Commit-ID: 5e307a6bc7b600999742675dd182bcb8a6fe308e Gitweb: https://git.kernel.org/tip/5e307a6bc7b600999742675dd182bcb8a6fe308e Author: Josh Poimboeuf <jpoim...@redhat.com> AuthorDate: Wed, 17 Jul 2019 20:36:43 -0500 Committer: Thomas Gleixner <t...@linutronix.de> CommitDate: Thu, 18 Jul 2019 21:01:05 +0200
x86/uaccess: Don't leak AC flag into fentry from mcsafe_handle_tail() 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 <jpoim...@redhat.com> Signed-off-by: Thomas Gleixner <t...@linutronix.de> Acked-by: Peter Zijlstra (Intel) <pet...@infradead.org> Link: https://lkml.kernel.org/r/8e13d6f0da1c8a3f7603903da6cbf6d582bbfe10.1563413318.git.jpoim...@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++) {
