From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8F67CC0650E for ; Mon, 1 Jul 2019 14:17:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4979221721 for ; Mon, 1 Jul 2019 14:17:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561990650; bh=w8Wk7AjHDoQqWlpva98ONdWRY1Lp+SJxg5BRLsNN9Ac=; h=Subject:To:Cc:From:Date:List-ID:From; b=Kj1vBZ6pHMVatnD9Uwq8AI112KToZS0A4YQl1vnb1SdDv4waWpf9XgLPhCwP8O7OC U3o07ZawXrpdrf0A4x9KmKHGHzBWr8V1RJY2rk/YJ91iwwHOlHiGe1ZmxpJJEirLso wQfx5a7VybS7NRZXBB8MGqh3br6xU0yM3SBDLpIM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726731AbfGAOR3 (ORCPT ); Mon, 1 Jul 2019 10:17:29 -0400 Received: from new3-smtp.messagingengine.com ([66.111.4.229]:54767 "EHLO new3-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726462AbfGAOR3 (ORCPT ); Mon, 1 Jul 2019 10:17:29 -0400 Received: from compute6.internal (compute6.nyi.internal [10.202.2.46]) by mailnew.nyi.internal (Postfix) with ESMTP id BA7F31E79; Mon, 1 Jul 2019 10:17:25 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute6.internal (MEProxy); Mon, 01 Jul 2019 10:17:25 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:content-type :date:from:message-id:mime-version:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm3; bh=KWTcSg OinSYr3oTprXcCbZSpVQm1p5//qLiBRVYVcuI=; b=Dmyw0Y1nlml0yA/EW3jfeU WiKukuxsSH4cpfuerTR0JlXxYo34k1828ACz3b5G3qsP+WtVp/fvooIaL1Cumrqa q8cajtznNzMSgcExIK/2cP94iLo+gea2IRZHTo3owaW06S87zmtyw0qjjIkUdIUh D5jcHxi03Ia+dD3axGhwNOTnEKQf2JTPyfh6tYs1hw4BfBw9sI4DAdCOaaCV97bl M3ukvbNBag89Js6lZM3wWfIR+R6uc5lm+OWUecnJYs/FoNfspSQhsJYH2nLQaQ8M QrBdiWRk3bR5C4C5Cb777/yMXBf3uENTKz+ZzAZOo/scrdAwELZ0SoEE38OnaGDg == X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduvddrvdeigdejhecutefuodetggdotefrodftvf curfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfghnecu uegrihhlohhuthemuceftddtnecunecujfgurhepuffvhfffkfggtgfgsehtkeertddttd flnecuhfhrohhmpeeoghhrvghgkhhhsehlihhnuhigfhhouhhnuggrthhiohhnrdhorhhg qeenucffohhmrghinhepkhgvrhhnvghlrdhorhhgnecukfhppeekfedrkeeirdekledrud dtjeenucfrrghrrghmpehmrghilhhfrhhomhepghhrvghgsehkrhhorghhrdgtohhmnecu vehluhhsthgvrhfuihiivgeptd X-ME-Proxy: Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) by mail.messagingengine.com (Postfix) with ESMTPA id 2A2478006A; Mon, 1 Jul 2019 10:17:22 -0400 (EDT) Subject: FAILED: patch "[PATCH] signal: remove the wrong signal_pending() check in" failed to apply to 5.1-stable tree To: oleg@redhat.com, David.Laight@ACULAB.COM, akpm@linux-foundation.org, arnd@arndb.de, axboe@kernel.dk, dave@stgolabs.net, deepa.kernel@gmail.com, e@80x24.org, ebiederm@xmission.com, jbaron@akamai.com, mtk.manpages@gmail.com, stable@vger.kernel.org, tglx@linutronix.de, torvalds@linux-foundation.org, viro@ZenIV.linux.org.uk Cc: From: Date: Mon, 01 Jul 2019 16:17:19 +0200 Message-ID: <1561990639229217@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 5.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 97abc889ee296faf95ca0e978340fb7b942a3e32 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Fri, 28 Jun 2019 12:06:50 -0700 Subject: [PATCH] signal: remove the wrong signal_pending() check in restore_user_sigmask() This is the minimal fix for stable, I'll send cleanups later. Commit 854a6ed56839 ("signal: Add restore_user_sigmask()") introduced the visible change which breaks user-space: a signal temporary unblocked by set_user_sigmask() can be delivered even if the caller returns success or timeout. Change restore_user_sigmask() to accept the additional "interrupted" argument which should be used instead of signal_pending() check, and update the callers. Eric said: : For clarity. I don't think this is required by posix, or fundamentally to : remove the races in select. It is what linux has always done and we have : applications who care so I agree this fix is needed. : : Further in any case where the semantic change that this patch rolls back : (aka where allowing a signal to be delivered and the select like call to : complete) would be advantage we can do as well if not better by using : signalfd. : : Michael is there any