drivers: misc: ti-st: fix potential race if st_kim_start fails

If st_kim_start() fails registered protocols should be removed. This is
done by calling st_reg_complete(), which as comment states is called
with spin lock held. But in st_register() when st_kim_start fails it
is called without holding spin lock, creating possibility of concurrent
access to st_gdata data members.
Hold spin lock while calling st_reg_complete if st_kim_start() fails.

Signed-off-by: Oleksandr Kozaruk <oleksandr.kozaruk@globallogic.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/misc/ti-st/st_core.c b/drivers/misc/ti-st/st_core.c
index 0a14280..8d64b68 100644 (file)
--- a/drivers/misc/ti-st/st_core.c
+++ b/drivers/misc/ti-st/st_core.c
@@ -562,7 +562,9 @@ long st_register(struct st_proto_s *new_proto)
                        if ((st_gdata->protos_registered != ST_EMPTY) &&
                            (test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
                                pr_err(" KIM failure complete callback ");
+                               spin_lock_irqsave(&st_gdata->lock, flags);
                                st_reg_complete(st_gdata, err);
+                               spin_unlock_irqrestore(&st_gdata->lock, flags);
                                clear_bit(ST_REG_PENDING, &st_gdata->st_state);
                        }
                        return -EINVAL;