From nobody Mon Nov 25 02:34:55 2024 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 291131BB6BC for ; Thu, 31 Oct 2024 15:46:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730389594; cv=none; b=uRiXJfTjOLq7+dfDYoCvagog3ll1JqVeQXjkdcnEgHD2wTDpzEkKqZ2sV4X/Kg/Ay1rOtTVhVCLapaKZHnDq4h0BqjNANedoME29Slescjeir0NZix4EdlRibn6bYb50493kYcnfS2DuDgtgvy3UKDQ3g/L92NpkV31i5YQts1I= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730389594; c=relaxed/simple; bh=RpPe8akei2X3DFyo/GviuhYgA/IaiJ9f1ZzIceIbO44=; h=Message-ID:From:To:Cc:Subject:References:MIME-Version: Content-Type:Date; b=dqx5NN/MbXex8l3Hc7CwJr4QOm9T6d9LGNRDDpu9a3QK8ChSxvgc5/j+ELE9osFTU1nmtJ3w1PH18mY/ibGbgmeUGt0gtESWxwq4znnNaIZeDlpI59vWTA3sWsmZp7xUtsOTRu7flYvyWnbahy+lpr38o12ckW0My7oG+hCoiRk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=TD86oS8R; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=oyppJDHK; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="TD86oS8R"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="oyppJDHK" Message-ID: <20241031154424.928822095@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1730389590; 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=lWQ3QAq9jnqUt7hBgMDxaHm03/0EIaipDycR2Op2VkE=; b=TD86oS8R1SKv29u0CWICDsPzzN7y4U3iRNCmhTxNjHgI1c7OM4wtY4tCFBkPFIuxM3T6T0 QgqMhv+gjDRNfq8ZZhocTYaxl0Rhq/HO35qhbwp0aVbo++FVL1q/qQB6eNdFdbTlWi2EMa 7M0PNLILNUFZ46uLluvmERBvV7U8za0P8qcIJSsuyMZxxQA/wBEaJgbACYfVf1mhOxfXz6 YzcsNhEdDHbTw2GqTai9NQfvo9zvSLO6xUKevqa65bj23Q6GPa9UXltiZ5ygFRSNcGlKXW OpBFQ3JfLX2DBm9X142xOrQEXze23ktefY0QtHpfSgsFKjMPqI83R9IGpyBR6A== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1730389590; 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=lWQ3QAq9jnqUt7hBgMDxaHm03/0EIaipDycR2Op2VkE=; b=oyppJDHKozieTZTJwt2/H36jT+L+5Nyn823Imi6gXRgeuY+vjXhCRwHZulVjn7LZyxKkd9 OAb0m6pslfp/wIAQ== From: Thomas Gleixner To: LKML Cc: Anna-Maria Behnsen , Frederic Weisbecker , John Stultz , Peter Zijlstra , Ingo Molnar , Stephen Boyd , Eric Biederman , Oleg Nesterov Subject: [patch v6 06/20] signal: Split up __sigqueue_alloc() References: <20241031151625.361697424@linutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Date: Thu, 31 Oct 2024 16:46:30 +0100 (CET) Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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 Reviewed-by: Frederic Weisbecker Acked-by: Peter Zijlstra (Intel) --- kernel/signal.c | 52 +++++++++++++++++++++++++++++++++++----------------- 1 file changed, 35 insertions(+), 17 deletions(-) --- diff --git a/kernel/signal.c b/kernel/signal.c index a99274287902..87c349a2ddf7 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -396,16 +396,9 @@ void task_join_group_stop(struct task_struct *task) task_set_jobctl_pending(task, mask | JOBCTL_STOP_PENDING); } =20 -/* - * allocate a new signal queue record - * - this may be called without locks if and only if t =3D=3D current, oth= erwise 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 =3D NULL; struct ucounts *ucounts; long sigpending; =20 @@ -424,19 +417,44 @@ __sigqueue_alloc(int sig, struct task_struct *t, gfp_= t gfp_flags, if (!sigpending) return NULL; =20 - if (override_rlimit || likely(sigpending <=3D task_rlimit(t, RLIMIT_SIGPE= NDING))) { - q =3D kmem_cache_alloc(sigqueue_cachep, gfp_flags); - } else { + if (unlikely(!override_rlimit && sigpending > task_rlimit(t, RLIMIT_SIGPE= NDING))) { + dec_rlimit_put_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING); print_dropped_signal(sig); + return NULL; } =20 - if (unlikely(q =3D=3D 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 =3D sigqueue_flags; + q->ucounts =3D ucounts; +} + +/* + * allocate a new signal queue record + * - this may be called without locks if and only if t =3D=3D current, oth= erwise an + * appropriate lock must be held to stop the target task from exiting + */ +static struct sigqueue *__sigqueue_alloc(int sig, struct task_struct *t, g= fp_t gfp_flags, + int override_rlimit, const unsigned int sigqueue_flags) +{ + struct ucounts *ucounts =3D sig_get_ucounts(t, sig, override_rlimit); + struct sigqueue *q; + + if (!ucounts) + return NULL; + + q =3D 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 =3D sigqueue_flags; - q->ucounts =3D ucounts; + return NULL; } + + __sigqueue_init(q, ucounts, sigqueue_flags); return q; }