From: Hillf Danton <hdanton@sina.com>
Date: Wed, 8 Apr 2020 15:59:24 +0000 (-0400)
Subject: mm/gup: Let __get_user_pages_locked() return -EINTR for fatal signal
X-Git-Tag: v5.7-rc1~49
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=ae46d2aa6a7f;p=linux.git

mm/gup: Let __get_user_pages_locked() return -EINTR for fatal signal

__get_user_pages_locked() will return 0 instead of -EINTR after commit
4426e945df588 ("mm/gup: allow VM_FAULT_RETRY for multiple times") which
added extra code to allow gup detect fatal signal faster.

Restore the original -EINTR behavior.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Fixes: 4426e945df58 ("mm/gup: allow VM_FAULT_RETRY for multiple times")
Reported-by: syzbot+3be1a33f04dc782e9fd5@syzkaller.appspotmail.com
Signed-off-by: Hillf Danton <hdanton@sina.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/mm/gup.c b/mm/gup.c
index afce0bc47e70..6076df8e04a4 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1326,8 +1326,11 @@ retry:
 		 * start trying again otherwise it can loop forever.
 		 */
 
-		if (fatal_signal_pending(current))
+		if (fatal_signal_pending(current)) {
+			if (!pages_done)
+				pages_done = -EINTR;
 			break;
+		}
 
 		ret = down_read_killable(&mm->mmap_sem);
 		if (ret) {