From patchwork Fri Apr 4 21:14:43 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 14038924 Received: from mail-pl1-f201.google.com (mail-pl1-f201.google.com [209.85.214.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 93E2C218ABA for ; Fri, 4 Apr 2025 21:15:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743801308; cv=none; b=lduPXy6xXjLmrNBietn4rR/jCv0/hraK+bRQJDj20NBQeI1mUzOs6Fe5pUfHtzLYpZhWUt5HjW5k+z4SsCOBUK2xDSbtdj0npSl7aY4WdqxOfBRXEkx5U0aehVSMlVtwSk3YLkVBG/pK9gd0QA1WQR84by4VimOjX9kAOtFAKfE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743801308; c=relaxed/simple; bh=3eQJAa9cubM3sOJ48FmMAgTG/qqYFR22T28SrTWB6pw=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=txU/Nx/16FdOk4jtMi0SDP1GJlEDF/Au6HV/zdkygHMC5eDnkQBp7KIBIB127F8xRemmCMOKy/Rqvn2Oc10bAE/hVQWEJfhWk6uZSbEa1jZBhGzmSqJWc5GUI23V/By6fmrzcR8KYVVJ6sWNxEnCKLx4TIu5ECy9pJsJPlkiCk4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=EfOsY+J3; arc=none smtp.client-ip=209.85.214.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="EfOsY+J3" Received: by mail-pl1-f201.google.com with SMTP id d9443c01a7336-227a8cdd272so22374355ad.2 for ; Fri, 04 Apr 2025 14:15:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1743801306; x=1744406106; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=BV0n160bdAMJIwF9gIdsee0gSXMixk7gnYOIwMBSkTY=; b=EfOsY+J3Evu+cdhO1HPL7EDI03ImmRIYF1A7PuHvIEFMhk5UvDwD522hXpb0XwDHJW nzvVcLngrduWzo7d9x+x0diqFCq6iGo9FFNuEWI+86kSKSKTHx/sOLEt0M4cW+brQVBY uiroOjTm5+Jiwia87wnXKX+5bWN+/mawF9sfZJhrEm+Xy5wHM6vvJsuVtud1J5bB6XKg pOaLmA91rZv6OWfZDHKcPap1yWOIqTCrvDuIgW77EtiiKOcjoBo8WhiHT7pvUAcvfjnm /BaoeKPccn0D7xL6mdd3bGO2S5CN8leinwGIfALc5NfI0OE7NFyXQ8IhNndIauMeDX+f 3Nww== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1743801306; x=1744406106; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=BV0n160bdAMJIwF9gIdsee0gSXMixk7gnYOIwMBSkTY=; b=QVUToXQA/B2hxneeAwW4gY1qwf1iPApUnVclrXRXMZTwkXA6TbNKW3sfEwqc39FxxN 2/lQMiA6p7EoCUf6j8fSEk5Mz7wkZtxWp5vED/UCZ66nIm5wCdHwGlMC4g7Ztu4oSLnk V1co0TNOoyyDRSDxMRoZsm+NrbtDsj47x4zmQWNIR/4DxF4dtn3mFrHff07vnyez7PTB iQCrHvXKbnR0kJdicMvNNvvXw3TjovfXfOOZfyw6t8nW0bBzqNfUkqnSCnlSVdcg9yQD WYZwjIgGg3fxNBbTPK/rjfLzY6pKmib59M0gh7FYFQ7Yb1ENVA5oparsIBUkWqSfFmpn dTYQ== X-Gm-Message-State: AOJu0YwUs9gUNtUiWVmaFRv8MtfqJKBzhThcf5eUWBZ9eqDDfq7SxToH UTtErbi3Of6fbvodHw3DryMvyvIu6qLYvD5HaEfGxQnhzpIe04W+eJFwQedBbo6cxhFsn5x2kyq Chg== X-Google-Smtp-Source: AGHT+IHGnE8XslHm/Dp26htMuuamh5CyH4BkTccpSE3E94306LmR6+QWCeFh1nKaosRJPLYDlX1yhMluHf0= X-Received: from pfcf1.prod.google.com ([2002:a05:6a00:2381:b0:732:858a:729f]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:902:e883:b0:224:255b:c932 with SMTP id d9443c01a7336-22a8a04a526mr44725315ad.3.1743801305822; Fri, 04 Apr 2025 14:15:05 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 4 Apr 2025 14:14:43 -0700 In-Reply-To: <20250404211449.1443336-1-seanjc@google.