diff options
| author | Lukas Wunner <lukas@wunner.de> | 2019-08-09 12:28:43 +0200 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2019-10-04 15:39:36 -0500 |
| commit | 157c1062fcd86ade3c674503705033051fd3d401 (patch) | |
| tree | 78038be473f0c5df2880a57ce078df1f7d4806b5 /drivers/pci/hotplug/pciehp_ctrl.c | |
| parent | 54ecb8f7028c5eb3d740bb82b0f1d90f2df63c5c (diff) | |
PCI: pciehp: Avoid returning prematurely from sysfs requests
A sysfs request to enable or disable a PCIe hotplug slot should not
return before it has been carried out. That is sought to be achieved by
waiting until the controller's "pending_events" have been cleared.
However the IRQ thread pciehp_ist() clears the "pending_events" before
it acts on them. If pciehp_sysfs_enable_slot() / _disable_slot() happen
to check the "pending_events" after they have been cleared but while
pciehp_ist() is still running, the functions may return prematurely
with an incorrect return value.
Fix by introducing an "ist_running" flag which must be false before a sysfs
request is allowed to return.
Fixes: 32a8cef274fe ("PCI: pciehp: Enable/disable exclusively from IRQ thread")
Link: https://lore.kernel.org/linux-pci/1562226638-54134-1-git-send-email-wangxiongfeng2@huawei.com
Link: https://lore.kernel.org/r/4174210466e27eb7e2243dd1d801d5f75baaffd8.1565345211.git.lukas@wunner.de
Reported-and-tested-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org # v4.19+
Diffstat (limited to 'drivers/pci/hotplug/pciehp_ctrl.c')
| -rw-r--r-- | drivers/pci/hotplug/pciehp_ctrl.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp_ctrl.c index 21af7b16d7a4..dd8e4a5fb282 100644 --- a/drivers/pci/hotplug/pciehp_ctrl.c +++ b/drivers/pci/hotplug/pciehp_ctrl.c @@ -375,7 +375,8 @@ int pciehp_sysfs_enable_slot(struct hotplug_slot *hotplug_slot) ctrl->request_result = -ENODEV; pciehp_request(ctrl, PCI_EXP_SLTSTA_PDC); wait_event(ctrl->requester, - !atomic_read(&ctrl->pending_events)); + !atomic_read(&ctrl->pending_events) && + !ctrl->ist_running); return ctrl->request_result; case POWERON_STATE: ctrl_info(ctrl, "Slot(%s): Already in powering on state\n", @@ -408,7 +409,8 @@ int pciehp_sysfs_disable_slot(struct hotplug_slot *hotplug_slot) mutex_unlock(&ctrl->state_lock); pciehp_request(ctrl, DISABLE_SLOT); wait_event(ctrl->requester, - !atomic_read(&ctrl->pending_events)); + !atomic_read(&ctrl->pending_events) && + !ctrl->ist_running); return ctrl->request_result; case POWEROFF_STATE: ctrl_info(ctrl, "Slot(%s): Already in powering off state\n", |