From: Dietmar Eggemann <dietmar.eggemann@arm.com>
Date: Thu, 27 May 2021 09:11:05 +0000 (+0200)
Subject: debugfs: Fix debugfs_read_file_str()
X-Git-Tag: v5.15~978^2
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=f501b6a2312e27fffe671d461770426fe5162184;p=platform%2Fkernel%2Flinux-starfive.git

debugfs: Fix debugfs_read_file_str()

Read the entire size of the buffer, including the trailing new line
character.
Discovered while reading the sched domain names of CPU0:

before:

cat /sys/kernel/debug/sched/domains/cpu0/domain*/name
SMTMCDIE

after:

cat /sys/kernel/debug/sched/domains/cpu0/domain*/name
SMT
MC
DIE

Fixes: 9af0440ec86eb ("debugfs: Implement debugfs_create_str()")
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Link: https://lore.kernel.org/r/20210527091105.258457-1-dietmar.eggemann@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
index e813acf..ba7c01c 100644
--- a/fs/debugfs/file.c
+++ b/fs/debugfs/file.c
@@ -893,7 +893,7 @@ ssize_t debugfs_read_file_str(struct file *file, char __user *user_buf,
 
 	copy[copy_len] = '\n';
 
-	ret = simple_read_from_buffer(user_buf, count, ppos, copy, copy_len);
+	ret = simple_read_from_buffer(user_buf, count, ppos, copy, len);
 	kfree(copy);
 
 	return ret;