| Message ID | 147318057623.30325.10495460878595242707.stgit@dwillia2-desk3.amr.corp.intel.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | ca120cf68887 |
| Headers | show |
On Tue, 06 Sep 2016 09:49:36 -0700 Dan Williams <dan.j.williams@intel.com> wrote: > Attempting to dump /proc/<pid>/smaps for a process with pmd dax mappings > currently results in the following VM_BUG_ONs: > > kernel BUG at mm/huge_memory.c:1105! > task: ffff88045f16b140 task.stack: ffff88045be14000 > RIP: 0010:[<ffffffff81268f9b>] [<ffffffff81268f9b>] follow_trans_huge_pmd+0x2cb/0x340 > [..] > Call Trace: > [<ffffffff81306030>] smaps_pte_range+0xa0/0x4b0 > [<ffffffff814c2755>] ? vsnprintf+0x255/0x4c0 > [<ffffffff8123c46e>] __walk_page_range+0x1fe/0x4d0 > [<ffffffff8123c8a2>] walk_page_vma+0x62/0x80 > [<ffffffff81307656>] show_smap+0xa6/0x2b0 > > kernel BUG at fs/proc/task_mmu.c:585! > RIP: 0010:[<ffffffff81306469>] [<ffffffff81306469>] smaps_pte_range+0x499/0x4b0 > Call Trace: > [<ffffffff814c2795>] ? vsnprintf+0x255/0x4c0 > [<ffffffff8123c46e>] __walk_page_range+0x1fe/0x4d0 > [<ffffffff8123c8a2>] walk_page_vma+0x62/0x80 > [<ffffffff81307696>] show_smap+0xa6/0x2b0 > > These locations are sanity checking page flags that must be set for an > anonymous transparent huge page, but are not set for the zone_device > pages associated with dax mappings. Acked-by: Andrew Morton <akpm@linux-foundation.org>
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 187d84ef9de9..f6fa99eca515 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -581,6 +581,8 @@ static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr, mss->anonymous_thp += HPAGE_PMD_SIZE; else if (PageSwapBacked(page)) mss->shmem_thp += HPAGE_PMD_SIZE; + else if (is_zone_device_page(page)) + /* pass */; else VM_BUG_ON_PAGE(1, page); smaps_account(mss, page, true, pmd_young(*pmd), pmd_dirty(*pmd)); diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 2db2112aa31e..a6abd76baa72 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1078,7 +1078,7 @@ struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, goto out; page = pmd_page(*pmd); - VM_BUG_ON_PAGE(!PageHead(page), page); + VM_BUG_ON_PAGE(!PageHead(page) && !is_zone_device_page(page), page); if (flags & FOLL_TOUCH) touch_pmd(vma, addr, pmd); if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) { @@ -1116,7 +1116,7 @@ struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, } skip_mlock: page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; - VM_BUG_ON_PAGE(!PageCompound(page), page); + VM_BUG_ON_PAGE(!PageCompound(page) && !is_zone_device_page(page), page); if (flags & FOLL_GET) get_page(page);
Attempting to dump /proc/<pid>/smaps for a process with pmd dax mappings currently results in the following VM_BUG_ONs: kernel BUG at mm/huge_memory.c:1105! task: ffff88045f16b140 task.stack: ffff88045be14000 RIP: 0010:[<ffffffff81268f9b>] [<ffffffff81268f9b>] follow_trans_huge_pmd+0x2cb/0x340 [..] Call Trace: [<ffffffff81306030>] smaps_pte_range+0xa0/0x4b0 [<ffffffff814c2755>] ? vsnprintf+0x255/0x4c0 [<ffffffff8123c46e>] __walk_page_range+0x1fe/0x4d0 [<ffffffff8123c8a2>] walk_page_vma+0x62/0x80 [<ffffffff81307656>] show_smap+0xa6/0x2b0 kernel BUG at fs/proc/task_mmu.c:585! RIP: 0010:[<ffffffff81306469>] [<ffffffff81306469>] smaps_pte_range+0x499/0x4b0 Call Trace: [<ffffffff814c2795>] ? vsnprintf+0x255/0x4c0 [<ffffffff8123c46e>] __walk_page_range+0x1fe/0x4d0 [<ffffffff8123c8a2>] walk_page_vma+0x62/0x80 [<ffffffff81307696>] show_smap+0xa6/0x2b0 These locations are sanity checking page flags that must be set for an anonymous transparent huge page, but are not set for the zone_device pages associated with dax mappings. Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com> --- fs/proc/task_mmu.c | 2 ++ mm/huge_memory.c | 4 ++-- 2 files changed, 4 insertions(+), 2 deletions(-)