mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-05 22:36:40 +07:00
ed5bd7dc88
The user_header gets caught by kmemleak with the following splat as missing a free: unreferenced object 0xffff99667a733d80 (size 96): comm "swapper/0", pid 1, jiffies 4294892317 (age 62191.468s) hex dump (first 32 bytes): a0 b6 92 b4 ff ff ff ff 00 00 00 00 01 00 00 00 ................ 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: kmemleak_alloc+0x4a/0xa0 __kmalloc+0x144/0x260 __register_sysctl_table+0x54/0x5e0 register_sysctl+0x1b/0x20 user_namespace_sysctl_init+0x17/0x34 do_one_initcall+0x52/0x1a0 kernel_init_freeable+0x173/0x200 kernel_init+0xe/0x100 ret_from_fork+0x2c/0x40 The BUG_ON()s are intended to crash so no need to clean up after ourselves on error there. This is also a kernel/ subsys_init() we don't need a respective exit call here as this is never modular, so just white list it. Link: http://lkml.kernel.org/r/20170203211404.31458-1-mcgrof@kernel.org Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Kees Cook <keescook@chromium.org> Cc: Nikolay Borisov <n.borisov.lkml@gmail.com> Cc: Serge Hallyn <serge@hallyn.com> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
237 lines
5.5 KiB
C
237 lines
5.5 KiB
C
/*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation, version 2 of the
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* License.
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*/
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#include <linux/stat.h>
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#include <linux/sysctl.h>
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#include <linux/slab.h>
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#include <linux/hash.h>
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#include <linux/user_namespace.h>
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#define UCOUNTS_HASHTABLE_BITS 10
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static struct hlist_head ucounts_hashtable[(1 << UCOUNTS_HASHTABLE_BITS)];
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static DEFINE_SPINLOCK(ucounts_lock);
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#define ucounts_hashfn(ns, uid) \
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hash_long((unsigned long)__kuid_val(uid) + (unsigned long)(ns), \
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UCOUNTS_HASHTABLE_BITS)
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#define ucounts_hashentry(ns, uid) \
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(ucounts_hashtable + ucounts_hashfn(ns, uid))
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#ifdef CONFIG_SYSCTL
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static struct ctl_table_set *
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set_lookup(struct ctl_table_root *root)
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{
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return ¤t_user_ns()->set;
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}
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static int set_is_seen(struct ctl_table_set *set)
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{
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return ¤t_user_ns()->set == set;
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}
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static int set_permissions(struct ctl_table_header *head,
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struct ctl_table *table)
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{
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struct user_namespace *user_ns =
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container_of(head->set, struct user_namespace, set);
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int mode;
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/* Allow users with CAP_SYS_RESOURCE unrestrained access */
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if (ns_capable(user_ns, CAP_SYS_RESOURCE))
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mode = (table->mode & S_IRWXU) >> 6;
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else
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/* Allow all others at most read-only access */
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mode = table->mode & S_IROTH;
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return (mode << 6) | (mode << 3) | mode;
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}
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static struct ctl_table_root set_root = {
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.lookup = set_lookup,
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.permissions = set_permissions,
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};
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static int zero = 0;
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static int int_max = INT_MAX;
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#define UCOUNT_ENTRY(name) \
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{ \
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.procname = name, \
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.maxlen = sizeof(int), \
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.mode = 0644, \
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.proc_handler = proc_dointvec_minmax, \
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.extra1 = &zero, \
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.extra2 = &int_max, \
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}
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static struct ctl_table user_table[] = {
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UCOUNT_ENTRY("max_user_namespaces"),
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UCOUNT_ENTRY("max_pid_namespaces"),
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UCOUNT_ENTRY("max_uts_namespaces"),
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UCOUNT_ENTRY("max_ipc_namespaces"),
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UCOUNT_ENTRY("max_net_namespaces"),
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UCOUNT_ENTRY("max_mnt_namespaces"),
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UCOUNT_ENTRY("max_cgroup_namespaces"),
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{ }
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};
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#endif /* CONFIG_SYSCTL */
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bool setup_userns_sysctls(struct user_namespace *ns)
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{
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#ifdef CONFIG_SYSCTL
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struct ctl_table *tbl;
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setup_sysctl_set(&ns->set, &set_root, set_is_seen);
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tbl = kmemdup(user_table, sizeof(user_table), GFP_KERNEL);
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if (tbl) {
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int i;
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for (i = 0; i < UCOUNT_COUNTS; i++) {
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tbl[i].data = &ns->ucount_max[i];
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}
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ns->sysctls = __register_sysctl_table(&ns->set, "user", tbl);
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}
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if (!ns->sysctls) {
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kfree(tbl);
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retire_sysctl_set(&ns->set);
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return false;
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}
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#endif
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return true;
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}
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void retire_userns_sysctls(struct user_namespace *ns)
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{
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#ifdef CONFIG_SYSCTL
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struct ctl_table *tbl;
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tbl = ns->sysctls->ctl_table_arg;
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unregister_sysctl_table(ns->sysctls);
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retire_sysctl_set(&ns->set);
