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author | David P <megver83@parabola.nu> | 2020-01-21 13:13:40 -0300 |
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committer | David P <megver83@parabola.nu> | 2020-01-21 13:13:40 -0300 |
commit | 5152941afaaaab20b026fc8f12605d8c468fd707 (patch) | |
tree | 2033ef39ca615533298c9f9e7d2ca3a6bdeaa937 /libre/linux-libre-pae/0005-PCI-pciehp-Prevent-deadlock-on-disconnect.patch | |
parent | dcb2d06dc4eba114130d461f67948a61ae148205 (diff) | |
download | abslibre-5152941afaaaab20b026fc8f12605d8c468fd707.tar.gz abslibre-5152941afaaaab20b026fc8f12605d8c468fd707.tar.bz2 abslibre-5152941afaaaab20b026fc8f12605d8c468fd707.zip |
updpkg: libre/linux-libre-pae 5.4.13-1
Signed-off-by: David P <megver83@parabola.nu>
Diffstat (limited to 'libre/linux-libre-pae/0005-PCI-pciehp-Prevent-deadlock-on-disconnect.patch')
-rw-r--r-- | libre/linux-libre-pae/0005-PCI-pciehp-Prevent-deadlock-on-disconnect.patch | 272 |
1 files changed, 0 insertions, 272 deletions
diff --git a/libre/linux-libre-pae/0005-PCI-pciehp-Prevent-deadlock-on-disconnect.patch b/libre/linux-libre-pae/0005-PCI-pciehp-Prevent-deadlock-on-disconnect.patch deleted file mode 100644 index 68d8477ed..000000000 --- a/libre/linux-libre-pae/0005-PCI-pciehp-Prevent-deadlock-on-disconnect.patch +++ /dev/null @@ -1,272 +0,0 @@ -From 54f60fe91123c1d95ee104c971d546b49e9d67f0 Mon Sep 17 00:00:00 2001 -From: Mika Westerberg <mika.westerberg@linux.intel.com> -Date: Tue, 29 Oct 2019 20:00:22 +0300 -Subject: [PATCH 05/15] PCI: pciehp: Prevent deadlock on disconnect - -This addresses deadlocks in these common cases in hierarchies containing -two switches: - - - All involved ports are runtime suspended and they are unplugged. This - can happen easily if the drivers involved automatically enable runtime - PM (xHCI for example does that). - - - System is suspended (e.g., closing the lid on a laptop) with a dock + - something else connected, and the dock is unplugged while suspended. - -These cases lead to the following deadlock: - - INFO: task irq/126-pciehp:198 blocked for more than 120 seconds. - irq/126-pciehp D 0 198 2 0x80000000 - Call Trace: - schedule+0x2c/0x80 - schedule_timeout+0x246/0x350 - wait_for_completion+0xb7/0x140 - kthread_stop+0x49/0x110 - free_irq+0x32/0x70 - pcie_shutdown_notification+0x2f/0x50 - pciehp_remove+0x27/0x50 - pcie_port_remove_service+0x36/0x50 - device_release_driver+0x12/0x20 - bus_remove_device+0xec/0x160 - device_del+0x13b/0x350 - device_unregister+0x1a/0x60 - remove_iter+0x1e/0x30 - device_for_each_child+0x56/0x90 - pcie_port_device_remove+0x22/0x40 - pcie_portdrv_remove+0x20/0x60 - pci_device_remove+0x3e/0xc0 - device_release_driver_internal+0x18c/0x250 - device_release_driver+0x12/0x20 - pci_stop_bus_device+0x6f/0x90 - pci_stop_bus_device+0x31/0x90 - pci_stop_and_remove_bus_device+0x12/0x20 - pciehp_unconfigure_device+0x88/0x140 - pciehp_disable_slot+0x6a/0x110 - pciehp_handle_presence_or_link_change+0x263/0x400 - pciehp_ist+0x1c9/0x1d0 - irq_thread_fn+0x24/0x60 - irq_thread+0xeb/0x190 - kthread+0x120/0x140 - - INFO: task irq/190-pciehp:2288 blocked for more than 120 seconds. - irq/190-pciehp D 0 2288 2 0x80000000 - Call Trace: - __schedule+0x2a2/0x880 - schedule+0x2c/0x80 - schedule_preempt_disabled+0xe/0x10 - mutex_lock+0x2c/0x30 - pci_lock_rescan_remove+0x15/0x20 - pciehp_unconfigure_device+0x4d/0x140 - pciehp_disable_slot+0x6a/0x110 - pciehp_handle_presence_or_link_change+0x263/0x400 - pciehp_ist+0x1c9/0x1d0 - irq_thread_fn+0x24/0x60 - irq_thread+0xeb/0x190 - kthread+0x120/0x140 - -What happens here is that the whole hierarchy is runtime resumed and the -parent PCIe downstream port, which got the hot-remove event, starts -removing devices below it, taking pci_lock_rescan_remove() lock. When the -child PCIe port is runtime resumed it