| Message ID | c97284f912128cbc3f2fe09d68e90e65fb3e6026.1565361876.git.christophe.leroy@c-s.fr (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 45ff3c55958542c3b76075d59741297b8cb31cbb |
| Headers | show |
| Series | powerpc/kasan: fix parallele loading of modules. | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch next (f3365d1a959d5c6527efe3d38276acc9b58e3f3f) |
| snowpatch_ozlabs/build-ppc64le | success | Build succeeded |
| snowpatch_ozlabs/build-ppc64be | success | Build succeeded |
| snowpatch_ozlabs/build-ppc64e | success | Build succeeded |
| snowpatch_ozlabs/build-pmac32 | success | Build succeeded |
| snowpatch_ozlabs/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 39 lines checked |
On Fri, 2019-08-09 at 14:58:09 UTC, Christophe Leroy wrote: > Parallele loading of modules may lead to bad setup of shadow > page table entries. > > First, lets align modules so that two modules never share the same > shadow page. > > Second, ensure that two modules cannot allocate two page tables for > the same PMD entry at the same time. This is done by using > init_mm.page_table_lock in the same way as __pte_alloc_kernel() > > Fixes: 2edb16efc899 ("powerpc/32: Add KASAN support") > Cc: stable@vger.kernel.org > Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/45ff3c55958542c3b76075d59741297b8cb31cbb cheers
diff --git a/arch/powerpc/mm/kasan/kasan_init_32.c b/arch/powerpc/mm/kasan/kasan_init_32.c index 99eac3fab83c..802387b231ad 100644 --- a/arch/powerpc/mm/kasan/kasan_init_32.c +++ b/arch/powerpc/mm/kasan/kasan_init_32.c @@ -5,6 +5,7 @@ #include <linux/kasan.h> #include <linux/printk.h> #include <linux/memblock.h> +#include <linux/moduleloader.h> #include <linux/sched/task.h> #include <linux/vmalloc.h> #include <asm/pgalloc.h> @@ -46,7 +47,19 @@ static int __ref kasan_init_shadow_page_tables(unsigned long k_start, unsigned l kasan_populate_pte(new, PAGE_READONLY); else kasan_populate_pte(new, PAGE_KERNEL_RO); - pmd_populate_kernel(&init_mm, pmd, new); + + smp_wmb(); /* See comment in __pte_alloc */ + + spin_lock(&init_mm.page_table_lock); + /* Has another populated it ? */ + if (likely((void *)pmd_page_vaddr(*pmd) == kasan_early_shadow_pte)) { + pmd_populate_kernel(&init_mm, pmd, new); + new = NULL; + } + spin_unlock(&init_mm.page_table_lock); + + if (new && slab_is_available()) + pte_free_kernel(&init_mm, new); } return 0; } @@ -137,7 +150,11 @@ void __init kasan_init(void) #ifdef CONFIG_MODULES void *module_alloc(unsigned long size) { - void *base = vmalloc_exec(size); + void *base; + + base = __vmalloc_node_range(size, MODULE_ALIGN, VMALLOC_START, VMALLOC_END, + GFP_KERNEL, PAGE_KERNEL_EXEC, VM_FLUSH_RESET_PERMS, + NUMA_NO_NODE, __builtin_return_address(0)); if (!base) return NULL;
Parallele loading of modules may lead to bad setup of shadow page table entries. First, lets align modules so that two modules never share the same shadow page. Second, ensure that two modules cannot allocate two page tables for the same PMD entry at the same time. This is done by using init_mm.page_table_lock in the same way as __pte_alloc_kernel() Fixes: 2edb16efc899 ("powerpc/32: Add KASAN support") Cc: stable@vger.kernel.org Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> --- arch/powerpc/mm/kasan/kasan_init_32.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-)