Under memory pressure, it is possible for dirty_thresh, calculated by global_dirty_limits() in balance_dirty_pages(), to equal zero. Then, if strictlimit is true, bdi_dirty_limits() tries to resolve the proportion: bdi_bg_thresh : bdi_thresh = background_thresh : dirty_thresh by dividing by zero.
Unified · Split
| @@ -1306,9 +1306,9 @@ static inline void bdi_dirty_limits(struct backing_dev_info *bdi, · 1305 unmodified lines | |||
| 1306 | *bdi_thresh = bdi_dirty_limit(bdi, dirty_thresh); | 1306 | *bdi_thresh = bdi_dirty_limit(bdi, dirty_thresh); |
| 1307 | 1307 | ||
| 1308 | if (bdi_bg_thresh) | 1308 | if (bdi_bg_thresh) |
| 1309 | *bdi_bg_thresh = div_u64((u64)*bdi_thresh * | 1309 | *bdi_bg_thresh = dirty_thresh ? div_u64((u64)*bdi_thresh * |
| 1310 | background_thresh, | 1310 | background_thresh, |
| 1311 | dirty_thresh); | 1311 | dirty_thresh) : 0; |
| 1312 | 1312 | ||
| 1313 | /* | 1313 | /* |
| 1314 | * In order to avoid the stacked BDI deadlock we need | 1314 | * In order to avoid the stacked BDI deadlock we need |