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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Ido Schimmel <idosch@mellanox.com>,
        Jiri Pirko <jiri@mellanox.com>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 068/109] mlxsw: spectrum_router: Remove inappropriate usage of WARN_ON()
Date:   Tue, 14 Jul 2020 20:44:11 +0200
Message-Id: <20200714184108.794078147@linuxfoundation.org>
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From: Ido Schimmel <idosch@mellanox.com>

[ Upstream commit d9d5420273997664a1c09151ca86ac993f2f89c1 ]

We should not trigger a warning when a memory allocation fails. Remove
the WARN_ON().

The warning is constantly triggered by syzkaller when it is injecting
faults:

[ 2230.758664] FAULT_INJECTION: forcing a failure.
[ 2230.758664] name failslab, interval 1, probability 0, space 0, times 0
[ 2230.762329] CPU: 3 PID: 1407 Comm: syz-executor.0 Not tainted 5.8.0-rc2+ #28
...
[ 2230.898175] WARNING: CPU: 3 PID: 1407 at drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c:6265 mlxsw_sp_router_fib_event+0xfad/0x13e0
[ 2230.898179] Kernel panic - not syncing: panic_on_warn set ...
[ 2230.898183] CPU: 3 PID: 1407 Comm: syz-executor.0 Not tainted 5.8.0-rc2+ #28
[ 2230.898190] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014

Fixes: 3057224e014c ("mlxsw: spectrum_router: Implement FIB offload in deferred work")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
index efdf8cb5114c2..2f013fc716985 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
@@ -6287,7 +6287,7 @@ static int mlxsw_sp_router_fib_event(struct notifier_block *nb,
 	}
 
 	fib_work = kzalloc(sizeof(*fib_work), GFP_ATOMIC);
-	if (WARN_ON(!fib_work))
+	if (!fib_work)
 		return NOTIFY_BAD;
 
 	fib_work->mlxsw_sp = router->mlxsw_sp;
-- 
2.25.1