From patchwork Thu Jun 4 11:23:17 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Johannes Berg X-Patchwork-Id: 1303460 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=lists.infradead.org (client-ip=2607:7c80:54:e::133; helo=bombadil.infradead.org; envelope-from=linux-um-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=sipsolutions.net Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20170209 header.b=l0bHSF3N; dkim-atps=neutral Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 49d3M01Ttdz9sSc for ; Thu, 4 Jun 2020 21:23:56 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-Id:Date:Subject:To :From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=VhbLzxY8HjdkyirxqCYmovkKU8EGvOnIwJdi4Ui0MV0=; b=l0bHSF3NPyGV2Q llt6xjBtp55YRsQoVh/y5q/gUfSlAeZIRX7Aa7sSQh68aw+GhURH/kXGf5koif8pGHx/z+pWtSt/p 91pU4w5sNXUIdfN4JYx2oQkvDutOephpL0AhKxeioGxPfBEfiRghl+Q7DdFjI5tggTaJ4I0AYQrZn +imubL/PkOBb78twPcMaaylSgumeOSPLw+XWZrkSLaKOdsD0VnwFy6rMGADzxxrdVKXbiwz0iQbCt Cmp34Vf2zL5LAADqxi2a9Gvv2SPnah+K5uxCyAwvGUjYcMUOaZSI0gCztRiXL1Mk94mDS7OnJlqGC jQAf+0Fxylcy92QSbTGA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jgny8-0002kC-9u; Thu, 04 Jun 2020 11:23:32 +0000 Received: from s3.sipsolutions.net ([2a01:4f8:191:4433::2] helo=sipsolutions.net) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jgny5-0002Yj-5c for linux-um@lists.infradead.org; Thu, 04 Jun 2020 11:23:30 +0000 Received: by sipsolutions.net with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.93) (envelope-from ) id 1jgny0-009HpX-2U; Thu, 04 Jun 2020 13:23:24 +0200 From: Johannes Berg To: linux-um@lists.infradead.org Subject: [PATCH] um: change sigio_spinlock to a mutex Date: Thu, 4 Jun 2020 13:23:17 +0200 Message-Id: <20200604132317.75a2f85a7e52.Ifa9c62fa63625d4685383003e6a5d6c27d7b4e45@changeid> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200604_042329_207319_A61512F7 X-CRM114-Status: UNSURE ( 8.56 ) X-CRM114-Notice: Please train this message. X-Spam-Score: 0.4 (/) X-Spam-Report: SpamAssassin version 3.4.4 on bombadil.infradead.org summary: Content analysis details: (0.4 points) pts rule name description ---- ---------------------- -------------------------------------------------- 0.0 SPF_NONE SPF: sender does not publish an SPF Record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record 0.4 KHOP_HELO_FCRDNS Relay HELO differs from its IP's reverse DNS X-BeenThere: linux-um@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Johannes Berg Sender: "linux-um" Errors-To: linux-um-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org From: Johannes Berg Lockdep complains at boot: ============================= [ BUG: Invalid wait context ] 5.7.0-05093-g46d91ecd597b #98 Not tainted ----------------------------- swapper/1 is trying to lock: 0000000060931b98 (&desc[i].request_mutex){+.+.}-{3:3}, at: __setup_irq+0x11d/0x623 other info that might help us debug this: context-{4:4} 1 lock held by swapper/1: #0: 000000006074fed8 (sigio_spinlock){+.+.}-{2:2}, at: sigio_lock+0x1a/0x1c stack backtrace: CPU: 0 PID: 1 Comm: swapper Not tainted 5.7.0-05093-g46d91ecd597b #98 Stack: 7fa4fab0 6028dfd1 0000002a 6008bea5 7fa50700 7fa50040 7fa4fac0 6028e016 7fa4fb50 6007f6da 60959c18 00000000 Call Trace: [<60023a0e>] show_stack+0x13b/0x155 [<6028e016>] dump_stack+0x2a/0x2c [<6007f6da>] __lock_acquire+0x515/0x15f2 [<6007eb50>] lock_acquire+0x245/0x273 [<6050d9f1>] __mutex_lock+0xbd/0x325 [<6050dc76>] mutex_lock_nested+0x1d/0x1f [<6008e27e>] __setup_irq+0x11d/0x623 [<6008e8ed>] request_threaded_irq+0x169/0x1a6 [<60021eb0>] um_request_irq+0x1ee/0x24b [<600234ee>] write_sigio_irq+0x3b/0x76 [<600383ca>] sigio_broken+0x146/0x2e4 [<60020bd8>] do_one_initcall+0xde/0x281 Because we hold sigio_spinlock and then get into requesting an interrupt with a mutex. Change the spinlock to a mutex to avoid that. Signed-off-by: Johannes Berg --- arch/um/kernel/sigio.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/um/kernel/sigio.c b/arch/um/kernel/sigio.c index 10c99e058fca..d1cffc2a7f21 100644 --- a/arch/um/kernel/sigio.c +++ b/arch/um/kernel/sigio.c @@ -35,14 +35,14 @@ int write_sigio_irq(int fd) } /* These are called from os-Linux/sigio.c to protect its pollfds arrays. */ -static DEFINE_SPINLOCK(sigio_spinlock); +static DEFINE_MUTEX(sigio_mutex); void sigio_lock(void) { - spin_lock(&sigio_spinlock); + mutex_lock(&sigio_mutex); } void sigio_unlock(void) { - spin_unlock(&sigio_spinlock); + mutex_unlock(&sigio_mutex); }