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| author | Josh Poimboeuf <jpoimboe@redhat.com> | 2019-07-17 20:36:43 -0500 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2019-07-18 21:01:05 +0200 |
| commit | 5e307a6bc7b600999742675dd182bcb8a6fe308e (patch) | |
| tree | 85cd9e6e8e2c094d723c47b754f1f5d64c4fc0f2 | |
| parent | 3a6ab4bcc52263dd5b1d2fd2e4ce95a38c798b4d (diff) | |
| download | renesas-5e307a6bc7b600999742675dd182bcb8a6fe308e.tar.gz | |
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
| -rw-r--r-- | arch/x86/lib/usercopy_64.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/lib/usercopy_64.c b/arch/x86/lib/usercopy_64.c index e0e006f1624e2c..fff28c6f73a212 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++) { |