kernel/linux.git/drivers/pci/hotplug, branch v5.4.113

PCI: rpadlpar: Fix potential drc_name corruption in store functions

2021-03-24T10:26:43+00:00

commit cc7a0bb058b85ea03db87169c60c7cfdd5d34678 upstream. Both add_slot_store() and remove_slot_store() try to fix up the drc_name copied from the store buffer by placing a NUL terminator at nbyte + 1 or in place of a '\n' if present. However, the static buffer that we copy the drc_name data into is not zeroed and can contain anything past the n-th byte. This is problematic if a '\n' byte appears in that buffer after nbytes and the string copied into the store buffer was not NUL terminated to start with as the strchr() search for a '\n' byte will mark this incorrectly as the end of the drc_name string resulting in a drc_name string that contains garbage data after the n-th byte. Additionally it will cause us to overwrite that '\n' byte on the stack with NUL, potentially corrupting data on the stack. The following debugging shows an example of the drmgr utility writing "PHB 4543" to the add_slot sysfs attribute, but add_slot_store() logging a corrupted string value. drmgr: drmgr: -c phb -a -s PHB 4543 -d 1 add_slot_store: drc_name = PHB 4543°|<82>!, rc = -19 Fix this by using strscpy() instead of memcpy() to ensure the string is NUL terminated when copied into the static drc_name buffer. Further, since the string is now NUL terminated the code only needs to change '\n' to '\0' when present. Cc: stable@vger.kernel.org Signed-off-by: Tyrel Datwyler [mpe: Reformat change log and add mention of possible stack corruption] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210315214821.452959-1-tyreld@linux.ibm.com Signed-off-by: Greg Kroah-Hartman

PCI: pciehp: Fix MSI interrupt race

2020-10-01T11:17:52+00:00

[ Upstream commit 8edf5332c39340b9583cf9cba659eb7ec71f75b5 ] Without this commit, a PCIe hotplug port can stop generating interrupts on hotplug events, so device adds and removals will not be seen: The pciehp interrupt handler pciehp_isr() reads the Slot Status register and then writes back to it to clear the bits that caused the interrupt. If a different interrupt event bit gets set between the read and the write, pciehp_isr() returns without having cleared all of the interrupt event bits. If this happens when the MSI isn't masked (which by default it isn't in handle_edge_irq(), and which it will never be when MSI per-vector masking is not supported), we won't get any more hotplug interrupts from that device. That is expected behavior, according to the PCIe Base Spec r5.0, section 6.7.3.4, "Software Notification of Hot-Plug Events". Because the Presence Detect Changed and Data Link Layer State Changed event bits can both get set at nearly the same time when a device is added or removed, this is more likely to happen than it might seem. The issue was found (and can be reproduced rather easily) by connecting and disconnecting an NVMe storage device on at least one system model where the NVMe devices were being connected to an AMD PCIe port (PCI device 0x1022/0x1483). Fix the issue by modifying pciehp_isr() to loop back and re-read the Slot Status register immediately after writing to it, until it sees that all of the event status bits have been cleared. [lukas: drop loop count limitation, write "events" instead of "status", don't loop back in INTx and poll modes, tweak code comment & commit msg] Link: https://lore.kernel.org/r/78b4ced5072bfe6e369d20e8b47c279b8c7af12e.1582121613.git.lukas@wunner.de Tested-by: Stuart Hayes Signed-off-by: Stuart Hayes Signed-off-by: Lukas Wunner Signed-off-by: Bjorn Helgaas Reviewed-by: Joerg Roedel Signed-off-by: Sasha Levin

PCI: hotplug: ACPI: Fix context refcounting in acpiphp_grab_context()

2020-08-21T11:05:20+00:00

commit dae68d7fd4930315389117e9da35b763f12238f9 upstream. If context is not NULL in acpiphp_grab_context(), but the is_going_away flag is set for the device's parent, the reference counter of the context needs to be decremented before returning NULL or the context will never be freed, so make that happen. Fixes: edf5bf34d408 ("ACPI / dock: Use callback pointers from devices' ACPI hotplug contexts") Reported-by: Vasily Averin Cc: 3.15+ # 3.15+ Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman

