From c164154f66f0c9b02673f07aa4f044f1d9c70274 Mon Sep 17 00:00:00 2001 From: Lorenzo Stoakes Date: Thu, 13 Oct 2016 01:20:13 +0100 Subject: mm: replace get_user_pages_unlocked() write/force parameters with gup_flags This removes the 'write' and 'force' use from get_user_pages_unlocked() and replaces them with 'gup_flags' to make the use of FOLL_FORCE explicit in callers as use of this flag can result in surprising behaviour (and hence bugs) within the mm subsystem. Signed-off-by: Lorenzo Stoakes Reviewed-by: Jan Kara Acked-by: Michal Hocko Signed-off-by: Linus Torvalds --- arch/mips/mm/gup.c | 2 +- arch/s390/mm/gup.c | 3 ++- arch/sh/mm/gup.c | 3 ++- arch/sparc/mm/gup.c | 3 ++- arch/x86/mm/gup.c | 2 +- 5 files changed, 8 insertions(+), 5 deletions(-) (limited to 'arch') diff --git a/arch/mips/mm/gup.c b/arch/mips/mm/gup.c index 42d124fb6474..d8c3c159289a 100644 --- a/arch/mips/mm/gup.c +++ b/arch/mips/mm/gup.c @@ -287,7 +287,7 @@ slow_irqon: pages += nr; ret = get_user_pages_unlocked(start, (end - start) >> PAGE_SHIFT, - write, 0, pages); + pages, write ? FOLL_WRITE : 0); /* Have to be a bit careful with return values */ if (nr > 0) { diff --git a/arch/s390/mm/gup.c b/arch/s390/mm/gup.c index adb0c34bf431..18d4107e10ee 100644 --- a/arch/s390/mm/gup.c +++ b/arch/s390/mm/gup.c @@ -266,7 +266,8 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write, /* Try to get the remaining pages with get_user_pages */ start += nr << PAGE_SHIFT; pages += nr; - ret = get_user_pages_unlocked(start, nr_pages - nr, write, 0, pages); + ret = get_user_pages_unlocked(start, nr_pages - nr, pages, + write ? FOLL_WRITE : 0); /* Have to be a bit careful with return values */ if (nr > 0) ret = (ret < 0) ? nr : ret + nr; diff --git a/arch/sh/mm/gup.c b/arch/sh/mm/gup.c index 40fa6c8adc43..063c298ba56c 100644 --- a/arch/sh/mm/gup.c +++ b/arch/sh/mm/gup.c @@ -258,7 +258,8 @@ slow_irqon: pages += nr; ret = get_user_pages_unlocked(start, - (end - start) >> PAGE_SHIFT, write, 0, pages); + (end - start) >> PAGE_SHIFT, pages, + write ? FOLL_WRITE : 0); /* Have to be a bit careful with return values */ if (nr > 0) { diff --git a/arch/sparc/mm/gup.c b/arch/sparc/mm/gup.c index 4e06750a5d29..cd0e32bbcb1d 100644 --- a/arch/sparc/mm/gup.c +++ b/arch/sparc/mm/gup.c @@ -238,7 +238,8 @@ slow: pages += nr; ret = get_user_pages_unlocked(start, - (end - start) >> PAGE_SHIFT, write, 0, pages); + (end - start) >> PAGE_SHIFT, pages, + write ? FOLL_WRITE : 0); /* Have to be a bit careful with return values */ if (nr > 0) { diff --git a/arch/x86/mm/gup.c b/arch/x86/mm/gup.c index b8b6a60b32cf..0d4fb3ebbbac 100644 --- a/arch/x86/mm/gup.c +++ b/arch/x86/mm/gup.c @@ -435,7 +435,7 @@ slow_irqon: ret = get_user_pages_unlocked(start, (end - start) >> PAGE_SHIFT, - write, 0, pages); + pages, write ? FOLL_WRITE : 0); /* Have to be a bit careful with return values */ if (nr > 0) { -- cgit v1.2.3 From 768ae309a96103ed02eb1e111e838c87854d8b51 Mon Sep 17 00:00:00 2001 From: Lorenzo Stoakes Date: Thu, 13 Oct 2016 01:20:16 +0100 Subject: mm: replace get_user_pages() write/force parameters with gup_flags MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This removes the 'write' and 'force' from get_user_pages() and replaces them with 'gup_flags' to make the use of FOLL_FORCE explicit in callers as use of this flag can result in surprising behaviour (and hence bugs) within the mm subsystem. Signed-off-by: Lorenzo Stoakes Acked-by: Christian König Acked-by: Jesper Nilsson Acked-by: Michal Hocko Reviewed-by: Jan Kara Signed-off-by: Linus Torvalds --- arch/cris/arch-v32/drivers/cryptocop.c | 4 +--- arch/ia64/kernel/err_inject.c | 2 +- arch/x86/mm/mpx.c | 5 ++--- drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 7 +++++-- drivers/gpu/drm/radeon/radeon_ttm.c | 3 ++- drivers/gpu/drm/via/via_dmablit.c | 4 ++-- drivers/infiniband/core/umem.c | 6 +++++- drivers/infiniband/hw/mthca/mthca_memfree.c | 2 +- drivers/infiniband/hw/qib/qib_user_pages.c | 3 ++- drivers/infiniband/hw/usnic/usnic_uiom.c | 5 ++++- drivers/media/v4l2-core/videobuf-dma-sg.c | 7 +++++-- drivers/misc/mic/scif/scif_rma.c | 3 +-- drivers/misc/sgi-gru/grufault.c | 2 +- drivers/platform/goldfish/goldfish_pipe.c | 3 ++- drivers/rapidio/devices/rio_mport_cdev.c | 3 ++- .../vc04_services/interface/vchiq_arm/vchiq_2835_arm.c | 3 +-- .../vc04_services/interface/vchiq_arm/vchiq_arm.c | 3 +-- drivers/virt/fsl_hypervisor.c | 4 ++-- include/linux/mm.h | 2 +- mm/gup.c | 12 +++--------- mm/mempolicy.c | 2 +- mm/nommu.c | 18 ++++-------------- 22 files changed, 49 insertions(+), 54 deletions(-) (limited to 'arch') diff --git a/arch/cris/arch-v32/drivers/cryptocop.c b/arch/cris/arch-v32/drivers/cryptocop.c index b5698c876fcc..099e170a93ee 100644 --- a/arch/cris/arch-v32/drivers/cryptocop.c +++ b/arch/cris/arch-v32/drivers/cryptocop.c @@ -2722,7 +2722,6 @@ static int cryptocop_ioctl_process(struct inode *inode, struct file *filp, unsig err = get_user_pages((unsigned long int)(oper.indata + prev_ix), noinpages, 0, /* read access only for in data */ - 0, /* no force */ inpages, NULL); @@ -2736,8 +2735,7 @@ static int cryptocop_ioctl_process(struct inode *inode, struct file *filp, unsig if (oper.do_cipher){ err = get_user_pages((unsigned long int)oper.cipher_outdata, nooutpages, - 1, /* write access for out data */ - 0, /* no force */ + FOLL_WRITE, /* write access for out data */ outpages, NULL); up_read(¤t->mm->mmap_sem); diff --git a/arch/ia64/kernel/err_inject.c b/arch/ia64/kernel/err_inject.c index 09f845793d12..5ed0ea92c5bf 100644 --- a/arch/ia64/kernel/err_inject.c +++ b/arch/ia64/kernel/err_inject.c @@ -142,7 +142,7 @@ store_virtual_to_phys(struct device *dev, struct device_attribute *attr, u64 virt_addr=simple_strtoull(buf, NULL, 16); int ret; - ret = get_user_pages(virt_addr, 1, VM_READ, 0, NULL, NULL); + ret = get_user_pages(virt_addr, 1, FOLL_WRITE, NULL, NULL); if (ret<=0) { #ifdef ERR_INJ_DEBUG printk("Virtual address %lx is not existing.\n",virt_addr); diff --git a/arch/x86/mm/mpx.c b/arch/x86/mm/mpx.c index 80476878eb4c..e4f800999b32 100644 --- a/arch/x86/mm/mpx.c +++ b/arch/x86/mm/mpx.c @@ -544,10 +544,9 @@ static int mpx_resolve_fault(long __user *addr, int write) { long gup_ret; int nr_pages = 1; - int force = 0; - gup_ret = get_user_pages((unsigned long)addr, nr_pages, write, - force, NULL, NULL); + gup_ret = get_user_pages((unsigned long)addr, nr_pages, + write ? FOLL_WRITE : 0, NULL, NULL); /* * get_user_pages() returns number of pages gotten. * 0 means we failed to fault in and get anything, diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c index 887483b8b818..dcaf691f56b5 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c @@ -555,10 +555,13 @@ struct amdgpu_ttm_tt { int amdgpu_ttm_tt_get_user_pages(struct ttm_tt *ttm, struct page **pages) { struct amdgpu_ttm_tt *gtt = (void *)ttm; - int write = !(gtt->userflags & AMDGPU_GEM_USERPTR_READONLY); + unsigned int flags = 0; unsigned pinned = 0; int r; + if (!(gtt->userflags & AMDGPU_GEM_USERPTR_READONLY)) + flags |= FOLL_WRITE; + if (gtt->userflags & AMDGPU_GEM_USERPTR_ANONONLY) { /* check that we only use anonymous memory to prevent problems with writeback */ @@ -581,7 +584,7 @@ int amdgpu_ttm_tt_get_user_pages(struct ttm_tt *ttm, struct page **pages) list_add(&guptask.list, >t->guptasks); spin_unlock(>t->guptasklock); - r = get_user_pages(userptr, num_pages, write, 0, p, NULL); + r = get_user_pages(userptr, num_pages, flags, p, NULL); spin_lock(>t->guptasklock); list_del(&guptask.list); diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c b/drivers/gpu/drm/radeon/radeon_ttm.c index 455268214b89..3de5e6e21662 100644 --- a/drivers/gpu/drm/radeon/radeon_ttm.c +++ b/drivers/gpu/drm/radeon/radeon_ttm.c @@ -566,7 +566,8 @@ static int radeon_ttm_tt_pin_userptr(struct ttm_tt *ttm) uint64_t userptr = gtt->userptr + pinned * PAGE_SIZE; struct page **pages = ttm->pages + pinned; - r = get_user_pages(userptr, num_pages, write, 0, pages, NULL); + r = get_user_pages(userptr, num_pages, write ? FOLL_WRITE : 0, + pages, NULL); if (r < 0) goto release_pages; diff --git a/drivers/gpu/drm/via/via_dmablit.c b/drivers/gpu/drm/via/via_dmablit.c index 7e2a12c4fed2..1a3ad769f8c8 100644 --- a/drivers/gpu/drm/via/via_dmablit.c +++ b/drivers/gpu/drm/via/via_dmablit.c @@ -241,8 +241,8 @@ via_lock_all_dma_pages(drm_via_sg_info_t *vsg, drm_via_dmablit_t *xfer) down_read(¤t->mm->mmap_sem); ret = get_user_pages((unsigned long)xfer->mem_addr, vsg->num_pages, - (vsg->direction == DMA_FROM_DEVICE), - 0, vsg->pages, NULL); + (vsg->direction == DMA_FROM_DEVICE) ? FOLL_WRITE : 0, + vsg->pages, NULL); up_read(¤t->mm->mmap_sem); if (ret != vsg->num_pages) { diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c index c68746ce6624..224ad274ea0b 100644 --- a/drivers/infiniband/core/umem.c +++ b/drivers/infiniband/core/umem.c @@ -94,6 +94,7 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr, unsigned long dma_attrs = 0; struct scatterlist *sg, *sg_list_start; int need_release = 0; + unsigned int gup_flags = FOLL_WRITE; if (dmasync) dma_attrs |= DMA_ATTR_WRITE_BARRIER; @@ -183,6 +184,9 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr, if (ret) goto out; + if (!umem->writable) + gup_flags |= FOLL_FORCE; + need_release = 1; sg_list_start = umem->sg_head.sgl; @@ -190,7 +194,7 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr, ret = get_user_pages(cur_base, min_t(unsigned long, npages, PAGE_SIZE / sizeof (struct page *)), - 1, !umem->writable, page_list, vma_list); + gup_flags, page_list, vma_list); if (ret < 0) goto out; diff --git a/drivers/infiniband/hw/mthca/mthca_memfree.c b/drivers/infiniband/hw/mthca/mthca_memfree.c index 6c00d04b8b28..c6fe89d79248 100644 --- a/drivers/infiniband/hw/mthca/mthca_memfree.c +++ b/drivers/infiniband/hw/mthca/mthca_memfree.c @@ -472,7 +472,7 @@ int mthca_map_user_db(struct mthca_dev *dev, struct mthca_uar *uar, goto out; } - ret = get_user_pages(uaddr & PAGE_MASK, 1, 1, 0, pages, NULL); + ret = get_user_pages(uaddr & PAGE_MASK, 1, FOLL_WRITE, pages, NULL); if (ret < 0) goto out; diff --git a/drivers/infiniband/hw/qib/qib_user_pages.c b/drivers/infiniband/hw/qib/qib_user_pages.c index 2d2b94fd3633..75f08624ac05 100644 --- a/drivers/infiniband/hw/qib/qib_user_pages.c +++ b/drivers/infiniband/hw/qib/qib_user_pages.c @@ -67,7 +67,8 @@ static int __qib_get_user_pages(unsigned long start_page, size_t num_pages, for (got = 0; got < num_pages; got += ret) { ret = get_user_pages(start_page + got * PAGE_SIZE, - num_pages - got, 1, 1, + num_pages - got, + FOLL_WRITE | FOLL_FORCE, p + got, NULL); if (ret < 0) goto bail_release; diff --git a/drivers/infiniband/hw/usnic/usnic_uiom.c b/drivers/infiniband/hw/usnic/usnic_uiom.c index a0b6ebee4d8a..1ccee6ea5bc3 100644 --- a/drivers/infiniband/hw/usnic/usnic_uiom.c +++ b/drivers/infiniband/hw/usnic/usnic_uiom.c @@ -111,6 +111,7 @@ static int usnic_uiom_get_pages(unsigned long addr, size_t size, int writable, int i; int flags; dma_addr_t pa; + unsigned int gup_flags; if (!can_do_mlock()) return -EPERM; @@ -135,6 +136,8 @@ static int usnic_uiom_get_pages(unsigned long addr, size_t size, int writable, flags = IOMMU_READ | IOMMU_CACHE; flags |= (writable) ? IOMMU_WRITE : 0; + gup_flags = FOLL_WRITE; + gup_flags |= (writable) ? 0 : FOLL_FORCE; cur_base = addr & PAGE_MASK; ret = 0; @@ -142,7 +145,7 @@ static int usnic_uiom_get_pages(unsigned long addr, size_t size, int writable, ret = get_user_pages(cur_base, min_t(unsigned long, npages, PAGE_SIZE / sizeof(struct page *)), - 1, !writable, page_list, NULL); + gup_flags, page_list, NULL); if (ret < 0) goto out; diff --git a/drivers/media/v4l2-core/videobuf-dma-sg.c b/drivers/media/v4l2-core/videobuf-dma-sg.c index f300f060b3f3..1db0af6c7f94 100644 --- a/drivers/media/v4l2-core/videobuf-dma-sg.c +++ b/drivers/media/v4l2-core/videobuf-dma-sg.c @@ -156,6 +156,7 @@ static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma, { unsigned long first, last; int err, rw = 0; + unsigned int flags = FOLL_FORCE; dma->direction = direction; switch (dma->direction) { @@ -178,12 +179,14 @@ static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma, if (NULL == dma->pages) return -ENOMEM; + if (rw == READ) + flags |= FOLL_WRITE; + dprintk(1, "init user [0x%lx+0x%lx => %d pages]\n", data, size, dma->nr_pages); err = get_user_pages(data & PAGE_MASK, dma->nr_pages, - rw == READ, 1, /* force */ - dma->pages, NULL); + flags, dma->pages, NULL); if (err != dma->nr_pages) { dma->nr_pages = (err >= 0) ? err : 0; diff --git a/drivers/misc/mic/scif/scif_rma.c b/drivers/misc/mic/scif/scif_rma.c index e0203b1a20fd..f806a4471eb9 100644 --- a/drivers/misc/mic/scif/scif_rma.c +++ b/drivers/misc/mic/scif/scif_rma.c @@ -1396,8 +1396,7 @@ retry: pinned_pages->nr_pages = get_user_pages( (u64)addr, nr_pages, - !!(prot & SCIF_PROT_WRITE), - 0, + (prot & SCIF_PROT_WRITE) ? FOLL_WRITE : 0, pinned_pages->pages, NULL); up_write(&mm->mmap_sem); diff --git a/drivers/misc/sgi-gru/grufault.c b/drivers/misc/sgi-gru/grufault.c index a2d97b9b17e3..6fb773dbcd0c 100644 --- a/drivers/misc/sgi-gru/grufault.c +++ b/drivers/misc/sgi-gru/grufault.c @@ -198,7 +198,7 @@ static int non_atomic_pte_lookup(struct vm_area_struct *vma, #else *pageshift = PAGE_SHIFT; #endif - if (get_user_pages(vaddr, 1, write, 0, &page, NULL) <= 0) + if (get_user_pages(vaddr, 1, write ? FOLL_WRITE : 0, &page, NULL) <= 0) return -EFAULT; *paddr = page_to_phys(page); put_page(page); diff --git a/drivers/platform/goldfish/goldfish_pipe.c b/drivers/platform/goldfish/goldfish_pipe.c index 07462d79d040..1aba2c74160e 100644 --- a/drivers/platform/goldfish/goldfish_pipe.c +++ b/drivers/platform/goldfish/goldfish_pipe.c @@ -309,7 +309,8 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer, * much memory to the process. */ down_read(¤t->mm->mmap_sem); - ret = get_user_pages(address, 1, !is_write, 0, &page, NULL); + ret = get_user_pages(address, 1, is_write ? 