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From: Dan Williams <dan.j.williams@intel.com>
To: mingo@redhat.com
Cc: Taku Izumi <izumi.taku@jp.fujitsu.com>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org,
	kexec@lists.infradead.org, x86@kernel.org
Subject: [PATCH v2 3/4] efi: Fix efi_memmap_alloc() leaks
Date: Tue, 31 Dec 2019 14:04:33 -0800	[thread overview]
Message-ID: <157782987346.367056.16932641815225610530.stgit@dwillia2-desk3.amr.corp.intel.com> (raw)
In-Reply-To: <157782985777.367056.14741265874314204783.stgit@dwillia2-desk3.amr.corp.intel.com>

With efi_fake_memmap() and efi_arch_mem_reserve() the efi table may be
updated and replaced multiple times. When that happens a previous
dynamically allocated efi memory map can be garbage collected. Use the
new EFI_MEMMAP_{SLAB,MEMBLOCK} flags to detect when a dynamically
allocated memory map is being replaced.

Cc: Taku Izumi <izumi.taku@jp.fujitsu.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/firmware/efi/memmap.c |   24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/firmware/efi/memmap.c b/drivers/firmware/efi/memmap.c
index 2b81ee6858a9..188ab3cd5c52 100644
--- a/drivers/firmware/efi/memmap.c
+++ b/drivers/firmware/efi/memmap.c
@@ -29,6 +29,28 @@ static phys_addr_t __init __efi_memmap_alloc_late(unsigned long size)
 	return PFN_PHYS(page_to_pfn(p));
 }
 
+static void __init __efi_memmap_free(u64 phys, unsigned long size, unsigned long flags)
+{
+	if (WARN_ON(slab_is_available() && (flags & EFI_MEMMAP_MEMBLOCK)))
+		return;
+
+	if (flags & EFI_MEMMAP_MEMBLOCK) {
+		memblock_free(phys, size);
+	} else if (flags & EFI_MEMMAP_SLAB) {
+		struct page *p = pfn_to_page(PHYS_PFN(phys));
+		unsigned int order = get_order(size);
+
+		free_pages((unsigned long) page_address(p), order);
+	}
+}
+
+static void __init efi_memmap_free(void)
+{
+	__efi_memmap_free(efi.memmap.phys_map,
+			efi.memmap.desc_size * efi.memmap.nr_map,
+			efi.memmap.flags);
+}
+
 /**
  * efi_memmap_alloc - Allocate memory for the EFI memory map
  * @num_entries: Number of entries in the allocated map.
@@ -209,6 +231,8 @@ int __init efi_memmap_install(phys_addr_t addr, unsigned int nr_map,
 	data.desc_size = efi.memmap.desc_size;
 	flags |= efi.memmap.flags & EFI_MEMMAP_LATE;
 
+	efi_memmap_free();
+
 	return __efi_memmap_init(&data, flags);
 }
 


  parent reply	other threads:[~2019-12-31 22:20 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-31 22:04 [PATCH v2 0/4] efi: Fix handling of multiple efi_fake_mem= entries Dan Williams
2019-12-31 22:04 ` [PATCH v2 1/4] efi: Add a flags parameter to efi_memory_map Dan Williams
2019-12-31 22:04 ` [PATCH v2 2/4] efi: Add tracking for dynamically allocated memmaps Dan Williams
2019-12-31 22:04 ` Dan Williams [this message]
2020-01-01  3:35   ` [PATCH v2 3/4] efi: Fix efi_memmap_alloc() leaks Dave Young
2020-01-01  4:52     ` Dan Williams
2019-12-31 22:04 ` [PATCH v2 4/4] efi: Fix handling of multiple efi_fake_mem= entries Dan Williams
2020-01-01  4:51   ` Dave Young
2020-01-01  5:04     ` Dan Williams
2020-01-01  6:15       ` Dave Young
2020-01-01  6:20         ` Dave Young
2020-01-01 18:36           ` Dan Williams
2020-01-02  2:21             ` Dave Young

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