8 files changed, 55 insertions, 21 deletions

diff --git a/mm/internal.h b/mm/internal.h
index f6f3353b0868..bff7fd702331 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -442,9 +442,10 @@ extern u64 hwpoison_filter_flags_value;
 extern u64 hwpoison_filter_memcg;
 extern u32 hwpoison_filter_enable;
 
-extern unsigned long vm_mmap_pgoff(struct file *, unsigned long,
+extern unsigned long  __must_check vm_mmap_pgoff(struct file *, unsigned long,
         unsigned long, unsigned long,
-        unsigned long, unsigned long);
+        unsigned long, unsigned long,
+        bool);
 
 extern void set_pageblock_order(void);
 unsigned long reclaim_clean_pages_from_list(struct zone *zone,
diff --git a/mm/madvise.c b/mm/madvise.c
index 07427d3fcead..93fb63e88b5e 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -707,10 +707,12 @@ SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior)
                 return error;
 
         write = madvise_need_mmap_write(behavior);
-        if (write)
-                down_write(&current->mm->mmap_sem);
-        else
+        if (write) {
+                if (down_write_killable(&current->mm->mmap_sem))
+                        return -EINTR;
+        } else {
                 down_read(&current->mm->mmap_sem);
+        }
 
         /*
          * If the interval [start,end) covers some unmapped address
diff --git a/mm/mlock.c b/mm/mlock.c
index 96f001041928..ef8dc9f395c4 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -617,7 +617,7 @@ static int apply_vma_lock_flags(unsigned long start, size_t len,
         return error;
 }
 
-static int do_mlock(unsigned long start, size_t len, vm_flags_t flags)
+static __must_check int do_mlock(unsigned long start, size_t len, vm_flags_t flags)
 {
         unsigned long locked;
         unsigned long lock_limit;
@@ -635,7 +635,8 @@ static int do_mlock(unsigned long start, size_t len, vm_flags_t flags)
         lock_limit >>= PAGE_SHIFT;
         locked = len >> PAGE_SHIFT;
 
-        down_write(&current->mm->mmap_sem);
+        if (down_write_killable(&current->mm->mmap_sem))
+                return -EINTR;
 
         locked += current->mm->locked_vm;
 
@@ -678,7 +679,8 @@ SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len)
         len = PAGE_ALIGN(len + (offset_in_page(start)));
         start &= PAGE_MASK;
 
-        down_write(&current->mm->mmap_sem);
+        if (down_write_killable(&current->mm->mmap_sem))
+                return -EINTR;
         ret = apply_vma_lock_flags(start, len, 0);
         up_write(&current->mm->mmap_sem);
 
@@ -748,9 +750,10 @@ SYSCALL_DEFINE1(mlockall, int, flags)
         lock_limit = rlimit(RLIMIT_MEMLOCK);
         lock_limit >>= PAGE_SHIFT;
 
-        ret = -ENOMEM;
-        down_write(&current->mm->mmap_sem);
+        if (down_write_killable(&current->mm->mmap_sem))
+                return -EINTR;
 
+        ret = -ENOMEM;
         if (!(flags & MCL_CURRENT) || (current->mm->total_vm <= lock_limit) ||
             capable(CAP_IPC_LOCK))
                 ret = apply_mlockall_flags(flags);
@@ -765,7 +768,8 @@ SYSCALL_DEFINE0(munlockall)
 {
         int ret;
 
-        down_write(&current->mm->mmap_sem);
+        if (down_write_killable(&current->mm->mmap_sem))
+                return -EINTR;
         ret = apply_mlockall_flags(0);
         up_write(&current->mm->mmap_sem);
         return ret;
diff --git a/mm/mmap.c b/mm/mmap.c
index b9274a0c82c9..11e1f2ca72af 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -178,7 +178,8 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
         unsigned long min_brk;
         bool populate;
 
-        down_write(&mm->mmap_sem);
+        if (down_write_killable(&mm->mmap_sem))
+                return -EINTR;
 
 #ifdef CONFIG_COMPAT_BRK
         /*
@@ -1332,7 +1333,7 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
 
         flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
 
-        retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
+        retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff, true);
 out_fput:
         if (file)
                 fput(file);
@@ -2493,6 +2494,10 @@ int vm_munmap(unsigned long start, size_t len)
         int ret;
         struct mm_struct *mm = current->mm;
 
