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authorAndrew Morton <akpm@linux-foundation.org>2012-10-23 14:09:39 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-10-28 10:02:12 -0700
commita322f9a0799883553a0898c7062a944ff64a3056 (patch)
tree87863d7901ea1754290b39324e88f65c6b5a185d /drivers
parentf0c76f5fa97e436cf24cb57a4aeceb7c83835704 (diff)
amd64_edac:__amd64_set_scrub_rate(): avoid overindexing scrubrates[]
commit 168bfeef7bba3f9784f7540b053e4ac72b769ce9 upstream. 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: Doug Thompson <dougthompson@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Borislav Petkov <borislav.petkov@amd.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/edac/amd64_edac.c11
1 files changed, 4 insertions, 7 deletions
diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c
index 9a8bebcf6b17..feb2d10bba66 100644
--- a/drivers/edac/amd64_edac.c
+++ b/drivers/edac/amd64_edac.c
@@ -161,8 +161,11 @@ static int __amd64_set_scrub_rate(struct pci_dev *ctl, u32 new_bw, u32 min_rate)
* 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)
@@ -172,12 +175,6 @@ static int __amd64_set_scrub_rate(struct pci_dev *ctl, u32 new_bw, u32 min_rate)
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;