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 Signed-off-by: Vasily Averin <vvs@xxxxxxxxxxxxx> --- fs/jbd2/journal.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c index 5e408ee..b3e2433 100644 --- a/fs/jbd2/journal.c +++ b/fs/jbd2/journal.c @@ -982,6 +982,7 @@ static void *jbd2_seq_info_start(struct seq_file *seq, loff_t *pos) static void *jbd2_seq_info_next(struct seq_file *seq, void *v, loff_t *pos) { + (*pos)++; return NULL; } -- 1.8.3.1