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[198.145.29.99]) by mx.google.com with ESMTPS id 14si18847662ple.218.2019.04.24.07.48.27 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 24 Apr 2019 07:48:28 -0700 (PDT) Received-SPF: pass (google.com: domain of sashal@kernel.org designates 198.145.29.99 as permitted sender) client-ip=198.145.29.99; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=E+a9eU1w; spf=pass (google.com: domain of sashal@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=sashal@kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2082D218FE; Wed, 24 Apr 2019 14:48:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556117307; bh=5HDGAh0QbI2VY/kbAiK5FAqvJFcRtvLJDVA3Il/vCuM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=E+a9eU1wrQsk6nObqZ/8xl7udl4eQ87xlUgJCS1FPmODkgXUSwG97za5zI4KuIsFO ZAfm4xKML72RP4P7wz7aO5nCMN10isHOBDOUtXF/SMM13R9sKtUcq+SNR6hiPV79vE ioW8LARRKUc43W1i37zX7kfggsng+gBr4vXbUv60= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Catalin Marinas , Paul Mackerras , Benjamin Herrenschmidt , Avi Kivity , Paolo Bonzini , Radim Krcmar , Andrew Morton , Linus Torvalds , Sasha Levin , kvm-ppc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org Subject: [PATCH AUTOSEL 4.14 29/35] kmemleak: powerpc: skip scanning holes in the .bss section Date: Wed, 24 Apr 2019 10:47:03 -0400 Message-Id: <20190424144709.30215-29-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190424144709.30215-1-sashal@kernel.org> References: <20190424144709.30215-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Catalin Marinas [ Upstream commit 298a32b132087550d3fa80641ca58323c5dfd4d9 ] Commit 2d4f567103ff ("KVM: PPC: Introduce kvm_tmp framework") adds kvm_tmp[] into the .bss section and then free the rest of unused spaces back to the page allocator. kernel_init kvm_guest_init kvm_free_tmp free_reserved_area free_unref_page free_unref_page_prepare With DEBUG_PAGEALLOC=y, it will unmap those pages from kernel. As the result, kmemleak scan will trigger a panic when it scans the .bss section with unmapped pages. This patch creates dedicated kmemleak objects for the .data, .bss and potentially .data..ro_after_init sections to allow partial freeing via the kmemleak_free_part() in the powerpc kvm_free_tmp() function. Link: http://lkml.kernel.org/r/20190321171917.62049-1-catalin.marinas@arm.com Signed-off-by: Catalin Marinas Reported-by: Qian Cai Acked-by: Michael Ellerman (powerpc) Tested-by: Qian Cai Cc: Paul Mackerras Cc: Benjamin Herrenschmidt Cc: Avi Kivity Cc: Paolo Bonzini Cc: Radim Krcmar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- arch/powerpc/kernel/kvm.c | 7 +++++++ mm/kmemleak.c | 16 +++++++++++----- 2 files changed, 18 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/kernel/kvm.c b/arch/powerpc/kernel/kvm.c index 9ad37f827a97..7b59cc853abf 100644 --- a/arch/powerpc/kernel/kvm.c +++ b/arch/powerpc/kernel/kvm.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include #include @@ -712,6 +713,12 @@ static void kvm_use_magic_page(void) static __init void kvm_free_tmp(void) { + /* + * Inform kmemleak about the hole in the .bss section since the + * corresponding pages will be unmapped with DEBUG_PAGEALLOC=y. + */ + kmemleak_free_part(&kvm_tmp[kvm_tmp_index], + ARRAY_SIZE(kvm_tmp) - kvm_tmp_index); free_reserved_area(&kvm_tmp[kvm_tmp_index], &kvm_tmp[ARRAY_SIZE(kvm_tmp)], -1, NULL); } diff --git a/mm/kmemleak.c b/mm/kmemleak.c index d9e0be2a8189..337be9aacb7a 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -1492,11 +1492,6 @@ static void kmemleak_scan(void) } rcu_read_unlock(); - /* data/bss scanning */ - scan_large_block(_sdata, _edata); - scan_large_block(__bss_start, __bss_stop); - scan_large_block(__start_ro_after_init, __end_ro_after_init); - #ifdef CONFIG_SMP /* per-cpu sections scanning */ for_each_possible_cpu(i) @@ -2027,6 +2022,17 @@ void __init kmemleak_init(void) } local_irq_restore(flags); + /* register the data/bss sections */ + create_object((unsigned long)_sdata, _edata - _sdata, + KMEMLEAK_GREY, GFP_ATOMIC); + create_object((unsigned long)__bss_start, __bss_stop - __bss_start, + KMEMLEAK_GREY, GFP_ATOMIC); + /* only register .data..ro_after_init if not within .data */ + if (__start_ro_after_init < _sdata || __end_ro_after_init > _edata) + create_object((unsigned long)__start_ro_after_init, + __end_ro_after_init - __start_ro_after_init, + KMEMLEAK_GREY, GFP_ATOMIC); + /* * This is the point where tracking allocations is safe. Automatic * scanning is started during the late initcall. Add the early logged -- 2.19.1