power: supply: ltc2941-battery-gauge: fix use-after-free

[sagit-ice-cold/kernel_xiaomi_msm8998.git] / block / bio.c

diff --git a/block/bio.c b/block/bio.c
index 46e2cc1..cf513f7 100644 (file)
--- a/block/bio.c
+++ b/block/bio.c
@@ -373,10 +373,14 @@ static void punt_bios_to_rescuer(struct bio_set *bs)
        bio_list_init(&punt);
        bio_list_init(&nopunt);
 
-       while ((bio = bio_list_pop(current->bio_list)))
+       while ((bio = bio_list_pop(&current->bio_list[0])))
                bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio);
+       current->bio_list[0] = nopunt;
 
-       *current->bio_list = nopunt;
+       bio_list_init(&nopunt);
+       while ((bio = bio_list_pop(&current->bio_list[1])))
+               bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio);
+       current->bio_list[1] = nopunt;
 
        spin_lock(&bs->rescue_lock);
        bio_list_merge(&bs->rescue_list, &punt);
@@ -464,7 +468,9 @@ struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
                 * we retry with the original gfp_flags.
                 */
 
-               if (current->bio_list && !bio_list_empty(current->bio_list))
+               if (current->bio_list &&
+                   (!bio_list_empty(&current->bio_list[0]) ||
+                    !bio_list_empty(&current->bio_list[1])))
                        gfp_mask &= ~__GFP_DIRECT_RECLAIM;
 
                p = mempool_alloc(bs->bio_pool, gfp_mask);
@@ -1210,8 +1216,11 @@ struct bio *bio_copy_user_iov(struct request_queue *q,
                        }
                }
 
-               if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes)
+               if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes) {
+                       if (!map_data)
+                               __free_page(page);
                        break;
+               }
 
                len -= bytes;
                offset = 0;
@@ -1262,6 +1271,7 @@ struct bio *bio_map_user_iov(struct request_queue *q,
        int ret, offset;
        struct iov_iter i;
        struct iovec iov;
+       struct bio_vec *bvec;
 
        iov_for_each(iov, i, *iter) {
                unsigned long uaddr = (unsigned long) iov.iov_base;
@@ -1306,7 +1316,12 @@ struct bio *bio_map_user_iov(struct request_queue *q,
                ret = get_user_pages_fast(uaddr, local_nr_pages,
                                (iter->type & WRITE) != WRITE,
                                &pages[cur_page]);
-               if (ret < local_nr_pages) {
+               if (unlikely(ret < local_nr_pages)) {
+                       for (j = cur_page; j < page_limit; j++) {
+                               if (!pages[j])
+                                       break;
+                               put_page(pages[j]);
+                       }
                        ret = -EFAULT;
                        goto out_unmap;
                }
@@ -1314,6 +1329,7 @@ struct bio *bio_map_user_iov(struct request_queue *q,
                offset = uaddr & ~PAGE_MASK;
                for (j = cur_page; j < page_limit; j++) {
                        unsigned int bytes = PAGE_SIZE - offset;
+                       unsigned short prev_bi_vcnt = bio->bi_vcnt;
 
                        if (len <= 0)
                                break;
@@ -1328,6 +1344,13 @@ struct bio *bio_map_user_iov(struct request_queue *q,
                                            bytes)
                                break;
 
+                       /*
+                        * check if vector was merged with previous
+                        * drop page reference if needed
+                        */
+                       if (bio->bi_vcnt == prev_bi_vcnt)
+                               put_page(pages[j]);
+
                        len -= bytes;
                        offset = 0;
                }
@@ -1360,10 +1383,8 @@ struct bio *bio_map_user_iov(struct request_queue *q,
        return bio;
 
  out_unmap:
-       for (j = 0; j < nr_pages; j++) {
-               if (!pages[j])
-                       break;
-               page_cache_release(pages[j]);
+       bio_for_each_segment_all(bvec, bio, j) {
+               put_page(bvec->bv_page);
        }
  out:
        kfree(pages);