Messages in this thread Patch in this message | | | From | Josh Poimboeuf <> | Subject | [PATCH 08/22] x86/uaccess: Don't leak AC flag into fentry from mcsafe_handle_tail() | Date | Sun, 14 Jul 2019 19:37:03 -0500 |
| |
After adding mcsafe_handle_tail() to the objtool uaccess safe list, objtool reports:
arch/x86/lib/usercopy_64.o: warning: objtool: mcsafe_handle_tail()+0x0: call to __fentry__() with UACCESS enabled
With SMAP, this function is called with AC=1, so it needs to be careful about which functions it calls. Disable the ftrace entry hook, which can potentially pull in a lot of extra code.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> --- arch/x86/lib/usercopy_64.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/lib/usercopy_64.c b/arch/x86/lib/usercopy_64.c index e0e006f1624e..fff28c6f73a2 100644 --- a/arch/x86/lib/usercopy_64.c +++ b/arch/x86/lib/usercopy_64.c @@ -60,7 +60,7 @@ EXPORT_SYMBOL(clear_user); * but reuse __memcpy_mcsafe in case a new read error is encountered. * clac() is handled in _copy_to_iter_mcsafe(). */ -__visible unsigned long +__visible notrace unsigned long mcsafe_handle_tail(char *to, char *from, unsigned len) { for (; len; --len, to++, from++) { -- 2.20.1
| |