5f16975233
[ Upstream commit 588159009d5b7a09c3e5904cffddbe4a4e170301 ] An attempt to acquire exclusive lock can race with the current lock owner closing the image: 1. lock is held by client123, rbd_lock() returns -EBUSY 2. get_lock_owner_info() returns client123 instance details 3. client123 closes the image, lock is released 4. find_watcher() returns 0 as there is no matching watcher anymore 5. client123 instance gets erroneously blocklisted Particularly impacted is mirror snapshot scheduler in snapshot-based mirroring since it happens to open and close images a lot (images are opened only for as long as it takes to take the next mirror snapshot, the same client instance is used for all images). To reduce the potential for erroneous blocklisting, retrieve the lock owner again after find_watcher() returns 0. If it's still there, make sure it matches the previously detected lock owner. Cc: stable@vger.kernel.org # f38cb9d9c204: rbd: make get_lock_owner_info() return a single locker or NULL Cc: stable@vger.kernel.org # 8ff2c64c9765: rbd: harden get_lock_owner_info() a bit Cc: stable@vger.kernel.org Signed-off-by: Ilya Dryomov <idryomov@gmail.com> Reviewed-by: Dongsheng Yang <dongsheng.yang@easystack.cn> Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.