Commit af3b8544 authored by Benjamin Poirier's avatar Benjamin Poirier Committed by Linus Torvalds
Browse files

mm/page_alloc.c: allow error injection

Model call chain after should_failslab().  Likewise, we can now use a
kprobe to override the return value of should_fail_alloc_page() and inject
allocation failures into alloc_page*().

This will allow injecting allocation failures using the BCC tools even
without building kernel with CONFIG_FAIL_PAGE_ALLOC and booting it with a
fail_page_alloc= parameter, which incurs some overhead even when failures
are not being injected.  On the other hand, this patch adds an
unconditional call to should_fail_alloc_page() from page allocation
hotpath.  That overhead should be rather negligible with
CONFIG_FAIL_PAGE_ALLOC=n when there's no kprobe attached, though.

[ changelog addition]

Signed-off-by: default avatarBenjamin Poirier <>
Acked-by: default avatarVlastimil Babka <>
Cc: Arnd Bergmann <>
Cc: Michal Hocko <>
Cc: Pavel Tatashin <>
Cc: Oscar Salvador <>
Cc: Mike Rapoport <>
Cc: Joonsoo Kim <>
Cc: Alexander Duyck <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent ab41ee68
......@@ -8,6 +8,7 @@ enum {
EI_ETYPE_NULL, /* Return NULL if failure */
EI_ETYPE_ERRNO, /* Return -ERRNO if failure */
EI_ETYPE_ERRNO_NULL, /* Return -ERRNO or NULL if failure */
EI_ETYPE_TRUE, /* Return true if failure */
struct error_injection_entry {
......@@ -3131,7 +3131,7 @@ static int __init setup_fail_page_alloc(char *str)
__setup("fail_page_alloc=", setup_fail_page_alloc);
static bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
static bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
if (order < fail_page_alloc.min_order)
return false;
......@@ -3181,13 +3181,19 @@ late_initcall(fail_page_alloc_debugfs);
static inline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
static inline bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
return false;
static noinline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
return __should_fail_alloc_page(gfp_mask, order);
ALLOW_ERROR_INJECTION(should_fail_alloc_page, TRUE);
* Return true if free base pages are above 'mark'. For high-order checks it
* will return true of the order-0 watermark is reached and there is at least
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