linux-kernel - [PATCH] net/cisco: Fix a sleep-in-atomic-context bug in enic_init_affinity

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Message-Id: <1592816814-32241-1-git-send-email-likaige@loongson.cn>
Date:   Mon, 22 Jun 2020 17:06:54 +0800
From:   Kaige Li <likaige@...ngson.cn>
To:     Christian Benvenuti <benve@...co.com>,
        Govindarajulu Varadarajan <_govind@....com>
Cc:     Tiezhu Yang <yangtiezhu@...ngson.cn>,
        Xuefeng Li <lixuefeng@...ngson.cn>,
        Kaige Li <likaige@...ngson.cn>, linux-mips@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH] net/cisco: Fix a sleep-in-atomic-context bug in enic_init_affinity_hint()

The kernel module may sleep with holding a spinlock.

The function call paths (from bottom to top) are:

[FUNC] zalloc_cpumask_var(GFP_KERNEL)
drivers/net/ethernet/cisco/enic/enic_main.c, 125: zalloc_cpumask_var in enic_init_affinity_hint
drivers/net/ethernet/cisco/enic/enic_main.c, 1918: enic_init_affinity_hint in enic_open
drivers/net/ethernet/cisco/enic/enic_main.c, 2348: enic_open in enic_reset
drivers/net/ethernet/cisco/enic/enic_main.c, 2341: spin_lock in enic_reset

To fix this bug, GFP_KERNEL is replaced with GFP_ATOMIC.

Signed-off-by: Kaige Li <likaige@...ngson.cn>
---
 drivers/net/ethernet/cisco/enic/enic_main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/cisco/enic/enic_main.c b/drivers/net/ethernet/cisco/enic/enic_main.c
index cd5fe4f..ee62065 100644
--- a/drivers/net/ethernet/cisco/enic/enic_main.c
+++ b/drivers/net/ethernet/cisco/enic/enic_main.c
@@ -122,7 +122,7 @@ static void enic_init_affinity_hint(struct enic *enic)
 		     !cpumask_empty(enic->msix[i].affinity_mask)))
 			continue;
 		if (zalloc_cpumask_var(&enic->msix[i].affinity_mask,
-				       GFP_KERNEL))
+				       GFP_ATOMIC))
 			cpumask_set_cpu(cpumask_local_spread(i, numa_node),
 					enic->msix[i].affinity_mask);
 	}
-- 
2.1.0