Christoph Hellwig
906b4dcc18
[ Upstream commit 7df835a32a8bedf7ce88efcfa7c9b245b52ff139 ] Commitb0140891a8("md: Fix race when creating a new md device.") not only moved assigning mddev->gendisk before calling add_disk, which fixes the races described in the commit log, but also added a mddev->open_mutex critical section over add_disk and creation of the md kobj. Adding a kobject after add_disk is racy vs deleting the gendisk right after adding it, but md already prevents against that by holding a mddev->active reference. On the other hand taking this lock added a lock order reversal with what is not disk->open_mutex (used to be bdev->bd_mutex when the commit was added) for partition devices, which need that lock for the internal open for the partition scan, and a recent commit also takes it for non-partitioned devices, leading to further lockdep splatter. Fixes:b0140891a8("md: Fix race when creating a new md device.") Fixes: d62633873590 ("block: support delayed holder registration") Reported-by: syzbot+fadc0aaf497e6a493b9f@syzkaller.appspotmail.com Signed-off-by: Christoph Hellwig <hch@lst.de> Tested-by: syzbot+fadc0aaf497e6a493b9f@syzkaller.appspotmail.com Reviewed-by: NeilBrown <neilb@suse.de> Signed-off-by: Song Liu <songliubraving@fb.com> 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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.