[PATCH 3.17rc4] kdb: Avoid printing KERN_ levels to consoles

From: Daniel Thompson
Date: Wed Sep 24 2014 - 06:38:54 EST


Currently when kdb traps printk messages then the log level prefix
does not get stripped off before the message is issued to the various
I/O handlers supported by kdb. This results in annoying visual noise
and problems with grepping for ^.

This patch addresses the problem by stripping log levels from messages
before they are issued to the I/O handlers.

printk(), which is used as an I/O handler for logging purposes, is
handled as a special case; if the caller provided a log level then this
will be preserved.

Signed-off-by: Daniel Thompson <daniel.thompson@xxxxxxxxxx>
Cc: Jason Wessel <jason.wessel@xxxxxxxxxxxxx>
Cc: Mike Travis <travis@xxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/debug/kdb/kdb_io.c | 20 +++++++++++++-------
1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index 7c70812..381f297 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -691,19 +691,22 @@ kdb_printit:
* Write to all consoles.
*/
retlen = strlen(kdb_buffer);
+ cp = kdb_buffer;
+ if (cp[0] == KERN_SOH_ASCII && cp[1] != '\0')
+ cp += 2;
if (!dbg_kdb_mode && kgdb_connected) {
- gdbstub_msg_write(kdb_buffer, retlen);
+ gdbstub_msg_write(cp, retlen - (cp - kdb_buffer));
} else {
if (dbg_io_ops && !dbg_io_ops->is_console) {
- len = retlen;
- cp = kdb_buffer;
+ len = retlen - (cp - kdb_buffer);
+ cp2 = cp;
while (len--) {
- dbg_io_ops->write_char(*cp);
- cp++;
+ dbg_io_ops->write_char(*cp2);
+ cp2++;
}
}
while (c) {
- c->write(c, kdb_buffer, retlen);
+ c->write(c, cp, retlen - (cp - kdb_buffer));
touch_nmi_watchdog();
c = c->next;
}
@@ -711,7 +714,10 @@ kdb_printit:
if (logging) {
saved_loglevel = console_loglevel;
console_loglevel = CONSOLE_LOGLEVEL_SILENT;
- printk(KERN_INFO "%s", kdb_buffer);
+ if (cp == kdb_buffer)
+ printk(KERN_INFO "%s", kdb_buffer);
+ else
+ printk("%s", kdb_buffer);
}

if (KDB_STATE(PAGER)) {
--
1.9.3

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