diff options
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/user.c | 27 |
1 files changed, 17 insertions, 10 deletions
diff --git a/kernel/user.c b/kernel/user.c index d1ae2349347e..d9deae43a9ab 100644 --- a/kernel/user.c +++ b/kernel/user.c | |||
@@ -33,6 +33,10 @@ static struct list_head uidhash_table[UIDHASH_SZ]; | |||
33 | * The uidhash_lock is mostly taken from process context, but it is | 33 | * The uidhash_lock is mostly taken from process context, but it is |
34 | * occasionally also taken from softirq/tasklet context, when | 34 | * occasionally also taken from softirq/tasklet context, when |
35 | * task-structs get RCU-freed. Hence all locking must be softirq-safe. | 35 | * task-structs get RCU-freed. Hence all locking must be softirq-safe. |
36 | * But free_uid() is also called with local interrupts disabled, and running | ||
37 | * local_bh_enable() with local interrupts disabled is an error - we'll run | ||
38 | * softirq callbacks, and they can unconditionally enable interrupts, and | ||
39 | * the caller of free_uid() didn't expect that.. | ||
36 | */ | 40 | */ |
37 | static DEFINE_SPINLOCK(uidhash_lock); | 41 | static DEFINE_SPINLOCK(uidhash_lock); |
38 | 42 | ||
@@ -89,16 +93,19 @@ static inline struct user_struct *uid_hash_find(uid_t uid, struct list_head *has | |||
89 | struct user_struct *find_user(uid_t uid) | 93 | struct user_struct *find_user(uid_t uid) |
90 | { | 94 | { |
91 | struct user_struct *ret; | 95 | struct user_struct *ret; |
96 | unsigned long flags; | ||
92 | 97 | ||
93 | spin_lock_bh(&uidhash_lock); | 98 | spin_lock_irqsave(&uidhash_lock, flags); |
94 | ret = uid_hash_find(uid, uidhashentry(uid)); | 99 | ret = uid_hash_find(uid, uidhashentry(uid)); |
95 | spin_unlock_bh(&uidhash_lock); | 100 | spin_unlock_irqrestore(&uidhash_lock, flags); |
96 | return ret; | 101 | return ret; |
97 | } | 102 | } |
98 | 103 | ||
99 | void free_uid(struct user_struct *up) | 104 | void free_uid(struct user_struct *up) |
100 | { | 105 | { |
101 | local_bh_disable(); | 106 | unsigned long flags; |
107 | |||
108 | local_irq_save(flags); | ||
102 | if (up && atomic_dec_and_lock(&up->__count, &uidhash_lock)) { | 109 | if (up && atomic_dec_and_lock(&up->__count, &uidhash_lock)) { |
103 | uid_hash_remove(up); | 110 | uid_hash_remove(up); |
104 | key_put(up->uid_keyring); | 111 | key_put(up->uid_keyring); |
@@ -106,7 +113,7 @@ void free_uid(struct user_struct *up) | |||
106 | kmem_cache_free(uid_cachep, up); | 113 | kmem_cache_free(uid_cachep, up); |
107 | spin_unlock(&uidhash_lock); | 114 | spin_unlock(&uidhash_lock); |
108 | } | 115 | } |
109 | local_bh_enable(); | 116 | local_irq_restore(flags); |
110 | } | 117 | } |
111 | 118 | ||
112 | struct user_struct * alloc_uid(uid_t uid) | 119 | struct user_struct * alloc_uid(uid_t uid) |
@@ -114,9 +121,9 @@ struct user_struct * alloc_uid(uid_t uid) | |||
114 | struct list_head *hashent = uidhashentry(uid); | 121 | struct list_head *hashent = uidhashentry(uid); |
115 | struct user_struct *up; | 122 | struct user_struct *up; |
116 | 123 | ||
117 | spin_lock_bh(&uidhash_lock); | 124 | spin_lock_irq(&uidhash_lock); |
118 | up = uid_hash_find(uid, hashent); | 125 | up = uid_hash_find(uid, hashent); |
119 | spin_unlock_bh(&uidhash_lock); | 126 | spin_unlock_irq(&uidhash_lock); |
120 | 127 | ||
121 | if (!up) { | 128 | if (!up) { |
122 | struct user_struct *new; | 129 | struct user_struct *new; |
@@ -146,7 +153,7 @@ struct user_struct * alloc_uid(uid_t uid) | |||
146 | * Before adding this, check whether we raced | 153 | * Before adding this, check whether we raced |
147 | * on adding the same user already.. | 154 | * on adding the same user already.. |
148 | */ | 155 | */ |
149 | spin_lock_bh(&uidhash_lock); | 156 | spin_lock_irq(&uidhash_lock); |
150 | up = uid_hash_find(uid, hashent); | 157 | up = uid_hash_find(uid, hashent); |
151 | if (up) { | 158 | if (up) { |
152 | key_put(new->uid_keyring); | 159 | key_put(new->uid_keyring); |
@@ -156,7 +163,7 @@ struct user_struct * alloc_uid(uid_t uid) | |||
156 | uid_hash_insert(new, hashent); | 163 | uid_hash_insert(new, hashent); |
157 | up = new; | 164 | up = new; |
158 | } | 165 | } |
159 | spin_unlock_bh(&uidhash_lock); | 166 | spin_unlock_irq(&uidhash_lock); |
160 | 167 | ||
161 | } | 168 | } |
162 | return up; | 169 | return up; |
@@ -192,9 +199,9 @@ static int __init uid_cache_init(void) | |||
192 | INIT_LIST_HEAD(uidhash_table + n); | 199 | INIT_LIST_HEAD(uidhash_table + n); |
193 | 200 | ||
194 | /* Insert the root user immediately (init already runs as root) */ | 201 | /* Insert the root user immediately (init already runs as root) */ |
195 | spin_lock_bh(&uidhash_lock); | 202 | spin_lock_irq(&uidhash_lock); |
196 | uid_hash_insert(&root_user, uidhashentry(0)); | 203 | uid_hash_insert(&root_user, uidhashentry(0)); |
197 | spin_unlock_bh(&uidhash_lock); | 204 | spin_unlock_irq(&uidhash_lock); |
198 | 205 | ||
199 | return 0; | 206 | return 0; |
200 | } | 207 | } |