From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 36C5447DD6E for ; Tue, 28 Apr 2026 18:34:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777401241; cv=none; b=BrGTuZF30M/NjWYDHMRz5x0kosLz76jfOirckpTPv0dKYZPhwQhcsqrjSvjXJUN0OqQ2twtMmLfInq3AM84GfWu15pe9iCl39XCvv+2dKP1of51ljKRaGiEY5rmnvE3oDTWH7ZCR0kQiV/4AdRI8RIYjeAbXeef3oUubbsOeeWA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777401241; c=relaxed/simple; bh=lf8FNqMoY3bRcXhsXqO47iWYBbsuI1PT5XjhAchyLzA=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=S4y7wmgLnblntZNeVg3LmtBKZQu+jINz1r4OZODJeWSu9NlrlYaC5vQayfxhobmzpWOCHmiq6sWXNhsxsb6js532VCuJ7HvFeOk9eNM8uS13sek0/q1FkFYSrBjfv1hjLGwy56b5Am2YjXAydnzyAtvA0AbYewSa46fVDUjDaUA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=hH4eFv/r; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="hH4eFv/r" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3EA02C2BCB3; Tue, 28 Apr 2026 18:34:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777401241; bh=lf8FNqMoY3bRcXhsXqO47iWYBbsuI1PT5XjhAchyLzA=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=hH4eFv/r3Ct/0fM0RVmVj1w5VgfvyfC8dc6MpnKeCDivTlmJbzfFG6SGiiCXbl18g UJjXpVhSjqzzgatsJoxPNy4bJwIgKpvMVgZJePHRMcxgArSsS0/o6AO58KSQM+FQrK JFAvxMCUqMEY9H8338oGFaRUYzte1KEgWLCQnhu3njrI9r6MUnhxFNVOBNdbdnM3tz V3uNd3b9p8T1ujyJ1HLFT9kaSZBBf31lB9RrmE19+tcZ/StxXebZqS54iU+2jCaDnr Xv8ygPv0K8A8VmYCKPXKM+YsLsg8KxucsbFVTXGjRch37PYTYaBuVGhUWpEkgyY+Lv igWMUgBCmtTlQ== From: Sudeep Holla Date: Tue, 28 Apr 2026 19:33:34 +0100 Subject: [PATCH v2 10/11] firmware: arm_ffa: Snapshot notifier callbacks under lock Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260428-ffa_fixes-v2-10-8595ae450034@kernel.org> References: <20260428-ffa_fixes-v2-0-8595ae450034@kernel.org> In-Reply-To: <20260428-ffa_fixes-v2-0-8595ae450034@kernel.org> To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: Jens Wiklander , Sudeep Holla X-Mailer: b4 0.15.2 Both notification handlers currently look up a notifier callback under notify_lock, drop the lock, and then dereference the returned notifier entry. A concurrent unregister can delete and free that entry in the gap, leaving the handler to dereference stale memory. Copy the callback pointer and callback data while notify_lock is still held and invoke the callback only after the lock is dropped. This keeps the existing callback execution model while removing the use-after-free window in both the framework and non-framework notification paths. Fixes: 285a5ea0f542 ("firmware: arm_ffa: Add support for handling framework notifications") Signed-off-by: Sudeep Holla --- drivers/firmware/arm_ffa/driver.c | 35 +++++++++++++++++++++++------------ 1 file changed, 23 insertions(+), 12 deletions(-) diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c index 9181cc752ce1..2e9820395162 100644 --- a/drivers/firmware/arm_ffa/driver.c +++ b/drivers/firmware/arm_ffa/driver.c @@ -1465,20 +1465,25 @@ static int ffa_notify_send(struct ffa_device *dev, int notify_id, static void handle_notif_callbacks(u64 bitmap, enum notify_type type) { + ffa_notifier_cb cb; + void *cb_data; int notify_id; - struct notifier_cb_info *cb_info = NULL; for (notify_id = 0; notify_id <= FFA_MAX_NOTIFICATIONS && bitmap; notify_id++, bitmap >>= 1) { if (!(bitmap & 1)) continue; - read_lock(&drv_info->notify_lock); - cb_info = notifier_hnode_get_by_type(notify_id, type); - read_unlock(&drv_info->notify_lock); + scoped_guard(read_lock, &drv_info->notify_lock) { + struct notifier_cb_info *cb_info; + + cb_info = notifier_hnode_get_by_type(notify_id, type); + cb = cb_info ? cb_info->cb : NULL; + cb_data = cb_info ? cb_info->cb_data : NULL; + } - if (cb_info && cb_info->cb) - cb_info->cb(notify_id, cb_info->cb_data); + if (cb) + cb(notify_id, cb_data); } } @@ -1486,9 +1491,10 @@ static void handle_fwk_notif_callbacks(u32 bitmap) { void *buf; uuid_t uuid; + void *fwk_cb_data; int notify_id = 0, target; + ffa_fwk_notifier_cb fwk_cb; struct ffa_indirect_msg_hdr *msg; - struct notifier_cb_info *cb_info = NULL; size_t min_offset = offsetof(struct ffa_indirect_msg_hdr, uuid); /* Only one framework notification defined and supported for now */ @@ -1524,12 +1530,17 @@ static void handle_fwk_notif_callbacks(u32 bitmap) ffa_rx_release(); } - read_lock(&drv_info->notify_lock); - cb_info = notifier_hnode_get_by_vmid_uuid(notify_id, target, &uuid); - read_unlock(&drv_info->notify_lock); + scoped_guard(read_lock, &drv_info->notify_lock) { + struct notifier_cb_info *cb_info; + + cb_info = notifier_hnode_get_by_vmid_uuid(notify_id, target, + &uuid); + fwk_cb = cb_info ? cb_info->fwk_cb : NULL; + fwk_cb_data = cb_info ? cb_info->cb_data : NULL; + } - if (cb_info && cb_info->fwk_cb) - cb_info->fwk_cb(notify_id, cb_info->cb_data, buf); + if (fwk_cb) + fwk_cb(notify_id, fwk_cb_data, buf); kfree(buf); } -- 2.43.0