From: Peter Xu Date: Mon, 12 Aug 2024 18:12:19 +0000 (-0400) Subject: mm/dax: dump start address in fault handler X-Git-Tag: v6.12-rc1~115^2~316 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=5b198b4759ef7e618817d390601740b30ff56041;p=thirdparty%2Fkernel%2Flinux.git mm/dax: dump start address in fault handler Patch series "mm/mprotect: Fix dax puds", v5. Dax supports pud pages for a while, but mprotect on puds was missing since the start. This series tries to fix that by providing pud handling in mprotect(). The goal is to add more types of pud mappings like hugetlb or pfnmaps. This series paves way for it by fixing known pud entries. Considering nobody reported this until when I looked at those other types of pud mappings, I am thinking maybe it doesn't need to be a fix for stable and this may not need to be backported. I would guess whoever cares about mprotect() won't care 1G dax puds yet, vice versa. I hope fixing that in new kernels would be fine, but I'm open to suggestions. There're a few small things changed to teach mprotect work on PUDs. E.g. it will need to start with dropping NUMA_HUGE_PTE_UPDATES which may stop making sense when there can be more than one type of huge pte. OTOH, we'll also need to push the mmu notifiers from pmd to pud layers, which might need some attention but so far I think it's safe. For such details, please refer to each patch's commit message. The mprotect() pud process should be straightforward, as I kept it as simple as possible. There's no NUMA handled as dax simply doesn't support that. There's also no userfault involvements as file memory (even if work with userfault-wp async mode) will need to split a pud, so pud entry doesn't need to yet know userfault's existance (but hugetlb entries will; that's also for later). This patch (of 7): Currently the dax fault handler dumps the vma range when dynamic debugging enabled. That's mostly not useful. Dump the (aligned) address instead with the order info. Link: https://lkml.kernel.org/r/20240812181225.1360970-1-peterx@redhat.com Link: https://lkml.kernel.org/r/20240812181225.1360970-2-peterx@redhat.com Signed-off-by: Peter Xu Acked-by: David Hildenbrand Cc: Aneesh Kumar K.V Cc: Borislav Petkov Cc: Christophe Leroy Cc: Dan Williams Cc: Dave Hansen Cc: Dave Jiang Cc: David Rientjes Cc: "Edgecombe, Rick P" Cc: Hugh Dickins Cc: Ingo Molnar Cc: Kirill A. Shutemov Cc: Matthew Wilcox Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Oscar Salvador Cc: Paolo Bonzini Cc: Rik van Riel Cc: Sean Christopherson Cc: Thomas Gleixner Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- diff --git a/drivers/dax/device.c b/drivers/dax/device.c index 2051e4f73c8a4..9c1a729cd77e9 100644 --- a/drivers/dax/device.c +++ b/drivers/dax/device.c @@ -235,9 +235,9 @@ static vm_fault_t dev_dax_huge_fault(struct vm_fault *vmf, unsigned int order) int id; struct dev_dax *dev_dax = filp->private_data; - dev_dbg(&dev_dax->dev, "%s: %s (%#lx - %#lx) order:%d\n", current->comm, - (vmf->flags & FAULT_FLAG_WRITE) ? "write" : "read", - vmf->vma->vm_start, vmf->vma->vm_end, order); + dev_dbg(&dev_dax->dev, "%s: op=%s addr=%#lx order=%d\n", current->comm, + (vmf->flags & FAULT_FLAG_WRITE) ? "write" : "read", + vmf->address & ~((1UL << (order + PAGE_SHIFT)) - 1), order); id = dax_read_lock(); if (order == 0)