calls pciehp_check_presence() which -ends up calling pciehp_card_present() and pciehp_check_link_active(). Both -of these use pcie_capability_read_word(), which notices that the underlying -device is already gone and returns PCIBIOS_DEVICE_NOT_FOUND with the -capability value set to 0. When pciehp gets this value it thinks that its -child device is also hot-removed and schedules its IRQ thread to handle the -event. - -The deadlock happens when the child's IRQ thread runs and tries to acquire -pci_lock_rescan_remove() which is already taken by the parent and the -parent waits for the child's IRQ thread to finish. - -Prevent this from happening by checking the return value of -pcie_capability_read_word() and if it is PCIBIOS_DEVICE_NOT_FOUND stop -performing any hot-removal activities. - -[bhelgaas: add common scenarios to commit log] -Link: https://lore.kernel.org/r/20191029170022.57528-2-mika.westerberg@linux.intel.com -Tested-by: Kai-Heng Feng <kai.heng.feng@canonical.com> -Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> -Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> ---- - drivers/pci/hotplug/pciehp.h | 6 ++-- - drivers/pci/hotplug/pciehp_core.c | 11 ++++-- - drivers/pci/hotplug/pciehp_ctrl.c | 4 +-- - drivers/pci/hotplug/pciehp_hpc.c | 59 +++++++++++++++++++++++++------ - 4 files changed, 61 insertions(+), 19 deletions(-) - -diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h -index 882ce82c4699..aa61d4c219d7 100644 ---- a/drivers/pci/hotplug/pciehp.h -+++ b/drivers/pci/hotplug/pciehp.h -@@ -174,10 +174,10 @@ void pciehp_set_indicators(struct controller *ctrl, int pwr, int attn); - - void pciehp_get_latch_status(struct controller *ctrl, u8 *status); - int pciehp_query_power_fault(struct controller *ctrl); --bool pciehp_card_present(struct controller *ctrl); --bool pciehp_card_present_or_link_active(struct controller *ctrl); -+int pciehp_card_present(struct controller *ctrl); -+int pciehp_card_present_or_link_active(struct controller *ctrl); - int pciehp_check_link_status(struct controller *ctrl); --bool pciehp_check_link_active(struct controller *ctrl); -+int pciehp_check_link_active(struct controller *ctrl); - void pciehp_release_ctrl(struct controller *ctrl); - - int pciehp_sysfs_enable_slot(struct hotplug_slot *hotplug_slot); -diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c -index 56daad828c9e..312cc45c44c7 100644 ---- a/drivers/pci/hotplug/pciehp_core.c -+++ b/drivers/pci/hotplug/pciehp_core.c -@@ -139,10 +139,15 @@ static int get_adapter_status(struct hotplug_slot *hotplug_slot, u8 *value) - { - struct controller *ctrl = to_ctrl(hotplug_slot); - struct pci_dev *pdev = ctrl->pcie->port; -+ int ret; - - pci_config_pm_runtime_get(pdev); -- *value = pciehp_card_present_or_link_active(ctrl); -+ ret = pciehp_card_present_or_link_active(ctrl); - pci_config_pm_runtime_put(pdev); -+ if (ret < 0) -+ return ret; -+ -+ *value = ret; - return 0; - } - -@@ -158,13 +163,13 @@ static int get_adapter_status(struct hotplug_slot *hotplug_slot, u8 *value) - */ - static void pciehp_check_presence(struct controller *ctrl) - { -- bool occupied; -+ int occupied; - - down_read(&ctrl->reset_lock); - mutex_lock(&ctrl->state_lock); - - occupied = pciehp_card_present_or_link_active(ctrl); -- if ((occupied && (ctrl->state == OFF_STATE || -+ if ((occupied > 0 && (ctrl->state == OFF_STATE || - ctrl->state == BLINKINGON_STATE)) || - (!occupied && (ctrl->state == ON_STATE || - ctrl->state == BLINKINGOFF_STATE))) -diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp_ctrl.c -index dd8e4a5fb282..6503d15effbb 100644 ---- a/drivers/pci/hotplug/pciehp_ctrl.c -+++ b/drivers/pci/hotplug/pciehp_ctrl.c -@@ -226,7 +226,7 @@ void pciehp_handle_disable_request(struct controller *ctrl) - - void pciehp_handle_presence_or_link_change(struct controller *ctrl, u32 