| From 1a8e9cf40c9a6a2e40b1e924b13ed303aeea4418 Mon Sep 17 00:00:00 2001 |
| From: Vasily Averin <vvs@virtuozzo.com> |
| Date: Thu, 23 Jan 2020 12:05:10 +0300 |
| Subject: jbd2_seq_info_next should increase position index |
| |
| From: Vasily Averin <vvs@virtuozzo.com> |
| |
| commit 1a8e9cf40c9a6a2e40b1e924b13ed303aeea4418 upstream. |
| |
| if seq_file .next fuction does not change position index, |
| read after some lseek can generate unexpected output. |
| |
| Script below generates endless output |
| $ q=;while read -r r;do echo "$((++q)) $r";done </proc/fs/jbd2/DEV/info |
| |
| https://bugzilla.kernel.org/show_bug.cgi?id=206283 |
| |
| Fixes: 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code and interface") |
| Cc: stable@kernel.org |
| Signed-off-by: Vasily Averin <vvs@virtuozzo.com> |
| Reviewed-by: Jan Kara <jack@suse.cz> |
| Link: https://lore.kernel.org/r/d13805e5-695e-8ac3-b678-26ca2313629f@virtuozzo.com |
| Signed-off-by: Theodore Ts'o <tytso@mit.edu> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| fs/jbd2/journal.c | 1 + |
| 1 file changed, 1 insertion(+) |
| |
| --- a/fs/jbd2/journal.c |
| +++ b/fs/jbd2/journal.c |
| @@ -1002,6 +1002,7 @@ static void *jbd2_seq_info_start(struct |
| |
| static void *jbd2_seq_info_next(struct seq_file *seq, void *v, loff_t *pos) |
| { |
| + (*pos)++; |
| return NULL; |
| } |
| |
