From: Matteo Croce <mcroce@xxxxxxxxxxxxxxxxxxx> commit fd49e03280e596e54edb93a91bc96170f8e97e4a upstream. When building a kernel with CONFIG_PSTORE=y and CONFIG_CRYPTO not set, a build error happens: ld: fs/pstore/platform.o: in function `pstore_dump': platform.c:(.text+0x3f9): undefined reference to `crypto_comp_compress' ld: fs/pstore/platform.o: in function `pstore_get_backend_records': platform.c:(.text+0x784): undefined reference to `crypto_comp_decompress' This because some pstore code uses crypto_comp_(de)compress regardless of the CONFIG_CRYPTO status. Fix it by wrapping the (de)compress usage by IS_ENABLED(CONFIG_PSTORE_COMPRESS) Signed-off-by: Matteo Croce <mcroce@xxxxxxxxxxxxxxxxxxx> Link: https://lore.kernel.org/lkml/20200706234045.9516-1-mcroce@xxxxxxxxxxxxxxxxxxx Fixes: cb3bee0369bc ("pstore: Use crypto compress API") Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/pstore/platform.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/fs/pstore/platform.c +++ b/fs/pstore/platform.c @@ -269,6 +269,9 @@ static int pstore_compress(const void *i { int ret; + if (!IS_ENABLED(CONFIG_PSTORE_COMPRESSION)) + return -EINVAL; + ret = crypto_comp_compress(tfm, in, inlen, out, &outlen); if (ret) { pr_err("crypto_comp_compress failed, ret = %d!\n", ret); @@ -668,7 +671,7 @@ static void decompress_record(struct pst int unzipped_len; char *unzipped, *workspace; - if (!record->compressed) + if (!IS_ENABLED(CONFIG_PSTORE_COMPRESSION) || !record->compressed) return; /* Only PSTORE_TYPE_DMESG support compression. */