+        /*
+         * XXX convert to down_write_killable as soon as all users are able
+         * to handle the error.
+         */
         down_write(&mm->mmap_sem);
         ret = do_munmap(mm, start, len);
         up_write(&mm->mmap_sem);
@@ -2502,8 +2507,15 @@ EXPORT_SYMBOL(vm_munmap);
 
 SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
 {
+        int ret;
+        struct mm_struct *mm = current->mm;
+
         profile_munmap(addr);
-        return vm_munmap(addr, len);
+        if (down_write_killable(&mm->mmap_sem))
+                return -EINTR;
+        ret = do_munmap(mm, addr, len);
+        up_write(&mm->mmap_sem);
+        return ret;
 }
 
 
@@ -2535,7 +2547,9 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
         if (pgoff + (size >> PAGE_SHIFT) < pgoff)
                 return ret;
 
-        down_write(&mm->mmap_sem);
+        if (down_write_killable(&mm->mmap_sem))
+                return -EINTR;
+
         vma = find_vma(mm, start);
 
         if (!vma || !(vma->vm_flags & VM_SHARED))
@@ -2700,6 +2714,11 @@ unsigned long vm_brk(unsigned long addr, unsigned long len)
         unsigned long ret;
         bool populate;
 
+        /*
+         * XXX not all users are chcecking the return value, convert
+         * to down_write_killable after they are able to cope with
+         * error
+         */
         down_write(&mm->mmap_sem);
         ret = do_brk(addr, len);
         populate = ((mm->def_flags & VM_LOCKED) != 0);
diff --git a/mm/mprotect.c b/mm/mprotect.c
index b650c5412f58..5019a1ef2848 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -379,7 +379,8 @@ SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len,
 
         reqprot = prot;
 
-        down_write(&current->mm->mmap_sem);
+        if (down_write_killable(&current->mm->mmap_sem))
+                return -EINTR;
 
         vma = find_vma(current->mm, start);
         error = -ENOMEM;
diff --git a/mm/mremap.c b/mm/mremap.c
index 9dc499977924..1f157adfdaf9 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -503,7 +503,8 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
         if (!new_len)
                 return ret;
 
-        down_write(&current->mm->mmap_sem);
+        if (down_write_killable(&current->mm->mmap_sem))
+                return -EINTR;
 
         if (flags & MREMAP_FIXED) {
                 ret = mremap_to(addr, old_len, new_addr, new_len,
diff --git a/mm/nommu.c b/mm/nommu.c
index c8bd59a03c71..b74512746aae 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1446,7 +1446,7 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
 
         flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
 
-        retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
+        retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff, true);
 
         if (file)
                 fput(file);
diff --git a/mm/util.c b/mm/util.c
index 8a1b3a1fb595..03b237746850 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -289,7 +289,7 @@ EXPORT_SYMBOL_GPL(get_user_pages_fast);
 
 unsigned long vm_mmap_pgoff(struct file *file, unsigned long addr,
         unsigned long len, unsigned long prot,
-        unsigned long flag, unsigned long pgoff)
+        unsigned long flag, unsigned long pgoff, bool killable)
 {
         unsigned long ret;
         struct mm_struct *mm = current->mm;
@@ -297,7 +297,12 @@ unsigned long vm_mmap_pgoff(struct file *file, unsigned long addr,
 
         ret = security_mmap_file(file, prot, flag);
         if (!ret) {
-                down_write(&mm->mmap_sem);
+                if (killable) {
+                        if (down_write_killable(&mm->mmap_sem))
+                                return -EINTR;
+                } else {
+                        down_write(&mm->mmap_sem);
+                }
                 ret = do_mmap_pgoff(file, addr, len, prot, flag, pgoff,
                                     &populate);
                 up_write(&mm->mmap_sem);
@@ -307,6 +312,7 @@ unsigned long vm_mmap_pgoff(struct file *file, unsigned long addr,
         return ret;
 }
 
+/* XXX are all callers checking an error */
 unsigned long vm_mmap(struct file *file, unsigned long addr,
         unsigned long len, unsigned long prot,
         unsigned long flag, unsigned long offset)
@@ -316,7 +322,7 @@ unsigned long vm_mmap(struct file *file, unsigned long addr,
         if (unlikely(offset_in_page(offset)))
                 return -EINVAL;
 
-        return vm_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT);
+        return vm_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT, false);
 }
 EXPORT_SYMBOL(vm_mmap);