amd64_edac:__amd64_set_scrub_rate(): avoid overindexing scrubrates[]
If none of the elements in scrubrates[] matches, this loop will cause
__amd64_set_scrub_rate() to incorrectly use the n+1th element.
As the function is designed to use the final scrubrates[] element in the
case of no match, we can fix this bug by simply terminating the array
search at the n-1th element.
Boris: this code is fragile anyway, see here why:
http://marc.info/?l=linux-kernel&m=135102834131236&w=2
It will be rewritten more robustly soonish.
Reported-by: Denis Kirjanov <kirjanov@gmail.com>
Cc: stable@vger.kernel.org
Cc: Doug Thompson <dougthompson@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c
index 5a297a2..cc8e7c7 100644
--- a/drivers/edac/amd64_edac.c
+++ b/drivers/edac/amd64_edac.c
@@ -170,8 +170,11 @@
* memory controller and apply to register. Search for the first
* bandwidth entry that is greater or equal than the setting requested
* and program that. If at last entry, turn off DRAM scrubbing.
+ *
+ * If no suitable bandwidth is found, turn off DRAM scrubbing entirely
+ * by falling back to the last element in scrubrates[].
*/
- for (i = 0; i < ARRAY_SIZE(scrubrates); i++) {
+ for (i = 0; i < ARRAY_SIZE(scrubrates) - 1; i++) {
/*
* skip scrub rates which aren't recommended
* (see F10 BKDG, F3x58)
@@ -181,12 +184,6 @@
if (scrubrates[i].bandwidth <= new_bw)
break;
-
- /*
- * if no suitable bandwidth found, turn off DRAM scrubbing
- * entirely by falling back to the last element in the
- * scrubrates array.
- */
}
scrubval = scrubrates[i].scrubval;