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md: init bioset in mddev_init

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IO operations may be needed before md_run(), such as updating metadata
after writing sysfs. Without bioset, this triggers a NULL pointer
dereference as below:

 BUG: kernel NULL pointer dereference, address: 0000000000000020
 Call Trace:
  md_update_sb+0x658/0xe00
  new_level_store+0xc5/0x120
  md_attr_store+0xc9/0x1e0
  sysfs_kf_write+0x6f/0xa0
  kernfs_fop_write_iter+0x141/0x2a0
  vfs_write+0x1fc/0x5a0
  ksys_write+0x79/0x180
  __x64_sys_write+0x1d/0x30
  x64_sys_call+0x2818/0x2880
  do_syscall_64+0xa9/0x580
  entry_SYSCALL_64_after_hwframe+0x4b/0x53

Reproducer
```
  mdadm -CR /dev/md0 -l1 -n2 /dev/sd[cd]
  echo inactive > /sys/block/md0/md/array_state
  echo 10 > /sys/block/md0/md/new_level
```

mddev_init() can only be called once per mddev, no need to test if bioset
has been initialized anymore.

Link: https://lore.kernel.org/linux-raid/20251103125757.1405796-3-linan666@huaweicloud.com
Fixes: d981ed8419 ("md: Add new_level sysfs interface")
Signed-off-by: Li Nan <linan122@huawei.com>
Reviewed-by: Xiao Ni <xni@redhat.com>
Signed-off-by: Yu Kuai <yukuai@fnnas.com>
This commit is contained in:
Li Nan
2025-11-03 20:57:54 +08:00
committed by Yu Kuai
parent 0ce112d917
commit 381a3ce1c0
1 changed files with 33 additions and 36 deletions
Download Patch File Download Diff File Expand all files Collapse all files

69
drivers/md/md.c
View File

@@ -730,6 +730,8 @@ static void mddev_clear_bitmap_ops(struct mddev *mddev)
int mddev_init(struct mddev *mddev)
{
int err = 0;
if (!IS_ENABLED(CONFIG_MD_BITMAP))
mddev->bitmap_id = ID_BITMAP_NONE;
else
@@ -741,10 +743,23 @@ int mddev_init(struct mddev *mddev)
if (percpu_ref_init(&mddev->writes_pending, no_op,
PERCPU_REF_ALLOW_REINIT, GFP_KERNEL)) {
percpu_ref_exit(&mddev->active_io);
return -ENOMEM;
err = -ENOMEM;
goto exit_acitve_io;
}
err = bioset_init(&mddev->bio_set, BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS);
if (err)
goto exit_writes_pending;
err = bioset_init(&mddev->sync_set, BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS);
if (err)
goto exit_bio_set;
err = bioset_init(&mddev->io_clone_set, BIO_POOL_SIZE,
offsetof(struct md_io_clone, bio_clone), 0);
if (err)
goto exit_sync_set;
/* We want to start with the refcount at zero */
percpu_ref_put(&mddev->writes_pending);
@@ -773,11 +788,24 @@ int mddev_init(struct mddev *mddev)
INIT_WORK(&mddev->del_work, mddev_delayed_delete);
return 0;
exit_sync_set:
bioset_exit(&mddev->sync_set);
exit_bio_set:
bioset_exit(&mddev->bio_set);
exit_writes_pending:
percpu_ref_exit(&mddev->writes_pending);
exit_acitve_io:
percpu_ref_exit(&mddev->active_io);
return err;
}
EXPORT_SYMBOL_GPL(mddev_init);
void mddev_destroy(struct mddev *mddev)
{
bioset_exit(&mddev->bio_set);
bioset_exit(&mddev->sync_set);
bioset_exit(&mddev->io_clone_set);
percpu_ref_exit(&mddev->active_io);
percpu_ref_exit(&mddev->writes_pending);
}
@@ -6394,29 +6422,9 @@ int md_run(struct mddev *mddev)
nowait = nowait && bdev_nowait(rdev->bdev);
}
if (!bioset_initialized(&mddev->bio_set)) {
err = bioset_init(&mddev->bio_set, BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS);
if (err)
return err;
}
if (!bioset_initialized(&mddev->sync_set)) {
err = bioset_init(&mddev->sync_set, BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS);
if (err)
goto exit_bio_set;
}
if (!bioset_initialized(&mddev->io_clone_set)) {
err = bioset_init(&mddev->io_clone_set, BIO_POOL_SIZE,
offsetof(struct md_io_clone, bio_clone), 0);
if (err)
goto exit_sync_set;
}
pers = get_pers(mddev->level, mddev->clevel);
if (!pers) {
err = -EINVAL;
goto abort;
}
if (!pers)
return -EINVAL;
if (mddev->level != pers->head.id) {
mddev->level = pers->head.id;
mddev->new_level = pers->head.id;
@@ -6427,8 +6435,7 @@ int md_run(struct mddev *mddev)
pers->start_reshape == NULL) {
/* This personality cannot handle reshaping... */
put_pers(pers);
err = -EINVAL;
goto abort;
return -EINVAL;
}
if (pers->sync_request) {
@@ -6555,12 +6562,6 @@ bitmap_abort:
mddev->private = NULL;
put_pers(pers);
md_bitmap_destroy(mddev);
abort:
bioset_exit(&mddev->io_clone_set);
exit_sync_set:
bioset_exit(&mddev->sync_set);
exit_bio_set:
bioset_exit(&mddev->bio_set);
return err;
}
EXPORT_SYMBOL_GPL(md_run);
@@ -6785,10 +6786,6 @@ static void __md_stop(struct mddev *mddev)
mddev->private = NULL;
put_pers(pers);
clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
bioset_exit(&mddev->bio_set);
bioset_exit(&mddev->sync_set);
bioset_exit(&mddev->io_clone_set);
}
void md_stop(struct mddev *mddev)