1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/fault-inject.h> 3 #include <linux/error-injection.h> 4 #include <linux/debugfs.h> 5 #include <linux/slab.h> 6 #include <linux/mm.h> 7 #include "slab.h" 8 9 static struct { 10 struct fault_attr attr; 11 bool ignore_gfp_reclaim; 12 bool cache_filter; 13 } failslab = { 14 .attr = FAULT_ATTR_INITIALIZER, 15 .ignore_gfp_reclaim = true, 16 .cache_filter = false, 17 }; 18 19 int should_failslab(struct kmem_cache *s, gfp_t gfpflags) 20 { 21 int flags = 0; 22 23 /* No fault-injection for bootstrap cache */ 24 if (unlikely(s == kmem_cache)) 25 return 0; 26 27 if (gfpflags & __GFP_NOFAIL) 28 return 0; 29 30 if (failslab.ignore_gfp_reclaim && 31 (gfpflags & __GFP_DIRECT_RECLAIM)) 32 return 0; 33 34 if (failslab.cache_filter && !(s->flags & SLAB_FAILSLAB)) 35 return 0; 36 37 /* 38 * In some cases, it expects to specify __GFP_NOWARN 39 * to avoid printing any information(not just a warning), 40 * thus avoiding deadlocks. See commit 6b9dbedbe349 for 41 * details. 42 */ 43 if (gfpflags & __GFP_NOWARN) 44 flags |= FAULT_NOWARN; 45 46 return should_fail_ex(&failslab.attr, s->object_size, flags) ? -ENOMEM : 0; 47 } 48 ALLOW_ERROR_INJECTION(should_failslab, ERRNO); 49 50 static int __init setup_failslab(char *str) 51 { 52 return setup_fault_attr(&failslab.attr, str); 53 } 54 __setup("failslab=", setup_failslab); 55 56 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS 57 static int __init failslab_debugfs_init(void) 58 { 59 struct dentry *dir; 60 umode_t mode = S_IFREG | 0600; 61 62 dir = fault_create_debugfs_attr("failslab", NULL, &failslab.attr); 63 if (IS_ERR(dir)) 64 return PTR_ERR(dir); 65 66 debugfs_create_bool("ignore-gfp-wait", mode, dir, 67 &failslab.ignore_gfp_reclaim); 68 debugfs_create_bool("cache-filter", mode, dir, 69 &failslab.cache_filter); 70 71 return 0; 72 } 73 74 late_initcall(failslab_debugfs_init); 75 76 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */ 77