chance we can get this guarantee of the linux : implementation of pselect and friends clearly documented. The guarantee : that if the system call completes successfully we are guaranteed that no : signal that is unblocked by using sigmask will be delivered? Link: http://lkml.kernel.org/r/20190604134117.GA29963@redhat.com Fixes: 854a6ed56839a40f6b5d02a2962f48841482eec4 ("signal: Add restore_user_sigmask()") Signed-off-by: Oleg Nesterov Reported-by: Eric Wong Tested-by: Eric Wong Acked-by: "Eric W. Biederman" Acked-by: Arnd Bergmann Acked-by: Deepa Dinamani Cc: Michael Kerrisk Cc: Jens Axboe Cc: Davidlohr Bueso Cc: Jason Baron Cc: Thomas Gleixner Cc: Al Viro Cc: David Laight Cc: [5.0+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds diff --git a/fs/aio.c b/fs/aio.c index 3490d1fa0e16..c1e581dd32f5 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -2095,6 +2095,7 @@ SYSCALL_DEFINE6(io_pgetevents, struct __aio_sigset ksig = { NULL, }; sigset_t ksigmask, sigsaved; struct timespec64 ts; + bool interrupted; int ret; if (timeout && unlikely(get_timespec64(&ts, timeout))) @@ -2108,8 +2109,10 @@ SYSCALL_DEFINE6(io_pgetevents, return ret; ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL); - restore_user_sigmask(ksig.sigmask, &sigsaved); - if (signal_pending(current) && !ret) + + interrupted = signal_pending(current); + restore_user_sigmask(ksig.sigmask, &sigsaved, interrupted); + if (interrupted && !ret) ret = -ERESTARTNOHAND; return ret; @@ -2128,6 +2131,7 @@ SYSCALL_DEFINE6(io_pgetevents_time32, struct __aio_sigset ksig = { NULL, }; sigset_t ksigmask, sigsaved; struct timespec64 ts; + bool interrupted; int ret; if (timeout && unlikely(get_old_timespec32(&ts, timeout))) @@ -2142,8 +2146,10 @@ SYSCALL_DEFINE6(io_pgetevents_time32, return ret; ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL); - restore_user_sigmask(ksig.sigmask, &sigsaved); - if (signal_pending(current) && !ret) + + interrupted = signal_pending(current); + restore_user_sigmask(ksig.sigmask, &sigsaved, interrupted); + if (interrupted && !ret) ret = -ERESTARTNOHAND; return ret; @@ -2193,6 +2199,7 @@ COMPAT_SYSCALL_DEFINE6(io_pgetevents, struct __compat_aio_sigset ksig = { NULL, }; sigset_t ksigmask, sigsaved; struct timespec64 t; + bool interrupted; int ret; if (timeout && get_old_timespec32(&t, timeout)) @@ -2206,8 +2213,10 @@ COMPAT_SYSCALL_DEFINE6(io_pgetevents, return ret; ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL); - restore_user_sigmask(ksig.sigmask, &sigsaved); - if (signal_pending(current) && !ret) + + interrupted = signal_pending(current); + restore_user_sigmask(ksig.sigmask, &sigsaved, interrupted); + if (interrupted && !ret) ret = -ERESTARTNOHAND; return ret; @@ -2226,6 +2235,7 @@ COMPAT_SYSCALL_DEFINE6(io_pgetevents_time64, struct __compat_aio_sigset ksig = { NULL, }; sigset_t ksigmask, sigsaved; struct timespec64 t; + bool interrupted; int ret; if (timeout && get_timespec64(&t, timeout)) @@ -2239,8 +2249,10 @@ COMPAT_SYSCALL_DEFINE6(io_pgetevents_time64, return ret; ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL); - restore_user_sigmask(ksig.sigmask, &sigsaved); - if (signal_pending(current) && !ret) + + interrupted = signal_pending(current); + restore_user_sigmask(ksig.sigmask, &sigsaved, interrupted); + if (interrupted && !ret) ret = -ERESTARTNOHAND; return ret; diff --git a/fs/eventpoll.c b/fs/eventpoll.c index c6f513100cc9..4c74c768ae43 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -2325,7 +2325,7 @@ SYSCALL_DEFINE6(epoll_pwait, int, epfd, struct epoll_event __user *, events, error = do_epoll_wait(epfd, events, maxevents, timeout); - restore_user_sigmask(sigmask, &sigsaved); + restore_user_sigmask(sigmask, &sigsaved, error == -EINTR); return error; } @@ -2350,7 +2350,7 @@ COMPAT_SYSCALL_DEFINE6(epoll_pwait, int, epfd, err = do_epoll_wait(epfd, events, maxevents, timeout); - restore_user_sigmask(sigmask, &sigsaved); + restore_user_sigmask(sigmask, &sigsaved, err == -EINTR); return err; } diff --git a/fs/io_uring.c b/fs/io_uring.c index 86a2bd721900..e6981d3f4468 