On Mon, Dec 05, 2022 at 11:49:57AM +0800, Chen Zhongjin wrote: > syzkaller reported a memleak: > https://syzkaller.appspot.com/bug?id=62f37ff612f0021641eda5b17f056f1668aa9aed > > unreferenced object 0xffff88811009c7f8 (size 136): > ... > backtrace: > [<ffffffff821db19b>] z_erofs_do_read_page+0x99b/0x1740 > [<ffffffff821dee9e>] z_erofs_readahead+0x24e/0x580 > [<ffffffff814bc0d6>] read_pages+0x86/0x3d0 > ... > > syzkaller constructed a case: in z_erofs_register_pcluster(), > ztailpacking = false and map->m_pa = zero. This makes pcl->obj.index be > zero although pcl is not a inline pcluster. > > Then following path adds refcount for grp, but the refcount won't be put > because pcl is inline. > > z_erofs_readahead() > z_erofs_do_read_page() # for another page > z_erofs_collector_begin() > erofs_find_workgroup() > erofs_workgroup_get() > > Since it's illegal for the block address of a pcluster to be zero, add > check here to avoid registering the pcluster which would be leaked. > > Fixes: cecf864d3d76 ("erofs: support inline data decompression") > Reported-by: [email protected] > Signed-off-by: Chen Zhongjin <[email protected]>
Reviewed-by: Gao Xiang <[email protected]> Thanks, Gao Xiang
