From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Petr Mladek <pmladek@suse.com>, Jan Kara <jack@suse.cz>,
Tejun Heo <tj@kernel.org>, Calvin Owens <calvinowens@fb.com>,
Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Andy Lutomirski <luto@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Peter Hurley <peter@hurleysoftware.com>,
linux-kernel@vger.kernel.org,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Subject: [PATCHv6 4/7] printk: always use deferred printk when flush printk_safe lines
Date: Wed, 21 Dec 2016 23:36:02 +0900 [thread overview]
Message-ID: <20161221143605.2272-5-sergey.senozhatsky@gmail.com> (raw)
In-Reply-To: <20161221143605.2272-1-sergey.senozhatsky@gmail.com>
Always use printk_deferred() in printk_safe_flush_line().
Flushing can be done from NMI or printk_safe contexts (when
we are in panic), so we can't call console drivers, yet still
want to store the messages in the logbuf buffer. Therefore we
use a deferred printk version.
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Suggested-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
---
kernel/printk/printk_safe.c | 12 +++++-------
1 file changed, 5 insertions(+), 7 deletions(-)
diff --git a/kernel/printk/printk_safe.c b/kernel/printk/printk_safe.c
index a041927a127b..9e8ef6a2070c 100644
--- a/kernel/printk/printk_safe.c
+++ b/kernel/printk/printk_safe.c
@@ -113,14 +113,12 @@ static int printk_safe_log_store(struct printk_safe_seq_buf *s,
static void printk_safe_flush_line(const char *text, int len)
{
/*
- * 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.
+ * Avoid any console drivers calls from here, because we may be
+ * in NMI or printk_safe context (when in 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", len, text);
- else
- printk("%.*s", len, text);
+ printk_deferred("%.*s", len, text);
}
/* printk part of the temporary buffer line by line */
--
2.11.0
next prev parent reply other threads:[~2016-12-21 14:41 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-21 14:35 [PATCHv6 0/7] printk: use printk_safe to handle printk() recursive calls Sergey Senozhatsky
2016-12-21 14:35 ` [PATCHv6 1/7] printk: use vprintk_func in vprintk() Sergey Senozhatsky
2016-12-21 14:36 ` [PATCHv6 2/7] printk: rename nmi.c and exported api Sergey Senozhatsky
2016-12-21 19:45 ` Linus Torvalds
2016-12-22 1:17 ` Sergey Senozhatsky
2016-12-21 14:36 ` [PATCHv6 3/7] printk: introduce per-cpu safe_print seq buffer Sergey Senozhatsky
2016-12-22 0:53 ` kbuild test robot
2016-12-22 1:18 ` Sergey Senozhatsky
2016-12-22 16:36 ` Petr Mladek
2016-12-21 14:36 ` Sergey Senozhatsky [this message]
2016-12-21 14:36 ` [PATCHv6 5/7] printk: report lost messages in printk safe/nmi contexts Sergey Senozhatsky
2016-12-23 10:54 ` Petr Mladek
2016-12-23 15:08 ` Sergey Senozhatsky
2016-12-21 14:36 ` [PATCHv6 6/7] printk: use printk_safe buffers in printk Sergey Senozhatsky
2016-12-22 5:31 ` Sergey Senozhatsky
2016-12-22 17:10 ` Petr Mladek
2016-12-23 1:46 ` Sergey Senozhatsky
2016-12-23 9:53 ` Petr Mladek
2016-12-21 14:36 ` [PATCHv6 7/7] printk: remove zap_locks() function Sergey Senozhatsky
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