PCI: pciehp: Prevent deadlock on disconnect

2020-04-29T14:33:04+00:00

[ Upstream commit 87d0f2a5536fdf5053a6d341880f96135549a644 ] 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 Signed-off-by: Mika Westerberg Signed-off-by: Bjorn Helgaas Signed-off-by: Sasha Levin

PCI: pciehp: Fix indefinite wait on sysfs requests

2020-04-17T08:50:10+00:00

commit 3e487d2e4aa466decd226353755c9d423e8fbacc upstream. David Hoyer reports that powering pciehp slots up or down via sysfs may hang: The call to wait_event() in pciehp_sysfs_enable_slot() and _disable_slot() does not return because ctrl->ist_running remains true. This flag, which was introduced by commit 157c1062fcd8 ("PCI: pciehp: Avoid returning prematurely from sysfs requests"), signifies that the IRQ thread pciehp_ist() is running. It is set to true at the top of pciehp_ist() and reset to false at the end. However there are two additional return statements in pciehp_ist() before which the commit neglected to reset the flag to false and wake up waiters for the flag. That omission opens up the following race when powering up the slot: * pciehp_ist() runs because a PCI_EXP_SLTSTA_PDC event was requested by pciehp_sysfs_enable_slot() * pciehp_ist() turns on slot power via the following call stack: pciehp_handle_presence_or_link_change() -> pciehp_enable_slot() -> __pciehp_enable_slot() -> board_added() -> pciehp_power_on_slot() * after slot power is turned on, the link comes up, resulting in a PCI_EXP_SLTSTA_DLLSC event * the IRQ handler pciehp_isr() stores the event in ctrl->pending_events and returns IRQ_WAKE_THREAD * the IRQ thread is already woken (it's bringing up the slot), but the genirq code remembers to re-run the IRQ thread after it has finished (such that it can deal with the new event) by setting IRQTF_RUNTHREAD via __handle_irq_event_percpu() -> __irq_wake_thread() * the IRQ thread removes PCI_EXP_SLTSTA_DLLSC from ctrl->pending_events via board_added() -> pciehp_check_link_status() in order to deal with presence and link flaps per commit 6c35a1ac3da6 ("PCI: pciehp: Tolerate initially unstable link") * after pciehp_ist() has successfully brought up the slot, it resets ctrl->ist_running to false and wakes up the sysfs requester * the genirq code re-runs pciehp_ist(), which sets ctrl->ist_running to true but then returns with IRQ_NONE because ctrl->pending_events is empty * pciehp_sysfs_enable_slot() is finally woken but notices that ctrl->ist_running is true, hence continues waiting The only way to get the hung task going again is to trigger a hotplug event which brings down the slot, e.g. by yanking out the card. The same race exists when powering down the slot because remove_board() likewise clears link or presence changes in ctrl->pending_events per commit 3943af9d01e9 ("PCI: pciehp: Ignore Link State Changes after powering off a slot") and thereby may cause a re-run of pciehp_ist() which returns with IRQ_NONE without resetting ctrl->ist_running to false. Fix by adding a goto label before the teardown steps at the end of pciehp_ist() and jumping to that label from the two return statements which currently neglect to reset the ctrl->ist_running flag. Fixes: 157c1062fcd8 ("PCI: pciehp: Avoid returning prematurely from sysfs requests") Link: https://lore.kernel.org/r/cca1effa488065cb055120aa01b65719094bdcb5.1584530321.git.lukas@wunner.de Reported-by: David Hoyer Signed-off-by: Lukas Wunner Signed-off-by: Bjorn Helgaas Reviewed-by: Keith Busch Cc: stable@vger.kernel.org # v4.19+ Signed-off-by: Greg Kroah-Hartman

