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From: Ido Schimmel <idosch@idosch.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Jiri Pirko <jiri@mellanox.com>,
	Ido Schimmel <idosch@mellanox.com>,
	"David S. Miller" <davem@davemloft.net>,
	Yotam Gigi <yotamg@mellanox.com>,
	Nogah Frankel <nogahf@mellanox.com>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] mlxsw: spectrum_router: avoid potential uninitialized data usage
Date: Fri, 30 Sep 2016 20:57:00 +0300	[thread overview]
Message-ID: <20160930175700.GA641@splinter> (raw)
In-Reply-To: <20160930161734.70928-2-arnd@arndb.de>

On Fri, Sep 30, 2016 at 06:17:10PM +0200, Arnd Bergmann wrote:
> If fi->fib_nhs is zero, the router interface pointer is uninitialized, as shown by
> this warning:
> 
> drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c: In function 'mlxsw_sp_router_fib_event':
> drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c:1674:21: error: 'r' may be used uninitialized in this function [-Werror=maybe-uninitialized]
> drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c:1643:23: note: 'r' was declared here
> 
> This changes the loop so we handle the case the same way as finding no router
> interface pointer attached to one of the nexthops to ensure we always
> trap here instead of using uninitialized data.
> 
> Fixes: b45f64d16d45 ("mlxsw: spectrum_router: Use FIB notifications instead of switchdev calls")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

For net-next:
Acked-by: Ido Schimmel <idosch@mellanox.com>

BTW, which flags did you pass to generate this error? I can only
reproduce this with EXTRA_CFLAGS="-Wmaybe-uninitialized -Werror", but
for some reason EXTRA_CFLAGS="-Wall -Werror" is silent. Any idea why? I
would like to add this to my git hooks and avoid these errors in the
future :)

Thanks!

  reply	other threads:[~2016-09-30 18:03 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-30 16:17 [PATCH 1/2] net/mlx5e: shut up maybe-uninitialized warning Arnd Bergmann
2016-09-30 16:17 ` [PATCH 2/2] mlxsw: spectrum_router: avoid potential uninitialized data usage Arnd Bergmann
2016-09-30 17:57   ` Ido Schimmel [this message]
2016-10-01  3:36     ` Arnd Bergmann
2016-10-03  5:56   ` David Miller
2016-10-01 15:08 ` [PATCH 1/2] net/mlx5e: shut up maybe-uninitialized warning Or Gerlitz
2016-10-03  5:56 ` David Miller

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