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md: protect md_thread with rcu

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Currently, there are many places that md_thread can be accessed without
protection, following are known scenarios that can cause
null-ptr-dereference or uaf:

1) sync_thread that is allocated and started from md_start_sync()
2) mddev->thread can be accessed directly from timeout_store() and
   md_bitmap_daemon_work()
3) md_unregister_thread() from action_store().

Currently, a global spinlock 'pers_lock' is borrowed to protect
'mddev->thread' in some places, this problem can be fixed likewise,
however, use a global lock for all the cases is not good.

Fix this problem by protecting all md_thread with rcu.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230523021017.3048783-6-yukuai1@huaweicloud.com
This commit is contained in:
Yu Kuai 2023-05-23 10:10:17 +08:00 committed by Song Liu
parent 4eeb6535cd
commit 4469315439
12 changed files with 97 additions and 81 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
drivers/md/md-bitmap.c
View File

@ -1237,13 +1237,19 @@ static bitmap_counter_t *md_bitmap_get_counter(struct bitmap_counts *bitmap,
static void mddev_set_timeout(struct mddev *mddev, unsigned long timeout,
bool force)
{
struct md_thread *thread = mddev->thread;
struct md_thread *thread;
rcu_read_lock();
thread = rcu_dereference(mddev->thread);
if (!thread)
return;
goto out;
if (force || thread->timeout < MAX_SCHEDULE_TIMEOUT)
thread->timeout = timeout;
out:
rcu_read_unlock();
}
/*

17
drivers/md/md-cluster.c
View File

@ -75,14 +75,14 @@ struct md_cluster_info {
sector_t suspend_hi;
int suspend_from; /* the slot which broadcast suspend_lo/hi */
struct md_thread *recovery_thread;
struct md_thread __rcu *recovery_thread;
unsigned long recovery_map;
/* communication loc resources */
struct dlm_lock_resource *ack_lockres;
struct dlm_lock_resource *message_lockres;
struct dlm_lock_resource *token_lockres;
struct dlm_lock_resource *no_new_dev_lockres;
struct md_thread *recv_thread;
struct md_thread __rcu *recv_thread;
struct completion newdisk_completion;
wait_queue_head_t wait;
unsigned long state;
@ -362,8 +362,8 @@ static void __recover_slot(struct mddev *mddev, int slot)
set_bit(slot, &cinfo->recovery_map);
if (!cinfo->recovery_thread) {
cinfo->recovery_thread = md_register_thread(recover_bitmaps,
mddev, "recover");
rcu_assign_pointer(cinfo->recovery_thread,
md_register_thread(recover_bitmaps, mddev, "recover"));
if (!cinfo->recovery_thread) {
pr_warn("md-cluster: Could not create recovery thread\n");
return;
@ -526,11 +526,15 @@ static void process_add_new_disk(struct mddev *mddev, struct cluster_msg *cmsg)
static void process_metadata_update(struct mddev *mddev, struct cluster_msg *msg)
{
int got_lock = 0;
struct md_thread *thread;
struct md_cluster_info *cinfo = mddev->cluster_info;
mddev->good_device_nr = le32_to_cpu(msg->raid_slot);
dlm_lock_sync(cinfo->no_new_dev_lockres, DLM_LOCK_CR);
wait_event(mddev->thread->wqueue,
/* daemaon thread must exist */
thread = rcu_dereference_protected(mddev->thread, true);
wait_event(thread->wqueue,
(got_lock = mddev_trylock(mddev)) ||
test_bit(MD_CLUSTER_HOLDING_MUTEX_FOR_RECVD, &cinfo->state));
md_reload_sb(mddev, mddev->good_device_nr);
@ -889,7 +893,8 @@ static int join(struct mddev *mddev, int nodes)
}
/* Initiate the communication resources */
ret = -ENOMEM;
cinfo->recv_thread = md_register_thread(recv_daemon, mddev, "cluster_recv");
rcu_assign_pointer(cinfo->recv_thread,
md_register_thread(recv_daemon, mddev, "cluster_recv"));
if (!cinfo->recv_thread) {
pr_err("md-cluster: cannot allocate memory for recv_thread!\n");
goto err;

4
drivers/md/md-multipath.c
View File

@ -400,8 +400,8 @@ static int multipath_run (struct mddev *mddev)
if (ret)
goto out_free_conf;
mddev->thread = md_register_thread(multipathd, mddev,
"multipath");
rcu_assign_pointer(mddev->thread,
md_register_thread(multipathd, mddev, "multipath"));
if (!mddev->thread)
goto out_free_conf;

