From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
To: Petr Mladek <pmladek@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Jan Kara <jack@suse.cz>,
linux-kernel@vger.kernel.org,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Subject: [PATCH v2] printk/nmi: avoid direct printk()-s from __printk_nmi_flush()
Date: Wed, 31 Aug 2016 01:13:54 +0900
Message-ID: <20160830161354.581-1-sergey.senozhatsky@gmail.com> (raw)
From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
__printk_nmi_flush() can be called from nmi_panic(), therefore it has to
test whether it's executed in NMI context and thus must route the messages
through deferred printk() or via direct printk(). Except for two places
where __printk_nmi_flush() does unconditional direct printk() calls:
- pr_err("printk_nmi_flush: internal error ...")
- pr_cont("\n")
Factor out print_nmi_seq_line() parts into a new printk_nmi_flush_line()
function, which takes care of in_nmi(), and use it in __printk_nmi_flush()
for printing and error-reporting.
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
---
kernel/printk/nmi.c | 38 +++++++++++++++++++++++---------------
1 file changed, 23 insertions(+), 15 deletions(-)
diff --git a/kernel/printk/nmi.c b/kernel/printk/nmi.c
index b69eb8a..16bab47 100644
--- a/kernel/printk/nmi.c
+++ b/kernel/printk/nmi.c
@@ -99,27 +99,33 @@ again:
return add;
}
-/*
- * printk one line from the temporary buffer from @start index until
- * and including the @end index.
- */
-static void print_nmi_seq_line(struct nmi_seq_buf *s, int start, int end)
+static void printk_nmi_flush_line(const char *text, int len)
{
- const char *buf = s->buffer + start;
-
/*
* The buffers are flushed in NMI only on panic. The messages must
* go only into the ring buffer at this stage. Consoles will get
* explicitly called later when a crashdump is not generated.
*/
if (in_nmi())
- printk_deferred("%.*s", (end - start) + 1, buf);
+ printk_deferred("%.*s", len, text);
else
- printk("%.*s", (end - start) + 1, buf);
+ printk("%.*s", len, text);
}
/*
+ * printk one line from the temporary buffer from @start index until
+ * and including the @end index.
+ */
+static void printk_nmi_flush_seq_line(struct nmi_seq_buf *s,
+ int start, int end)
+{
+ const char *buf = s->buffer + start;
+
+ printk_nmi_flush_line(buf, (end - start) + 1);
+}
+
+/*
* Flush data from the associated per_CPU buffer. The function
* can be called either via IRQ work or independently.
*/
@@ -150,9 +156,11 @@ more:
* the buffer an unexpected way. If we printed something then
* @len must only increase.
*/
- if (i && i >= len)
- pr_err("printk_nmi_flush: internal error: i=%d >= len=%zu\n",
- i, len);
+ if (i && i >= len) {
+ const char *msg = "printk_nmi_flush: internal error\n";
+
+ printk_nmi_flush_line(msg, strlen(msg));
+ }
if (!len)
goto out; /* Someone else has already flushed the buffer. */
@@ -166,14 +174,14 @@ more:
/* Print line by line. */
for (; i < size; i++) {
if (s->buffer[i] == '\n') {
- print_nmi_seq_line(s, last_i, i);
+ printk_nmi_flush_seq_line(s, last_i, i);
last_i = i + 1;
}
}
/* Check if there was a partial line. */
if (last_i < size) {
- print_nmi_seq_line(s, last_i, size - 1);
- pr_cont("\n");
+ printk_nmi_flush_seq_line(s, last_i, size - 1);
+ printk_nmi_flush_line("\n", strlen("\n"));
}
/*
--
2.9.3
next reply index
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-30 16:13 Sergey Senozhatsky [this message]
2016-08-30 22:03 ` Andrew Morton
2016-08-31 1:44 ` Sergey Senozhatsky
2016-08-31 20:15 ` Andrew Morton
2016-09-01 0:55 ` Sergey Senozhatsky
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20160830161354.581-1-sergey.senozhatsky@gmail.com \
--to=sergey.senozhatsky@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=jack@suse.cz \
--cc=linux-kernel@vger.kernel.org \
--cc=pmladek@suse.com \
--cc=sergey.senozhatsky.work@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
LKML Archive on lore.kernel.org
Archives are clonable:
git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git
git clone --mirror https://lore.kernel.org/lkml/8 lkml/git/8.git
git clone --mirror https://lore.kernel.org/lkml/9 lkml/git/9.git
# If you have public-inbox 1.1+ installed, you may
# initialize and index your mirror using the following commands:
public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
linux-kernel@vger.kernel.org
public-inbox-index lkml
Example config snippet for mirrors
Newsgroup available over NNTP:
nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel
AGPL code for this site: git clone https://public-inbox.org/public-inbox.git