From: mark gross Fix an off by one bug in the fault reason string reporting function, and clean up some of the code around this buglet. Signed-off-by: mark gross Signed-off-by: Andrew Morton --- drivers/pci/intel-iommu.c | 13 ++++++------- include/linux/dmar.h | 2 +- 2 files changed, 7 insertions(+), 8 deletions(-) diff -puN drivers/pci/intel-iommu.c~intel-iommu-fault_reason_index_cleanuppatch drivers/pci/intel-iommu.c --- a/drivers/pci/intel-iommu.c~intel-iommu-fault_reason_index_cleanuppatch +++ a/drivers/pci/intel-iommu.c @@ -745,7 +745,7 @@ static int iommu_disable_translation(str /* iommu interrupt handling. Most stuff are MSI-like. */ -static char *fault_reason_strings[] = +static const char *fault_reason_strings[] = { "Software", "Present bit in root entry is clear", @@ -759,15 +759,14 @@ static char *fault_reason_strings[] = "Context table ptr is invalid", "non-zero reserved fields in RTP", "non-zero reserved fields in CTP", - "non-zero reserved fields in PTE", - "Unknown" + "non-zero reserved fields in PTE" }; #define MAX_FAULT_REASON_IDX (ARRAY_SIZE(fault_reason_strings) - 1) -char *dmar_get_fault_reason(u8 fault_reason) +const char *dmar_get_fault_reason(u8 fault_reason) { - if (fault_reason >= MAX_FAULT_REASON_IDX) - return fault_reason_strings[MAX_FAULT_REASON_IDX - 1]; + if (fault_reason > MAX_FAULT_REASON_IDX) + return "Unknown"; else return fault_reason_strings[fault_reason]; } @@ -825,7 +824,7 @@ void dmar_msi_read(int irq, struct msi_m static int iommu_page_fault_do_one(struct intel_iommu *iommu, int type, u8 fault_reason, u16 source_id, u64 addr) { - char *reason; + const char *reason; reason = dmar_get_fault_reason(fault_reason); diff -puN include/linux/dmar.h~intel-iommu-fault_reason_index_cleanuppatch include/linux/dmar.h --- a/include/linux/dmar.h~intel-iommu-fault_reason_index_cleanuppatch +++ a/include/linux/dmar.h @@ -28,7 +28,7 @@ #ifdef CONFIG_DMAR struct intel_iommu; -extern char *dmar_get_fault_reason(u8 fault_reason); +extern const char *dmar_get_fault_reason(u8 fault_reason); /* Can't use the common MSI interrupt functions * since DMAR is not a pci device _