On Wed, 1 Jan 2014 17:44:06 +0530 Arun KS <arunks.li...@gmail.com> wrote:
> >From d751f9a0cb6329ae3171f6e1cb85e4a3aa792d73 Mon Sep 17 00:00:00 2001
> From: Arun KS <arun...@broadcom.com>
> Date: Wed, 1 Jan 2014 17:24:46 +0530
> Subject: printk: flush conflicting continuation line
>
> An earlier newline was missing and current print is from different task.
> In this scenario flush the continuation line and store this line seperatly.
>
> This patch fix the below scenario of timestamp interleaving,
> <6>[ 28.154370 ] read_word_reg : reg[0x 3], reg[0x 4] data [0x 642]
> <6>[ 28.155428 ] uart disconnect
> <6>[ 31.947341 ] dvfs[cpufreq.c<275>]:plug-in cpu<1> done
> <4>[ 28.155445 ] UART detached : send switch state 201
> <6>[ 32.014112 ] read_reg : reg[0x 3] data[0x21]
>
> ...
>
> --- a/kernel/printk/printk.c
> +++ b/kernel/printk/printk.c
> @@ -1604,7 +1604,10 @@ asmlinkage int vprintk_emit(int facility, int level,
> if (!(lflags & LOG_PREFIX))
> stored = cont_add(facility, level, text, text_len);
> cont_flush(LOG_NEWLINE);
> - }
> + /* Flush conflicting buffer. An earlier newline was missing
> + * and current print is from different task */
> + } else if (cont.len && cont.owner != current)
> + cont_flush(LOG_NEWLINE);
>
> if (!stored)
> log_store(facility, level, lflags, 0,
Your email client makes a horrid mess of the patches :(
I *think* it's right. But the code can be significantly simplified and
optimised. Please review:
} else {
bool stored = false;
/*
* If an earlier newline was missing and it was the same task,
* either merge it with the current buffer and flush, or if
* there was a race with interrupts (prefix == true) then just
* flush it out and store this line separately.
* If the preceding printk was from a different task and missed
* a newline, flush and append the newline.
*/
if (cont.len) {
if (cont.owner == current && !(lflags & LOG_PREFIX))
stored = cont_add(facility, level, text,
text_len);
cont_flush(LOG_NEWLINE);
}
if (!stored)
log_store(facility, level, lflags, 0,
dict, dictlen, text, text_len);
}
--- a/kernel/printk/printk.c~printk-flush-conflicting-continuation-line-fix
+++ a/kernel/printk/printk.c
@@ -1595,15 +1595,15 @@ asmlinkage int vprintk_emit(int facility
* either merge it with the current buffer and flush, or if
* there was a race with interrupts (prefix == true) then just
* flush it out and store this line separately.
+ * If the preceding printk was from a different task and missed
+ * a newline, flush and append the newline.
*/
- if (cont.len && cont.owner == current) {
- if (!(lflags & LOG_PREFIX))
- stored = cont_add(facility, level, text,
text_len);
- cont_flush(LOG_NEWLINE);
- /* Flush conflicting buffer. An earlier newline was missing
- * and current print is from different task */
- } else if (cont.len && cont.owner != current)
+ if (cont.len) {
+ if (cont.owner == current && !(lflags & LOG_PREFIX))
+ stored = cont_add(facility, level, text,
+ text_len);
cont_flush(LOG_NEWLINE);
+ }
if (!stored)
log_store(facility, level, lflags, 0,
_
--
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