From: Daniel Bristot de Oliveira Printk messages often finish with '\n' to cause a new line. But as each tracepoint is already printed in a new line, printk messages that finish with '\n' ends up adding a blank line to the trace output. For example: kworker/0:1-86 [000] d... 46.006949: console: [ 46.006946] usb 1-3: USB disconnect, device number 3 kworker/2:2-374 [002] d... 48.699342: console: [ 48.699339] usb 1-3: new high-speed USB device number 4 using ehci-pci kworker/2:2-374 [002] d... 49.041450: console: [ 49.041448] usb 1-3: New USB device found, idVendor=5986, idProduct=0 To avoid unneeded blank lines, this patch checks if the printk message finishes with '\n', if so, it cut is off the '\n' to avoid blank lines. In a patched kernel, the same messages are printed without extra blank lines. For example: kworker/0:4-185 [000] d... 23.641738: console: [ 23.641736] usb 1-3: USB disconnect, device number 3 kworker/0:4-185 [000] d... 24.918703: console: [ 24.918700] usb 1-3: new high-speed USB device number 4 using ehci-pci kworker/0:4-185 [000] d... 25.228308: console: [ 25.228306] usb 1-3: New USB device found, idVendor=5986, idProduct=02d5 Link: http://lkml.kernel.org/r/c350fb2521baaf681a1b4d67981ca0e900108e8e.1467407618.git.bristot@redhat.com Cc: Trond Myklebust Cc: Anna Schumaker Cc: Ingo Molnar Reviewed-by: Steven Rostedt Signed-off-by: Daniel Bristot de Oliveira Signed-off-by: Steven Rostedt --- include/trace/events/printk.h | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/include/trace/events/printk.h b/include/trace/events/printk.h index 542a7558154a..f350170059c6 100644 --- a/include/trace/events/printk.h +++ b/include/trace/events/printk.h @@ -16,6 +16,14 @@ TRACE_EVENT(console, ), TP_fast_assign( + /* + * Each trace entry is printed in a new line. + * If the msg finishes with '\n', cut it off + * to avoid blank lines in the trace. + */ + if ((len > 0) && (text[len-1] == '\n')) + len -= 1; + memcpy(__get_str(msg), text, len); __get_str(msg)[len] = 0; ), -- 2.8.1