linux-kernel - Re: [PATCH 5/7] bcachefs: Fix -Wincompatible-function-pointer-types-strict from key

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Message-ID: <20230913215752.dj3jbeth3j6f7udc@google.com>
Date:   Wed, 13 Sep 2023 21:57:52 +0000
From:   Justin Stitt <justinstitt@...gle.com>
To:     Nathan Chancellor <nathan@...nel.org>
Cc:     kent.overstreet@...ux.dev, bfoster@...hat.com,
        linux-bcachefs@...r.kernel.org, linux-kernel@...r.kernel.org,
        llvm@...ts.linux.dev, patches@...ts.linux.dev
Subject: Re: [PATCH 5/7] bcachefs: Fix
 -Wincompatible-function-pointer-types-strict from key_invalid callbacks

On Tue, Sep 12, 2023 at 12:15:42PM -0700, Nathan Chancellor wrote:
> When building bcachefs with -Wincompatible-function-pointer-types-strict,
> a clang warning designed to catch issues with mismatched function
> pointer types, which will be fatal at runtime due to kernel Control Flow
> Integrity (kCFI), there are several instances along the lines of:
>
>   fs/bcachefs/bkey_methods.c:118:2: error: incompatible function pointer types initializing 'int (*)(const struct bch_fs *, struct bkey_s_c, enum bkey_invalid_flags, struct printbuf *)' with an expression of type 'int (const struct bch_fs *, struct bkey_s_c, unsigned int, struct printbuf *)' [-Werror,-Wincompatible-function-pointer-types-strict]
>     118 |         BCH_BKEY_TYPES()
>         |         ^~~~~~~~~~~~~~~~
>   fs/bcachefs/bcachefs_format.h:342:2: note: expanded from macro 'BCH_BKEY_TYPES'
>     342 |         x(deleted,              0)                      \
>         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~
>   fs/bcachefs/bkey_methods.c:117:41: note: expanded from macro 'x'
>     117 | #define x(name, nr) [KEY_TYPE_##name]   = bch2_bkey_ops_##name,
>         |                                           ^~~~~~~~~~~~~~~~~~~~
>   <scratch space>:206:1: note: expanded from here
>     206 | bch2_bkey_ops_deleted
>         | ^~~~~~~~~~~~~~~~~~~~~
>   fs/bcachefs/bkey_methods.c:34:17: note: expanded from macro 'bch2_bkey_ops_deleted'
>      34 |         .key_invalid = deleted_key_invalid,             \
>         |                        ^~~~~~~~~~~~~~~~~~~
>
> The flags parameter should be of type 'enum bkey_invalid_flags', not
> 'unsigned int'. Adjust the type everywhere so that there is no more
> warning.
>
> Signed-off-by: Nathan Chancellor <nathan@...nel.org>
Reviewed-by: Justin Stitt <justinstitt@...gle.com>
> ---
>  fs/bcachefs/bkey_methods.c | 10 +++++-----
>  fs/bcachefs/subvolume.c    |  2 +-
>  fs/bcachefs/subvolume.h    |  2 +-
>  3 files changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/fs/bcachefs/bkey_methods.c b/fs/bcachefs/bkey_methods.c
> index 6547142db428..2a284c954c7a 100644
> --- a/fs/bcachefs/bkey_methods.c
> +++ b/fs/bcachefs/bkey_methods.c
> @@ -25,7 +25,7 @@ const char * const bch2_bkey_types[] = {
>  };
>
>  static int deleted_key_invalid(const struct bch_fs *c, struct bkey_s_c k,
> -			       unsigned flags, struct printbuf *err)
> +			       enum bkey_invalid_flags flags, struct printbuf *err)
>  {
>  	return 0;
>  }
> @@ -39,7 +39,7 @@ static int deleted_key_invalid(const struct bch_fs *c, struct bkey_s_c k,
>  })
>
>  static int empty_val_key_invalid(const struct bch_fs *c, struct bkey_s_c k,
> -				 unsigned flags, struct printbuf *err)
> +				 enum bkey_invalid_flags flags, struct printbuf *err)
>  {
>  	if (bkey_val_bytes(k.k)) {
>  		prt_printf(err, "incorrect value size (%zu != 0)",
> @@ -55,7 +55,7 @@ static int empty_val_key_invalid(const struct bch_fs *c, struct bkey_s_c k,
>  })
>
>  static int key_type_cookie_invalid(const struct bch_fs *c, struct bkey_s_c k,
> -				   unsigned flags, struct printbuf *err)
> +				   enum bkey_invalid_flags flags, struct printbuf *err)
>  {
>  	return 0;
>  }
> @@ -70,7 +70,7 @@ static int key_type_cookie_invalid(const struct bch_fs *c, struct bkey_s_c k,
>  })
>
>  static int key_type_inline_data_invalid(const struct bch_fs *c, struct bkey_s_c k,
> -					unsigned flags, struct printbuf *err)
> +					enum bkey_invalid_flags flags, struct printbuf *err)
>  {
>  	return 0;
>  }
> @@ -91,7 +91,7 @@ static void key_type_inline_data_to_text(struct printbuf *out, struct bch_fs *c,
>  })
>
>  static int key_type_set_invalid(const struct bch_fs *c, struct bkey_s_c k,
> -				unsigned flags, struct printbuf *err)
> +				enum bkey_invalid_flags flags, struct printbuf *err)
>  {
>  	if (bkey_val_bytes(k.k)) {
>  		prt_printf(err, "incorrect value size (%zu != %zu)",
> diff --git a/fs/bcachefs/subvolume.c b/fs/bcachefs/subvolume.c
> index 0214a98deb4f..b371a5c4e06e 100644
> --- a/fs/bcachefs/subvolume.c
> +++ b/fs/bcachefs/subvolume.c
> @@ -99,7 +99,7 @@ int bch2_check_subvols(struct bch_fs *c)
>  /* Subvolumes: */
>
>  int bch2_subvolume_invalid(const struct bch_fs *c, struct bkey_s_c k,
> -			   unsigned flags, struct printbuf *err)
> +			   enum bkey_invalid_flags flags, struct printbuf *err)
>  {
>  	if (bkey_lt(k.k->p, SUBVOL_POS_MIN) ||
>  	    bkey_gt(k.k->p, SUBVOL_POS_MAX)) {
> diff --git a/fs/bcachefs/subvolume.h b/fs/bcachefs/subvolume.h
> index 8d4c50f4cd05..bb14f92e8687 100644
> --- a/fs/bcachefs/subvolume.h
> +++ b/fs/bcachefs/subvolume.h
> @@ -10,7 +10,7 @@ enum bkey_invalid_flags;
>  int bch2_check_subvols(struct bch_fs *);
>
>  int bch2_subvolume_invalid(const struct bch_fs *, struct bkey_s_c,
> -			   unsigned, struct printbuf *);
> +			   enum bkey_invalid_flags, struct printbuf *);
>  void bch2_subvolume_to_text(struct printbuf *, struct bch_fs *, struct bkey_s_c);
>
>  #define bch2_bkey_ops_subvolume ((struct bkey_ops) {		\
>
> --
> 2.42.0
>