From 8835ca59dac2bc1e0136791abf3ccd51588803ce Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Wed, 19 Oct 2016 09:11:24 -0700 Subject: [PATCH] printk: suppress empty continuation lines We have a fairly common pattern where you print several things as continuations on one single line in a loop, and then at the end you do printk(KERN_CONT "\n"); to flush the buffered output. But if the output was flushed by something else (concurrent printk activity, or just system logging), we don't want that final flushing to just print an empty line. So just suppress empty continuation lines when they couldn't be merged into the line they are a continuation of. Signed-off-by: Linus Torvalds --- kernel/printk/printk.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index d5e397315473..de08fc90baaf 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -1769,6 +1769,10 @@ static size_t log_output(int facility, int level, enum log_flags lflags, const c cont_flush(); } + /* Skip empty continuation lines that couldn't be added - they just flush */ + if (!text_len && (lflags & LOG_CONT)) + return 0; + /* If it doesn't end in a newline, try to buffer the current line */ if (!(lflags & LOG_NEWLINE)) { if (cont_add(facility, level, lflags, text, text_len)) -- 2.20.1