From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752031AbcAEObd (ORCPT ); Tue, 5 Jan 2016 09:31:33 -0500 Received: from terminus.zytor.com ([198.137.202.10]:35480 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751663AbcAEOb3 (ORCPT ); Tue, 5 Jan 2016 09:31:29 -0500 Date: Tue, 5 Jan 2016 06:30:51 -0800 From: tip-bot for Toshi Kani Message-ID: Cc: stsp@list.ru, bp@suse.de, tglx@linutronix.de, toshi.kani@hpe.com, hpa@zytor.com, mingo@redhat.com, linux-kernel@vger.kernel.org, mingo@kernel.org Reply-To: bp@suse.de, stsp@list.ru, linux-kernel@vger.kernel.org, mingo@redhat.com, hpa@zytor.com, toshi.kani@hpe.com, tglx@linutronix.de, mingo@kernel.org In-Reply-To: <1450832064-10093-2-git-send-email-toshi.kani@hpe.com> References: <1450832064-10093-2-git-send-email-toshi.kani@hpe.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/mm] x86/mm/pat: Add untrack_pfn_moved for mremap Git-Commit-ID: d9fe4fab11976e56b2e992980bf6ce948bdf02ac X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: d9fe4fab11976e56b2e992980bf6ce948bdf02ac Gitweb: http://git.kernel.org/tip/d9fe4fab11976e56b2e992980bf6ce948bdf02ac Author: Toshi Kani AuthorDate: Tue, 22 Dec 2015 17:54:23 -0700 Committer: Thomas Gleixner CommitDate: Tue, 5 Jan 2016 11:10:05 +0100 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: [] dump_stack+0x45/0x57 [] warn_slowpath_common+0x86/0xc0 [] warn_slowpath_null+0x1a/0x20 [] untrack_pfn+0xbd/0xd0 [] unmap_single_vma+0x80e/0x860 [] unmap_vmas+0x55/0xb0 [] unmap_region+0xac/0x120 [] do_munmap+0x28a/0x460 [] move_vma+0x1b3/0x2e0 [] SyS_mremap+0x3b3/0x510 [] 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 Signed-off-by: Toshi Kani Cc: Thomas Gleixner Cc: Ingo Molnar Cc: H. Peter Anvin Cc: Borislav Petkov 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 --- arch/x86/mm/pat.c | 10 ++++++++++ include/asm-generic/pgtable.h | 10 +++++++++- mm/mremap.c | 4 ++++ 3 files changed, 23 insertions(+), 1 deletion(-) diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index 188e3e0..1aca073 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -992,6 +992,16 @@ void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn, vma->vm_flags &= ~VM_PAT; } +/* + * untrack_pfn_moved is called, while mremapping a pfnmap for a new region, + * with the old vma after its pfnmap page table has been removed. The new + * vma has a new pfnmap to the same pfn & cache type with VM_PAT set. + */ +void untrack_pfn_moved(struct vm_area_struct *vma) +{ + vma->vm_flags &= ~VM_PAT; +} + pgprot_t pgprot_writecombine(pgprot_t prot) { return __pgprot(pgprot_val(prot) | diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h index 14b0ff32..3a6803c 100644 --- a/include/asm-generic/pgtable.h +++ b/include/asm-generic/pgtable.h @@ -569,7 +569,7 @@ static inline int track_pfn_copy(struct vm_area_struct *vma) } /* - * untrack_pfn_vma is called while unmapping a pfnmap for a region. + * untrack_pfn is called while unmapping a pfnmap for a region. * untrack can be called for a specific region indicated by pfn and size or * can be for the entire vma (in which case pfn, size are zero). */ @@ -577,6 +577,13 @@ static inline void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn, unsigned long size) { } + +/* + * untrack_pfn_moved is called while mremapping a pfnmap for a new region. + */ +static inline void untrack_pfn_moved(struct vm_area_struct *vma) +{ +} #else extern int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot, unsigned long pfn, unsigned long addr, @@ -586,6 +593,7 @@ extern int track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot, extern int track_pfn_copy(struct vm_area_struct *vma); extern void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn, unsigned long size); +extern void untrack_pfn_moved(struct vm_area_struct *vma); #endif #ifdef __HAVE_COLOR_ZERO_PAGE diff --git a/mm/mremap.c b/mm/mremap.c index c25bc62..de824e7 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);