x86/mm: Don't free P4D table when it is folded at runtime
When the P4D page table layer is folded at runtime, the p4d_free()
should do nothing, the same as in <asm-generic/pgtable-nop4d.h>.
It seems this bug should cause double-free in efi_call_phys_epilog(),
but I don't know how to trigger that code path, so I can't confirm that
by testing.
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org # 4.17
Fixes: 98219dda2a
("x86/mm: Fold p4d page table layer at runtime")
Link: http://lkml.kernel.org/r/20180625102427.15015-1-aryabinin@virtuozzo.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
parent
236f0cd286
commit
0e311d237d
|
@ -184,6 +184,9 @@ static inline p4d_t *p4d_alloc_one(struct mm_struct *mm, unsigned long addr)
|
|||
|
||||
static inline void p4d_free(struct mm_struct *mm, p4d_t *p4d)
|
||||
{
|
||||
if (!pgtable_l5_enabled())
|
||||
return;
|
||||
|
||||
BUG_ON((unsigned long)p4d & (PAGE_SIZE-1));
|
||||
free_page((unsigned long)p4d);
|
||||
}
|
||||
|
|
Loading…
Reference in a new issue