Commit 70ad35db authored Oct 19, 2016 by Namhyung Kim Committed by Kees Cook Nov 15, 2016

pstore: Convert console write to use ->write_buf



Maybe I'm missing something, but I don't know why it needs to copy the
input buffer to psinfo->buf and then write.  Instead we can write the
input buffer directly.  The only implementation that supports console
message (i.e. ramoops) already does it for ftrace messages.

For the upcoming virtio backend driver, it needs to protect psinfo->buf
overwritten from console messages.  If it could use ->write_buf method
instead of ->write, the problem will be solved easily.

Cc: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>

parent e9e360b0

fs/pstore/platform.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -585,8 +585,8 @@ static void pstore_console_write(struct console con, const char s, unsigned c)
		} else {
		spin_lock_irqsave(&psinfo->buf_lock, flags);
		}
		memcpy(psinfo->buf, s, c);
		psinfo->write(PSTORE_TYPE_CONSOLE, 0, &id, 0, 0, 0, c, psinfo);
		psinfo->write_buf(PSTORE_TYPE_CONSOLE, 0, &id, 0,
		s, 0, c, psinfo);
		spin_unlock_irqrestore(&psinfo->buf_lock, flags);
		s += c;
		c = e - s;

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