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author | Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com> | 2021-07-17 18:07:19 +0800 |
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committer | Miquel Raynal <miquel.raynal@bootlin.com> | 2021-08-06 21:44:16 +0200 |
commit | b7abb051682263e51866bc78762fd0083d64c5ed (patch) | |
tree | 713b1e0360420fb748de7623f88cb9e8eea10162 /.mailmap | |
parent | 99dc4ad992bf156692b088fab4d98deab7cbd3e6 (diff) | |
download | linux-b7abb051682263e51866bc78762fd0083d64c5ed.tar.bz2 |
mtd: fix lock hierarchy in deregister_mtd_blktrans
There is a lock hierarchy of major_names_lock --> mtd_table_mutex. One
existing chain is as follows:
1. major_names_lock --> loop_ctl_mutex (when blk_request_module calls
loop_probe)
2. loop_ctl_mutex --> bdev->bd_mutex (when loop_control_ioctl calls
loop_remove, which then calls del_gendisk)
3. bdev->bd_mutex --> mtd_table_mutex (when blkdev_get_by_dev calls
__blkdev_get, which then calls blktrans_open)
Since unregister_blkdev grabs the major_names_lock, we need to call it
outside the critical section for mtd_table_mutex, otherwise we invert
the lock hierarchy.
Reported-by: Hillf Danton <hdanton@sina.com>
Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210717100719.728829-1-desmondcheongzx@gmail.com
Diffstat (limited to '.mailmap')
0 files changed, 0 insertions, 0 deletions