From mboxrd@z Thu Jan 1 00:00:00 1970 From: Len Brown Subject: [PATCH 66/76] ACPI: Fix use-after-free in acpi_map_lsapic Date: Fri, 30 Mar 2012 06:14:09 -0400 Message-ID: References: <1333102459-23750-1-git-send-email-lenb@kernel.org> Reply-To: Len Brown Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-reply-to: <1333102459-23750-1-git-send-email-lenb@kernel.org> In-reply-to: <09f98a825a821f7a3f1b162f9ed023f37213a63b.1333101989.git.len.brown@intel.com> References: <09f98a825a821f7a3f1b162f9ed023f37213a63b.1333101989.git.len.brown@intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org To: linux-acpi@vger.kernel.org, linux-pm@lists.linux-foundation.org Cc: Len Brown , Alok N Kataria , Petr Vandrovec , linux-kernel@vger.kernel.org List-Id: linux-pm@vger.kernel.org From: Petr Vandrovec When processor is being hot-added to the system, acpi_map_lsapic invokes ACPI _MAT method to find APIC ID and flags, verifies that returned structure is indeed ACPI's local APIC structure, and that flags contain MADT_ENABLED bit. Then saves APIC ID, frees structure - and accesses structure when computing arguments for acpi_register_lapic call. Which sometime leads to acpi_register_lapic call being made with second argument zero, failing to bring processor online with error 'Unable to map lapic to logical cpu number'. As lapic->lapic_flags & ACPI_MADT_ENABLED was already confirmed to be non-zero few lines above, we can just pass unconditional ACPI_MADT_ENABLED to the acpi_register_lapic. Signed-off-by: Petr Vandrovec Signed-off-by: Alok N Kataria Reviewed-by: Toshi Kani Signed-off-by: Len Brown --- arch/x86/kernel/acpi/boot.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c index ce664f3..bbcc2c3 100644 --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -642,6 +642,7 @@ static int __cpuinit _acpi_map_lsapic(acpi_handle handle, int *pcpu) kfree(buffer.pointer); buffer.length = ACPI_ALLOCATE_BUFFER; buffer.pointer = NULL; + lapic = NULL; if (!alloc_cpumask_var(&tmp_map, GFP_KERNEL)) goto out; @@ -650,7 +651,7 @@ static int __cpuinit _acpi_map_lsapic(acpi_handle handle, int *pcpu) goto free_tmp_map; cpumask_copy(tmp_map, cpu_present_mask); - acpi_register_lapic(physid, lapic->lapic_flags & ACPI_MADT_ENABLED); + acpi_register_lapic(physid, ACPI_MADT_ENABLED); /* * If mp_register_lapic successfully generates a new logical cpu -- 1.7.10.rc2.19.gfae9d