lib: Add might_fault() to strncpy_from_user.
When updating a piece of broken logic from using get_user to
strncpy_from_user, we noticed that a warning which is expected when
calling a function that might fault from an atomic context with
pagefaults enabled disappeared.
Not having this warning in place can lead to calling strncpy_from_user
from an atomic context and eventually kernel crashes/stack corruption.
Signed-off-by: KP Singh <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Andrew Morton <[email protected]>
Cc: Jann Horn <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
diff --git a/lib/strncpy_from_user.c b/lib/strncpy_from_user.c
index b90ec55..34696a3 100644
--- a/lib/strncpy_from_user.c
+++ b/lib/strncpy_from_user.c
@@ -98,6 +98,7 @@ long strncpy_from_user(char *dst, const char __user *src, long count)
{
unsigned long max_addr, src_addr;
+ might_fault();
if (unlikely(count <= 0))
return 0;
