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Commit 168bfeef7bba3f9784f7540b053e4ac72b769ce9

Authored by Andrew Morton
Committed by Borislav Petkov
1 parent 6f0c0580b7
Exists in smarc-l5.0.0_1.0.0-ga and in 5 other branches imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga

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>

Showing 1 changed file with 4 additions and 7 deletions Side-by-side Diff

drivers/edac/amd64_edac.c
Diff comments   View file @ 168bfee
... ... @@ -170,8 +170,11 @@
170 170 * memory controller and apply to register. Search for the first
171 171 * bandwidth entry that is greater or equal than the setting requested
172 172 * 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 /*
176 179 * skip scrub rates which aren't recommended
177 180 * (see F10 BKDG, F3x58)
... ... @@ -181,12 +184,6 @@
181 184  
182 185 if (scrubrates[i].bandwidth <= new_bw)
183 186 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  
192 189 scrubval = scrubrates[i].scrubval;