From dc50eab76b709d68175a358d6e23a5a3890764d3 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 18 May 2024 19:39:57 +0200 Subject: Merging upstream version 6.7.7. Signed-off-by: Daniel Baumann --- fs/userfaultfd.c | 98 ++++++++++++++++++++++++-------------------------------- 1 file changed, 41 insertions(+), 57 deletions(-) (limited to 'fs/userfaultfd.c') diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 56eaae9dac..e8af40b055 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -49,7 +49,7 @@ static struct ctl_table vm_userfaultfd_table[] = { }; #endif -static struct kmem_cache *userfaultfd_ctx_cachep __read_mostly; +static struct kmem_cache *userfaultfd_ctx_cachep __ro_after_init; /* * Start with fault_pending_wqh and fault_wqh so they're more likely @@ -123,6 +123,11 @@ static bool userfaultfd_is_initialized(struct userfaultfd_ctx *ctx) return ctx->features & UFFD_FEATURE_INITIALIZED; } +static bool userfaultfd_wp_async_ctx(struct userfaultfd_ctx *ctx) +{ + return ctx && (ctx->features & UFFD_FEATURE_WP_ASYNC); +} + /* * Whether WP_UNPOPULATED is enabled on the uffd context. It is only * meaningful when userfaultfd_wp()==true on the vma and when it's @@ -922,20 +927,15 @@ static int userfaultfd_release(struct inode *inode, struct file *file) continue; } new_flags = vma->vm_flags & ~__VM_UFFD_FLAGS; - prev = vma_merge(&vmi, mm, prev, vma->vm_start, vma->vm_end, - new_flags, vma->anon_vma, - vma->vm_file, vma->vm_pgoff, - vma_policy(vma), - NULL_VM_UFFD_CTX, anon_vma_name(vma)); - if (prev) { - vma = prev; - } else { - prev = vma; - } + vma = vma_modify_flags_uffd(&vmi, prev, vma, vma->vm_start, + vma->vm_end, new_flags, + NULL_VM_UFFD_CTX); vma_start_write(vma); userfaultfd_set_vm_flags(vma, new_flags); vma->vm_userfaultfd_ctx = NULL_VM_UFFD_CTX; + + prev = vma; } mmap_write_unlock(mm); mmput(mm); @@ -1325,7 +1325,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, bool basic_ioctls; unsigned long start, end, vma_end; struct vma_iterator vmi; - pgoff_t pgoff; + bool wp_async = userfaultfd_wp_async_ctx(ctx); user_uffdio_register = (struct uffdio_register __user *) arg; @@ -1399,7 +1399,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, /* check not compatible vmas */ ret = -EINVAL; - if (!vma_can_userfault(cur, vm_flags)) + if (!vma_can_userfault(cur, vm_flags, wp_async)) goto out_unlock; /* @@ -1460,7 +1460,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, for_each_vma_range(vmi, vma, end) { cond_resched(); - BUG_ON(!vma_can_userfault(vma, vm_flags)); + BUG_ON(!vma_can_userfault(vma, vm_flags, wp_async)); BUG_ON(vma->vm_userfaultfd_ctx.ctx && vma->vm_userfaultfd_ctx.ctx != ctx); WARN_ON(!(vma->vm_flags & VM_MAYWRITE)); @@ -1478,28 +1478,14 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, vma_end = min(end, vma->vm_end); new_flags = (vma->vm_flags & ~__VM_UFFD_FLAGS) | vm_flags; - pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT); - prev = vma_merge(&vmi, mm, prev, start, vma_end, new_flags, - vma->anon_vma, vma->vm_file, pgoff, - vma_policy(vma), - ((struct vm_userfaultfd_ctx){ ctx }), - anon_vma_name(vma)); - if (prev) { - /* vma_merge() invalidated the mas */ - vma = prev; - goto next; - } - if (vma->vm_start < start) { - ret = split_vma(&vmi, vma, start, 1); - if (ret) - break; - } - if (vma->vm_end > end) { - ret = split_vma(&vmi, vma, end, 0); - if (ret) - break; + vma = vma_modify_flags_uffd(&vmi, prev, vma, start, vma_end, + new_flags, + (struct vm_userfaultfd_ctx){ctx}); + if (IS_ERR(vma)) { + ret = PTR_ERR(vma); + break; } - next: + /* * In the vma_merge() successful mprotect-like case 8: * the next vma was merged into the current one and @@ -1561,7 +1547,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, unsigned long start, end, vma_end; const void __user *buf = (void __user *)arg; struct vma_iterator vmi; - pgoff_t pgoff; + bool wp_async = userfaultfd_wp_async_ctx(ctx); ret = -EFAULT; if (copy_from_user(&uffdio_unregister, buf, sizeof(uffdio_unregister))) @@ -1615,7 +1601,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, * provides for more strict behavior to notice * unregistration errors. */ - if (!vma_can_userfault(cur, cur->vm_flags)) + if (!vma_can_userfault(cur, cur->vm_flags, wp_async)) goto out_unlock; found = true; @@ -1631,7 +1617,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, for_each_vma_range(vmi, vma, end) { cond_resched(); - BUG_ON(!vma_can_userfault(vma, vma->vm_flags)); + BUG_ON(!vma_can_userfault(vma, vma->vm_flags, wp_async)); /* * Nothing to do: this vma is already registered into this @@ -1664,26 +1650,13 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, uffd_wp_range(vma, start, vma_end - start, false); new_flags = vma->vm_flags & ~__VM_UFFD_FLAGS; - pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT); - prev = vma_merge(&vmi, mm, prev, start, vma_end, new_flags, - vma->anon_vma, vma->vm_file, pgoff, - vma_policy(vma), - NULL_VM_UFFD_CTX, anon_vma_name(vma)); - if (prev) { - vma = prev; - goto next; - } - if (vma->vm_start < start) { - ret = split_vma(&vmi, vma, start, 1); - if (ret) - break; - } - if (vma->vm_end > end) { - ret = split_vma(&vmi, vma, end, 0); - if (ret) - break; + vma = vma_modify_flags_uffd(&vmi, prev, vma, start, vma_end, + new_flags, NULL_VM_UFFD_CTX); + if (IS_ERR(vma)) { + ret = PTR_ERR(vma); + break; } - next: + /* * In the vma_merge() successful mprotect-like case 8: * the next vma was merged into the current one and @@ -2018,6 +1991,11 @@ out: return ret; } +bool userfaultfd_wp_async(struct vm_area_struct *vma) +{ + return userfaultfd_wp_async_ctx(vma->vm_userfaultfd_ctx.ctx); +} + static inline unsigned int uffd_ctx_features(__u64 user_features) { /* @@ -2051,6 +2029,11 @@ static int userfaultfd_api(struct userfaultfd_ctx *ctx, ret = -EPERM; if ((features & UFFD_FEATURE_EVENT_FORK) && !capable(CAP_SYS_PTRACE)) goto err_out; + + /* WP_ASYNC relies on WP_UNPOPULATED, choose it unconditionally */ + if (features & UFFD_FEATURE_WP_ASYNC) + features |= UFFD_FEATURE_WP_UNPOPULATED; + /* report all available features and ioctls to userland */ uffdio_api.features = UFFD_API_FEATURES; #ifndef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR @@ -2063,6 +2046,7 @@ static int userfaultfd_api(struct userfaultfd_ctx *ctx, #ifndef CONFIG_PTE_MARKER_UFFD_WP uffdio_api.features &= ~UFFD_FEATURE_WP_HUGETLBFS_SHMEM; uffdio_api.features &= ~UFFD_FEATURE_WP_UNPOPULATED; + uffdio_api.features &= ~UFFD_FEATURE_WP_ASYNC; #endif uffdio_api.ioctls = UFFD_API_IOCTLS; ret = -EFAULT; -- cgit v1.2.3