0 : FOLL_WRITE, + &page, NULL); up_read(¤t->mm->mmap_sem); if (ret < 0) break; diff --git a/drivers/rapidio/devices/rio_mport_cdev.c b/drivers/rapidio/devices/rio_mport_cdev.c index 436dfe871d32..9013a585507e 100644 --- a/drivers/rapidio/devices/rio_mport_cdev.c +++ b/drivers/rapidio/devices/rio_mport_cdev.c @@ -892,7 +892,8 @@ rio_dma_transfer(struct file *filp, u32 transfer_mode, down_read(¤t->mm->mmap_sem); pinned = get_user_pages( (unsigned long)xfer->loc_addr & PAGE_MASK, - nr_pages, dir == DMA_FROM_DEVICE, 0, + nr_pages, + dir == DMA_FROM_DEVICE ? FOLL_WRITE : 0, page_list, NULL); up_read(¤t->mm->mmap_sem); diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c index c29040fdf9a7..1091b9f1dd07 100644 --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c @@ -423,8 +423,7 @@ create_pagelist(char __user *buf, size_t count, unsigned short type, actual_pages = get_user_pages(task, task->mm, (unsigned long)buf & ~(PAGE_SIZE - 1), num_pages, - (type == PAGELIST_READ) /*Write */ , - 0 /*Force */ , + (type == PAGELIST_READ) ? FOLL_WRITE : 0, pages, NULL /*vmas */); up_read(&task->mm->mmap_sem); diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c index e11c0e07471b..7b6cd4d80621 100644 --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c @@ -1477,8 +1477,7 @@ dump_phys_mem(void *virt_addr, uint32_t num_bytes) current->mm, /* mm */ (unsigned long)virt_addr, /* start */ num_pages, /* len */ - 0, /* write */ - 0, /* force */ + 0, /* gup_flags */ pages, /* pages (array of page pointers) */ NULL); /* vmas */ up_read(¤t->mm->mmap_sem); diff --git a/drivers/virt/fsl_hypervisor.c b/drivers/virt/fsl_hypervisor.c index 60bdad3a689b..150ce2abf6c8 100644 --- a/drivers/virt/fsl_hypervisor.c +++ b/drivers/virt/fsl_hypervisor.c @@ -245,8 +245,8 @@ static long ioctl_memcpy(struct fsl_hv_ioctl_memcpy __user *p) /* Get the physical addresses of the source buffer */ down_read(¤t->mm->mmap_sem); num_pinned = get_user_pages(param.local_vaddr - lb_offset, - num_pages, (param.source == -1) ? READ : WRITE, - 0, pages, NULL); + num_pages, (param.source == -1) ? 0 : FOLL_WRITE, + pages, NULL); up_read(¤t->mm->mmap_sem); if (num_pinned != num_pages) { diff --git a/include/linux/mm.h b/include/linux/mm.h index 91cc923ce985..30bb5d9631bb 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1279,7 +1279,7 @@ long get_user_pages_remote(struct task_struct *tsk, struct mm_struct *mm, int write, int force, struct page **pages, struct vm_area_struct **vmas); long get_user_pages(unsigned long start, unsigned long nr_pages, - int write, int force, struct page **pages, + unsigned int gup_flags, struct page **pages, struct vm_area_struct **vmas); long get_user_pages_locked(unsigned long start, unsigned long nr_pages, unsigned int gup_flags, struct page **pages, int *locked); diff --git a/mm/gup.c b/mm/gup.c index 3cfb55ef0cf4..bbc2e76cdd77 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -987,18 +987,12 @@ EXPORT_SYMBOL(get_user_pages_remote); * obviously don't pass FOLL_REMOTE in here. */ long get_user_pages(unsigned long start, unsigned long nr_pages, - int write, int force, struct page **pages, + unsigned int gup_flags, struct page **pages, struct vm_area_struct **vmas) { - unsigned int flags = FOLL_TOUCH; - - if (write) - flags |= FOLL_WRITE; - if (force) - flags |= FOLL_FORCE; - return __get_user_pages_locked(current, current->mm, start, nr_pages, - pages, vmas, NULL, false, flags); + pages, vmas, NULL, false, + gup_flags | FOLL_TOUCH); } EXPORT_SYMBOL(get_user_pages); diff --git a/mm/mempolicy.c b/mm/mempolicy.c index ad1c96ac313c..0b859af06b87 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -850,7 +850,7 @@ static int lookup_node(unsigned long addr) struct page *p; int err; - err = get_user_pages(addr & PAGE_MASK, 1, 0, 0, &p, NULL); + err = get_user_pages(addr & PAGE_MASK, 1, 0, &p, NULL); if (err >= 0) { err = page_to_nid(p); put_page(p); diff --git a/mm/nommu.c b/mm/nommu.c index 842cfdd1a31e..70cb844dfd95 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -160,18 +160,11 @@ finish_or_fault: * - don't permit access to VMAs that don't support it, such as I/O mappings */ long get_user_pages(unsigned long start, unsigned long nr_pages, - int write, int force, struct page **pages, + unsigned int gup_flags, struct page **pages, struct vm_area_struct **vmas) { - int flags = 0; - - if (write) - flags |= FOLL_WRITE; - if (force) - flags |= FOLL_FORCE; - - return __get_user_pages(current, current->mm, start, nr_pages, flags, - pages, vmas, NULL); + return __get_user_pages(current, current->mm, start, nr_pages, + gup_flags, pages, vmas, NULL); } EXPORT_SYMBOL(get_user_pages); @@ -179,10 +172,7 @@ long get_user_pages_locked(unsigned long start, unsigned long nr_pages, unsigned int gup_flags, struct page **pages, int *locked) { - int write = gup_flags & FOLL_WRITE; - int force = gup_flags & FOLL_FORCE; - - return get_user_pages(start, nr_pages, write, force, pages, NULL); + return get_user_pages(start, nr_pages, gup_flags, pages, NULL); } EXPORT_SYMBOL(get_user_pages_locked); -- cgit v1.2.3 From f307ab6dcea03f9d8e4d70508fd7d1ca57cfa7f9 Mon Sep 17 00:00:00 2001 From: Lorenzo Stoakes Date: Thu, 13 Oct 2016 01:20:20 +0100 