From: Linus Torvalds <torvalds@g5.osdl.org>
Date: Fri, 9 Sep 2005 22:42:34 +0000 (-0700)
Subject: Preempt-safe RCU file usage
X-Git-Tag: archive/raspbian/4.9.13-1+rpi1~10^2~49801
X-Git-Url: https://dgit.raspbian.org/%22http:/www.example.com/cgi/%22https:/www.github.com/%22bookmarks:///%22http:/www.example.com/cgi/%22https:/www.github.com/%22bookmarks:/?a=commitdiff_plain;h=ac5b8b6f22118620cd1133d9943b1f31dc40a913;p=linux-4.9.git

Preempt-safe RCU file usage

Fix up fs/compat.c fixes.
---

diff --git a/fs/compat.c b/fs/compat.c
index c2e0813164b4..ac3fb9ed8eea 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -1645,8 +1645,10 @@ compat_sys_select(int n, compat_ulong_t __user *inp, compat_ulong_t __user *outp
 		goto out_nofds;
 
 	/* max_fdset can increase, so grab it once to avoid race */
+	rcu_read_lock();
 	fdt = files_fdtable(current->files);
 	max_fdset = fdt->max_fdset;
+	rcu_read_unlock();
 	if (n > max_fdset)
 		n = max_fdset;