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powerpc/mm: Fix null-pointer dereference in pgtable_cache_add

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kasprintf() returns a pointer to dynamically allocated memory
which can be NULL upon failure. Ensure the allocation was successful
by checking the pointer validity.

Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Kunwu Chan <chentao@kylinos.cn>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231204023223.2447523-1-chentao@kylinos.cn
This commit is contained in:
Kunwu Chan 2023-12-04 10:32:23 +08:00 committed by Michael Ellerman
parent b20f98e8b3
commit f46c8a7526
1 changed files with 3 additions and 2 deletions
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5
arch/powerpc/mm/init-common.c
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@ -126,7 +126,7 @@ void pgtable_cache_add(unsigned int shift)
* as to leave enough 0 bits in the address to contain it. */ * as to leave enough 0 bits in the address to contain it. */
unsigned long minalign = max(MAX_PGTABLE_INDEX_SIZE + 1, unsigned long minalign = max(MAX_PGTABLE_INDEX_SIZE + 1,
HUGEPD_SHIFT_MASK + 1); HUGEPD_SHIFT_MASK + 1);
struct kmem_cache *new; struct kmem_cache *new = NULL;
/* It would be nice if this was a BUILD_BUG_ON(), but at the /* It would be nice if this was a BUILD_BUG_ON(), but at the
* moment, gcc doesn't seem to recognize is_power_of_2 as a * moment, gcc doesn't seem to recognize is_power_of_2 as a
@ -139,7 +139,8 @@ void pgtable_cache_add(unsigned int shift)
align = max_t(unsigned long, align, minalign); align = max_t(unsigned long, align, minalign);
name = kasprintf(GFP_KERNEL, "pgtable-2^%d", shift); name = kasprintf(GFP_KERNEL, "pgtable-2^%d", shift);
new = kmem_cache_create(name, table_size, align, 0, ctor(shift)); if (name)
new = kmem_cache_create(name, table_size, align, 0, ctor(shift));
if (!new) if (!new)
panic("Could not allocate pgtable cache for order %d", shift); panic("Could not allocate pgtable cache for order %d", shift);