From: Laurent Dufour <ldufour@linux.vnet.ibm.com> To: paulmck@linux.vnet.ibm.com, peterz@infradead.org, akpm@linux-foundation.org, kirill@shutemov.name, ak@linux.intel.com, mhocko@kernel.org, dave@stgolabs.net, jack@suse.cz Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, haren@linux.vnet.ibm.com, khandual@linux.vnet.ibm.com, npiggin@gmail.com, bsingharora@gmail.com Subject: [RFC v3 10/17] mm/spf: don't set fault entry's fields if locking failed Date: Thu, 27 Apr 2017 17:52:49 +0200 [thread overview] Message-ID: <1493308376-23851-11-git-send-email-ldufour@linux.vnet.ibm.com> (raw) In-Reply-To: <1493308376-23851-1-git-send-email-ldufour@linux.vnet.ibm.com> In the case pte_map_lock failed to lock the pte or if the VMA is no more valid, the fault entry's fields should not be set so that caller won't try to unlock it. Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com> --- mm/memory.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index f8afd52f0d34..3b28de5838c7 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2135,6 +2135,8 @@ static bool pte_spinlock(struct vm_fault *vmf) static bool pte_map_lock(struct vm_fault *vmf) { bool ret = false; + pte_t *pte; + spinlock_t *ptl; if (!(vmf->flags & FAULT_FLAG_SPECULATIVE)) { vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd, @@ -2159,18 +2161,20 @@ static bool pte_map_lock(struct vm_fault *vmf) * to invalidate TLB but this CPU has irq disabled. * Since we are in a speculative patch, accept it could fail */ - vmf->ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd); - vmf->pte = pte_offset_map(vmf->pmd, vmf->address); - if (unlikely(!spin_trylock(vmf->ptl))) { - pte_unmap(vmf->pte); + ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd); + pte = pte_offset_map(vmf->pmd, vmf->address); + if (unlikely(!spin_trylock(ptl))) { + pte_unmap(pte); goto out; } if (vma_is_dead(vmf->vma, vmf->sequence)) { - pte_unmap_unlock(vmf->pte, vmf->ptl); + pte_unmap_unlock(pte, ptl); goto out; } + vmf->pte = pte; + vmf->ptl = ptl; ret = true; out: local_irq_enable(); -- 2.7.4
WARNING: multiple messages have this Message-ID (diff)
From: Laurent Dufour <ldufour@linux.vnet.ibm.com> To: paulmck@linux.vnet.ibm.com, peterz@infradead.org, akpm@linux-foundation.org, kirill@shutemov.name, ak@linux.intel.com, mhocko@kernel.org, dave@stgolabs.net, jack@suse.cz Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, haren@linux.vnet.ibm.com, khandual@linux.vnet.ibm.com, npiggin@gmail.com, bsingharora@gmail.com Subject: [RFC v3 10/17] mm/spf: don't set fault entry's fields if locking failed Date: Thu, 27 Apr 2017 17:52:49 +0200 [thread overview] Message-ID: <1493308376-23851-11-git-send-email-ldufour@linux.vnet.ibm.com> (raw) In-Reply-To: <1493308376-23851-1-git-send-email-ldufour@linux.vnet.ibm.com> In the case pte_map_lock failed to lock the pte or if the VMA is no more valid, the fault entry's fields should not be set so that caller won't try to unlock it. Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com> --- mm/memory.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index f8afd52f0d34..3b28de5838c7 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2135,6 +2135,8 @@ static bool pte_spinlock(struct vm_fault *vmf) static bool pte_map_lock(struct vm_fault *vmf) { bool ret = false; + pte_t *pte; + spinlock_t *ptl; if (!