From: Andrew Lunn <andrew@lunn.ch>
To: Jakub Kicinski <kuba@kernel.org>
Cc: davem@davemloft.net, netdev@vger.kernel.org, edumazet@google.com,
pabeni@redhat.com, andrew+netdev@lunn.ch, horms@kernel.org,
vadim.fedorenko@linux.dev
Subject: Re: [PATCH net-next] ethtool: tsconfig: reject zero-valued tx_type and rx_filter bitsets
Date: Wed, 12 Aug 2026 18:27:42 +0200 [thread overview]
Message-ID: <a44d3a88-a322-4640-b920-8b78200d22e7@lunn.ch> (raw)
In-Reply-To: <20260812162230.1837788-1-kuba@kernel.org>
On Wed, Aug 12, 2026 at 09:22:30AM -0700, Jakub Kicinski wrote:
> The ffs()/fls() guard in ethnl_set_tsconfig() was meant to enforce
> that the user selects exactly one tx_type (and one rx_filter)
> at a time (off / none are explicit types with non-zero values).
> However, both ffs(0) and fls(0) return 0, so the guard passes
> a zero-valued bitset through.
>
> The subsequent ffs(req_tx_type) - 1 would produce -1, if user selected
> no bit. net_hwtstamp_validate() catches the invalid -1 downstream,
> but returns a generic error (-ERANGE) without telling the user
> what went wrong. Return -EINVAL + extack instead.
>
> Replace the ffs()/fls() comparison with a hweight32() == 1 check.
>
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Andrew
next prev parent reply other threads:[~2026-08-12 16:27 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-12 16:22 [PATCH net-next] ethtool: tsconfig: reject zero-valued tx_type and rx_filter bitsets Jakub Kicinski
2026-08-12 16:27 ` Andrew Lunn [this message]
2026-08-12 18:37 ` Joe Damato
2026-08-12 20:09 ` Vadim Fedorenko
2026-08-14 3:24 ` patchwork-bot+netdevbpf
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