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FAILED: patch "[PATCH] sigaltstack: support SS_AUTODISARM for CONFIG_COMPAT" failed to apply to 4.4-stable tree

PATCH [email protected] 1 participant 1 message Mar 8, 2017 Stable branch

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The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

Quoted 1 line

From 441398d378f29a5ad6d0fcda07918e54e4961800 Mon Sep 17 00:00:00 2001

From: Stas Sergeev <[email protected]>
Date: Mon, 27 Feb 2017 14:27:25 -0800
Subject: [PATCH] sigaltstack: support SS_AUTODISARM for CONFIG_COMPAT

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/[email protected] open here
Signed-off-by Stas Sergeev <[email protected]>
Cc Milosz Tanski <[email protected]>
Cc Andy Lutomirski <[email protected]>
Cc Al Viro <[email protected]>
Cc Arnd Bergmann <[email protected]>
Cc Thomas Gleixner <[email protected]>
Cc Ingo Molnar <[email protected]>
Cc Oleg Nesterov <[email protected]>
Cc Nicolas Pitre <[email protected]>
Cc Waiman Long <[email protected]>
Cc Dave Hansen <[email protected]>
Cc Dmitry Safonov <[email protected]>
Cc Wang Xiaoqiang <[email protected]>
Cc Oleg Nesterov <[email protected]>
Cc <[email protected]>
Signed-off-by Andrew Morton <[email protected]>
Signed-off-by Linus Torvalds <[email protected]>
include/linux/compat.h +3 -1
index 9e40be522793..aef47be2a5c1 100644
@@ -711,8 +711,10 @@ int __compat_save_altstack(compat_stack_t __user *, unsigned long);
 	compat_stack_t __user *__uss = uss; \
 	struct task_struct *t = current; \
 	put_user_ex(ptr_to_compat((void __user *)t->sas_ss_sp), &__uss->ss_sp); \
-	put_user_ex(sas_ss_flags(sp), &__uss->ss_flags); \
+	put_user_ex(t->sas_ss_flags, &__uss->ss_flags); \
 	put_user_ex(t->sas_ss_size, &__uss->ss_size); \
+	if (t->sas_ss_flags & SS_AUTODISARM) \
+		sas_ss_reset(t); \
 } while (0);
 
 asmlinkage long compat_sys_sched_rr_get_interval(compat_pid_t pid,
kernel/signal.c +9 -2
index 13f9def8b24a..214a8feeb771 100644
@@ -3239,10 +3239,17 @@ int compat_restore_altstack(const compat_stack_t __user *uss)
 
 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