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Date: Wed, 14 Feb 2024 12:34:35 -0800
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Subject: Re: [PATCH] net/mlx5: fix possible stack overflows
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To: Arnd Bergmann <arnd@kernel.org>, Saeed Mahameed <saeedm@nvidia.com>, "Leon
 Romanovsky" <leon@kernel.org>
CC: Arnd Bergmann <arnd@arndb.de>, "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>, Hamdan Igbaria <hamdani@nvidia.com>,
	<netdev@vger.kernel.org>, <linux-rdma@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>
References: <20240213100848.458819-1-arnd@kernel.org>
From: Jacob Keller <jacob.e.keller@intel.com>
In-Reply-To: <20240213100848.458819-1-arnd@kernel.org>
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On 2/13/2024 2:08 AM, Arnd Bergmann 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")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>