mm/failslab.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/fault-inject.h>
   3 #include <linux/slab.h>
   4 #include <linux/mm.h>
   5 #include "slab.h"
   6
   7 static struct {
   8         struct fault_attr attr;
   9         bool ignore_gfp_reclaim;
  10         bool cache_filter;
  11 } failslab = {
  12         .attr = FAULT_ATTR_INITIALIZER,
  13         .ignore_gfp_reclaim = true,
  14         .cache_filter = false,
  15 };
  16
  17 bool __should_failslab(struct kmem_cache *s, gfp_t gfpflags)
  18 {
  19         int flags = 0;
  20
  21         /* No fault-injection for bootstrap cache */
  22         if (unlikely(s == kmem_cache))
  23                 return false;
  24
  25         if (gfpflags & __GFP_NOFAIL)
  26                 return false;
  27
  28         if (failslab.ignore_gfp_reclaim &&
  29                         (gfpflags & __GFP_DIRECT_RECLAIM))
  30                 return false;
  31
  32         if (failslab.cache_filter && !(s->flags & SLAB_FAILSLAB))
  33                 return false;
  34
  35         /*
  36          * In some cases, it expects to specify __GFP_NOWARN
  37          * to avoid printing any information(not just a warning),
  38          * thus avoiding deadlocks. See commit 6b9dbedbe349 for
  39          * details.
  40          */
  41         if (gfpflags & __GFP_NOWARN)
  42                 flags |= FAULT_NOWARN;
  43
  44         return should_fail_ex(&failslab.attr, s->object_size, flags);
  45 }
  46
  47 static int __init setup_failslab(char *str)
  48 {
  49         return setup_fault_attr(&failslab.attr, str);
  50 }
  51 __setup("failslab=", setup_failslab);
  52
  53 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
  54 static int __init failslab_debugfs_init(void)
  55 {
  56         struct dentry *dir;
  57         umode_t mode = S_IFREG | 0600;
  58
  59         dir = fault_create_debugfs_attr("failslab", NULL, &failslab.attr);
  60         if (IS_ERR(dir))
  61                 return PTR_ERR(dir);
  62
  63         debugfs_create_bool("ignore-gfp-wait", mode, dir,
  64                             &failslab.ignore_gfp_reclaim);
  65         debugfs_create_bool("cache-filter", mode, dir,
  66                             &failslab.cache_filter);
  67
  68         return 0;
  69 }
  70
  71 late_initcall(failslab_debugfs_init);
  72
  73 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */