From: Alexander Potapenko <glider@xxxxxxxxxx> commit eadd7deca0ad8a83edb2b894d8326c78e78635d6 upstream. KMSAN reports uses of uninitialized memory in zlib's longest_match() called on memory originating from zlib_alloc_workspace(). This issue is known by zlib maintainers and is claimed to be harmless, but to be on the safe side we'd better initialize the memory. Link: https://zlib.net/zlib_faq.html#faq36 Reported-by: syzbot+14d9e7602ebdf7ec0a60@xxxxxxxxxxxxxxxxxxxxxxxxx CC: stable@xxxxxxxxxxxxxxx # 5.4+ Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx> Reviewed-by: David Sterba <dsterba@xxxxxxxx> Signed-off-by: David Sterba <dsterba@xxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/btrfs/zlib.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/btrfs/zlib.c +++ b/fs/btrfs/zlib.c @@ -74,7 +74,7 @@ static struct list_head *zlib_alloc_work workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL), zlib_inflate_workspacesize()); - workspace->strm.workspace = kvmalloc(workspacesize, GFP_KERNEL); + workspace->strm.workspace = kvzalloc(workspacesize, GFP_KERNEL); workspace->level = level; workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL); if (!workspace->strm.workspace || !workspace->buf)
