commit 1e817fb62cd185a2232ad4302579491805609489
author Kees Cook <keescook@chromium.org> Mon Nov 19 10:26:16 2012 -0800
committer John Stultz <john.stultz@linaro.org> Tue Jan 15 18:16:02 2013 -0800
tree d4155fb65a9fb32cd9236405a8b7534f39c293b9
parent 9c3f9e281697d02889c3b08922f3b30be75f56c2

time: create __getnstimeofday for WARNless calls

The pstore RAM backend can get called during resume, and must be defensive
against a suspended time source. Expose getnstimeofday logic that returns
an error instead of a WARN. This can be detected and the timestamp can
be zeroed out.

Reported-by: Doug Anderson <dianders@chromium.org>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Anton Vorontsov <anton.vorontsov@linaro.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>

fs/pstore/ram.c

diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 1a4f6da..dacfe78 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -168,12 +168,16 @@
 static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz)
 {
 	char *hdr;
-	struct timeval timestamp;
+	struct timespec timestamp;
 	size_t len;
 
-	do_gettimeofday(&timestamp);
+	/* Report zeroed timestamp if called before timekeeping has resumed. */
+	if (__getnstimeofday(&timestamp)) {
+		timestamp.tv_sec = 0;
+		timestamp.tv_nsec = 0;
+	}
 	hdr = kasprintf(GFP_ATOMIC, RAMOOPS_KERNMSG_HDR "%lu.%lu\n",
-		(long)timestamp.tv_sec, (long)timestamp.tv_usec);
+		(long)timestamp.tv_sec, (long)(timestamp.tv_nsec / 1000));
 	WARN_ON_ONCE(!hdr);
 	len = hdr ? strlen(hdr) : 0;
 	persistent_ram_write(prz, hdr, len);