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[ Upstream commitdc6b698a86] With CONFIG_PROVE_LOCKING=y, using sysfs to remove a bridge with a device below it causes a lockdep warning, e.g., # echo 1 > /sys/class/pci_bus/0000:00/device/0000:00:00.0/remove ============================================ WARNING: possible recursive locking detected ... pci_bus 0000:01: busn_res: [bus 01] is released The remove recursively removes the subtree below the bridge. Each call uses a different lock so there's no deadlock, but the locks were all created with the same lockdep key so the lockdep checker can't tell them apart. Mark the "remove" sysfs attribute with __ATTR_IGNORE_LOCKDEP() as it is safe to ignore the lockdep check between different "remove" kernfs instances. There's discussion about a similar issue in USB at [1], which resulted in356c05d58a("sysfs: get rid of some lockdep false positives") ande9b526fe70("i2c: suppress lockdep warning on delete_device"), which do basically the same thing for USB "remove" and i2c "delete_device" files. [1] https://lore.kernel.org/r/Pine.LNX.4.44L0.1204251436140.1206-100000@iolanthe.rowland.org Link: https://lore.kernel.org/r/20190526225151.3865-1-marek.vasut@gmail.com Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com> [bhelgaas: trim commit log, details at above links] Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Cc: Geert Uytterhoeven <geert+renesas@glider.be> Cc: Phil Edworthy <phil.edworthy@renesas.com> Cc: Simon Horman <horms+renesas@verge.net.au> Cc: Tejun Heo <tj@kernel.org> Cc: Wolfram Sang <wsa@the-dreams.de> 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.