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| author | Qu Wenruo <quwenruo@cn.fujitsu.com> | 2017-03-29 03:33:22 +0200 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2017-04-18 14:07:26 +0200 |
| commit | e501bfe323356ea3f7ef79d4b0d95389b70a7193 (patch) | |
| tree | 870724f193b99f9388dce8e7cbdfcb96b3cfeed5 /fs/btrfs | |
| parent | btrfs: Wait for in-flight bios before freeing target device for raid56 (diff) | |
| download | linux-e501bfe323356ea3f7ef79d4b0d95389b70a7193.tar.xz linux-e501bfe323356ea3f7ef79d4b0d95389b70a7193.zip | |
btrfs: Prevent scrub recheck from racing with dev replace
scrub_setup_recheck_block() calls btrfs_map_sblock() and then accesses
bbio without protection of bio_counter.
This can lead to use-after-free if racing with dev replace cancel.
Fix it by increasing bio_counter before calling btrfs_map_sblock() and
decreasing the bio_counter when corresponding recover is finished.
Cc: Liu Bo <bo.li.liu@oracle.com>
Reported-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs')
| -rw-r--r-- | fs/btrfs/scrub.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index e9612016325f..c4d1e60e831e 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -860,9 +860,11 @@ static inline void scrub_get_recover(struct scrub_recover *recover) refcount_inc(&recover->refs); } -static inline void scrub_put_recover(struct scrub_recover *recover) +static inline void scrub_put_recover(struct btrfs_fs_info *fs_info, + struct scrub_recover *recover) { if (refcount_dec_and_test(&recover->refs)) { + btrfs_bio_counter_dec(fs_info); btrfs_put_bbio(recover->bbio); kfree(recover); } @@ -1241,7 +1243,7 @@ out: sblock->pagev[page_index]->sblock = NULL; recover = sblock->pagev[page_index]->recover; if (recover) { - scrub_put_recover(recover); + scrub_put_recover(fs_info, recover); sblock->pagev[page_index]->recover = NULL; } @@ -1330,16 +1332,19 @@ static int scrub_setup_recheck_block(struct scrub_block *original_sblock, * with a length of PAGE_SIZE, each returned stripe * represents one mirror */ + btrfs_bio_counter_inc_blocked(fs_info); ret = btrfs_map_sblock(fs_info, BTRFS_MAP_GET_READ_MIRRORS, logical, &mapped_length, &bbio); if (ret || !bbio || mapped_length < sublen) { btrfs_put_bbio(bbio); + btrfs_bio_counter_dec(fs_info); return -EIO; } recover = kzalloc(sizeof(struct scrub_recover), GFP_NOFS); if (!recover) { btrfs_put_bbio(bbio); + btrfs_bio_counter_dec(fs_info); return -ENOMEM; } @@ -1365,7 +1370,7 @@ leave_nomem: spin_lock(&sctx->stat_lock); sctx->stat.malloc_errors++; spin_unlock(&sctx->stat_lock); - scrub_put_recover(recover); + scrub_put_recover(fs_info, recover); return -ENOMEM; } scrub_page_get(page); @@ -1407,7 +1412,7 @@ leave_nomem: scrub_get_recover(recover); page->recover = recover; } - scrub_put_recover(recover); + scrub_put_recover(fs_info, recover); length -= sublen; logical += sublen; page_index++; |