Jeff Moyer reports that: " With a device dax alignment of 4KB or 2MB, I get sigbus when running the attached fio job file for the current kernel (4.11.0-rc1+). If I specify an alignment of 1GB, it works.
I turned on debug output, and saw that it was failing in the huge fault code. [ 4614.138357] dax dax1.0: dax_open [ 4614.154838] dax dax1.0: dax_mmap [ 4614.171898] dax dax1.0: dax_dev_huge_fault: fio: write (0x7f08f0a00000 - 0x7f0ce0800000) [ 4614.211720] dax dax1.0: __dax_dev_pud_fault: phys_to_pgoff(0xffffffffcf600) failed [ 4614.568911] dax dax1.0: dax_release fio config for reproduce: [global] ioengine=dev-dax direct=0 filename=/dev/dax0.0 bs=2m [write] rw=write [read] stonewall rw=read " It looks like the code does not fallback at all when handling faults. Adding additional boundary checks and code that determines when to fallback. This patch is part 2 that fixes the pud handler. Reported-by: Jeff Moyer <[email protected]> Signed-off-by: Dave Jiang <[email protected]> --- drivers/dax/dax.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/dax/dax.c b/drivers/dax/dax.c index 828f168..80c6db279 100644 --- a/drivers/dax/dax.c +++ b/drivers/dax/dax.c @@ -518,6 +518,8 @@ static int __dax_dev_pud_fault(struct dax_dev *dax_dev, struct vm_fault *vmf) phys_addr_t phys; pgoff_t pgoff; pfn_t pfn; + unsigned int fault_size = PUD_SIZE; + if (check_vma(dax_dev, vmf->vma, __func__)) return VM_FAULT_SIGBUS; @@ -534,6 +536,16 @@ static int __dax_dev_pud_fault(struct dax_dev *dax_dev, struct vm_fault *vmf) return VM_FAULT_SIGBUS; } + if (fault_size < dax_region->align) + return VM_FAULT_SIGBUS; + else if (fault_size > dax_region->align) + return VM_FAULT_FALLBACK; + + /* if we are outside of the VMA */ + if (pud_addr < vmf->vma->vm_start || + (pud_addr + PUD_SIZE) > vmf->vma->vm_end) + return VM_FAULT_SIGBUS; + pgoff = linear_page_index(vmf->vma, pud_addr); phys = pgoff_to_phys(dax_dev, pgoff, PUD_SIZE); if (phys == -1) { _______________________________________________ Linux-nvdimm mailing list [email protected] https://lists.01.org/mailman/listinfo/linux-nvdimm
