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Date: Thu, 21 Mar 2024 10:48:01 +0100
From: Jiri Pirko <jiri@resnulli.us>
To: Arnd Bergmann <arnd@kernel.org>
Cc: Saeed Mahameed <saeedm@nvidia.com>, Leon Romanovsky <leon@kernel.org>,
	Arnd Bergmann <arnd@arndb.de>, Simon Horman <horms@kernel.org>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Yevgeny Kliteynik <kliteyn@nvidia.com>,
	Alex Vesker <valex@nvidia.com>, Erez Shitrit <erezsh@nvidia.com>,
	Hamdan Igbaria <hamdani@nvidia.com>, netdev@vger.kernel.org,
	linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] [v3] net/mlx5: fix possible stack overflows
Message-ID: <ZfwCURACC48Injgk@nanopsycho>
References: <20240320180831.185128-1-arnd@kernel.org>
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In-Reply-To: <20240320180831.185128-1-arnd@kernel.org>

Wed, Mar 20, 2024 at 07:08:09PM CET, arnd@kernel.org wrote:
>From: Arnd Bergmann <arnd@arndb.de>
>
>A couple of debug functions use a 512 byte temporary buffer and call another
>function that has another buffer of the same size, which in turn exceeds the
>usual warning limit for excessive stack usage:
>
>drivers/net/ethernet/mellanox/mlx5/core/steering/dr_dbg.c:1073:1: error: stack frame size (1448) exceeds limit (1024) in 'dr_dump_start' [-Werror,-Wframe-larger-than]
>dr_dump_start(struct seq_file *file, loff_t *pos)
>drivers/net/ethernet/mellanox/mlx5/core/steering/dr_dbg.c:1009:1: error: stack frame size (1120) exceeds limit (1024) in 'dr_dump_domain' [-Werror,-Wframe-larger-than]
>dr_dump_domain(struct seq_file *file, struct mlx5dr_domain *dmn)
>drivers/net/ethernet/mellanox/mlx5/core/steering/dr_dbg.c:705:1: error: stack frame size (1104) exceeds limit (1024) in 'dr_dump_matcher_rx_tx' [-Werror,-Wframe-larger-than]
>dr_dump_matcher_rx_tx(struct seq_file *file, bool is_rx,
>
>Rework these so that each of the various code paths only ever has one of
>these buffers in it, and exactly the functions that declare one have
>the 'noinline_for_stack' annotation that prevents them from all being
>inlined into the same caller.
>
>Fixes: 917d1e799ddf ("net/mlx5: DR, Change SWS usage to debug fs seq_file interface")
>Reviewed-by: Simon Horman <horms@kernel.org>
>Link: https://lore.kernel.org/all/20240219100506.648089-1-arnd@kernel.org/
>Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Reviewed-by: Jiri Pirko <jiri@nvidia.com>