MIPS: Fix off-by-one in pci_resource_to_user()
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Message ID -
State Accepted
Delegated to: Paul Burton
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Series
  • MIPS: Fix off-by-one in pci_resource_to_user()
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Commit Message

Paul Burton July 12, 2018, 4:33 p.m. UTC 
The MIPS implementation of pci_resource_to_user() introduced in v3.12 by
commit 4c2924b725fb ("MIPS: PCI: Use pci_resource_to_user to map pci
memory space properly") incorrectly sets *end to the address of the
byte after the resource, rather than the last byte of the resource.

This results in userland seeing resources as a byte larger than they
actually are, for example a 32 byte BAR will be reported by a tool such
as lspci as being 33 bytes in size:

    Region 2: I/O ports at 1000 [disabled] [size=33]

Correct this by subtracting one from the calculated end address,
reporting the correct address to userland.

Signed-off-by: Paul Burton <>
Reported-by: Rui Wang <>
Fixes: 4c2924b725fb ("MIPS: PCI: Use pci_resource_to_user to map pci memory space properly")
Cc: James Hogan <>
Cc: Ralf Baechle <>
Cc: Wolfgang Grandegger <>
Cc: 
Cc:  # v3.12+
---

 arch/mips/pci/pci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Patch
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diff --git a/arch/mips/pci/pci.c b/arch/mips/pci/pci.c
index 9632436d74d7..c2e94cf5ecda 100644
--- a/arch/mips/pci/pci.c
+++ b/arch/mips/pci/pci.c
@@ -54,5 +54,5 @@  void pci_resource_to_user(const struct pci_dev *dev, int bar,
 	phys_addr_t size = resource_size(rsrc);
 
 	*start = fixup_bigphys_addr(rsrc->start, size);
-	*end = rsrc->start + size;
+	*end = rsrc->start + size - 1;
 }