =3D arg2; - struct pollfd *pfd =3D NULL; + struct pollfd *pfd =3D NULL, *heap_pfd =3D NULL; unsigned int i; abi_long ret; =20 @@ -1503,7 +1503,17 @@ static abi_long do_ppoll(abi_long arg1, abi_long arg= 2, abi_long arg3, return -TARGET_EFAULT; } =20 - pfd =3D alloca(sizeof(struct pollfd) * nfds); + /* arbitrary "small" number to limit stack usage */ + if (nfds <=3D 64) { + pfd =3D alloca(sizeof(struct pollfd) * nfds); + } else { + heap_pfd =3D g_try_new(struct pollfd, nfds); + if (!heap_pfd) { + ret =3D -TARGET_ENOMEM; + goto out; + } + pfd =3D heap_pfd; + } for (i =3D 0; i < nfds; i++) { pfd[i].fd =3D tswap32(target_pfd[i].fd); pfd[i].events =3D tswap16(target_pfd[i].events); @@ -1567,6 +1577,7 @@ static abi_long do_ppoll(abi_long arg1, abi_long arg2= , abi_long arg3, } =20 out: + g_free(heap_pfd); unlock_user(target_pfd, arg1, sizeof(struct target_pollfd) * nfds); return ret; } --=20 2.39.2