From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
dvyukov@google.com, pmladek@suse.com,
sergey.senozhatsky@gmail.com, syzkaller@googlegroups.com,
rostedt@goodmis.org, fengguang.wu@intel.com,
linux-kernel@vger.kernel.org, torvalds@linux-foundation.org,
akpm@linux-foundation.org
Subject: Re: [PATCH] printk: inject caller information into the body of message
Date: Thu, 17 May 2018 20:52:48 +0900 [thread overview]
Message-ID: <20180517115248.GA409@jagdpanzerIV> (raw)
In-Reply-To: <20180517112135.GB20796@jagdpanzerIV>
On (05/17/18 20:21), Sergey Senozhatsky wrote:
> Dunno...
> For instance, can we store context tracking info as a extended record
> data? We have that dict/dict_len thing. So may we can store tracking
> info there? Extended records will appear on the serial console /* if
> console supports extended data */ or can be read in via devkmsg_read().
Those extended records are already there for exactly the same
reason - people want to attach a special context to printk() entries.
See dev_vprintk_emit() and create_syslog_header(). So we can add more
key/value data to that context. Sounds kinda-sorta reasonable.
So, for example, this output
cat /dev/kmsg
6,577,3156036,-;snd_hda_codec_generic hdaudioC1D0: autoconfig for Generic: line_outs=0 (0x0/0x0/0x0/0x0/0x0) type:line
SUBSYSTEM=hdaudio
DEVICE=+hdaudio:hdaudioC1D
6,578,3156807,-;snd_hda_codec_generic hdaudioC1D0: speaker_outs=0 (0x0/0x0/0x0/0x0/0x0)
SUBSYSTEM=hdaudio
DEVICE=+hdaudio:hdaudioC1D
Becomes this:
6,566,3033752,-;snd_hda_codec_realtek hdaudioC0D0: Front Mic=0x19
3/207: 0/0/0
SUBSYSTEM=hdaudio
DEVICE=+hdaudio:hdaudioC0D
6,567,3033754,-;snd_hda_codec_realtek hdaudioC0D0: Rear Mic=0x18
3/207: 0/0/0
SUBSYSTEM=hdaudio
DEVICE=+hdaudio:hdaudioC0D
"3/207: 0/0/0" is smp_processor_id/task_pid_nr and then masked
out bits of preempt count: hard irq, soft irq, nmi.
We definitely can change the format, etc. This is just a very quick and
dirty PoC.
Something as follows?
/* just to demonstrate the idea */
---
kernel/printk/printk.c | 22 +++++++++++++++++++++-
1 file changed, 21 insertions(+), 1 deletion(-)
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 2f4af216bd6e..4a82d52a343d 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -580,16 +580,33 @@ static u32 truncate_msg(u16 *text_len, u16 *trunc_msg_len,
return msg_used_size(*text_len + *trunc_msg_len, 0, pad_len);
}
+static size_t add_log_origin(char *buf, size_t buf_len)
+{
+ return snprintf(buf,
+ buf_len,
+ "%d/%d: %lu/%lu/%lu",
+ raw_smp_processor_id(),
+ task_pid_nr(current),
+ preempt_count() & HARDIRQ_MASK,
+ preempt_count() & SOFTIRQ_MASK,
+ preempt_count() & NMI_MASK);
+}
+
/* insert record into the buffer, discard old ones, update heads */
static int log_store(int facility, int level,
enum log_flags flags, u64 ts_nsec,
const char *dict, u16 dict_len,
const char *text, u16 text_len)
{
+ static char log_origin[64];
+ static size_t log_origin_len;
struct printk_log *msg;
u32 size, pad_len;
u16 trunc_msg_len = 0;
+ log_origin_len = add_log_origin(log_origin, sizeof(log_origin));
+ dict_len += log_origin_len;
+
/* number of '\0' padding bytes to next message */
size = msg_used_size(text_len, dict_len, &pad_len);
@@ -620,7 +637,10 @@ static int log_store(int facility, int level,
memcpy(log_text(msg) + text_len, trunc_msg, trunc_msg_len);
msg->text_len += trunc_msg_len;
}
- memcpy(log_dict(msg), dict, dict_len);
+ memcpy(log_dict(msg), log_origin, log_origin_len);
+ memcpy(log_dict(msg) + log_origin_len + 1,
+ dict,
+ dict_len - log_origin_len);
msg->dict_len = dict_len;
msg->facility = facility;
msg->level = level & 7;
next prev parent reply other threads:[~2018-05-17 11:52 UTC|newest]
