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authorDmitry Safonov <dima@arista.com>2020-12-14 19:08:13 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2020-12-15 12:13:41 -0800
commitcd544fd1dc9293c6702fab6effa63dac1cc67e99 (patch)
tree5af943ffbac575fdf9576bc4ef772fa388efd3da
parentad8ee77ea9db1f74fe79c285e3546375efa75608 (diff)
mremap: don't allow MREMAP_DONTUNMAP on special_mappings and aio
As kernel expect to see only one of such mappings, any further operations on the VMA-copy may be unexpected by the kernel. Maybe it's being on the safe side, but there doesn't seem to be any expected use-case for this, so restrict it now. Link: https://lkml.kernel.org/r/20201013013416.390574-4-dima@arista.com Fixes: commit e346b3813067 ("mm/mremap: add MREMAP_DONTUNMAP to mremap()") Signed-off-by: Dmitry Safonov <dima@arista.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Andy Lutomirski <luto@kernel.org> Cc: Brian Geffon <bgeffon@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: John Hubbard <jhubbard@nvidia.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--arch/x86/kernel/cpu/resctrl/pseudo_lock.c2
-rw-r--r--fs/aio.c5
-rw-r--r--include/linux/mm.h2
-rw-r--r--mm/mmap.c6
-rw-r--r--mm/mremap.c2
5 files changed, 12 insertions, 5 deletions
diff --git a/arch/x86/kernel/cpu/resctrl/pseudo_lock.c b/arch/x86/kernel/cpu/resctrl/pseudo_lock.c
index 0daf2f1cf7a8..e916646adc69 100644
--- a/arch/x86/kernel/cpu/resctrl/pseudo_lock.c
+++ b/arch/x86/kernel/cpu/resctrl/pseudo_lock.c
@@ -1458,7 +1458,7 @@ static int pseudo_lock_dev_release(struct inode *inode, struct file *filp)
return 0;
}
-static int pseudo_lock_dev_mremap(struct vm_area_struct *area)
+static int pseudo_lock_dev_mremap(struct vm_area_struct *area, unsigned long flags)
{
/* Not supported */
return -EINVAL;
diff --git a/fs/aio.c b/fs/aio.c
index 6a21d8919409..fd2d68532506 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -324,13 +324,16 @@ static void aio_free_ring(struct kioctx *ctx)
}
}
-static int aio_ring_mremap(struct vm_area_struct *vma)
+static int aio_ring_mremap(struct vm_area_struct *vma, unsigned long flags)
{
struct file *file = vma->vm_file;
struct mm_struct *mm = vma->vm_mm;
struct kioctx_table *table;
int i, res = -EINVAL;
+ if (flags & MREMAP_DONTUNMAP)
+ return -EINVAL;
+
spin_lock(&mm->ioctx_lock);
rcu_read_lock();
table = rcu_dereference(mm->ioctx_table);
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 1d8e84bf718a..dacc889744b1 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -558,7 +558,7 @@ struct vm_operations_struct {
void (*open)(struct vm_area_struct * area);
void (*close)(struct vm_area_struct * area);
int (*split)(struct vm_area_struct * area, unsigned long addr);
- int (*mremap)(struct vm_area_struct * area);
+ int (*mremap)(struct vm_area_struct *area, unsigned long flags);
vm_fault_t (*fault)(struct vm_fault *vmf);
vm_fault_t (*huge_fault)(struct vm_fault *vmf,
enum page_entry_size pe_size);
diff --git a/mm/mmap.c b/mm/mmap.c
index 5c8b4485860d..8950c20239a0 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -3405,10 +3405,14 @@ static const char *special_mapping_name(struct vm_area_struct *vma)
return ((struct vm_special_mapping *)vma->vm_private_data)->name;
}
-static int special_mapping_mremap(struct vm_area_struct *new_vma)
+static int special_mapping_mremap(struct vm_area_struct *new_vma,
+ unsigned long flags)
{
struct vm_special_mapping *sm = new_vma->vm_private_data;
+ if (flags & MREMAP_DONTUNMAP)
+ return -EINVAL;
+
if (WARN_ON_ONCE(current->mm != new_vma->vm_mm))
return -EFAULT;
diff --git a/mm/mremap.c b/mm/mremap.c
index 90ff09c09e84..366b3dea992c 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -534,7 +534,7 @@ static unsigned long move_vma(struct vm_area_struct *vma,
if (moved_len < old_len) {
err = -ENOMEM;
} else if (vma->vm_ops && vma->vm_ops->mremap) {
- err = vma->vm_ops->mremap(new_vma);
+ err = vma->vm_ops->mremap(new_vma, flags);
}
if (unlikely(err)) {