diff options
| author | Nicolai Stange <nicstange@gmail.com> | 2017-01-05 13:51:29 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-01-07 08:58:07 +0100 |
| commit | 20b1e22d01a4b0b11d3a1066e9feb04be38607ec (patch) | |
| tree | 614e00a43b1e0d6af54685d52e12b106bc5cae23 /include | |
| parent | abfb7b686a3e5be27bf81db62f9c5c895b76f5d1 (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.h | 1 |
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); |