diff mbox series

[5.12,061/677] md: Fix missing unused status line of /proc/mdstat

Message ID 20210512144839.235519709@linuxfoundation.org
State Superseded
Headers show
Series None | expand

Commit Message

Greg Kroah-Hartman May 12, 2021, 2:41 p.m. UTC 
From: Jan Glauber <jglauber@digitalocean.com>

commit 7abfabaf5f805f5171d133ce6af9b65ab766e76a upstream.

Reading /proc/mdstat with a read buffer size that would not
fit the unused status line in the first read will skip this
line from the output.

So 'dd if=/proc/mdstat bs=64 2>/dev/null' will not print something
like: unused devices: <none>

Don't return NULL immediately in start() for v=2 but call
show() once to print the status line also for multiple reads.

Cc: stable@vger.kernel.org
Fixes: 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code and interface")
Signed-off-by: Jan Glauber <jglauber@digitalocean.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/md/md.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
diff mbox series

Patch

--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -8172,7 +8172,11 @@  static void *md_seq_start(struct seq_fil
 	loff_t l = *pos;
 	struct mddev *mddev;
 
-	if (l >= 0x10000)
+	if (l == 0x10000) {
+		++*pos;
+		return (void *)2;
+	}
+	if (l > 0x10000)
 		return NULL;
 	if (!l--)
 		/* header */