PCI: pciehp: Do not disable interrupt twice on suspend

2020-01-17T18:48:51+00:00

commit 75fcc0ce72e5cea2e357cdde858216c5bad40442 upstream. We try to keep PCIe hotplug ports runtime suspended when entering system suspend. Because the PCIe portdrv sets the DPM_FLAG_NEVER_SKIP flag, the PM core always calls system suspend/resume hooks even if the device is left runtime suspended. Since PCIe hotplug driver re-used the same function for both runtime suspend and system suspend, it ended up disabling hotplug interrupt twice and the second time following was printed: pciehp 0000:03:01.0:pcie204: pcie_do_write_cmd: no response from device Prevent this from happening by checking whether the device is already runtime suspended when the system suspend hook is called. Fixes: 9c62f0bfb832 ("PCI: pciehp: Implement runtime PM callbacks") Link: https://lore.kernel.org/r/20191029170022.57528-1-mika.westerberg@linux.intel.com Reported-by: Kai-Heng Feng Tested-by: Kai-Heng Feng Signed-off-by: Mika Westerberg Signed-off-by: Bjorn Helgaas Reviewed-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman

PCI: rpaphp: Correctly match ibm, my-drc-index to drc-name when using drc-info

2020-01-04T18:18:00+00:00

[ Upstream commit 4f9f2d3d7a434b7f882b72550194c9278f4a3925 ] The newer ibm,drc-info property is a condensed description of the old ibm,drc-* properties (ie. names, types, indexes, and power-domains). When matching a drc-index to a drc-name we need to verify that the index is within the start and last drc-index range and map it to a drc-name using the drc-name-prefix and logical index. Fix the mapping by checking that the index is within the range of the current drc-info entry, and build the name from the drc-name-prefix concatenated with the starting drc-name-suffix value and the sequential index obtained by subtracting ibm,my-drc-index from this entries drc-start-index. Signed-off-by: Tyrel Datwyler Acked-by: Bjorn Helgaas Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/1573449697-5448-10-git-send-email-tyreld@linux.ibm.com Signed-off-by: Sasha Levin

PCI: rpaphp: Annotate and correctly byte swap DRC properties

2020-01-04T18:17:57+00:00

[ Upstream commit 0737686778c6dbe0908d684dd5b9c05b127526ba ] The device tree is in big endian format and any properties directly retrieved using OF helpers that don't explicitly byte swap should be annotated. In particular there are several places where we grab the opaque property value for the old ibm,drc-* properties and the ibm,my-drc-index property. Fix this for better static checking by annotating values we know to explicitly big endian, and byte swap where appropriate. Signed-off-by: Tyrel Datwyler Acked-by: Bjorn Helgaas Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/1573449697-5448-9-git-send-email-tyreld@linux.ibm.com Signed-off-by: Sasha Levin

PCI: rpaphp: Don't rely on firmware feature to imply drc-info support

2020-01-04T18:17:55+00:00

[ Upstream commit 52e2b0f16574afd082cff0f0e8567b2d9f68c033 ] In the event that the partition is migrated to a platform with older firmware that doesn't support the ibm,drc-info property the device tree is modified to remove the ibm,drc-info property and replace it with the older style ibm,drc-* properties for types, names, indexes, and power-domains. One of the requirements of the drc-info firmware feature is that the client is able to handle both the new property, and old style properties at runtime. Therefore we can't rely on the firmware feature alone to dictate which property is currently present in the device tree. Fix this short coming by checking explicitly for the ibm,drc-info property, and falling back to the older ibm,drc-* properties if it doesn't exist. Signed-off-by: Tyrel Datwyler Acked-by: Bjorn Helgaas Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/1573449697-5448-6-git-send-email-tyreld@linux.ibm.com Signed-off-by: Sasha Levin

PCI: rpaphp: Fix up pointer to first drc-info entry

2020-01-04T18:17:44+00:00

[ Upstream commit 9723c25f99aff0451cfe6392e1b9fdd99d0bf9f0 ] The first entry of the ibm,drc-info property is an int encoded count of the number of drc-info entries that follow. The "value" pointer returned by of_prop_next_u32() is still pointing at the this value when we call of_read_drc_info_cell(), but the helper function expects that value to be pointing at the first element of an entry. Fix up by incrementing the "value" pointer to point at the first element of the first drc-info entry prior. Signed-off-by: Tyrel Datwyler Acked-by: Bjorn Helgaas Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/1573449697-5448-5-git-send-email-tyreld@linux.ibm.com Signed-off-by: Sasha Levin