ea4452de2a
When we specify __GFP_NOWARN, we only expect that no warnings will be
issued for current caller. But in the __should_failslab() and
__should_fail_alloc_page(), the local GFP flags alter the global
{failslab|fail_page_alloc}.attr, which is persistent and shared by all
tasks. This is not what we expected, let's fix it.
[akpm@linux-foundation.org: unexport should_fail_ex()]
Link: https://lkml.kernel.org/r/20221118100011.2634-1-zhengqi.arch@bytedance.com
Fixes: 3f913fc5f9 ("mm: fix missing handler for __GFP_NOWARN")
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Akinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
74 lines
1.6 KiB
C
74 lines
1.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
#include <linux/fault-inject.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/mm.h>
|
|
#include "slab.h"
|
|
|
|
static struct {
|
|
struct fault_attr attr;
|
|
bool ignore_gfp_reclaim;
|
|
bool cache_filter;
|
|
} failslab = {
|
|
.attr = FAULT_ATTR_INITIALIZER,
|
|
.ignore_gfp_reclaim = true,
|
|
.cache_filter = false,
|
|
};
|
|
|
|
bool __should_failslab(struct kmem_cache *s, gfp_t gfpflags)
|
|
{
|
|
int flags = 0;
|
|
|
|
/* No fault-injection for bootstrap cache */
|
|
if (unlikely(s == kmem_cache))
|
|
return false;
|
|
|
|
if (gfpflags & __GFP_NOFAIL)
|
|
return false;
|
|
|
|
if (failslab.ignore_gfp_reclaim &&
|
|
(gfpflags & __GFP_DIRECT_RECLAIM))
|
|
return false;
|
|
|
|
if (failslab.cache_filter && !(s->flags & SLAB_FAILSLAB))
|
|
return false;
|
|
|
|
/*
|
|
* In some cases, it expects to specify __GFP_NOWARN
|
|
* to avoid printing any information(not just a warning),
|
|
* thus avoiding deadlocks. See commit 6b9dbedbe349 for
|
|
* details.
|
|
*/
|
|
if (gfpflags & __GFP_NOWARN)
|
|
flags |= FAULT_NOWARN;
|
|
|
|
return should_fail_ex(&failslab.attr, s->object_size, flags);
|
|
}
|
|
|
|
static int __init setup_failslab(char *str)
|
|
{
|
|
return setup_fault_attr(&failslab.attr, str);
|
|
}
|
|
__setup("failslab=", setup_failslab);
|
|
|
|
#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
|
|
static int __init failslab_debugfs_init(void)
|
|
{
|
|
struct dentry *dir;
|
|
umode_t mode = S_IFREG | 0600;
|
|
|
|
dir = fault_create_debugfs_attr("failslab", NULL, &failslab.attr);
|
|
if (IS_ERR(dir))
|
|
return PTR_ERR(dir);
|
|
|
|
debugfs_create_bool("ignore-gfp-wait", mode, dir,
|
|
&failslab.ignore_gfp_reclaim);
|
|
debugfs_create_bool("cache-filter", mode, dir,
|
|
&failslab.cache_filter);
|
|
|
|
return 0;
|
|
}
|
|
|
|
late_initcall(failslab_debugfs_init);
|
|
|
|
#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
|