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https://github.com/torvalds/linux
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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>
73 lines
1.6 KiB
C
73 lines
1.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/fault-inject.h>
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#include <linux/slab.h>
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#include <linux/mm.h>
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#include "slab.h"
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static struct {
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struct fault_attr attr;
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bool ignore_gfp_reclaim;
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bool cache_filter;
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} failslab = {
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.attr = FAULT_ATTR_INITIALIZER,
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.ignore_gfp_reclaim = true,
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.cache_filter = false,
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};
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bool __should_failslab(struct kmem_cache *s, gfp_t gfpflags)
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{
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int flags = 0;
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/* No fault-injection for bootstrap cache */
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if (unlikely(s == kmem_cache))
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return false;
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if (gfpflags & __GFP_NOFAIL)
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return false;
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if (failslab.ignore_gfp_reclaim &&
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(gfpflags & __GFP_DIRECT_RECLAIM))
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return false;
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if (failslab.cache_filter && !(s->flags & SLAB_FAILSLAB))
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return false;
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/*
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* In some cases, it expects to specify __GFP_NOWARN
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* to avoid printing any information(not just a warning),
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* thus avoiding deadlocks. See commit 6b9dbedbe349 for
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* details.
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*/
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if (gfpflags & __GFP_NOWARN)
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flags |= FAULT_NOWARN;
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return should_fail_ex(&failslab.attr, s->object_size, flags);
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}
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static int __init setup_failslab(char *str)
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{
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return setup_fault_attr(&failslab.attr, str);
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}
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__setup("failslab=", setup_failslab);
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#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
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static int __init failslab_debugfs_init(void)
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{
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struct dentry *dir;
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umode_t mode = S_IFREG | 0600;
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dir = fault_create_debugfs_attr("failslab", NULL, &failslab.attr);
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if (IS_ERR(dir))
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return PTR_ERR(dir);
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debugfs_create_bool("ignore-gfp-wait", mode, dir,
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&failslab.ignore_gfp_reclaim);
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debugfs_create_bool("cache-filter", mode, dir,
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&failslab.cache_filter);
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return 0;
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}
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late_initcall(failslab_debugfs_init);
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#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
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