69
drivers/md/md.c
View File

@ -70,11 +70,7 @@
#include "md-bitmap.h"
#include "md-cluster.h"
/* pers_list is a list of registered personalities protected
* by pers_lock.
* pers_lock does extra service to protect accesses to
* mddev->thread when the mutex cannot be held.
*/
/* pers_list is a list of registered personalities protected by pers_lock. */
static LIST_HEAD(pers_list);
static DEFINE_SPINLOCK(pers_lock);
@ -92,7 +88,7 @@ static int remove_and_add_spares(struct mddev *mddev,
struct md_rdev *this);
static void mddev_detach(struct mddev *mddev);
static void export_rdev(struct md_rdev *rdev, struct mddev *mddev);
static void md_wakeup_thread_directly(struct md_thread *thread);
static void md_wakeup_thread_directly(struct md_thread __rcu *thread);
/*
* Default number of read corrections we'll attempt on an rdev
@ -442,8 +438,10 @@ static void md_submit_bio(struct bio *bio)
*/
void mddev_suspend(struct mddev *mddev)
{
WARN_ON_ONCE(mddev->thread && current == mddev->thread->tsk);
lockdep_assert_held(&mddev->reconfig_mutex);
struct md_thread *thread = rcu_dereference_protected(mddev->thread,
lockdep_is_held(&mddev->reconfig_mutex));
WARN_ON_ONCE(thread && current == thread->tsk);
if (mddev->suspended++)
return;
wake_up(&mddev->sb_wait);
@ -811,13 +809,8 @@ void mddev_unlock(struct mddev *mddev)
md_free_rdev(mddev);
/* As we've dropped the mutex we need a spinlock to
* make sure the thread doesn't disappear
*/
spin_lock(&pers_lock);
md_wakeup_thread(mddev->thread);
wake_up(&mddev->sb_wait);
spin_unlock(&pers_lock);
}
EXPORT_SYMBOL_GPL(mddev_unlock);
@ -7903,19 +7896,29 @@ static int md_thread(void *arg)
return 0;
}
static void md_wakeup_thread_directly(struct md_thread *thread)
static void md_wakeup_thread_directly(struct md_thread __rcu *thread)
{
if (thread)
wake_up_process(thread->tsk);
struct md_thread *t;
rcu_read_lock();
t = rcu_dereference(thread);
if (t)
wake_up_process(t->tsk);
rcu_read_unlock();
}
void md_wakeup_thread(struct md_thread *thread)
void md_wakeup_thread(struct md_thread __rcu *thread)
{
if (thread) {
pr_debug("md: waking up MD thread %s.\n", thread->tsk->comm);
set_bit(THREAD_WAKEUP, &thread->flags);
wake_up(&thread->wqueue);
struct md_thread *t;
rcu_read_lock();
t = rcu_dereference(thread);
if (t) {
pr_debug("md: waking up MD thread %s.\n", t->tsk->comm);
set_bit(THREAD_WAKEUP, &t->flags);
wake_up(&t->wqueue);
}
rcu_read_unlock();
}
EXPORT_SYMBOL(md_wakeup_thread);
@ -7945,22 +7948,15 @@ struct md_thread *md_register_thread(void (*run) (struct md_thread *),
}
EXPORT_SYMBOL(md_register_thread);
void md_unregister_thread(struct md_thread **threadp)
void md_unregister_thread(struct md_thread __rcu **threadp)
{
struct md_thread *thread;
struct md_thread *thread = rcu_dereference_protected(*threadp, true);
/*
* Locking ensures that mddev_unlock does not wake_up a
* non-existent thread
*/
spin_lock(&pers_lock);
thread = *threadp;
if (!thread) {
spin_unlock(&pers_lock);
if (!thread)
return;
}
*threadp = NULL;
spin_unlock(&pers_lock);
rcu_assign_pointer(*threadp, NULL);
synchronize_rcu();
pr_debug("interrupting MD-thread pid %d\n", task_pid_nr(thread->tsk));
kthread_stop(thread->tsk);
@ -9226,9 +9222,8 @@ static void md_start_sync(struct work_struct *ws)
{
struct mddev *mddev = container_of(ws, struct mddev, del_work);
mddev->sync_thread = md_register_thread(md_do_sync,
mddev,
"resync");
rcu_assign_pointer(mddev->sync_thread,
md_register_thread(md_do_sync, mddev, "resync"));
if (!mddev->sync_thread) {
pr_warn("%s: could not start resync thread...\n",
mdname(mddev));

