From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f49.google.com (mail-wm1-f49.google.com [209.85.128.49]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AA53451D50C for ; Mon, 7 Sep 2026 16:53:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.49 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788799982; cv=none; b=esoGxNNmFC4XeGSDgBmFFUbjWMl1tTHNzSiU13pmJvDtfgNrmO8fLig9GwMqYCTl3+1VWXqMV/8/U5MlQ/oDnvb2/VyTAsYi+8qLuinJx4aEwq7SLtd4boPrqMnkfR8K+yZjzbe8x6lQ0/HaImlzZ9ulevIGPXTtS2geRl7sQ30= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788799982; c=relaxed/simple; bh=oxBm833C8T+jxHgAdbU6D4xcv4E4TYoli1xZPpTW0yQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=UR+7urHHRZ3wFwEf4LAZTj3QIQnFRKaUVZU+xX0D+SKUP98jEDi3nY1FGB7paYvwvHZTEpt82yHzDNhgVvJfFtV1rq/PhugMI3p+VutqXKoYI6lmo9q1FQtkvrkZr+g3P+PRMeC+OomnaxPTNNYVwpB2anN/9//D+HsKxqHYcDk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=jfBW7WzR; arc=none smtp.client-ip=209.85.128.49 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="jfBW7WzR" Received: by mail-wm1-f49.google.com with SMTP id 5b1f17b1804b1-499b2981a7bso40194165e9.3 for ; Mon, 07 Sep 2026 09:53:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1788799978; x=1789404778; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=BcITG13Gvl8i0HA4g724jWVmnWns/ceZ5ECxTEaQlok=; b=jfBW7WzRy1LDdYAfQnEc9I7mCDw90Ps5LjnC8imAutx+H5oG0GQNtSpUarqQPRbWvc dXgYKxKmJTx1ZVCWaubdw1ZKolpVgVxr9pwoO+RzGUkmtSW4oHtHB4vFDCKUt83lUEsq 0krNRDpkkYQXu+QbiTCavOwrrSvxY34ZRAzpqMYg8VtF/rw+efZUbxzwmd89/4R2xULf ZSrFj+ctcmCm+CrY1oAN9JEugFOMgn/8aX1C4MZXxLia6XQqpjKnZn1iUf/2O0La3qk9 SwjoKhy6G2allTRGy4WXZDkcM3J8l59twAQOMwYkWiM7O1rxm59RVwsjW1yHieQ/nk6D 68QA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1788799978; x=1789404778; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=BcITG13Gvl8i0HA4g724jWVmnWns/ceZ5ECxTEaQlok=; b=clUG/6ICWOowL4yT25UnJ0i96wD6FdU7E5TTkViAzSR4fEUYe5FAgcONJwnMPNsi5r v1w020czD0dc/lNWddRiV6IRCzKHdLTNf9AJu5p7t3jNddi8l/X7oOfkhXK95nEZT0ul sFNz5OPLOyK0wUK5Zi3NuvG4lk+E+lyOQU/LkIkLLCYIf/PaTGhcWWuMZzscD4sCtsr0 aptzHsjV85Gq3aTqXq/OqWg6Z+vproAhtPJ9TOFtxXW4z78kXrbzNUMs0ufB9gTOgBED lsudym+l5hBE+EfkWv1BY9Tpy1UyB+vKlZZjOZH+l7eZkjn0cacmT4EIV5hsQc2QBMXE U9nQ== X-Forwarded-Encrypted: i=1; AKwUvBwBsKeseLManG4bmIfaDCTT7jmOmbfEsOmBYDKqI4DctrJW5fIiG13AbAd6D7taC/Ce6qib8tdf2ao2N0E=@vger.kernel.org X-Gm-Message-State: AFuF++mP+XpAUZUcPKUh2Kwb49WhjBeHDj/rLZt0vSia7Zwog3kQ0JWZ sVBurojF3WbGJ9EK2cBO25OqlYXpB1nEcS7qHWX4bJLKB8PzPbXA7Ztf X-Gm-Gg: AYBFou0V/18DWILo2JRBBQB9YSd088Qg7jjtYhEykDScnma8fMqKOrSVe1niNzgnbSQ MBTd96kAIzT3DfTYCCHu+V2VGGGiX/XMeLxiq3TvwyjMnpfFfQUiXV7Mdm6wlsBcto5Aj58K9cm pBCkTqF1OPmwG465WSX+6/j4Tx8ZSe+JzMYE7d9WzvX0LNOwJ+u8S8jmQQXXh4O8YhJjVNRWrfD 9Vxd1iqznVMw1EwXk8QHH0cAJcw0wI6ByIPc3MrYq8omRaOb5oIS7CFAmvqfEGY6kG4miKcwTHi PiJHKeCNCEvYexp9znp6bQcepybxb9e0ROQyxHHRc7U0RsXo67ox/GV/WvGLTim8jEoCC0oH3vU t3MmAEluVP62jmzGRUhgujLxnue00HHUp5e/mNUUVNj0tfomKVtoNwHUKRuhg/7ag+CZYDMLlUH dJJLVhvq2qjlHFyj9vUhzBRFpGGz47k1wWcQI66HC223su6TvhZ3JTtRWh1UaXBH+fWMbh8RFlh g== X-Received: by 2002:a05:600c:8b6d:b0:499:a277:e8b5 with SMTP id 5b1f17b1804b1-49cf7fdd67emr472395245e9.3.1788799978274; Mon, 07 Sep 2026 09:52:58 -0700 (PDT) Received: from dell-desktop ([2a02:587:4b5f:900:ef25:2f4:1792:4e6f]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-49d03543064sm233022415e9.13.2026.09.07.09.52.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 07 Sep 2026 09:52:57 -0700 (PDT) From: Anastasios Papagiannis To: bpf@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, david@kernel.org, akpm@linux-foundation.org, andrii@kernel.org, ast@kernel.org, brauner@kernel.org, daniel@iogearbox.net, eddyz87@gmail.com, kpsingh@kernel.org, ljs@kernel.org, matt@bobrowski.net, memxor@gmail.com, song@kernel.org, sun.jian.kdev@gmail.com, tasos.papagiannnis@gmail.com, utilityemal77@gmail.com, viro@zeniv.linux.org.uk Subject: [PATCH bpf-next v5 2/7] exec: Clear bprm->mm before dropping its reference Date: Mon, 7 Sep 2026 19:52:15 +0300 Message-ID: <20260907165220.52431-3-tasos.papagiannnis@gmail.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260907165220.52431-1-tasos.papagiannnis@gmail.com> References: <20260907165220.52431-1-tasos.papagiannnis@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Once mmput() drops the final reference to bprm->mm, the pointer must no longer remain accessible through struct linux_binprm. The successful exec path and the bprm initialization error path already clear bprm->mm when ownership is transferred or released. Do the same in free_bprm() before calling mmput(). This is required for BPF kfuncs where bprm->mm is either NULL or points to a live mm_struct to ensure safe access. Signed-off-by: Anastasios Papagiannis Reviewed-by: Sun Jian --- fs/exec.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/exec.c b/fs/exec.c index 745f6eb5279e..4ddd403fd91c 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1456,9 +1456,12 @@ void bprm_drop_loader(struct linux_binprm *bprm) static void free_bprm(struct linux_binprm *bprm) { - if (bprm->mm) { + struct mm_struct *mm = bprm->mm; + + if (mm) { acct_arg_size(bprm, 0); - mmput(bprm->mm); + bprm->mm = NULL; + mmput(mm); } if (bprm->user_ns) put_user_ns(bprm->user_ns); -- 2.55.0