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(). This is definitely going to cause problems. > 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. virt_addr_valid() gets used in some places to check whether the virtual address is part of the lowmem mapping and explicitly not part of vmalloc() or DMA coherent space: drivers/mtd/nand/gpmi-nand/gpmi-nand.c drivers/net/wireless/ath/ath6kl/sdio.c It opens up the checks in include/linux/scatterlist.h to start accepting non-streaming DMA capable buffers as well. It also bypasses a check in the slab code to ensure that it's a potentially valid pointer that was handed out by slab. .. etc .. _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm
