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Chao Shi
d6998ddd50
commit49f06cff50upstream. bdev_mark_dead()'s @surprise == true means the device is already gone. The filesystem callback fs_bdev_mark_dead() honours this and skips sync_filesystem(), but the bare block device path (no ->mark_dead op) lost its !surprise guard when the holder ->mark_dead callback was wired up (see Fixes), and now calls sync_blockdev() unconditionally, which can hang forever waiting on writeback that can no longer complete. syzkaller hit this via nvme_reset_work()'s "I/O queues lost" path: nvme_mark_namespaces_dead() -> blk_mark_disk_dead() -> bdev_mark_dead(bdev, true) -> sync_blockdev() blocks in folio_wait_writeback(), wedging the reset worker and every task waiting on it. Skip the sync on surprise removal, matching fs_bdev_mark_dead(); invalidate_bdev() still runs. Orderly removal (surprise == false) is unchanged. Found by FuzzNvme. Fixes:d8530de5a6("block: call into the file system for bdev_mark_dead") Acked-by: Sungwoo Kim <iam@sung-woo.kim> Acked-by: Dave Tian <daveti@purdue.edu> Acked-by: Weidong Zhu <weizhu@fiu.edu> Signed-off-by: Chao Shi <coshi036@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://patch.msgid.link/20260522220025.1770388-1-coshi036@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> [ adjusted for 6.6.y: bdev_mark_dead() there still unlocks bd_holder_lock after the if/else and the else arm is a bare sync_blockdev(), so the !surprise guard is added as "else if (!surprise)" instead of inside the mainline else block. ] Signed-off-by: Chao Shi <coshi036@gmail.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.
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.