Subject: mm: replace access_process_vm() write parameter with gup_flags This removes the 'write' argument from access_process_vm() and replaces it with 'gup_flags' as use of this function previously silently implied FOLL_FORCE, whereas after this patch callers explicitly pass this flag. We make this explicit as use of FOLL_FORCE can result in surprising behaviour (and hence bugs) within the mm subsystem. Signed-off-by: Lorenzo Stoakes Acked-by: Jesper Nilsson Acked-by: Michal Hocko Acked-by: Michael Ellerman Signed-off-by: Linus Torvalds --- arch/alpha/kernel/ptrace.c | 9 ++++++--- arch/blackfin/kernel/ptrace.c | 5 +++-- arch/cris/arch-v32/kernel/ptrace.c | 4 ++-- arch/ia64/kernel/ptrace.c | 14 +++++++++----- arch/m32r/kernel/ptrace.c | 15 ++++++++++----- arch/mips/kernel/ptrace32.c | 5 +++-- arch/powerpc/kernel/ptrace32.c | 5 +++-- arch/score/kernel/ptrace.c | 10 ++++++---- arch/sparc/kernel/ptrace_64.c | 24 ++++++++++++++++-------- arch/x86/kernel/step.c | 3 ++- arch/x86/um/ptrace_32.c | 3 ++- arch/x86/um/ptrace_64.c | 3 ++- include/linux/mm.h | 3 ++- kernel/ptrace.c | 16 ++++++++++------ mm/memory.c | 8 ++------ mm/nommu.c | 6 +++--- mm/util.c | 5 +++-- 17 files changed, 84 insertions(+), 54 deletions(-) (limited to 'arch') diff --git a/arch/alpha/kernel/ptrace.c b/arch/alpha/kernel/ptrace.c index d9ee81769899..940dfb406591 100644 --- a/arch/alpha/kernel/ptrace.c +++ b/arch/alpha/kernel/ptrace.c @@ -157,14 +157,16 @@ put_reg(struct task_struct *task, unsigned long regno, unsigned long data) static inline int read_int(struct task_struct *task, unsigned long addr, int * data) { - int copied = access_process_vm(task, addr, data, sizeof(int), 0); + int copied = access_process_vm(task, addr, data, sizeof(int), + FOLL_FORCE); return (copied == sizeof(int)) ? 0 : -EIO; } static inline int write_int(struct task_struct *task, unsigned long addr, int data) { - int copied = access_process_vm(task, addr, &data, sizeof(int), 1); + int copied = access_process_vm(task, addr, &data, sizeof(int), + FOLL_FORCE | FOLL_WRITE); return (copied == sizeof(int)) ? 0 : -EIO; } @@ -281,7 +283,8 @@ long arch_ptrace(struct task_struct *child, long request, /* When I and D space are separate, these will need to be fixed. */ case PTRACE_PEEKTEXT: /* read word at location addr. */ case PTRACE_PEEKDATA: - copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0); + copied = access_process_vm(child, addr, &tmp, sizeof(tmp), + FOLL_FORCE); ret = -EIO; if (copied != sizeof(tmp)) break; diff --git a/arch/blackfin/kernel/ptrace.c b/arch/blackfin/kernel/ptrace.c index 8b8fe671b1a6..8d79286ee4e8 100644 --- a/arch/blackfin/kernel/ptrace.c +++ b/arch/blackfin/kernel/ptrace.c @@ -271,7 +271,7 @@ long arch_ptrace(struct task_struct *child, long request, case BFIN_MEM_ACCESS_CORE: case BFIN_MEM_ACCESS_CORE_ONLY: copied = access_process_vm(child, addr, &tmp, - to_copy, 0); + to_copy, FOLL_FORCE); if (copied) break; @@ -324,7 +324,8 @@ long arch_ptrace(struct task_struct *child, long request, case BFIN_MEM_ACCESS_CORE: case BFIN_MEM_ACCESS_CORE_ONLY: copied = access_process_vm(child, addr, &data, - to_copy, 1); + to_copy, + FOLL_FORCE | FOLL_WRITE); break; case BFIN_MEM_ACCESS_DMA: if (safe_dma_memcpy(paddr, &data, to_copy)) diff --git a/arch/cris/arch-v32/kernel/ptrace.c b/arch/cris/arch-v32/kernel/ptrace.c index f085229cf870..f0df654ac6fc 100644 --- a/arch/cris/arch-v32/kernel/ptrace.c +++ b/arch/cris/arch-v32/kernel/ptrace.c @@ -147,7 +147,7 @@ long arch_ptrace(struct task_struct *child, long request, /* The trampoline page is globally mapped, no page table to traverse.*/ tmp = *(unsigned long*)addr; } else { - copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0); + copied = access_process_vm(child, addr, &tmp, sizeof(tmp), FOLL_FORCE); if (copied != sizeof(tmp)) break; @@ -279,7 +279,7 @@ static int insn_size(struct task_struct *child, unsigned long pc) int opsize = 0; /* Read the opcode at pc (do what PTRACE_PEEKTEXT would do). */ - copied = access_process_vm(child, pc, &opcode, sizeof(opcode), 0); + copied = access_process_vm(child, pc, &opcode, sizeof(opcode), FOLL_FORCE); if (copied != sizeof(opcode)) return 0; diff --git a/arch/ia64/kernel/ptrace.c b/arch/ia64/kernel/ptrace.c index 6f54d511cc50..31aa8c0f68e1 100644 --- a/arch/ia64/kernel/ptrace.c +++ b/arch/ia64/kernel/ptrace.c @@ -453,7 +453,7 @@ ia64_peek (struct task_struct *child, struct switch_stack *child_stack, return 0; } } - copied = access_process_vm(child, addr, &ret, sizeof(ret), 0); + copied = access_process_vm(child, addr, &ret, sizeof(ret), FOLL_FORCE); if (copied != sizeof(ret)) return -EIO; *val = ret; @@ -489,7 +489,8 @@ ia64_poke (struct task_struct *child, struct switch_stack *child_stack, *ia64_rse_skip_regs(krbs, regnum) = val; } } - } else