From mboxrd@z Thu Jan 1 00:00:00 1970 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 5E3C538E8A9; Fri, 7 Aug 2026 15:26:25 +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=1786116386; cv=none; b=EWFW6b8tR9IV5kXmVPDwUW4LRb3asdOZKZC65stHkZeBzf+n0THBEdDBQGxqELGMlKXuvgkwvdmUZmKyg6fgF+TtkpXU4NeGFN+5J1y0/3tIKFyQFeIo8hc69BjZpAuuPQSI7RnGfyAgEYCUbmQJJsQAMNPDanRoXY7cwL1K1Rs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786116386; c=relaxed/simple; bh=soJny9rdf2IOQ6GUARgypyumpYW1uYiSHKd9Nfp378E=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=E2UNiv4n0ETO3KPpuZl74ic4qUzwOQeWom9kz1p55fpykOnTy/FG7pLQ6bzsXazfu2JDWYta87W+WgAk8IX2KKj6t7E/TA7QrbULBzdxUc9qyd/x7KoouGOlKIzCLHViGGdrr2GVJQq2Kf7C1qTDopgPRTRrK702KVr1yLdvYgA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=q2S/+L6p; 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="q2S/+L6p" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7EB811F000E9; Fri, 7 Aug 2026 15:26:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786116385; bh=LjxAZj9sxjyhAHedhsMCWwA3dgG78UU073S0SHGZ0tI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=q2S/+L6p0ddAaemnlday9q2ALm/960no8u53e6ZpALwNB4UV5rK/U2QIHRqtjEjC/ zHGWBgepjpQnGXV4v52cSmj3os6R8M4zPWqCgbX36UbV1IRzCG0X/RRVD6zWlG278P hCgfHRh/VUGSp76MEdhfbJA4gx3qdNVKW+41Rt0k= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Liem , Frank Li , Carlos Song , Andi Shyti Subject: [PATCH 6.6 168/261] i2c: imx: Fix slave registration race and error handling Date: Fri, 7 Aug 2026 16:38:45 +0200 Message-ID: <20260807143418.993186593@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260807143415.358597922@linuxfoundation.org> References: <20260807143415.358597922@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 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Liem commit d64ec362c369bbc33833f7936d5f3a706b0d5c45 upstream. In i2c_imx_reg_slave(), the slave pointer was assigned before pm_runtime_resume_and_get(). If pm_runtime_resume_and_get() failed, the error path returned without clearing i2c_imx->slave, leaving it non-NULL and causing all subsequent registration attempts to fail with -EBUSY. Additionally, because this driver uses a shared IRQ, the interrupt handler i2c_imx_isr() can execute concurrently and, after acquiring slave_lock, dereference i2c_imx->slave. The previous fix attempt added a lockless i2c_imx->slave = NULL on the error path, but that could race with the ISR under the lock and still cause a NULL pointer dereference. Fix both issues by deferring the assignment of i2c_imx->slave and i2c_imx->last_slave_event to after a successful resume, and by performing the assignment inside the slave_lock critical section. This guarantees that the slave pointer is never left stale on the error path and is always valid when observed by the interrupt handler. Fixes: f7414cd6923f ("i2c: imx: support slave mode for imx I2C driver") Signed-off-by: Liem Cc: # v5.11+ Reviewed-by: Frank Li Acked-by: Carlos Song Signed-off-by: Andi Shyti Link: https://lore.kernel.org/r/20260629023829.152651-2-liem16213@gmail.com Signed-off-by: Greg Kroah-Hartman --- drivers/i2c/busses/i2c-imx.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) --- a/drivers/i2c/busses/i2c-imx.c +++ b/drivers/i2c/busses/i2c-imx.c @@ -870,9 +870,6 @@ static int i2c_imx_reg_slave(struct i2c_ if (i2c_imx->slave) return -EBUSY; - i2c_imx->slave = client; - i2c_imx->last_slave_event = I2C_SLAVE_STOP; - /* Resume */ ret = pm_runtime_resume_and_get(i2c_imx->adapter.dev.parent); if (ret < 0) { @@ -880,6 +877,11 @@ static int i2c_imx_reg_slave(struct i2c_ return ret; } + scoped_guard(spinlock_irqsave, &i2c_imx->slave_lock) { + i2c_imx->slave = client; + i2c_imx->last_slave_event = I2C_SLAVE_STOP; + } + i2c_imx_slave_init(i2c_imx); return 0;