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| author | Yu Kuai <yukuai3@huawei.com> | 2023-05-23 10:10:17 +0800 |
|---|---|---|
| committer | Song Liu <song@kernel.org> | 2023-06-13 15:25:39 -0700 |
| commit | 4469315439827290923fce4f3f672599cabeb366 (patch) | |
| tree | 83e7d30c4570cd28774226f0e9d36b110c823ff8 /drivers/md/md.h | |
| parent | 4eeb6535cd51100460ec8873bb68addef17b3e81 (diff) | |
| download | lwn-4469315439827290923fce4f3f672599cabeb366.tar.gz lwn-4469315439827290923fce4f3f672599cabeb366.zip | |
md: protect md_thread with rcu
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
Diffstat (limited to 'drivers/md/md.h')
| -rw-r--r-- | drivers/md/md.h | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/drivers/md/md.h b/drivers/md/md.h index 7156fc05f834..a50122165fa1 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -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); |