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[2620:137:e000::1:20]) by mx.google.com with ESMTP id g1-20020ac87f41000000b003f5398419e0si6385414qtk.373.2023.06.06.07.55.57; Tue, 06 Jun 2023 07:56:13 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@linutronix.de header.s=2020 header.b=tl52fd+o; dkim=neutral (no key) header.i=@linutronix.de header.b=tKLxhZYk; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=linutronix.de Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238295AbjFFOlQ (ORCPT + 99 others); Tue, 6 Jun 2023 10:41:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42000 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238454AbjFFOkL (ORCPT ); Tue, 6 Jun 2023 10:40:11 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C4FBA2127 for ; Tue, 6 Jun 2023 07:38:54 -0700 (PDT) Message-ID: <20230606142032.826604145@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1686062290; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=wHuT7Hr0NdOKLI1EunOgn59lsnWIJRlvleS26aoiaoA=; b=tl52fd+obPeHQXAjdOtL/sLgOTRfX+FOkkGpvpvRPKOjZH6KoaVfGmKYfD/ixurZHJq2aO p9b15raE24WnbUgpqOWt49PpPr4S/Xj91olySxUAnLLT19vCBUZTrzFOy1JsVMM3C0gMCV Kj78hiY2NhIhJNP+6kxOiRArkqZt1Q71wFNmm5TmA/vCbaG9vstMsUjbu9/tNxUa1ULaLJ OPHNxDm+w9CZgFwXjrPDFEpzQ4QoqCZIKzYHfQKCwXaQj2mYwbGIZkhKdgyJ95SWWbFxCI 7mSNxPw0qqixkzC26R8FNCjKgDwECT/6KhlSIuXysweXwKUEKeckVCddnfKK7w== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1686062290; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=wHuT7Hr0NdOKLI1EunOgn59lsnWIJRlvleS26aoiaoA=; b=tKLxhZYkjMhy1U7P7k4zoE3Aq3+VKrKcHWCwEdcwwhgUinWe88yTvqhy/x4nyfdjb1Q9GJ E1Zgn7CDIDpelQCg== From: Thomas Gleixner To: LKML Cc: Frederic Weisbecker , Anna-Maria Behnsen , John Stultz , Peter Zijlstra , Ingo Molnar , Stephen Boyd , Eric Biederman , Oleg Nesterov Subject: [patch 32/45] signal: Split up __sigqueue_alloc() References: <20230606132949.068951363@linutronix.de> MIME-Version: 1.0 Date: Tue, 6 Jun 2023 16:38:09 +0200 (CEST) X-Spam-Status: No, score=-4.4 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_MED,SPF_HELO_NONE, SPF_PASS,T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1767965587402927717?= X-GMAIL-MSGID: =?utf-8?q?1767965587402927717?= To cure the SIG_IGN handling for posix interval timers, the preallocated sigqueue needs to be embedded into struct k_itimer to prevent life time races of all sorts. Reorganize __sigqueue_alloc() so the ucounts retrieval and the initialization can be used independently. No functional change. Signed-off-by: Thomas Gleixner --- kernel/signal.c | 52 +++++++++++++++++++++++++++++++++++----------------- 1 file changed, 35 insertions(+), 17 deletions(-) --- a/kernel/signal.c +++ b/kernel/signal.c @@ -403,16 +403,9 @@ void task_join_group_stop(struct task_st task_set_jobctl_pending(task, mask | JOBCTL_STOP_PENDING); } -/* - * allocate a new signal queue record - * - this may be called without locks if and only if t == current, otherwise an - * appropriate lock must be held to stop the target task from exiting - */ -static struct sigqueue * -__sigqueue_alloc(int sig, struct task_struct *t, gfp_t gfp_flags, - int override_rlimit, const unsigned int sigqueue_flags) +static struct ucounts *sig_get_ucounts(struct task_struct *t, int sig, + int override_rlimit) { - struct sigqueue *q = NULL; struct ucounts *ucounts = NULL; long sigpending; @@ -431,19 +424,44 @@ static struct sigqueue * if (!sigpending) return NULL; - if (override_rlimit || likely(sigpending <= task_rlimit(t, RLIMIT_SIGPENDING))) { - q = kmem_cache_alloc(sigqueue_cachep, gfp_flags); - } else { + if (unlikely(!override_rlimit && sigpending > task_rlimit(t, RLIMIT_SIGPENDING))) { + dec_rlimit_put_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING); print_dropped_signal(sig); + return NULL; } - if (unlikely(q == NULL)) { + return ucounts; +} + +static void __sigqueue_init(struct sigqueue *q, struct ucounts *ucounts, + const unsigned int sigqueue_flags) +{ + INIT_LIST_HEAD(&q->list); + q->flags = sigqueue_flags; + q->ucounts = ucounts; +} + +/* + * allocate a new signal queue record + * - this may be called without locks if and only if t == current, otherwise an + * appropriate lock must be held to stop the target task from exiting + */ +static struct sigqueue *__sigqueue_alloc(int sig, struct task_struct *t, gfp_t gfp_flags, + int override_rlimit, const unsigned int sigqueue_flags) +{ + struct ucounts *ucounts = sig_get_ucounts(t, sig, override_rlimit); + struct sigqueue *q; + + if (!ucounts) + return NULL; + + q = kmem_cache_alloc(sigqueue_cachep, gfp_flags); + if (!q) { dec_rlimit_put_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING); - } else { - INIT_LIST_HEAD(&q->list); - q->flags = sigqueue_flags; - q->ucounts = ucounts; + return NULL; } + + __sigqueue_init(q, ucounts, sigqueue_flags); return q; }