Subject: [PATCH 28/62] net: qualcomm: rmnet: Fix incorrect allocation flag in transmit

From: Subash Abhinov Kasiviswanathan <[email-masked]>
Date: Tue, 2 Oct 2018 18:52:02 -0600

[ Upstream commit 6392ff3c8e4c23d0a09b0ae9f94feb3effed490b ]

The incoming skb needs to be reallocated in case the headroom
is not sufficient to add the MAP header. This allocation needs to
be atomic otherwise it results in the following splat

[32805.801456] BUG: sleeping function called from invalid context
[32805.841141] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
[32805.904773] task: ffffffd7c5f62280 task.stack: ffffff80464a8000
[32805.910851] pc : ___might_sleep+0x180/0x188
[32805.915143] lr : ___might_sleep+0x180/0x188
[32806.131520] Call trace:
[32806.134041]  ___might_sleep+0x180/0x188
[32806.137980]  __might_sleep+0x50/0x84
[32806.141653]  __kmalloc_track_caller+0x80/0x3bc
[32806.146215]  __kmalloc_reserve+0x3c/0x88
[32806.150241]  pskb_expand_head+0x74/0x288
[32806.154269]  rmnet_egress_handler+0xb0/0x1d8
[32806.162239]  rmnet_vnd_start_xmit+0xc8/0x13c
[32806.166627]  dev_hard_start_xmit+0x148/0x280
[32806.181181]  sch_direct_xmit+0xa4/0x198
[32806.185125]  __qdisc_run+0x1f8/0x310
[32806.188803]  net_tx_action+0x23c/0x26c
[32806.192655]  __do_softirq+0x220/0x408
[32806.196420]  do_softirq+0x4c/0x70

Fixes: ceed73a2cf4a ("drivers: net: ethernet: qualcomm: rmnet: Initial implementation")
Signed-off-by: Subash Abhinov Kasiviswanathan <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
index 6908b26feb9e..1f98d65473cf 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
@@ -147,7 +147,7 @@ static int rmnet_map_egress_handler(struct sk_buff *skb,
 	}
 
 	if (skb_headroom(skb) < required_headroom) {
-		if (pskb_expand_head(skb, required_headroom, 0, GFP_KERNEL))
+		if (pskb_expand_head(skb, required_headroom, 0, GFP_ATOMIC))
 			return -ENOMEM;
 	}
 
-- 
2.17.2