8
drivers/md/md.h
View File

@ -365,8 +365,8 @@ struct mddev {
int new_chunk_sectors;
int reshape_backwards;
struct md_thread *thread; /* management thread */
struct md_thread *sync_thread; /* doing resync or reconstruct */
struct md_thread __rcu *thread; /* management thread */
struct md_thread __rcu *sync_thread; /* doing resync or reconstruct */
/* 'last_sync_action' is initialized to "none". It is set when a
* sync operation (i.e "data-check", "requested-resync", "resync",
@ -758,8 +758,8 @@ extern struct md_thread *md_register_thread(
void (*run)(struct md_thread *thread),
struct mddev *mddev,
const char *name);
extern void md_unregister_thread(struct md_thread **threadp);
extern void md_wakeup_thread(struct md_thread *thread);
extern void md_unregister_thread(struct md_thread __rcu **threadp);
extern void md_wakeup_thread(struct md_thread __rcu *thread);
extern void md_check_recovery(struct mddev *mddev);
extern void md_reap_sync_thread(struct mddev *mddev);
extern int mddev_init_writes_pending(struct mddev *mddev);

7
drivers/md/raid1.c
View File

@ -3087,7 +3087,8 @@ static struct r1conf *setup_conf(struct mddev *mddev)
}
err = -ENOMEM;
conf->thread = md_register_thread(raid1d, mddev, "raid1");
rcu_assign_pointer(conf->thread,
md_register_thread(raid1d, mddev, "raid1"));
if (!conf->thread)
goto abort;
@ -3180,8 +3181,8 @@ static int raid1_run(struct mddev *mddev)
/*
* Ok, everything is just fine now
*/
mddev->thread = conf->thread;
conf->thread = NULL;
rcu_assign_pointer(mddev->thread, conf->thread);
rcu_assign_pointer(conf->thread, NULL);
mddev->private = conf;
set_bit(MD_FAILFAST_SUPPORTED, &mddev->flags);

2
drivers/md/raid1.h
View File

@ -130,7 +130,7 @@ struct r1conf {
/* When taking over an array from a different personality, we store
* the new thread here until we fully activate the array.
*/
struct md_thread *thread;
struct md_thread __rcu *thread;
/* Keep track of cluster resync window to send to other
* nodes.

20
drivers/md/raid10.c
View File

@ -982,6 +982,7 @@ static void lower_barrier(struct r10conf *conf)
static bool stop_waiting_barrier(struct r10conf *conf)
{
struct bio_list *bio_list = current->bio_list;
struct md_thread *thread;
/* barrier is dropped */
if (!conf->barrier)
@ -997,12 +998,14 @@ static bool stop_waiting_barrier(struct r10conf *conf)
(!bio_list_empty(&bio_list[0]) || !bio_list_empty(&bio_list[1])))
return true;
/* daemon thread must exist while handling io */
thread = rcu_dereference_protected(conf->mddev->thread, true);
/*
* move on if io is issued from raid10d(), nr_pending is not released
* from original io(see handle_read_error()). All raise barrier is
* blocked until this io is done.
*/
if (conf->mddev->thread->tsk == current) {
if (thread->tsk == current) {
WARN_ON_ONCE(atomic_read(&conf->nr_pending) == 0);
return true;
}
@ -4107,7 +4110,8 @@ static struct r10conf *setup_conf(struct mddev *mddev)
atomic_set(&conf->nr_pending, 0);
err = -ENOMEM;
conf->thread = md_register_thread(raid10d, mddev, "raid10");
rcu_assign_pointer(conf->thread,
md_register_thread(raid10d, mddev, "raid10"));
if (!conf->thread)
goto out;
@ -4152,8 +4156,8 @@ static int raid10_run(struct mddev *mddev)
if (!conf)
goto out;
mddev->thread = conf->thread;
conf->thread = NULL;
rcu_assign_pointer(mddev->thread, conf->thread);
rcu_assign_pointer(conf->thread, NULL);
if (mddev_is_clustered(conf->mddev)) {
int fc, fo;
@ -4296,8 +4300,8 @@ static int raid10_run(struct mddev *mddev)
clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
mddev->sync_thread = md_register_thread(md_do_sync, mddev,
"reshape");
rcu_assign_pointer(mddev->sync_thread,
md_register_thread(md_do_sync, mddev, "reshape"));
if (!mddev->sync_thread)
goto out_free_conf;
}
@ -4698,8 +4702,8 @@ out:
set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
mddev->sync_thread = md_register_thread(md_do_sync, mddev,
"reshape");
rcu_assign_pointer(mddev->sync_thread,
md_register_thread(md_do_sync, mddev, "reshape"));
if (!mddev->sync_thread) {
ret = -EAGAIN;
goto abort;

2
drivers/md/raid10.h
View File

@ -100,7 +100,7 @@ struct r10conf {
/* When taking over an array from a different personality, we store
* the new thread here until we fully activate the array.
*/
struct md_thread *thread;
struct md_thread __rcu *thread;
/*
* Keep track of cluster resync window to send to other nodes.

