From 9511f9c7cd45eecbf46537be6ae244306f16bc1d Mon Sep 17 00:00:00 2001 From: Tim Bird Date: Tue, 7 Feb 2012 18:34:28 -0800 Subject: [PATCH] staging: android: logger: clarify non-update of w_off in do_write_log_from_user Add comment to explain when w_off is not updated in case of failed second fragment copy to buffer. Signed-off-by: Tim Bird Signed-off-by: Greg Kroah-Hartman --- drivers/staging/android/logger.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/staging/android/logger.c b/drivers/staging/android/logger.c index 6d92b7e..0d2367f 100644 --- a/drivers/staging/android/logger.c +++ b/drivers/staging/android/logger.c @@ -330,6 +330,12 @@ static ssize_t do_write_log_from_user(struct logger_log *log, if (count != len) if (copy_from_user(log->buffer, buf + len, count - len)) + /* + * Note that by not updating w_off, this abandons the + * portion of the new entry that *was* successfully + * copied, just above. This is intentional to avoid + * message corruption from missing fragments. + */ return -EFAULT; log->w_off = logger_offset(log, log->w_off + count); -- 2.7.4