From: Alexander Potapenko Date: Tue, 24 Jan 2023 11:32:34 +0000 (+0100) Subject: btrfs: zlib: zero-initialize zlib workspace X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=eadd7deca0ad8a83edb2b894d8326c78e78635d6;p=linux.git btrfs: zlib: zero-initialize zlib workspace 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 Reviewed-by: David Sterba Signed-off-by: David Sterba --- diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c index 01a13de118320..da7bb9187b68a 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; /*