(vmf->flags & FAULT_FLAG_SPECULATIVE)) { vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd, @@ -2159,18 +2161,20 @@ static bool pte_map_lock(struct vm_fault *vmf) * to invalidate TLB but this CPU has irq disabled. * Since we are in a speculative patch, accept it could fail */ - vmf->ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd); - vmf->pte = pte_offset_map(vmf->pmd, vmf->address); - if (unlikely(!spin_trylock(vmf->ptl))) { - pte_unmap(vmf->pte); + ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd); + pte = pte_offset_map(vmf->pmd, vmf->address); + if (unlikely(!spin_trylock(ptl))) { + pte_unmap(pte); goto out; } if (vma_is_dead(vmf->vma, vmf->sequence)) { - pte_unmap_unlock(vmf->pte, vmf->ptl); + pte_unmap_unlock(pte, ptl); goto out; } + vmf->pte = pte; + vmf->ptl = ptl; ret = true; out: local_irq_enable(); -- 2.7.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2017-04-27 15:56 UTC|newest] Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-04-27 15:52 [RFC v3 00/17] Speculative page faults Laurent Dufour 2017-04-27 15:52 ` Laurent Dufour 2017-04-27 15:52 ` [RFC v3 01/17] mm: Dont assume page-table invariance during faults Laurent Dufour 2017-04-27 15:52 ` Laurent Dufour 2017-04-27 15:52 ` [RFC v3 02/17] mm: Prepare for FAULT_FLAG_SPECULATIVE Laurent Dufour 2017-04-27 15:52 ` Laurent Dufour 2017-04-27 15:52 ` [RFC v3 03/17] mm: Introduce pte_spinlock Laurent Dufour 2017-04-27 15:52 ` Laurent Dufour 2017-04-30 4:47 ` Matthew Wilcox 2017-04-30 4:47 ` Matthew Wilcox 2017-05-03 13:01 ` Laurent Dufour 2017-05-03 13:01 ` Laurent Dufour 2017-04-27 15:52 ` [RFC v3 04/17] mm: VMA sequence count Laurent Dufour 2017-04-27 15:52 ` Laurent Dufour 2017-04-27 15:52 ` [RFC v3 05/17] RCU free VMAs Laurent Dufour 2017-04-27 15:52 ` Laurent Dufour 2017-04-27 18:28 ` Paul E. McKenney 2017-04-27 18:28 ` Paul E. McKenney 2017-04-30 4:57 ` Matthew Wilcox 2017-04-30 4:57 ` Matthew Wilcox 2017-04-30 5:05 ` Matthew Wilcox 2017-04-30 5:05 ` Matthew Wilcox 2017-05-03 7:23 ` Laurent Dufour 2017-05-03 7:23 ` Laurent Dufour 2017-04-27 15:52 ` [RFC v3 06/17] mm: Provide speculative fault infrastructure Laurent Dufour 2017-04-27 15:52 ` Laurent Dufour 2017-04-27 15:52 ` [RFC v3 07/17] mm,x86: Add speculative pagefault handling Laurent Dufour 2017-04-27 15:52 ` Laurent Dufour 2017-04-27 15:52 ` [RFC v3 08/17] mm/spf: Try spin lock in speculative path Laurent Dufour 2017-04-27 15:52 ` Laurent Dufour 2017-04-27 15:52 ` [RFC v3 09/17] mm/spf: Fix fe.sequence init in __handle_mm_fault() Laurent Dufour 2017-04-27 15:52 ` Laurent Dufour 2017-04-27 15:52 ` Laurent Dufour [this message] 2017-04-27 15:52 ` [RFC v3 10/17] mm/spf: don't set fault entry's fields if locking failed Laurent Dufour 2017-04-27 15:52 ` [RFC v3 11/17] mm/spf; fix lock dependency against mapping->i_mmap_rwsem Laurent Dufour 2017-04-27 15:52 ` Laurent Dufour 2017-04-27 15:52 ` [RFC v3 12/17] mm/spf: Protect changes to vm_flags Laurent Dufour 2017-04-27 15:52 ` Laurent Dufour 2017-04-27 15:52 ` [RFC v3 13/17] mm/spf Protect vm_policy's changes against speculative pf Laurent Dufour 2017-04-27 15:52 ` Laurent Dufour 2017-04-27 15:52 ` [RFC v3 14/17] x86/mm: Update the handle_speculative_fault's path Laurent Dufour 2017-04-27 15:52 ` Laurent Dufour 2017-04-27 15:52 ` [RFC v3 15/17] mm/spf: Add check on the VMA's flags Laurent Dufour 2017-04-27 15:52 ` Laurent Dufour 2017-04-27 15:52 ` [RFC v3 16/17] mm: protect madvise vs speculative pf Laurent Dufour 2017-04-27 15:52 ` Laurent Dufour 2017-04-27 15:52 ` [RFC v3 17/17] mm/spf: protect mremap() against " Laurent Dufour 2017-04-27 15:52 ` Laurent Dufour
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