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authorNicolai Stange <nicstange@gmail.com>2017-01-05 13:51:29 +0100
committerIngo Molnar <mingo@kernel.org>2017-01-07 08:58:07 +0100
commit20b1e22d01a4b0b11d3a1066e9feb04be38607ec (patch)
tree614e00a43b1e0d6af54685d52e12b106bc5cae23 /include
parentabfb7b686a3e5be27bf81db62f9c5c895b76f5d1 (diff)
x86/efi: Don't allocate memmap through memblock after mm_init()
With the following commit: 4bc9f92e64c8 ("x86/efi-bgrt: Use efi_mem_reserve() to avoid copying image data") ... efi_bgrt_init() calls into the memblock allocator through efi_mem_reserve() => efi_arch_mem_reserve() *after* mm_init() has been called. Indeed, KASAN reports a bad read access later on in efi_free_boot_services(): BUG: KASAN: use-after-free in efi_free_boot_services+0xae/0x24c at addr ffff88022de12740 Read of size 4 by task swapper/0/0 page:ffffea0008b78480 count:0 mapcount:-127 mapping: (null) index:0x1 flags: 0x5fff8000000000() [...] Call Trace: dump_stack+0x68/0x9f kasan_report_error+0x4c8/0x500 kasan_report+0x58/0x60 __asan_load4+0x61/0x80 efi_free_boot_services+0xae/0x24c start_kernel+0x527/0x562 x86_64_start_reservations+0x24/0x26 x86_64_start_kernel+0x157/0x17a start_cpu+0x5/0x14 The instruction at the given address is the first read from the memmap's memory, i.e. the read of md->type in efi_free_boot_services(). Note that the writes earlier in efi_arch_mem_reserve() don't splat because they're done through early_memremap()ed addresses. So, after memblock is gone, allocations should be done through the "normal" page allocator. Introduce a helper, efi_memmap_alloc() for this. Use it from efi_arch_mem_reserve(), efi_free_boot_services() and, for the sake of consistency, from efi_fake_memmap() as well. Note that for the latter, the memmap allocations cease to be page aligned. This isn't needed though. Tested-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Nicolai Stange <nicstange@gmail.com> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: <stable@vger.kernel.org> # v4.9 Cc: Dave Young <dyoung@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Mika Penttilä <mika.penttila@nextfour.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Fixes: 4bc9f92e64c8 ("x86/efi-bgrt: Use efi_mem_reserve() to avoid copying image data") Link: http://lkml.kernel.org/r/20170105125130.2815-1-nicstange@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/efi.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/efi.h b/include/linux/efi.h
index a07a476178cd..0c5420208c40 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -950,6 +950,7 @@ static inline efi_status_t efi_query_variable_store(u32 attributes,
#endif
extern void __iomem *efi_lookup_mapped_addr(u64 phys_addr);
+extern phys_addr_t __init efi_memmap_alloc(unsigned int num_entries);
extern int __init efi_memmap_init_early(struct efi_memory_map_data *data);
extern int __init efi_memmap_init_late(phys_addr_t addr, unsigned long size);
extern void __init efi_memmap_unmap(void);