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| author |   Joe Lawrence <joe.lawrence@stratus.com> | 2016-02-03 12:51:12 -0500 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-02-04 17:00:10 -0800 |
| commit | 89140fdaf11aec81e93d5590a993720f2ef0d26e (patch) | |
| tree | c7abad88a88cfe4fe2d599eff868a59e18f16f17 | |
| parent | Merge tag 'fixes-for-v4.5-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/balbi/usb into usb-linus (diff) | |
| download | linux-dev-89140fdaf11aec81e93d5590a993720f2ef0d26e.tar.xz linux-dev-89140fdaf11aec81e93d5590a993720f2ef0d26e.zip | |
xhci: harden xhci_find_next_ext_cap against device removal
xhci_find_next_ext_cap doesn't check for PCI hotplug removal and may use
the PCI master abort bit pattern (~0) to calculate a new PCI address
offset to read/write. The has lead to reproducable crashes when testing
surprise removal during device initialization on a Stratus platform, at
least after commit d5ddcdf4d672 ("xhci: rework xhci extended capability
list parsing functions").
The crash is repeatable on a Stratus platform when injecting hardware
faults to induce xHCI host controller hotplug during driver
initialization. If a PCI read in xhci_find_next_ext_cap returns the
master abort pattern, quirk_usb_handoff_xhci may start using a bogus
ext_cap_offset to start searching more bogus PCI addresses.
Signed-off-by: Joe Lawrence <joe.lawrence@stratus.com>
Acked-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/usb/host/xhci-ext-caps.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/usb/host/xhci-ext-caps.h b/drivers/usb/host/xhci-ext-caps.h index 04ce6b156b35..e0244fb3903d 100644 --- a/drivers/usb/host/xhci-ext-caps.h +++ b/drivers/usb/host/xhci-ext-caps.h @@ -112,12 +112,16 @@ static inline int xhci_find_next_ext_cap(void __iomem *base, u32 start, int id) offset = start; if (!start || start == XHCI_HCC_PARAMS_OFFSET) { val = readl(base + XHCI_HCC_PARAMS_OFFSET); + if (val == ~0) + return 0; offset = XHCI_HCC_EXT_CAPS(val) << 2; if (!offset) return 0; }; do { val = readl(base + offset); + if (val == ~0) + return 0; if (XHCI_EXT_CAPS_ID(val) == id && offset != start) return offset; |