events) - { -- bool present, link_active; -+ int present, link_active; - - /* - * If the slot is on and presence or link has changed, turn it off. -@@ -257,7 +257,7 @@ void pciehp_handle_presence_or_link_change(struct controller *ctrl, u32 events) - mutex_lock(&ctrl->state_lock); - present = pciehp_card_present(ctrl); - link_active = pciehp_check_link_active(ctrl); -- if (!present && !link_active) { -+ if (present <= 0 && link_active <= 0) { - mutex_unlock(&ctrl->state_lock); - return; - } -diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c -index 86d97f3112f0..a2a263764ef8 100644 ---- a/drivers/pci/hotplug/pciehp_hpc.c -+++ b/drivers/pci/hotplug/pciehp_hpc.c -@@ -201,17 +201,29 @@ static void pcie_write_cmd_nowait(struct controller *ctrl, u16 cmd, u16 mask) - pcie_do_write_cmd(ctrl, cmd, mask, false); - } - --bool pciehp_check_link_active(struct controller *ctrl) -+/** -+ * pciehp_check_link_active() - Is the link active -+ * @ctrl: PCIe hotplug controller -+ * -+ * Check whether the downstream link is currently active. Note it is -+ * possible that the card is removed immediately after this so the -+ * caller may need to take it into account. -+ * -+ * If the hotplug controller itself is not available anymore returns -+ * %-ENODEV. -+ */ -+int pciehp_check_link_active(struct controller *ctrl) - { - struct pci_dev *pdev = ctrl_dev(ctrl); - u16 lnk_status; -- bool ret; -+ int ret; - -- pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status); -- ret = !!(lnk_status & PCI_EXP_LNKSTA_DLLLA); -+ ret = pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status); -+ if (ret == PCIBIOS_DEVICE_NOT_FOUND || lnk_status == (u16)~0) -+ return -ENODEV; - -- if (ret) -- ctrl_dbg(ctrl, "%s: lnk_status = %x\n", __func__, lnk_status); -+ ret = !!(lnk_status & PCI_EXP_LNKSTA_DLLLA); -+ ctrl_dbg(ctrl, "%s: lnk_status = %x\n", __func__, lnk_status); - - return ret; - } -@@ -373,13 +385,29 @@ void pciehp_get_latch_status(struct controller *ctrl, u8 *status) - *status = !!(slot_status & PCI_EXP_SLTSTA_MRLSS); - } - --bool pciehp_card_present(struct controller *ctrl) -+/** -+ * pciehp_card_present() - Is the card present -+ * @ctrl: PCIe hotplug controller -+ * -+ * Function checks whether the card is currently present in the slot and -+ * in that case returns true. Note it is possible that the card is -+ * removed immediately after the check so the caller may need to take -+ * this into account. -+ * -+ * It the hotplug controller itself is not available anymore returns -+ * %-ENODEV. -+ */ -+int pciehp_card_present(struct controller *ctrl) - { - struct pci_dev *pdev = ctrl_dev(ctrl); - u16 slot_status; -+ int ret; - -- pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status); -- return slot_status & PCI_EXP_SLTSTA_PDS; -+ ret = pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status); -+ if (ret == PCIBIOS_DEVICE_NOT_FOUND || slot_status == (u16)~0) -+ return -ENODEV; -+ -+ return !!(slot_status & PCI_EXP_SLTSTA_PDS); - } - - /** -@@ -390,10 +418,19 @@ bool pciehp_card_present(struct controller *ctrl) - * Presence Detect State bit, this helper also returns true if the Link Active - * bit is set. This is a concession to broken hotplug ports which hardwire - * Presence Detect State to zero, such as Wilocity's [1ae9:0200]. -+ * -+ * Returns: %1 if the slot is occupied and %0 if it is not. If the hotplug -+ * port is not present anymore returns %-ENODEV. - */ --bool pciehp_card_present_or_link_active(struct controller *ctrl) -+int pciehp_card_present_or_link_active(struct controller *ctrl) - { -- return pciehp_card_present(ctrl) || pciehp_check_link_active(ctrl); -+ int ret; -+ -+ ret = pciehp_card_present(ctrl); -+ if (ret) -+ return ret; -+ -+ return pciehp_check_link_active(ctrl); - } - - int pciehp_query_power_fault(struct controller *ctrl) --- -2.24.1 - |