On Thursday 14 November 2013 07:22 PM, Christoffer Dall wrote: > On Thu, Nov 14, 2013 at 02:37:43PM -0500, Santosh Shilimkar wrote: >> Slab allocator can allocate memory beyond the lowmem watermark >> which can lead to false failure of virt_addr_valid(). >> >> So drop the check. The issue was seen with percpu_alloc() >> in KVM code which was allocating memory beyond lowmem watermark. >> >> Am not completly sure whether this is the right fix and if it could >> impact any other user of virt_addr_valid(). Without this fix as >> pointed out the KVM init was failing in my testing. >> >> Cc: Christoffer Dall <christoffer.dall@xxxxxxxxxx> >> Cc: Marc Zyngier <marc.zyngier@xxxxxxx> >> Cc: Russell King <linux@xxxxxxxxxxxxxxxx> >> Cc: Catalin Marinas <catalin.marinas@xxxxxxx> >> Cc: Will Deacon <will.deacon@xxxxxxx> >> >> Signed-off-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx> >> --- >> arch/arm/include/asm/memory.h | 3 +-- >> 1 file changed, 1 insertion(+), 2 deletions(-) >> >> diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h >> index 4dd2145..412da47 100644 >> --- a/arch/arm/include/asm/memory.h >> +++ b/arch/arm/include/asm/memory.h >> @@ -343,8 +343,7 @@ static inline __deprecated void *bus_to_virt(unsigned long x) >> #define ARCH_PFN_OFFSET PHYS_PFN_OFFSET >> >> #define virt_to_page(kaddr) pfn_to_page(__pa(kaddr) >> PAGE_SHIFT) >> -#define virt_addr_valid(kaddr) ((unsigned long)(kaddr) >= PAGE_OFFSET && (unsigned long)(kaddr) < (unsigned long)high_memory) >> - >> +#define virt_addr_valid(kaddr) ((unsigned long)(kaddr) >= PAGE_OFFSET) >> #endif >> >> #include <asm-generic/memory_model.h> >> -- >> 1.7.9.5 >> > > This looks wrong to me. Check Documentation/arm/memory.txt, this would > return true for the VMALLOC region, which would cause virt_to_phys to > give you something invalid, which would be bad. > I also thought it might not be right fix and hence added a disclaimer in the commit message ;-) Regards, Santosh _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm