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2201,11 +2201,12 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, } ret = wait_event_interruptible(ctx->wait, io_cqring_events(ring) >= min_events); - if (ret == -ERESTARTSYS) - ret = -EINTR; if (sig) - restore_user_sigmask(sig, &sigsaved); + restore_user_sigmask(sig, &sigsaved, ret == -ERESTARTSYS); + + if (ret == -ERESTARTSYS) + ret = -EINTR; return READ_ONCE(ring->r.head) == READ_ONCE(ring->r.tail) ? ret : 0; } diff --git a/fs/select.c b/fs/select.c index 6cbc9ff56ba0..a4d8f6e8b63c 100644 --- a/fs/select.c +++ b/fs/select.c @@ -758,10 +758,9 @@ static long do_pselect(int n, fd_set __user *inp, fd_set __user *outp, return ret; ret = core_sys_select(n, inp, outp, exp, to); + restore_user_sigmask(sigmask, &sigsaved, ret == -ERESTARTNOHAND); ret = poll_select_copy_remaining(&end_time, tsp, type, ret); - restore_user_sigmask(sigmask, &sigsaved); - return ret; } @@ -1106,8 +1105,7 @@ SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, unsigned int, nfds, ret = do_sys_poll(ufds, nfds, to); - restore_user_sigmask(sigmask, &sigsaved); - + restore_user_sigmask(sigmask, &sigsaved, ret == -EINTR); /* We can restart this syscall, usually */ if (ret == -EINTR) ret = -ERESTARTNOHAND; @@ -1142,8 +1140,7 @@ SYSCALL_DEFINE5(ppoll_time32, struct pollfd __user *, ufds, unsigned int, nfds, ret = do_sys_poll(ufds, nfds, to); - restore_user_sigmask(sigmask, &sigsaved); - + restore_user_sigmask(sigmask, &sigsaved, ret == -EINTR); /* We can restart this syscall, usually */ if (ret == -EINTR) ret = -ERESTARTNOHAND; @@ -1350,10 +1347,9 @@ static long do_compat_pselect(int n, compat_ulong_t __user *inp, return ret; ret = compat_core_sys_select(n, inp, outp, exp, to); + restore_user_sigmask(sigmask, &sigsaved, ret == -ERESTARTNOHAND); ret = poll_select_copy_remaining(&end_time, tsp, type, ret); - restore_user_sigmask(sigmask, &sigsaved); - return ret; } @@ -1425,8 +1421,7 @@ COMPAT_SYSCALL_DEFINE5(ppoll_time32, struct pollfd __user *, ufds, ret = do_sys_poll(ufds, nfds, to); - restore_user_sigmask(sigmask, &sigsaved); - + restore_user_sigmask(sigmask, &sigsaved, ret == -EINTR); /* We can restart this syscall, usually */ if (ret == -EINTR) ret = -ERESTARTNOHAND; @@ -1461,8 +1456,7 @@ COMPAT_SYSCALL_DEFINE5(ppoll_time64, struct pollfd __user *, ufds, ret = do_sys_poll(ufds, nfds, to); - restore_user_sigmask(sigmask, &sigsaved); - + restore_user_sigmask(sigmask, &sigsaved, ret == -EINTR); /* We can restart this syscall, usually */ if (ret == -EINTR) ret = -ERESTARTNOHAND; diff --git a/include/linux/signal.h b/include/linux/signal.h index 9702016734b1..78c2bb376954 100644 --- a/include/linux/signal.h +++ b/include/linux/signal.h @@ -276,7 +276,7 @@ extern int sigprocmask(int, sigset_t *, sigset_t *); extern int set_user_sigmask(const sigset_t __user *usigmask, sigset_t *set, sigset_t *oldset, size_t sigsetsize); extern void restore_user_sigmask(const void __user *usigmask, - sigset_t *sigsaved); + sigset_t *sigsaved, bool interrupted); extern void set_current_blocked(sigset_t *); extern void __set_current_blocked(const sigset_t *); extern int show_unhandled_signals; diff --git a/kernel/signal.c b/kernel/signal.c index d622eac9d169..edf8915ddd54 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2912,7 +2912,8 @@ EXPORT_SYMBOL(set_compat_user_sigmask); * This is useful for syscalls such as ppoll, pselect, io_pgetevents and * epoll_pwait where a new sigmask is passed in from userland for the syscalls. */ -void restore_user_sigmask(const void __user *usigmask, sigset_t *sigsaved) +void restore_user_sigmask(const void __user *usigmask, sigset_t *sigsaved, + bool interrupted) { if (!usigmask) @@ -2922,7 +2923,7 @@ void restore_user_sigmask(const void __user *usigmask, sigset_t *sigsaved) * Restoring sigmask here can lead to delivering signals that the above * syscalls are intended to block because of the sigmask passed in. */ - if (signal_pending(current)) { + if (interrupted) { current->saved_sigmask = *sigsaved; set_restore_sigmask(); return;