From: Alexander Potapenko glider@google.com
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@syzkaller.appspotmail.com CC: stable@vger.kernel.org # 5.4+ Signed-off-by: Alexander Potapenko glider@google.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/btrfs/zlib.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c index b4f44662cda7c..94d06a76edb17 100644 --- a/fs/btrfs/zlib.c +++ b/fs/btrfs/zlib.c @@ -63,7 +63,7 @@ struct list_head *zlib_alloc_workspace(unsigned int level)
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 = NULL; /*