Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8AFB9272E53; Thu, 20 Aug 2026 16:39:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787243972; cv=none; b=KlNeA3TykZ4MdoOfQbF/B8zJu/dMyrPJ0Untt4ty/qLGgpudcLlImxcKMtZS285S7U3wwc0qavVMBhOG/hPrJ2YyAuy5AC64ptuauVL7+uxuHJg/iL4ECW58RLB7+p3R3UlcT/BmZ20mA/YoZucyfASzPuavO5NvDuQFnWTUmYw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787243972; c=relaxed/simple; bh=RVQt0AjSLiGBwlWqz0txi1JYuJ1UsO6U7r1iAu+gzys=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Bnksn3HUqPdV7TBJsBlNS5S9hpnag2KQUWUShXQJJg3hGi2l7HgPuh0PBTr6u5asEyvMUHTJKvqjrOEl5otfyh8mrXZxzy7STbKtGLKXrLrqFwfx3navKsnTcuII3Ag5Vn3AtYa+5cHoTOm2aHbJthTOOdKRrHZqUxYqjTNmauA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=apcacb4V; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="apcacb4V" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E41D91F000E9; Thu, 20 Aug 2026 16:39:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1787243971; bh=xU6V91x4fomImutFVuNzTZgb6sxOJ8EtUHc+jsKfNqo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=apcacb4VRJYevG/YWgz6cSrjvXNSKKeoiGNEJES1FIKP6GL1F1khMPiMHPvN6h86e sPehsPErflUPjvaL1ACqxoR1Tvw3SrsT1iQl2M2w1mTQgYUWQge12AistE18yZ63cQ 7jD62SKi/rdV9Wxm2sd4hSWEN3tGKMKJMFL+GkiA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Christian Brauner (Amutable)" , Sasha Levin Subject: [PATCH 5.15 239/272] binfmt_misc: restore write access when removing an entry Date: Thu, 20 Aug 2026 16:57:03 +0200 Message-ID: <20260820145238.788082203@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260820145231.229664293@linuxfoundation.org> References: <20260820145231.229664293@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Christian Brauner [ Upstream commit db1856ea9196cf6e015d12199a34c0b9313c7bfa ] Registering an entry with the MISC_FMT_OPEN_FILE flag opens the interpreter via open_exec() which denies write access to it for as long as the entry exists. Removing the entry closes the interpreter file via filp_close() but never restores write access, leaving the inode's i_writecount permanently negative. Opening the interpreter for writing keeps failing with ETXTBSY long after the entry is gone until the inode is evicted from the inode cache. Commit 90f601b497d7 ("binfmt_misc: restore write access before closing files opened by open_exec()") fixed the same imbalance in the error path of bm_register_write() but the actual removal path has been leaking the write denial since the introduction of the flag. Restore write access in put_binfmt_handler() before closing the interpreter file. Link: https://patch.msgid.link/20260710-work-binfmt_misc-locking-v3-1-a162f7cb58d6@kernel.org Fixes: 948b701a607f ("binfmt_misc: add persistent opened binary handler for containers") Cc: stable@vger.kernel.org Signed-off-by: Christian Brauner (Amutable) Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- fs/binfmt_misc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/fs/binfmt_misc.c +++ b/fs/binfmt_misc.c @@ -163,8 +163,10 @@ static Node *get_binfmt_handler(struct l static void put_binfmt_handler(Node *e) { if (refcount_dec_and_test(&e->users)) { - if (e->flags & MISC_FMT_OPEN_FILE) + if (e->flags & MISC_FMT_OPEN_FILE) { + exe_file_allow_write_access(e->interp_file); filp_close(e->interp_file, NULL); + } kfree(e); } }