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authorAndrew Morton <akpm@linux-foundation.org>2012-10-23 17:09:39 -0400
committerBorislav Petkov <borislav.petkov@amd.com>2012-10-24 10:13:27 -0400
commit168bfeef7bba3f9784f7540b053e4ac72b769ce9 (patch)
treea02890616eb3d65377be628ff9cd1b577beb36df /drivers/edac/amd64_edac.c
parent6f0c0580b70c89094b3422ba81118c7b959c7556 (diff)
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>
Diffstat (limited to 'drivers/edac/amd64_edac.c')
-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 5a297a26211d..cc8e7c78a23c 100644
--- a/drivers/edac/amd64_edac.c
+++ b/drivers/edac/amd64_edac.c
@@ -170,8 +170,11 @@ static int __amd64_set_scrub_rate(struct pci_dev *ctl, u32 new_bw, u32 min_rate)
170 * memory controller and apply to register. Search for the first 170 * memory controller and apply to register. Search for the first
171 * bandwidth entry that is greater or equal than the setting requested 171 * bandwidth entry that is greater or equal than the setting requested
172 * and program that. If at last entry, turn off DRAM scrubbing. 172 * and program that. If at last entry, turn off DRAM scrubbing.
173 *
174 * If no suitable bandwidth is found, turn off DRAM scrubbing entirely
175 * by falling back to the last element in scrubrates[].
173 */ 176 */
174 for (i = 0; i < ARRAY_SIZE(scrubrates); i++) { 177 for (i = 0; i < ARRAY_SIZE(scrubrates) - 1; i++) {
175 /* 178 /*
176 * skip scrub rates which aren't recommended 179 * skip scrub rates which aren't recommended
177 * (see F10 BKDG, F3x58) 180 * (see F10 BKDG, F3x58)
@@ -181,12 +184,6 @@ static int __amd64_set_scrub_rate(struct pci_dev *ctl, u32 new_bw, u32 min_rate)
181 184
182 if (scrubrates[i].bandwidth <= new_bw) 185 if (scrubrates[i].bandwidth <= new_bw)
183 break; 186 break;
184
185 /*
186 * if no suitable bandwidth found, turn off DRAM scrubbing
187 * entirely by falling back to the last element in the
188 * scrubrates array.
189 */
190 } 187 }
191 188
192 scrubval = scrubrates[i].scrubval; 189 scrubval = scrubrates[i].scrubval;