Yinghai Lu 3bd7db63a8 PCI/ASPM: Always set link->downstream to avoid NULL dereference on remove ... We call pcie_aspm_exit_link_state() when we remove a device. If the device is the last PCIe function to be removed below a bridge and the bridge has an ASPM link_state struct, we disable ASPM on the link. Disabling ASPM requires link->downstream (used in pcie_config_aspm_link()). We previously set link->downstream in pcie_aspm_cap_init(), but only if the device was not blacklisted. Removing the blacklisted device caused a NULL pointer dereference in the pcie_aspm_exit_link_state() -> pcie_config_aspm_link() path: # echo 1 > /sys/bus/pci/devices/0000\:0b\:00.0/remove ... BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 IP: pcie_config_aspm_link+0x5d/0x2b0 Call Trace: pcie_aspm_exit_link_state+0x75/0x130 pci_stop_bus_device+0xa4/0xb0 pci_stop_and_remove_bus_device_locked+0x1a/0x30 remove_store+0x50/0x70 dev_attr_store+0x18/0x30 sysfs_kf_write+0x44/0x60 kernfs_fop_write+0x10e/0x190 __vfs_write+0x28/0x110 ? rcu_read_lock_sched_held+0x5d/0x80 ? rcu_sync_lockdep_assert+0x2c/0x60 ? __sb_start_write+0x173/0x1a0 ? vfs_write+0xb3/0x180 vfs_write+0xc4/0x180 SyS_write+0x49/0xa0 do_syscall_64+0xa6/0x1c0 entry_SYSCALL64_slow_path+0x25/0x25 ---[ end trace bd187ee0267df5d9 ]--- To avoid this, set link->downstream in alloc_pcie_link_state(), so every pcie_link_state structure has a valid link->downstream pointer. [bhelgaas: changelog] Signed-off-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Rajat Jain <rajatja@google.com> CC: stable@vger.kernel.org		2017-03-07 14:23:30 -06:00
..
dwc	PCI: exynos: Initialize elbi_base even when using PHY framework	2017-03-07 12:46:38 -06:00
host	pci-v4.11-fixes-1	2017-03-03 16:44:21 -08:00
hotplug	sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h>	2017-03-02 08:42:32 +01:00
pcie	PCI/ASPM: Always set link->downstream to avoid NULL dereference on remove	2017-03-07 14:23:30 -06:00
access.c	sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h>	2017-03-02 08:42:32 +01:00
ats.c
bus.c
ecam.c
host-bridge.c
hotplug-pci.c
htirq.c
iov.c
irq.c
Kconfig
Makefile
msi.c	PCI: add an API to get node from vector	2017-03-02 08:56:04 -07:00
of.c
pci-acpi.c
pci-driver.c
pci-label.c
pci-mid.c
pci-stub.c
pci-sysfs.c
pci.c
pci.h
probe.c
proc.c
quirks.c	PCI: Prevent VPD access for QLogic ISP2722	2017-03-07 14:16:57 -06:00
remove.c
rom.c
search.c
setup-bus.c
setup-irq.c
setup-res.c
slot.c
syscall.c
vc.c
vpd.c
xen-pcifront.c