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| author | Toshi Kani <toshi.kani@hpe.com> | 2015-12-22 17:54:23 -0700 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2016-01-05 11:10:05 +0100 |
| commit | d9fe4fab11976e56b2e992980bf6ce948bdf02ac (patch) | |
| tree | efbf8627823ee26cbbc397d8aa7ba158a849eb31 /mm/mremap.c | |
| parent | 9abb0ecdee69a2577560cc283368e490da974934 (diff) | |
| download | linux-0-day-d9fe4fab11976e56b2e992980bf6ce948bdf02ac.tar.gz linux-0-day-d9fe4fab11976e56b2e992980bf6ce948bdf02ac.tar.xz | |
x86/mm/pat: Add untrack_pfn_moved for mremap
mremap() with MREMAP_FIXED on a VM_PFNMAP range causes the following
WARN_ON_ONCE() message in untrack_pfn().
WARNING: CPU: 1 PID: 3493 at arch/x86/mm/pat.c:985 untrack_pfn+0xbd/0xd0()
Call Trace:
[<ffffffff817729ea>] dump_stack+0x45/0x57
[<ffffffff8109e4b6>] warn_slowpath_common+0x86/0xc0
[<ffffffff8109e5ea>] warn_slowpath_null+0x1a/0x20
[<ffffffff8106a88d>] untrack_pfn+0xbd/0xd0
[<ffffffff811d2d5e>] unmap_single_vma+0x80e/0x860
[<ffffffff811d3725>] unmap_vmas+0x55/0xb0
[<ffffffff811d916c>] unmap_region+0xac/0x120
[<ffffffff811db86a>] do_munmap+0x28a/0x460
[<ffffffff811dec33>] move_vma+0x1b3/0x2e0
[<ffffffff811df113>] SyS_mremap+0x3b3/0x510
[<ffffffff817793ee>] entry_SYSCALL_64_fastpath+0x12/0x71
MREMAP_FIXED moves a pfnmap from old vma to new vma. untrack_pfn() is
called with the old vma after its pfnmap page table has been removed,
which causes follow_phys() to fail. The new vma has a new pfnmap to
the same pfn & cache type with VM_PAT set. Therefore, we only need to
clear VM_PAT from the old vma in this case.
Add untrack_pfn_moved(), which clears VM_PAT from a given old vma.
move_vma() is changed to call this function with the old vma when
VM_PFNMAP is set. move_vma() then calls do_munmap(), and untrack_pfn()
is a no-op since VM_PAT is cleared.
Reported-by: Stas Sergeev <stsp@list.ru>
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/1450832064-10093-2-git-send-email-toshi.kani@hpe.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'mm/mremap.c')
| -rw-r--r-- | mm/mremap.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/mm/mremap.c b/mm/mremap.c index c25bc6268e465..de824e72c3e89 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -319,6 +319,10 @@ static unsigned long move_vma(struct vm_area_struct *vma, hiwater_vm = mm->hiwater_vm; vm_stat_account(mm, vma->vm_flags, vma->vm_file, new_len>>PAGE_SHIFT); + /* Tell pfnmap has moved from this vma */ + if (unlikely(vma->vm_flags & VM_PFNMAP)) + untrack_pfn_moved(vma); + if (do_munmap(mm, old_addr, old_len) < 0) { /* OOM: unable to split vma, just get accounts right */ vm_unacct_memory(excess >> PAGE_SHIFT); |