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 E815F47F2CE; Thu, 20 Aug 2026 17:55:20 +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=1787248522; cv=none; b=O6zmkJpYTwghr2SdNZm3gB9teFeOZdTLmRBnxC2At0WpWNWPqFudoR/VGuiBOazmeHPkha8XdyUmTorl4vRblEYPsBgFtFpdzIpC0SIsV6Dl2Kpz8PcyDwrflZloZiR3JJ23vepHanvtLCf+OZs75x0XADz5GQfAyB3k4L4VRlA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787248522; c=relaxed/simple; bh=jW/71XlGtdaG+zGTWwJQrwyhLe6d6+1y082bncmpAP0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=JUMO2Ke5IuH+0JNbqRET0S3FbVoQaZRlTAfzeyLaWcibeyhAD36UX6HztR2t9VIZ7aXidZoWPgVeF+0ukb9sKDadk8A7MCoJG/a5v7t68OLaWNlXxH6vIevkMbeDx/n3u0gpn/kgFyF8+vBzscEtThv7Yj7mKQ8jpvduJMR5UVs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=J0Wt69hJ; 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="J0Wt69hJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3E4421F000E9; Thu, 20 Aug 2026 17:55:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1787248520; bh=W0w0iyaWgZvFYxuhvngiU4lyWWzS3eHuvGQs2IEQGVo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=J0Wt69hJ2hKZn+za77cg3gk19KokYN5eLHTgF6ufDWHNRGSiPAY+wmcNa1mjCdDq/ pFFWO4cWe2ibeEU9TdNRCJxgQs1hClK8YB+c+m700kUjAD3OZnTjf6mhZYNXrOPfz8 ZrDqk8BHweIb+VrHBftEI1j9JHfONnr0KEAIMGWg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Christian Brauner (Amutable)" , Sasha Levin Subject: [PATCH 6.1 256/303] binfmt_misc: restore write access when removing an entry Date: Thu, 20 Aug 2026 16:56:32 +0200 Message-ID: <20260820145301.142135447@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260820145253.200766705@linuxfoundation.org> References: <20260820145253.200766705@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 6.1-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); } }