if (access_process_vm(child, addr, &val, sizeof(val), 1) + } else if (access_process_vm(child, addr, &val, sizeof(val), + FOLL_FORCE | FOLL_WRITE) != sizeof(val)) return -EIO; return 0; @@ -543,7 +544,8 @@ ia64_sync_user_rbs (struct task_struct *child, struct switch_stack *sw, ret = ia64_peek(child, sw, user_rbs_end, addr, &val); if (ret < 0) return ret; - if (access_process_vm(child, addr, &val, sizeof(val), 1) + if (access_process_vm(child, addr, &val, sizeof(val), + FOLL_FORCE | FOLL_WRITE) != sizeof(val)) return -EIO; } @@ -559,7 +561,8 @@ ia64_sync_kernel_rbs (struct task_struct *child, struct switch_stack *sw, /* now copy word for word from user rbs to kernel rbs: */ for (addr = user_rbs_start; addr < user_rbs_end; addr += 8) { - if (access_process_vm(child, addr, &val, sizeof(val), 0) + if (access_process_vm(child, addr, &val, sizeof(val), + FOLL_FORCE) != sizeof(val)) return -EIO; @@ -1156,7 +1159,8 @@ arch_ptrace (struct task_struct *child, long request, case PTRACE_PEEKTEXT: case PTRACE_PEEKDATA: /* read word at location addr */ - if (access_process_vm(child, addr, &data, sizeof(data), 0) + if (access_process_vm(child, addr, &data, sizeof(data), + FOLL_FORCE) != sizeof(data)) return -EIO; /* ensure return value is not mistaken for error code */ diff --git a/arch/m32r/kernel/ptrace.c b/arch/m32r/kernel/ptrace.c index 51f5e9aa4901..c145605a981f 100644 --- a/arch/m32r/kernel/ptrace.c +++ b/arch/m32r/kernel/ptrace.c @@ -493,7 +493,8 @@ unregister_all_debug_traps(struct task_struct *child) int i; for (i = 0; i < p->nr_trap; i++) - access_process_vm(child, p->addr[i], &p->insn[i], sizeof(p->insn[i]), 1); + access_process_vm(child, p->addr[i], &p->insn[i], sizeof(p->insn[i]), + FOLL_FORCE | FOLL_WRITE); p->nr_trap = 0; } @@ -537,7 +538,8 @@ embed_debug_trap(struct task_struct *child, unsigned long next_pc) unsigned long next_insn, code; unsigned long addr = next_pc & ~3; - if (access_process_vm(child, addr, &next_insn, sizeof(next_insn), 0) + if (access_process_vm(child, addr, &next_insn, sizeof(next_insn), + FOLL_FORCE) != sizeof(next_insn)) { return -1; /* error */ } @@ -546,7 +548,8 @@ embed_debug_trap(struct task_struct *child, unsigned long next_pc) if (register_debug_trap(child, next_pc, next_insn, &code)) { return -1; /* error */ } - if (access_process_vm(child, addr, &code, sizeof(code), 1) + if (access_process_vm(child, addr, &code, sizeof(code), + FOLL_FORCE | FOLL_WRITE) != sizeof(code)) { return -1; /* error */ } @@ -562,7 +565,8 @@ withdraw_debug_trap(struct pt_regs *regs) addr = (regs->bpc - 2) & ~3; regs->bpc -= 2; if (unregister_debug_trap(current, addr, &code)) { - access_process_vm(current, addr, &code, sizeof(code), 1); + access_process_vm(current, addr, &code, sizeof(code), + FOLL_FORCE | FOLL_WRITE); invalidate_cache(); } } @@ -589,7 +593,8 @@ void user_enable_single_step(struct task_struct *child) /* Compute next pc. */ pc = get_stack_long(child, PT_BPC); - if (access_process_vm(child, pc&~3, &insn, sizeof(insn), 0) + if (access_process_vm(child, pc&~3, &insn, sizeof(insn), + FOLL_FORCE) != sizeof(insn)) return; diff --git a/arch/mips/kernel/ptrace32.c b/arch/mips/kernel/ptrace32.c index 283b5a1967d1..7e71a4e0281b 100644 --- a/arch/mips/kernel/ptrace32.c +++ b/arch/mips/kernel/ptrace32.c @@ -70,7 +70,7 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request, break; copied = access_process_vm(child, (u64)addrOthers, &tmp, - sizeof(tmp), 0); + sizeof(tmp), FOLL_FORCE); if (copied != sizeof(tmp)) break; ret = put_user(tmp, (u32 __user *) (unsigned long) data); @@ -179,7 +179,8 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request, break; ret = 0; if (access_process_vm(child, (u64)addrOthers, &data, - sizeof(data), 1) == sizeof(data)) + sizeof(data), + FOLL_FORCE | FOLL_WRITE) == sizeof(data)) break; ret = -EIO; break; diff --git a/arch/powerpc/kernel/ptrace32.c b/arch/powerpc/kernel/ptrace32.c index f52b7db327c8..010b7b310237 100644 --- a/arch/powerpc/kernel/ptrace32.c +++ b/arch/powerpc/kernel/ptrace32.c @@ -74,7 +74,7 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request, break; copied = access_process_vm(child, (u64)addrOthers, &tmp, - sizeof(tmp), 0); + sizeof(tmp), FOLL_FORCE); if (copied != sizeof(tmp)) break; ret = put_user(tmp, (u32 __user *)data); @@ -179,7 +179,8 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request, break; ret = 0; if (access_process_vm(child, (u64)addrOthers, &tmp, - sizeof(tmp), 1) == sizeof(tmp)) + sizeof(tmp), + FOLL_FORCE | FOLL_WRITE) == sizeof(tmp)) break; ret = -EIO; break; diff --git a/arch/score/kernel/ptrace.c b/arch/score/kernel/ptrace.c index 55836188b217..4f7314d5f334 100644 --- a/arch/score/kernel/ptrace.c +++ b/arch/score/kernel/ptrace.c @@ -131,7 +131,7 @@ read_tsk_long(struct task_struct *child, { int copied; - copied = access_process_vm(child, addr, res, sizeof(*res), 0); + copied = access_process_vm(child, addr, res, sizeof(*res), FOLL_FORCE); return copied != sizeof(*res) ? -EIO : 0; } @@ -142,7 +142,7 @@ read_tsk_short(struct task_struct *child, { int copied; - copied = access_process_vm(child, addr, res, sizeof(*res), 0); + copied = access_process_vm(child, addr, res, sizeof(*res), FOLL_FORCE); return copied != sizeof(*res) ? -EIO : 0; } @@ -153,7 +153,8 @@ write_tsk_short(struct task_struct *child, { int copied; - copied = access_process_vm(child, addr, &val, sizeof(val), 1); + copied = access_process_vm(child, addr, &val, sizeof(val), + FOLL_FORCE | FOLL_WRITE); return copied != sizeof(val) ? -EIO : 0; } @@ -164,7 +165,8 @@ write_tsk_long(struct task_struct *child, { int copied; - copied = access_process_vm(child, addr, &val, sizeof(val), 1); + copied = access_process_vm(child, addr, &val, sizeof(val), + FOLL_FORCE | FOLL_WRITE); return copied != sizeof(val) ? -EIO : 0; } diff --git a/arch/sparc/kernel/ptrace_64.c b/arch/sparc/kernel/ptrace_64.c index 9ddc4928a089..ac082dd8c67d 100644 --- a/arch/sparc/kernel/ptrace_64.c +++ b/arch/sparc/kernel/ptrace_64.c @@ -127,7 +127,8 @@ static int get_from_target(struct task_struct *target, unsigned long uaddr, if (copy_from_user(kbuf, (void __user *) uaddr, len)) return -EFAULT; } else { - int len2 = access_process_vm(target, uaddr, kbuf, len, 0); + int len2 = access_process_vm(target, uaddr, kbuf, len, + FOLL_FORCE); if (len2 != len) return -EFAULT; } @@ -141,7 +142,8 @@ static int set_to_target(struct task_struct *target, unsigned long uaddr, if (copy_to_user((void __user *) uaddr, kbuf, len)) return -EFAULT; } else { - int len2 = access_process_vm(target, uaddr, kbuf, len, 1); + int len2 = access_process_vm(target, uaddr, kbuf, len, + FOLL_FORCE | FOLL_WRITE); if (len2 != len) return -EFAULT; } @@ -505,7 +507,8 @@ static int genregs32_get(struct task_struct *target, if (access_process_vm(target, (unsigned long) ®_window[pos], - k, sizeof(*k), 0) + k, sizeof(*k), + FOLL_FORCE) != sizeof(*k)) return -EFAULT; k++; @@ -531,12 +534,14 @@ static int genregs32_get(struct task_struct *target, if (access_process_vm(target, (unsigned long) ®_window[pos], - ®, sizeof(reg), 0) + ®, sizeof(reg), + FOLL_FORCE) != sizeof(reg)) return -EFAULT; if (access_process_vm(target, (unsigned long) u, - ®, sizeof(reg), 1) + ®, sizeof(reg), + FOLL_FORCE | FOLL_WRITE) != sizeof(reg)) return -EFAULT; pos++; @@ -615,7 +620,8 @@ static int genregs32_set(struct task_struct *target, (unsigned long) ®_window[pos], (void *) k, - sizeof(*k), 1) + sizeof(*k), + FOLL_FORCE | FOLL_WRITE) != sizeof(*k)) return -EFAULT; k++; @@ -642,13 +648,15 @@ static int genregs32_set(struct task_struct *target, if (access_process_vm(target, (unsigned long) u, - ®, sizeof(reg), 0) + ®, sizeof(reg), + FOLL_FORCE) != sizeof(reg)) return -EFAULT; if (access_process_vm(target, (unsigned long) ®_window[pos], - ®, sizeof(reg), 1) + ®, sizeof(reg), + FOLL_FORCE | FOLL_WRITE) != sizeof(reg)) return -EFAULT; pos++; diff --git a/arch/x86/kernel/step.c b/arch/x86/kernel/step.c index c9a073866ca7..a23ce84a3f6c 100644 --- a/arch/x86/kernel/step.c +++ b/arch/x86/kernel/step.c @@ -57,7 +57,8 @@ static int is_setting_trap_flag(struct task_struct *child, struct pt_regs *regs) unsigned char opcode[15]; unsigned long addr = convert_ip_to_linear(child, regs); - copied = access_process_vm(child, addr, opcode, sizeof(opcode), 0); + copied = access_process_vm(child, addr, opcode, sizeof(opcode), + FOLL_FORCE); for (i = 0; i < copied; i++) { switch (opcode[i]) { /* popf and iret */ diff --git a/arch/x86/um/ptrace_32.c b/arch/x86/um/ptrace_32.c index 5766ead6fdb9..60a5a5a85505 100644 --- a/arch/x86/um/ptrace_32.c +++ b/arch/x86/um/ptrace_32.c @@ -36,7 +36,8 @@ int is_syscall(unsigned long addr) * slow, but that doesn't matter, since it will be called only * in case of singlestepping, if copy_from_user failed. */ - n = access_process_vm(current, addr, &instr, sizeof(instr), 0); + n = access_process_vm(current, addr, &instr, sizeof(instr), + FOLL_FORCE); if (n != sizeof(instr)) { printk(KERN_ERR "is_syscall : failed to read " "instruction from 0x%lx\n", addr); diff --git a/arch/x86/um/ptrace_64.c b/arch/x86/um/ptrace_64.c index 0b5c184dd5b3..e30202b1716e 100644 --- a/arch/x86/um/ptrace_64.c +++ b/arch/x86/um/ptrace_64.c @@ -212,7 +212,8 @@ int is_syscall(unsigned long addr) * slow, but that doesn't matter, since it will be called only * in case of singlestepping, if copy_from_user failed. */ - n = access_process_vm(current, addr, &instr, sizeof(instr), 0); + n = access_process_vm(current, addr, &instr, sizeof(instr), + FOLL_FORCE); if (n != sizeof(instr)) { printk("is_syscall : failed to read