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250404211449.1443336-1-seanjc@google.com> X-Mailer: git-send-email 2.49.0.504.g3bcea36a83-goog Message-ID: <20250404211449.1443336-2-seanjc@google.com> Subject: [PATCH 1/7] irqbypass: Drop pointless and misleading THIS_MODULE get/put From: Sean Christopherson To: "Michael S. Tsirkin" , Jason Wang , Paolo Bonzini , Alex Williamson Cc: kvm@vger.kernel.org, virtualization@lists.linux.dev, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Sean Christopherson , Oliver Upton , David Matlack , Like Xu , Yong He Drop irqbypass.ko's superfluous and misleading get/put calls on THIS_MODULE. A module taking a reference to itself is useless; no amount of checks will prevent doom and destruction if the caller hasn't already guaranteed the liveliness of the module (this goes for any module). E.g. if try_module_get() fails because irqbypass.ko is being unloaded, then the kernel has already hit a use-after-free by virtue of executing code whose lifecycle is tied to irqbypass.ko. Signed-off-by: Sean Christopherson --- virt/lib/irqbypass.c | 20 -------------------- 1 file changed, 20 deletions(-) diff --git a/virt/lib/irqbypass.c b/virt/lib/irqbypass.c index 28fda42e471b..080c706f3b01 100644 --- a/virt/lib/irqbypass.c +++ b/virt/lib/irqbypass.c @@ -92,9 +92,6 @@ int irq_bypass_register_producer(struct irq_bypass_producer *producer) might_sleep(); - if (!try_module_get(THIS_MODULE)) - return -ENODEV; - mutex_lock(&lock); list_for_each_entry(tmp, &producers, node) { @@ -120,7 +117,6 @@ int irq_bypass_register_producer(struct irq_bypass_producer *producer) return 0; out_err: mutex_unlock(&lock); - module_put(THIS_MODULE); return ret; } EXPORT_SYMBOL_GPL(irq_bypass_register_producer); @@ -142,9 +138,6 @@ void irq_bypass_unregister_producer(struct irq_bypass_producer *producer) might_sleep(); - if (!try_module_get(THIS_MODULE)) - return; /* nothing in the list anyway */ - mutex_lock(&lock); list_for_each_entry(tmp, &producers, node) { @@ -159,13 +152,10 @@ void irq_bypass_unregister_producer(struct irq_bypass_producer *producer) } list_del(&producer->node); - module_put(THIS_MODULE); break; } mutex_unlock(&lock); - - module_put(THIS_MODULE); } EXPORT_SYMBOL_GPL(irq_bypass_unregister_producer); @@ -188,9 +178,6 @@ int irq_bypass_register_consumer(struct irq_bypass_consumer *consumer) might_sleep(); - if (!try_module_get(THIS_MODULE)) - return -ENODEV; - mutex_lock(&lock); list_for_each_entry(tmp, &consumers, node) { @@ -216,7 +203,6 @@ int irq_bypass_register_consumer(struct irq_bypass_consumer *consumer) return 0; out_err: mutex_unlock(&lock); - module_put(THIS_MODULE); return ret; } EXPORT_SYMBOL_GPL(irq_bypass_register_consumer); @@ -238,9 +224,6 @@ void irq_bypass_unregister_consumer(struct irq_bypass_consumer *consumer) might_sleep(); - if (!try_module_get(THIS_MODULE)) - return; /* nothing in the list anyway */ - mutex_lock(&lock); list_for_each_entry(tmp, &consumers, node) { @@ -255,12 +238,9 @@ void irq_bypass_unregister_consumer(struct irq_bypass_consumer *consumer) } list_del(&consumer->node); - module_put(THIS_MODULE); break; } mutex_unlock(&lock); - - module_put(THIS_MODULE); } EXPORT_SYMBOL_GPL(irq_bypass_unregister_consumer);