From: Andrew Morton Date: Tue, 23 Oct 2012 21:09:39 +0000 (-0700) Subject: amd64_edac:__amd64_set_scrub_rate(): avoid overindexing scrubrates[] X-Git-Tag: v3.0.49~16 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=a322f9a0799883553a0898c7062a944ff64a3056;p=karo-tx-linux.git 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 Cc: Doug Thompson Signed-off-by: Andrew Morton Signed-off-by: Borislav Petkov Signed-off-by: Greg Kroah-Hartman --- 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;