mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-12 05:48:40 +00:00
![]() An oops can occur if a user attempts to use both PCI logical hotplug and the ACPI physical hotplug driver (acpiphp) in this sequence, where $slot/address == $device. In other words, if acpiphp has claimed a PCI device, and that device is logically removed, then acpiphp may oops when it attempts to access it again. # echo 1 > /sys/bus/pci/devices/$device/remove # echo 0 > /sys/bus/pci/slots/$slot/power Unable to handle kernel NULL pointer dereference (address 0000000000000000) Call Trace: [<a000000100016390>] show_stack+0x50/0xa0 [<a000000100016c60>] show_regs+0x820/0x860 [<a00000010003b390>] die+0x190/0x2a0 [<a000000100066a40>] ia64_do_page_fault+0x8e0/0xa40 [<a00000010000c7a0>] ia64_native_leave_kernel+0x0/0x270 [<a0000001003b2660>] pci_remove_bus_device+0x120/0x260 [<a0000002060549f0>] acpiphp_disable_slot+0x410/0x540 [acpiphp] [<a0000002060505c0>] disable_slot+0xc0/0x120 [acpiphp] [<a0000002040d21c0>] power_write_file+0x1e0/0x2a0 [pci_hotplug] [<a0000001003bb820>] pci_slot_attr_store+0x60/0xa0 [<a000000100240f70>] sysfs_write_file+0x230/0x2c0 [<a000000100195750>] vfs_write+0x190/0x2e0 [<a0000001001961a0>] sys_write+0x80/0x100 [<a00000010000c600>] ia64_ret_from_syscall+0x0/0x20 [<a000000000010720>] __kernel_syscall_via_break+0x0/0x20 The root cause of this oops is that the logical remove ("echo 1 > /sys/bus/pci/devices/$device/remove") destroyed the pci_dev. The pci_dev struct itself wasn't deallocated because acpiphp kept a reference, but some of its fields became invalid. acpiphp doesn't have any real reason to keep a pointer to a pci_dev around. It can always derive it using pci_get_slot(). If a logical remove destroys the pci_dev, acpiphp won't find it and is thus prevented from causing mischief. Reviewed-by: Matthew Wilcox <willy@linux.intel.com> Reviewed-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Tested-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Reported-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Acked-by: Bjorn Helgaas <bjorn.helgaas@hp.com> Signed-off-by: Alex Chiang <achiang@hp.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org> |
||
---|---|---|
.. | ||
hotplug | ||
pcie | ||
.gitignore | ||
access.c | ||
bus.c | ||
dmar.c | ||
hotplug-pci.c | ||
hotplug.c | ||
htirq.c | ||
intel-iommu.c | ||
intr_remapping.c | ||
intr_remapping.h | ||
iov.c | ||
iova.c | ||
irq.c | ||
Kconfig | ||
Makefile | ||
msi.c | ||
msi.h | ||
pci-acpi.c | ||
pci-driver.c | ||
pci-stub.c | ||
pci-sysfs.c | ||
pci.c | ||
pci.h | ||
probe.c | ||
proc.c | ||
quirks.c | ||
remove.c | ||
rom.c | ||
search.c | ||
setup-bus.c | ||
setup-irq.c | ||
setup-res.c | ||
slot.c | ||
syscall.c |