From nobody Fri Nov 29 00:49:07 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 E6CEC18A6DD for ; Fri, 27 Sep 2024 08:48:56 +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=1727426938; cv=none; b=eDWVBTkVwJ9J4VrABz4LD7CmYWODIvJdWYp5cCNIr4CLIpvJltQJFxU82Pk0gFEPD24lsd6hWRX8lrmK7dvCciEoEqzqnnh3ITCFNlf9p19BCDEeaxbSPKYjDyxK1CaA7u483wBTbFtpcaaUNeZ4ix8r3nThbwRGwbxkboCF5Ao= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727426938; c=relaxed/simple; bh=DfYL3+3SFLsU0hRcuOo4JWa93YLYDt/I9LNPYUckKaw=; h=Message-ID:From:To:Cc:Subject:References:MIME-Version: Content-Type:Date; b=Lj4gXxxWwQjgxCBgWBebl+dQ9cgvj4vWiIib/rl1o5LoT9lHgJBL4lX/NQOtxIXu8+0c38eD5KwN0cFCQ2FtJ1bE0D++rWk+nVB2d4hxvzrDPUngpiJszuWKDb+8mPPzgyWXUPq580mfGLQepUtTBQOVyUlo9dstpl+/2IiYB7E= 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=Rd+IIPCa; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=NoQcX64W; 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="Rd+IIPCa"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="NoQcX64W" Message-ID: <20240927084817.696404991@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1727426935; 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=WYlva8bmBHl4f8vOKzz3cvfxu2ebItKHVNkITds+FdQ=; b=Rd+IIPCa4FwE09bRT9JG+4cNspjKEBYa1LNJ5AqEXkLkAmbzgqtOSIcd4z6wh6qlWUrG6O fIS44GoBXCKxckiPuAS6rRCBbMFi8tF4DCngkXHSHdgOblL8S35uQXHhe/18Ueg7CHfePs MWZIHtHkXGHVyK2o7iHosx/Di1FfwCYvag3y4rUBTHdg61jWMhORMa3NqYpffg6s7nAFUM 3+9aFgTFkKR7kucVVQtTBCvIiPvKxIf5fRk1z5B3b4GcpLCF4J1vG0Dx8Ue7EOWqNAeFCo SYGIu7vNx3oqFQWsF1TY25f4yFsqtTrwGRdGpTVu/oZUzdq3uOHvpEoa+iA8ng== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1727426935; 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=WYlva8bmBHl4f8vOKzz3cvfxu2ebItKHVNkITds+FdQ=; b=NoQcX64WCgiNHOKX+hppsmS+nd/ABdCOBYGCDClGtqDrwofq8Wu8lJrHB7Zu5Gjz4w7mWp K6+BHgjkPkX5qRCQ== 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 v4 13/27] signal: Split up __sigqueue_alloc() References: <20240927083900.989915582@linutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Date: Fri, 27 Sep 2024 10:48:55 +0200 (CEST) Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Thomas Gleixner 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 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; }