When using devices that support max_segments > BIO_MAX_PAGES (256), direct IO tries to allocate a bio with more pages than allowed, which leads to an oops in dio_bio_alloc(). Clamp that request to the supported maximum. Signed-off-by: David Dillow <dillowda@xxxxxxxx> -- dio_bio_alloc() doesn't check the result of bio_alloc(), so it dereferences a NULL pointer. bio_alloc(GFP_KERNEL, ...) doesn't fail unless it gets called for an invalid number of pages, so it seems a bit like overkill to check for failure in dio_bio_alloc(), though it would have saved me some time tracking this down. diff --git a/fs/direct-io.c b/fs/direct-io.c index 85882f6..9eb0553 100644 --- a/fs/direct-io.c +++ b/fs/direct-io.c @@ -583,6 +583,7 @@ static int dio_new_bio(struct dio *dio, sector_t start_sector) goto out; sector = start_sector << (dio->blkbits - 9); nr_pages = min(dio->pages_in_io, bio_get_nr_vecs(dio->map_bh.b_bdev)); + nr_pages = min(nr_pages, BIO_MAX_PAGES); BUG_ON(nr_pages <= 0); ret = dio_bio_alloc(dio, dio->map_bh.b_bdev, sector, nr_pages); dio->boundary = 0; -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
