sigaltstack: support SS_AUTODISARM for CONFIG_COMPAT
commit 441398d378f29a5ad6d0fcda07918e54e4961800 upstream.
Currently SS_AUTODISARM is not supported in compatibility mode, but does
not return -EINVAL either. This makes dosemu built with -m32 on x86_64
to crash. Also the kernel's sigaltstack selftest fails if compiled with
-m32.
This patch adds the needed support.
Link: http://lkml.kernel.org/r/20170205101213.8163-2-stsp@list.ru
Signed-off-by: Stas Sergeev <stsp@users.sourceforge.net>
Cc: Milosz Tanski <milosz@adfin.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Waiman Long <Waiman.Long@hpe.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dmitry Safonov <dsafonov@virtuozzo.com>
Cc: Wang Xiaoqiang <wangxq10@lzu.edu.cn>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/kernel/signal.c b/kernel/signal.c
index 75761ac..0b14157 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3226,10 +3226,17 @@
int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)
{
+ int err;
struct task_struct *t = current;
- return __put_user(ptr_to_compat((void __user *)t->sas_ss_sp), &uss->ss_sp) |
- __put_user(sas_ss_flags(sp), &uss->ss_flags) |
+ err = __put_user(ptr_to_compat((void __user *)t->sas_ss_sp),
+ &uss->ss_sp) |
+ __put_user(t->sas_ss_flags, &uss->ss_flags) |
__put_user(t->sas_ss_size, &uss->ss_size);
+ if (err)
+ return err;
+ if (t->sas_ss_flags & SS_AUTODISARM)
+ sas_ss_reset(t);
+ return 0;
}
#endif