Thread overview: 94+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <201804232233.CIC65675.OJSOMFQOFFHVtL@I-love.SAKURA.ne.jp>
[not found] ` <CACT4Y+boyw_Qy=y-iTnsKZrtTgF0Hk3nHN_xtqUdX4etgiYDQw@mail.gmail.com>
2018-04-24 1:33 ` printk feature for syzbot? Sergey Senozhatsky
2018-04-24 14:40 ` Steven Rostedt
2018-04-26 10:06 ` Petr Mladek
2018-05-10 4:22 ` Sergey Senozhatsky
2018-05-10 11:30 ` Petr Mladek
2018-05-10 12:11 ` Sergey Senozhatsky
2018-05-10 14:22 ` Steven Rostedt
2018-05-10 14:50 ` Tetsuo Handa
2018-05-11 1:45 ` Sergey Senozhatsky
[not found] ` <201805110238.w4B2cIGH079602@www262.sakura.ne.jp>
2018-05-11 6:21 ` Sergey Senozhatsky
2018-05-11 9:17 ` Dmitry Vyukov
2018-05-11 9:50 ` Sergey Senozhatsky
2018-05-11 11:58 ` [PATCH] printk: inject caller information into the body of message Tetsuo Handa
2018-05-17 11:21 ` Sergey Senozhatsky
2018-05-17 11:52 ` Sergey Senozhatsky [this message]
2018-05-18 12:15 ` Petr Mladek
2018-05-18 12:25 ` Dmitry Vyukov
2018-05-18 12:54 ` Petr Mladek
2018-05-18 13:08 ` Dmitry Vyukov
2018-05-24 2:21 ` Sergey Senozhatsky
2018-05-23 10:19 ` Tetsuo Handa
2018-05-24 2:14 ` Sergey Senozhatsky
2018-05-26 6:36 ` Dmitry Vyukov
2018-06-20 5:44 ` Dmitry Vyukov
2018-06-20 8:31 ` Sergey Senozhatsky
2018-06-20 8:45 ` Dmitry Vyukov
2018-06-20 9:06 ` Sergey Senozhatsky
2018-06-20 9:18 ` Sergey Senozhatsky
2018-06-20 9:31 ` Dmitry Vyukov
2018-06-20 11:07 ` Sergey Senozhatsky
2018-06-20 11:32 ` Dmitry Vyukov
2018-06-20 13:06 ` Sergey Senozhatsky
2018-06-22 13:06 ` Tetsuo Handa
2018-06-25 1:41 ` Sergey Senozhatsky
2018-06-25 9:36 ` Dmitry Vyukov
2018-06-27 10:29 ` Tetsuo Handa
2018-09-10 11:20 ` Alexander Potapenko
2018-09-12 6:53 ` Sergey Senozhatsky
2018-09-12 16:05 ` Steven Rostedt
2018-09-13 7:12 ` Sergey Senozhatsky
2018-09-13 12:26 ` Petr Mladek
2018-09-13 14:28 ` Sergey Senozhatsky
2018-09-14 1:22 ` Steven Rostedt
2018-09-14 2:15 ` Sergey Senozhatsky
2018-09-14 6:57 ` Sergey Senozhatsky
2018-09-14 10:37 ` Tetsuo Handa
2018-09-14 11:50 ` Sergey Senozhatsky
2018-09-14 12:03 ` Tetsuo Handa
2018-09-14 12:22 ` Sergey Senozhatsky
2018-09-19 11:02 ` Tetsuo Handa
2018-09-24 8:11 ` Tetsuo Handa
2018-09-27 16:10 ` Tetsuo Handa
2018-09-28 9:02 ` Sergey Senozhatsky
2018-09-28 9:09 ` Sergey Senozhatsky
2018-09-28 11:01 ` Tetsuo Handa
2018-09-29 10:51 ` Sergey Senozhatsky
2018-09-29 11:15 ` Tetsuo Handa
2018-10-01 2:37 ` Sergey Senozhatsky
2018-10-01 2:58 ` Sergey Senozhatsky
2018-10-01 11:21 ` Tetsuo Handa
2018-10-02 6:38 ` Sergey Senozhatsky
2018-10-08 10:31 ` Tetsuo Handa
2018-10-08 16:03 ` Petr Mladek
2018-10-08 20:48 ` Tetsuo Handa
2018-10-09 14:52 ` Petr Mladek
2018-10-09 21:19 ` Tetsuo Handa
2018-10-10 10:14 ` Tetsuo Handa
2018-10-11 10:20 ` Tetsuo Handa
2018-10-11 13:47 ` Steven Rostedt
2018-10-08 15:43 ` Petr Mladek
2018-09-28 8:56 ` Sergey Senozhatsky
2018-09-28 11:21 ` Tetsuo Handa
2018-09-29 11:13 ` Sergey Senozhatsky
2018-09-29 11:39 ` Tetsuo Handa
2018-10-01 5:52 ` Sergey Senozhatsky
2018-10-01 8:37 ` Sergey Senozhatsky
2018-10-01 18:06 ` Steven Rostedt
2018-09-14 1:12 ` Steven Rostedt
2018-09-14 1:55 ` Sergey Senozhatsky
2018-06-21 8:29 ` Sergey Senozhatsky
2018-06-20 9:30 ` Dmitry Vyukov
2018-06-20 11:19 ` Sergey Senozhatsky
2018-06-20 11:25 ` Dmitry Vyukov
2018-06-20 11:37 ` Fengguang Wu
2018-06-20 12:31 ` Dmitry Vyukov
2018-06-20 12:41 ` Fengguang Wu
2018-06-20 12:45 ` Dmitry Vyukov
2018-06-20 12:48 ` Fengguang Wu
2018-05-11 13:37 ` printk feature for syzbot? Steven Rostedt
2018-05-15 5:20 ` Sergey Senozhatsky
2018-05-15 14:39 ` Steven Rostedt
2018-05-11 11:02 ` [PATCH] printk: fix possible reuse of va_list variable Tetsuo Handa
2018-05-11 11:27 ` Sergey Senozhatsky
2018-05-17 11:57 ` Petr Mladek
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