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b=MwLjnXSfviTLdq9jtCBRjJ7TPc9rArvu5BF3yFxT0cBqG9x+tyTogp3Lc1qhqh69z uFYHFpG+VHxUsHihLc2TEeIMZaNdOTaRKyPVSaaCG2ZWqWjAG8ECUTigaHOf7wnTnf RAAQ+ZzkPvmTAXk3o0B57Ycpi0EQNrzDRjbTKeRFb2Glgyi/RixYR+X/IhBEPyJjra LRgi9kiXOjL1vTXk/wXBk0JScPth0gyJ+zmDjjpZI32zSvraREHR9k3aGPRouVwKIO jb0cgkDx1MUX21IY4W2XWSqg9/GOSjWSkAnMoSoOA9yTPnikigu2dz0CxtaZg5e4BE PD2T3jkLXTXUQ== From: Christian Brauner Date: Fri, 10 Jul 2026 00:30:09 +0200 Subject: [PATCH v2 14/23] binfmt_misc: return errors directly in load_misc_binary() MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260710-work-binfmt_misc-locking-v2-14-2a1c3d4126a7@kernel.org> References: <20260710-work-binfmt_misc-locking-v2-0-2a1c3d4126a7@kernel.org> In-Reply-To: <20260710-work-binfmt_misc-locking-v2-0-2a1c3d4126a7@kernel.org> To: linux-fsdevel@vger.kernel.org Cc: Alexander Viro , Christian Brauner , Jan Kara , linux-mm@kvack.org, Farid Zakaria , jannh@google.com X-Mailer: b4 0.16-dev-4217c X-Developer-Signature: v=1; a=openpgp-sha256; l=3789; i=brauner@kernel.org; h=from:subject:message-id; bh=Ll2FrYd9HjDHtPC5X13nUkIPqoyZg+Kg0S/zH98yQME=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWQFKHzl8J5u+SBfcfE922cCkXozTteofjMx471atNDmk 9WfhYeLOkpZGMS4GGTFFFkc2k3C5ZbzVGw2ytSAmcPKBDKEgYtTACZSdJLhf3C21+HtRWVMAjEt 0dIzVh4/P+tB6Ubj4k5h1sMqB0tkWRj+mcwJaOypT58RU+zIkSes+fni8QOflnZcySh92Lbz/+/ f3AA= X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: BD98340014 X-Stat-Signature: 4esnwosakddfgz3eqoif7c8s17753oox X-Rspam-User: X-HE-Tag: 1783636244-717475 X-HE-Meta: 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 rPIWZRNt Al9/p5peCSlgXFu8JcyxcSECS4n76EHcoXXQ4kdFI4XIGdRiULi1/BCEPkKdAhAS0KYFOoKiXtKcL+GzsDESnvgvYYQdcQisHNQ9BGPClbwklCDPWIxnZmWQVMMwXryCHABvTZWHMWRHKlbznaSRi9lNjlFkImSEfh7g4/Rqi2NJZKu3/wb41I5l0dq9CLGL1F0O/viEyQoRlKNWP6xxJVag6yuqLLnghB0xCYJggnYkByA/WUr8fxSG9v3Vh6mbgqQPx8nZZvx+MnU1R6R0/8TJVfLhrOlD5MuuDOojh1saPxUVxYisgWkzF6xJlFW7qfwFqw9SGJ7/4F3mMDIP9oh0h3Bqj6XdjQhQH7jMcwcmYbsrHw4xdqqJ2ch+Dkcun4OOc+54QQK81k6L7UzKor0fOLoaKOpqgfGCis3mgqx94HSg= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: load_misc_binary() seeds retval with the error for checks that happen further down, reassigns it along the way and funnels every exit through a ret label whose only job is dropping the entry reference, so figuring out what an early return actually returns means replaying the assignment history. Give put_binfmt_handler() a cleanup class and take the reference with __free() so every failure can return its error right where the condition is checked. The comment at the label restated what the put_binfmt_handler() kernel-doc already explains, it goes with the label. Drop the dead NULL initialization of interp_file which is assigned on all paths before use. No functional change. Signed-off-by: Christian Brauner (Amutable) --- fs/binfmt_misc.c | 41 ++++++++++++++--------------------------- 1 file changed, 14 insertions(+), 27 deletions(-) diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c index ac2276eeff4e..4172c0937161 100644 --- a/fs/binfmt_misc.c +++ b/fs/binfmt_misc.c @@ -183,6 +183,8 @@ static void put_binfmt_handler(struct binfmt_misc_entry *e) } } +DEFINE_FREE(put_binfmt_handler, struct binfmt_misc_entry *, if (_T) put_binfmt_handler(_T)) + /** * current_binfmt_misc - get the binfmt_misc instance of the caller's user namespace * @@ -215,30 +217,29 @@ static struct binfmt_misc *current_binfmt_misc(void) */ static int load_misc_binary(struct linux_binprm *bprm) { - struct binfmt_misc_entry *fmt; - struct file *interp_file = NULL; - int retval = -ENOEXEC; + struct binfmt_misc_entry *fmt __free(put_binfmt_handler) = NULL; + struct file *interp_file; struct binfmt_misc *misc; + int retval; misc = current_binfmt_misc(); if (!READ_ONCE(misc->enabled)) - return retval; + return -ENOEXEC; fmt = get_binfmt_handler(misc, bprm); if (!fmt) - return retval; + return -ENOEXEC; /* Need to be able to load the file after exec */ - retval = -ENOENT; if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE) - goto ret; + return -ENOENT; if (fmt->flags & MISC_FMT_PRESERVE_ARGV0) { bprm->interp_flags |= BINPRM_FLAGS_PRESERVE_ARGV0; } else { retval = remove_arg_zero(bprm); if (retval) - goto ret; + return retval; } if (fmt->flags & MISC_FMT_OPEN_BINARY) @@ -247,19 +248,19 @@ static int load_misc_binary(struct linux_binprm *bprm) /* make argv[1] be the path to the binary */ retval = copy_string_kernel(bprm->interp, bprm); if (retval < 0) - goto ret; + return retval; bprm->argc++; /* add the interp as argv[0] */ retval = copy_string_kernel(fmt->interpreter, bprm); if (retval < 0) - goto ret; + return retval; bprm->argc++; /* Update interp in case binfmt_script needs it. */ retval = bprm_change_interp(fmt->interpreter, bprm); if (retval < 0) - goto ret; + return retval; if (fmt->flags & MISC_FMT_OPEN_FILE) { interp_file = file_clone_open(fmt->interp_file); @@ -274,27 +275,13 @@ static int load_misc_binary(struct linux_binprm *bprm) } else { interp_file = open_exec(fmt->interpreter); } - retval = PTR_ERR(interp_file); if (IS_ERR(interp_file)) - goto ret; + return PTR_ERR(interp_file); bprm->interpreter = interp_file; if (fmt->flags & MISC_FMT_CREDENTIALS) bprm->execfd_creds = 1; - - retval = 0; -ret: - - /* - * If we actually put the entry here all concurrent calls to - * load_misc_binary() will have finished. We also know - * that for the refcount to be zero someone must have concurently - * removed the binary type handler from the list and it's our job to - * free it. - */ - put_binfmt_handler(fmt); - - return retval; + return 0; } /* Command parsers */ -- 2.53.0