[PATCH] arch/m68k/kernel/sys_m68k: Add missing mmap_read_lock() to sys_cacheflush()

From: Liam Howlett <liam.howlett@oracle.com>
To: Geert Uytterhoeven <geert@linux-m68k.org>,
	"linux-m68k@lists.linux-m68k.org"
	<linux-m68k@lists.linux-m68k.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc: Laurent Dufour <ldufour@linux.ibm.com>,
	Vlastimil Babka <vbabka@suse.cz>,
	Daniel Jordan <daniel.m.jordan@oracle.com>,
	Michel Lespinasse <walken@google.com>,
	Liam Howlett <liam.howlett@oracle.com>
Subject: [PATCH] arch/m68k/kernel/sys_m68k: Add missing mmap_read_lock() to sys_cacheflush()
Date: Wed, 7 Apr 2021 20:00:45 +0000	[thread overview]
Message-ID: <20210407200032.764445-1-Liam.Howlett@Oracle.com> (raw)

When the superuser flushes the entire cache, the mmap_read_lock() is not
taken, but mmap_read_unlock() is called.  Add the missing
mmap_read_lock() call.

Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
---
 arch/m68k/kernel/sys_m68k.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/m68k/kernel/sys_m68k.c b/arch/m68k/kernel/sys_m68k.c
index 1c235d8f53f3..f55bdcb8e4f1 100644
--- a/arch/m68k/kernel/sys_m68k.c
+++ b/arch/m68k/kernel/sys_m68k.c
@@ -388,6 +388,8 @@ sys_cacheflush (unsigned long addr, int scope, int cache, unsigned long len)
 		ret = -EPERM;
 		if (!capable(CAP_SYS_ADMIN))
 			goto out;
+
+		mmap_read_lock(current->mm);
 	} else {
 		struct vm_area_struct *vma;
 
-- 
2.30.0
