Re: Patch "can: ti_hecc: fix -Woverflow compiler warning" has been added to the 6.15-stable tree

Hi Sasha,

On Sun. 17 Aug. 2025 at 22:49, Sasha Levin sashal@kernel.org wrote:

This is a note to let you know that I've just added the patch titled

can: ti_hecc: fix -Woverflow compiler warning

to the 6.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: can-ti_hecc-fix-woverflow-compiler-warning.patch and it can be found in the queue-6.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

This only silences a compiler warning. There are no actual bugs in the original code. This is why I did not put the Fixes tag.

I am not against this being backported to stable but please note that this depends on the new BIT_U32() macro which where recently added in commit 5b572e8a9f3d ("bits: introduce fixed-type BIT_U*()") Link: https://git.kernel.org/torvalds/c/5b572e8a9f3d

So, unless you also backport the above patch, this will not compile.

The options are:

1. drop this patch (i.e. keep that benin -Woverflow in stable) 2. backport the new BIT_U*() macros and keep the patch as-is 3. modify the patch as below:

mbx_mask = ~(u32)BIT(HECC_RX_LAST_MBOX);

I'll let you decide what you prefer. That comment also applies to the other backports of that patch except for the 6.16.x branch which already has the BIT_U*() macros.

Yours sincerely, Vincent Mailhol

commit f37dbcbbea3844900081b44f372f2f4d4be1b5c6 Author: Vincent Mailhol mailhol.vincent@wanadoo.fr Date: Tue Jul 15 20:28:11 2025 +0900

can: ti_hecc: fix -Woverflow compiler warning

[ Upstream commit 7cae4d04717b002cffe41169da3f239c845a0723 ]

Fix below default (W=0) warning:

  drivers/net/can/ti_hecc.c: In function 'ti_hecc_start':
  drivers/net/can/ti_hecc.c:386:20: warning: conversion from 'long unsigned int' to 'u32' {aka 'unsigned int'} changes value from '18446744073709551599' to '4294967279' [-Woverflow]
    386 |         mbx_mask = ~BIT(HECC_RX_LAST_MBOX);
        |                    ^

Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Link: https://patch.msgid.link/20250715-can-compile-test-v2-1-f7fd566db86f@wanadoo.fr
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/net/can/ti_hecc.c b/drivers/net/can/ti_hecc.c index 644e8b8eb91e..e6d6661a908a 100644 --- a/drivers/net/can/ti_hecc.c +++ b/drivers/net/can/ti_hecc.c @@ -383,7 +383,7 @@ static void ti_hecc_start(struct net_device *ndev) * overflows instead of the hardware silently dropping the * messages. */

•   mbx_mask = ~BIT(HECC_RX_LAST_MBOX);
  

•   mbx_mask = ~BIT_U32(HECC_RX_LAST_MBOX);
    hecc_write(priv, HECC_CANOPC, mbx_mask);
  
    /* Enable interrupts */