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kfree(tbl);
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#endif
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}
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static struct ucounts *find_ucounts(struct user_namespace *ns, kuid_t uid, struct hlist_head *hashent)
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{
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struct ucounts *ucounts;
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hlist_for_each_entry(ucounts, hashent, node) {
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if (uid_eq(ucounts->uid, uid) && (ucounts->ns == ns))
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return ucounts;
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}
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return NULL;
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}
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static struct ucounts *get_ucounts(struct user_namespace *ns, kuid_t uid)
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{
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struct hlist_head *hashent = ucounts_hashentry(ns, uid);
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struct ucounts *ucounts, *new;
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spin_lock_irq(&ucounts_lock);
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ucounts = find_ucounts(ns, uid, hashent);
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if (!ucounts) {
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spin_unlock_irq(&ucounts_lock);
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new = kzalloc(sizeof(*new), GFP_KERNEL);
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if (!new)
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return NULL;
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new->ns = ns;
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new->uid = uid;
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atomic_set(&new->count, 0);
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spin_lock_irq(&ucounts_lock);
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ucounts = find_ucounts(ns, uid, hashent);
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if (ucounts) {
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kfree(new);
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} else {
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hlist_add_head(&new->node, hashent);
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ucounts = new;
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}
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}
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if (!atomic_add_unless(&ucounts->count, 1, INT_MAX))
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ucounts = NULL;
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spin_unlock_irq(&ucounts_lock);
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return ucounts;
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}
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static void put_ucounts(struct ucounts *ucounts)
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{
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unsigned long flags;
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if (atomic_dec_and_test(&ucounts->count)) {
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spin_lock_irqsave(&ucounts_lock, flags);
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hlist_del_init(&ucounts->node);
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spin_unlock_irqrestore(&ucounts_lock, flags);
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kfree(ucounts);
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}
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}
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static inline bool atomic_inc_below(atomic_t *v, int u)
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{
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int c, old;
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c = atomic_read(v);
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for (;;) {
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if (unlikely(c >= u))
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return false;
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old = atomic_cmpxchg(v, c, c+1);
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if (likely(old == c))
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return true;
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c = old;
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}
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}
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struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid,
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enum ucount_type type)
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{
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struct ucounts *ucounts, *iter, *bad;
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struct user_namespace *tns;
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ucounts = get_ucounts(ns, uid);
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for (iter = ucounts; iter; iter = tns->ucounts) {
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int max;
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tns = iter->ns;
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max = READ_ONCE(tns->ucount_max[type]);
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if (!atomic_inc_below(&iter->ucount[type], max))
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goto fail;
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}
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return ucounts;
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fail:
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bad = iter;
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for (iter = ucounts; iter != bad; iter = iter->ns->ucounts)
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atomic_dec(&iter->ucount[type]);
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put_ucounts(ucounts);
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return NULL;
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}
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void dec_ucount(struct ucounts *ucounts, enum ucount_type type)
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{
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struct ucounts *iter;
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for (iter = ucounts; iter; iter = iter->ns->ucounts) {
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int dec = atomic_dec_if_positive(&iter->ucount[type]);
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WARN_ON_ONCE(dec < 0);
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}
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put_ucounts(ucounts);
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}
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static __init int user_namespace_sysctl_init(void)
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{
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#ifdef CONFIG_SYSCTL
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static struct ctl_table_header *user_header;
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static struct ctl_table empty[1];
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/*
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* It is necessary to register the user directory in the
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* default set so that registrations in the child sets work
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* properly.
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*/
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user_header = register_sysctl("user", empty);
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kmemleak_ignore(user_header);
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BUG_ON(!user_header);
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BUG_ON(!setup_userns_sysctls(&init_user_ns));
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#endif
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return 0;
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}
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subsys_initcall(user_namespace_sysctl_init);
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