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Connor Williamson
af382ffca9
commit181bb9c9eaupstream. add_disk_final() sets GD_NEED_PART_SCAN before calling bdev_add(), then calls disk_scan_partitions() which sets the flag itself. The early set is redundant and introduces a race. Between bdev_add() and disk_scan_partitions(), concurrent openers (multipathd, blkid, LVM) see the flag in blkdev_get_whole() and trigger bdev_disk_changed(). When disk_scan_partitions() then runs, it calls bdev_disk_changed() again, dropping the partitions the concurrent opener already created before re-adding them, which can result in transient partition disappearances. The race is observable by inserting an msleep() between bdev_add() and disk_scan_partitions() while running concurrent open() calls during device bind. Without artificial delay, it manifests under scheduling pressure during boot on systems with aggressive device scanners (multipathd, systemd-udevd). Therefore, do not set GD_NEED_PART_SCAN in add_disk_final(). Other GD_NEED_PART_SCAN consumers (blkdev_get_whole(), sd_need_revalidate()) should not be affected as the flag is set internally by disk_scan_partitions(). The retry-on-next-open intention from commite5cfefa97b("block: fix scan partition for exclusively open device again") should also not be affected as the early return paths in disk_scan_partitions() should be unreachable at device registration time (bd_holder is NULL and open_partitions is zero). Fixes:e5cfefa97b("block: fix scan partition for exclusively open device again") Cc: stable@vger.kernel.org Signed-off-by: Connor Williamson <connordw@amazon.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://patch.msgid.link/20260615130715.53693-1-connordw@amazon.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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 reStructuredText 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.