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Date: Wed, 21 Dec 2016 23:36:02 +0900 From: Sergey Senozhatsky <sergey.senozhatsky@...il.com> To: Andrew Morton <akpm@...ux-foundation.org> Cc: Petr Mladek <pmladek@...e.com>, Jan Kara <jack@...e.cz>, Tejun Heo <tj@...nel.org>, Calvin Owens <calvinowens@...com>, Steven Rostedt <rostedt@...dmis.org>, Ingo Molnar <mingo@...hat.com>, Peter Zijlstra <peterz@...radead.org>, Andy Lutomirski <luto@...nel.org>, Linus Torvalds <torvalds@...ux-foundation.org>, Peter Hurley <peter@...leysoftware.com>, linux-kernel@...r.kernel.org, Sergey Senozhatsky <sergey.senozhatsky@...il.com>, Sergey Senozhatsky <sergey.senozhatsky.work@...il.com> Subject: [PATCHv6 4/7] printk: always use deferred printk when flush printk_safe lines 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@...il.com> Suggested-by: Petr Mladek <pmladek@...e.com> Reviewed-by: Petr Mladek <pmladek@...e.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
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