22
drivers/md/raid5-cache.c
View File

@ -120,7 +120,7 @@ struct r5l_log {
struct bio_set bs;
mempool_t meta_pool;
struct md_thread *reclaim_thread;
struct md_thread __rcu *reclaim_thread;
unsigned long reclaim_target; /* number of space that need to be
* reclaimed. if it's 0, reclaim spaces
* used by io_units which are in
@ -1576,17 +1576,18 @@ void r5l_wake_reclaim(struct r5l_log *log, sector_t space)
void r5l_quiesce(struct r5l_log *log, int quiesce)
{
struct mddev *mddev;
struct mddev *mddev = log->rdev->mddev;
struct md_thread *thread = rcu_dereference_protected(
log->reclaim_thread, lockdep_is_held(&mddev->reconfig_mutex));
if (quiesce) {
/* make sure r5l_write_super_and_discard_space exits */
mddev = log->rdev->mddev;
wake_up(&mddev->sb_wait);
kthread_park(log->reclaim_thread->tsk);
kthread_park(thread->tsk);
r5l_wake_reclaim(log, MaxSector);
r5l_do_reclaim(log);
} else
kthread_unpark(log->reclaim_thread->tsk);
kthread_unpark(thread->tsk);
}
bool r5l_log_disk_error(struct r5conf *conf)
@ -3063,6 +3064,7 @@ void r5c_update_on_rdev_error(struct mddev *mddev, struct md_rdev *rdev)
int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev)
{
struct r5l_log *log;
struct md_thread *thread;
int ret;
pr_debug("md/raid:%s: using device %pg as journal\n",
@ -3121,11 +3123,13 @@ int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev)
spin_lock_init(&log->tree_lock);
INIT_RADIX_TREE(&log->big_stripe_tree, GFP_NOWAIT | __GFP_NOWARN);
log->reclaim_thread = md_register_thread(r5l_reclaim_thread,
log->rdev->mddev, "reclaim");
if (!log->reclaim_thread)
thread = md_register_thread(r5l_reclaim_thread, log->rdev->mddev,
"reclaim");
if (!thread)
goto reclaim_thread;
log->reclaim_thread->timeout = R5C_RECLAIM_WAKEUP_INTERVAL;
thread->timeout = R5C_RECLAIM_WAKEUP_INTERVAL;
rcu_assign_pointer(log->reclaim_thread, thread);
init_waitqueue_head(&log->iounit_wait);

15
drivers/md/raid5.c
View File

@ -7731,7 +7731,8 @@ static struct r5conf *setup_conf(struct mddev *mddev)
}
sprintf(pers_name, "raid%d", mddev->new_level);
conf->thread = md_register_thread(raid5d, mddev, pers_name);
rcu_assign_pointer(conf->thread,
md_register_thread(raid5d, mddev, pers_name));
if (!conf->thread) {
pr_warn("md/raid:%s: couldn't allocate thread.\n",
mdname(mddev));
@ -7954,8 +7955,8 @@ static int raid5_run(struct mddev *mddev)
}
conf->min_offset_diff = min_offset_diff;
mddev->thread = conf->thread;
conf->thread = NULL;
rcu_assign_pointer(mddev->thread, conf->thread);
rcu_assign_pointer(conf->thread, NULL);
mddev->private = conf;
for (i = 0; i < conf->raid_disks && conf->previous_raid_disks;
@ -8052,8 +8053,8 @@ static int raid5_run(struct mddev *mddev)
clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
mddev->sync_thread = md_register_thread(md_do_sync, mddev,
"reshape");
rcu_assign_pointer(mddev->sync_thread,
md_register_thread(md_do_sync, mddev, "reshape"));
if (!mddev->sync_thread)
goto abort;
}
@ -8631,8 +8632,8 @@ static int raid5_start_reshape(struct mddev *mddev)
clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
mddev->sync_thread = md_register_thread(md_do_sync, mddev,
"reshape");
rcu_assign_pointer(mddev->sync_thread,
md_register_thread(md_do_sync, mddev, "reshape"));
if (!mddev->sync_thread) {
mddev->recovery = 0;
spin_lock_irq(&conf->device_lock);

2
drivers/md/raid5.h
View File

@ -679,7 +679,7 @@ struct r5conf {
/* When taking over an array from a different personality, we store
* the new thread here until we fully activate the array.
*/
struct md_thread *thread;
struct md_thread __rcu *thread;
struct list_head temp_inactive_list[NR_STRIPE_HASH_LOCKS];
struct r5worker_group *worker_groups;
int group_cnt;