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authorJosh Poimboeuf <jpoimboe@redhat.com>2019-07-18 04:36:43 +0300
committerThomas Gleixner <tglx@linutronix.de>2019-07-18 22:01:05 +0300
commit5e307a6bc7b600999742675dd182bcb8a6fe308e (patch)
tree85cd9e6e8e2c094d723c47b754f1f5d64c4fc0f2 /arch
parent3a6ab4bcc52263dd5b1d2fd2e4ce95a38c798b4d (diff)
downloadlinux-5e307a6bc7b600999742675dd182bcb8a6fe308e.tar.xz
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 <jpoimboe@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/8e13d6f0da1c8a3f7603903da6cbf6d582bbfe10.1563413318.git.jpoimboe@redhat.com
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/lib/usercopy_64.c2
1 files changed, 1 insertions, 1 deletions
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++) {