instruction from " "0x%lx\n", addr); diff --git a/include/linux/mm.h b/include/linux/mm.h index f31bf9058587..ffbd72979ee7 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1266,7 +1266,8 @@ static inline int fixup_user_fault(struct task_struct *tsk, } #endif -extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write); +extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, + unsigned int gup_flags); extern int access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, int len, unsigned int gup_flags); diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 2a99027312a6..e6474f7272ec 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -537,7 +537,7 @@ int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst int this_len, retval; this_len = (len > sizeof(buf)) ? sizeof(buf) : len; - retval = access_process_vm(tsk, src, buf, this_len, 0); + retval = access_process_vm(tsk, src, buf, this_len, FOLL_FORCE); if (!retval) { if (copied) break; @@ -564,7 +564,8 @@ int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long ds this_len = (len > sizeof(buf)) ? sizeof(buf) : len; if (copy_from_user(buf, src, this_len)) return -EFAULT; - retval = access_process_vm(tsk, dst, buf, this_len, 1); + retval = access_process_vm(tsk, dst, buf, this_len, + FOLL_FORCE | FOLL_WRITE); if (!retval) { if (copied) break; @@ -1127,7 +1128,7 @@ int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr, unsigned long tmp; int copied; - copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0); + copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), FOLL_FORCE); if (copied != sizeof(tmp)) return -EIO; return put_user(tmp, (unsigned long __user *)data); @@ -1138,7 +1139,8 @@ int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr, { int copied; - copied = access_process_vm(tsk, addr, &data, sizeof(data), 1); + copied = access_process_vm(tsk, addr, &data, sizeof(data), + FOLL_FORCE | FOLL_WRITE); return (copied == sizeof(data)) ? 0 : -EIO; } @@ -1155,7 +1157,8 @@ int compat_ptrace_request(struct task_struct *child, compat_long_t request, switch (request) { case PTRACE_PEEKTEXT: case PTRACE_PEEKDATA: - ret = access_process_vm(child, addr, &word, sizeof(word), 0); + ret = access_process_vm(child, addr, &word, sizeof(word), + FOLL_FORCE); if (ret != sizeof(word)) ret = -EIO; else @@ -1164,7 +1167,8 @@ int compat_ptrace_request(struct task_struct *child, compat_long_t request, case PTRACE_POKETEXT: case PTRACE_POKEDATA: - ret = access_process_vm(child, addr, &data, sizeof(data), 1); + ret = access_process_vm(child, addr, &data, sizeof(data), + FOLL_FORCE | FOLL_WRITE); ret = (ret != sizeof(data) ? -EIO : 0); break; diff --git a/mm/memory.c b/mm/memory.c index bac2d994850e..e18c57bdc75c 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3951,20 +3951,16 @@ int access_remote_vm(struct mm_struct *mm, unsigned long addr, * Do not walk the page table directly, use get_user_pages */ int access_process_vm(struct task_struct *tsk, unsigned long addr, - void *buf, int len, int write) + void *buf, int len, unsigned int gup_flags) { struct mm_struct *mm; int ret; - unsigned int flags = FOLL_FORCE; mm = get_task_mm(tsk); if (!mm) return 0; - if (write) - flags |= FOLL_WRITE; - - ret = __access_remote_vm(tsk, mm, addr, buf, len, flags); + ret = __access_remote_vm(tsk, mm, addr, buf, len, gup_flags); mmput(mm); diff --git a/mm/nommu.c b/mm/nommu.c index 93d5bb53fc63..db5fd1795298 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -1861,7 +1861,8 @@ int access_remote_vm(struct mm_struct *mm, unsigned long addr, * Access another process' address space. * - source/target buffer must be kernel space */ -int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write) +int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, + unsigned int gup_flags) { struct mm_struct *mm; @@ -1872,8 +1873,7 @@ int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, in if (!mm) return 0; - len = __access_remote_vm(tsk, mm, addr, buf, len, - write ? FOLL_WRITE : 0); + len = __access_remote_vm(tsk, mm, addr, buf, len, gup_flags); mmput(mm); return len; diff --git a/mm/util.c b/mm/util.c index 4c685bde5ebc..952cbe7ad7b7 100644 --- a/mm/util.c +++ b/mm/util.c @@ -624,7 +624,7 @@ int get_cmdline(struct task_struct *task, char *buffer, int buflen) if (len > buflen) len = buflen; - res = access_process_vm(task, arg_start, buffer, len, 0); + res = access_process_vm(task, arg_start, buffer, len, FOLL_FORCE); /* * If the nul at the end of args has been overwritten, then @@ -639,7 +639,8 @@ int get_cmdline(struct task_struct *task, char *buffer, int buflen) if (len > buflen - res) len = buflen - res; res += access_process_vm(task, env_start, - buffer+res, len, 0); + buffer+res, len, + FOLL_FORCE); res = strnlen(buffer, res); } } -- cgit v1.2.3