>From f0b7f6c2146f693fec6706bf9e3c34687c73f21a Mon Sep 17 00:00:00 2001
From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Date: Mon, 28 May 2018 21:49:51 +0900
Subject: [PATCH] kmemleak: don't use __GFP_NOFAIL
Commit d9570ee3bd1d4f20 ("kmemleak: allow to coexist with fault injection")
added __GFP_NOFAIL to gfp_kmemleak_mask() macro because memory allocation
fault injection trivially disables kmemleak.
But since !__GFP_DIRECT_RECLAIM && __GFP_NOFAIL memory allocation is not
supported, Mathieu Malaterre is observing warning messages upon
mempool_alloc(gfp_msk & ~__GFP_DIRECT_RECLAIM) allocation request.
[ 269.039118] NIP [c020e8f8] __alloc_pages_nodemask+0xa88/0xfec
[ 269.039124] LR [c020e2e0] __alloc_pages_nodemask+0x470/0xfec
[ 269.039128] Call Trace:
[ 269.039136] [dde3b750] [c020e2e0] __alloc_pages_nodemask+0x470/0xfec (unreliable)
[ 269.039146] [dde3b820] [c0288c14] new_slab+0x53c/0x970
[ 269.039155] [dde3b880] [c028b61c] ___slab_alloc.constprop.23+0x28c/0x468
[ 269.039163] [dde3b920] [c028c754] kmem_cache_alloc+0x290/0x3dc
[ 269.039177] [dde3b990] [c02a6030] create_object+0x50/0x3d0
[ 269.039185] [dde3b9e0] [c028c7a8] kmem_cache_alloc+0x2e4/0x3dc
[ 269.039193] [dde3ba50] [c0200f88] mempool_alloc+0x7c/0x164
[ 269.039205] [dde3bab0] [c03e33c0] bio_alloc_bioset+0x130/0x298
[ 269.039216] [dde3baf0] [c0278694] get_swap_bio+0x34/0xe8
[ 269.039223] [dde3bb30] [c0278fb4] __swap_writepage+0x22c/0x644
[ 269.039237] [dde3bbb0] [c022528c] pageout.isra.13+0x238/0x52c
[ 269.039246] [dde3bc10] [c02288a0] shrink_page_list+0x9d4/0x1768
[ 269.039254] [dde3bcb0] [c022a264] shrink_inactive_list+0x2c4/0xa34
[ 269.039262] [dde3bd40] [c022b454] shrink_node_memcg+0x344/0xe34
[ 269.039270] [dde3bde0] [c022c068] shrink_node+0x124/0x73c
[ 269.039277] [dde3be50] [c022d78c] kswapd+0x318/0xb2c
[ 269.039291] [dde3bf10] [c008e264] kthread+0x138/0x1f0
[ 269.039300] [dde3bf40] [c001b2e4] ret_from_kernel_thread+0x5c/0x64
Since the intent of adding __GFP_NOFAIL is not to disable kmemleak by
failing the N'th allocation request, it should be possible to workaround
it by simply retrying N'th allocation request. Thus, this patch changes
callers of gfp_kmemleak_mask() macro to retry for several times.
Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Reported-by: Mathieu Malaterre <malat@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
---
mm/kmemleak.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 9a085d5..973998b 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -126,7 +126,7 @@
/* GFP bitmask for kmemleak internal allocations */
#define gfp_kmemleak_mask(gfp) (((gfp) & (GFP_KERNEL | GFP_ATOMIC)) | \
__GFP_NORETRY | __GFP_NOMEMALLOC | \
- __GFP_NOWARN | __GFP_NOFAIL)
+ __GFP_NOWARN)
/* scanning area inside a memory block */
struct kmemleak_scan_area {
@@ -548,10 +548,12 @@ static struct kmemleak_object *create_object(unsigned long ptr, size_t size,
int min_count, gfp_t gfp)
{
unsigned long flags;
- struct kmemleak_object *object, *parent;
+ struct kmemleak_object *object = NULL, *parent;
struct rb_node **link, *rb_parent;
+ unsigned int i;
- object = kmem_cache_alloc(object_cache, gfp_kmemleak_mask(gfp));
+ for (i = 0; i < 10 && !object; i++)
+ object = kmem_cache_alloc(object_cache, gfp_kmemleak_mask(gfp));
if (!object) {
pr_warn("Cannot allocate a kmemleak_object structure\n");
kmemleak_disable();
@@ -763,7 +765,8 @@ static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp)
{
unsigned long flags;
struct kmemleak_object *object;
- struct kmemleak_scan_area *area;
+ struct kmemleak_scan_area *area = NULL;
+ unsigned int i;
object = find_and_get_object(ptr, 1);
if (!object) {
@@ -772,7 +775,9 @@ static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp)
return;
}
- area = kmem_cache_alloc(scan_area_cache, gfp_kmemleak_mask(gfp));
+ for (i = 0; i < 10 && !area; i++)
+ area = kmem_cache_alloc(scan_area_cache,
+ gfp_kmemleak_mask(gfp));
if (!area) {
pr_warn("Cannot allocate a scan area\n");
goto out;
--
1.8.3.1
