From: Marek Vasut marek.vasut+renesas@gmail.com
[ Upstream commit dc6b698a86fe40a50525433eb8e92a267847f6f9 ]
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 in 356c05d58af0 ("sysfs: get rid of some lockdep false positives") and e9b526fe7048 ("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... 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 --- drivers/pci/pci-sysfs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index c3f0473d1afa..ee7dccab771d 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -496,7 +496,7 @@ static ssize_t remove_store(struct device *dev, struct device_attribute *attr, pci_stop_and_remove_bus_device_locked(to_pci_dev(dev)); return count; } -static struct device_attribute dev_remove_attr = __ATTR(remove, +static struct device_attribute dev_remove_attr = __ATTR_IGNORE_LOCKDEP(remove, (S_IWUSR|S_IWGRP), NULL, remove_store);