From e277fa9ec702fea7bd3135393c67327c821d5a3a Mon Sep 17 00:00:00 2001
From: Omar Sandoval <osandov@fb.com>
Date: Wed, 23 May 2018 13:59:31 -0700
Subject: [PATCH] vmcore-dmesg: fix infinite loop if log buffer wraps around

We hit a bug where vmcore-dmesg would get stuck in a loop, and since we
were redirecting the output to a file, it wouldn't stop until it filled
up the disk. This only happened when the dmesg buffer had filled up and
wrapped around. It turns out that when we hit the end of the buffer, we
are looping back to the first record instead of the beginning of the
buffer, which will always loop forever.

Fixes: e08d26b3b7f1 ("vmcore-dmesg: avoid allocating large memory chunk for log buf")
Signed-off-by: Omar Sandoval <osandov@fb.com>
Acked-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Pingfan Liu <piliu@redhat.com>
---
 vmcore-dmesg/vmcore-dmesg.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/vmcore-dmesg/vmcore-dmesg.c b/vmcore-dmesg/vmcore-dmesg.c
index e340ef4..7972788 100644
--- a/vmcore-dmesg/vmcore-dmesg.c
+++ b/vmcore-dmesg/vmcore-dmesg.c
@@ -689,7 +689,7 @@ static void dump_dmesg_structured(int fd)
 		 */
 		loglen = struct_val_u16(buf, log_offset_len);
 		if (!loglen)
-			current_idx = log_first_idx;
+			current_idx = 0;
 		else
 			/* Move to next record */
 			current_idx += loglen;
-- 
2.7.4