linux.git/net/core/netpoll.c, branch v5.12

Revert "net: Have netpoll bring-up DSA management interface"

2021-02-06T22:42:57+00:00

This reverts commit 1532b9778478577152201adbafa7738b1e844868.

The above commit is good and it works, however it was meant as a bugfix
for stable kernels and now we have more self-contained ways in DSA to
handle the situation where the DSA master must be brought up.

Signed-off-by: Vladimir Oltean 
Reviewed-by: Andrew Lunn 
Reviewed-by: Florian Fainelli 
Signed-off-by: Jakub Kicinski

net: Have netpoll bring-up DSA management interface

2020-11-18T19:04:11+00:00

DSA network devices rely on having their DSA management interface up and
running otherwise their ndo_open() will return -ENETDOWN. Without doing
this it would not be possible to use DSA devices as netconsole when
configured on the command line. These devices also do not utilize the
upper/lower linking so the check about the netpoll device having upper
is not going to be a problem.

The solution adopted here is identical to the one done for
net/ipv4/ipconfig.c with 728c02089a0e ("net: ipv4: handle DSA enabled
master network devices"), with the network namespace scope being
restricted to that of the process configuring netpoll.

Fixes: 04ff53f96a93 ("net: dsa: Add netconsole support")
Tested-by: Vladimir Oltean 
Signed-off-by: Florian Fainelli 
Link: https://lore.kernel.org/r/20201117035236.22658-1-f.fainelli@gmail.com
Signed-off-by: Jakub Kicinski

net: make sure napi_list is safe for RCU traversal

2020-09-10T20:08:46+00:00

netpoll needs to traverse dev->napi_list under RCU, make
sure it uses the right iterator and that removal from this
list is handled safely.

Signed-off-by: Jakub Kicinski 
Signed-off-by: David S. Miller

net: disable netpoll on fresh napis

2020-08-26T23:16:39+00:00

napi_disable() makes sure to set the NAPI_STATE_NPSVC bit to prevent
netpoll from accessing rings before init is complete. However, the
same is not done for fresh napi instances in netif_napi_add(),
even though we expect NAPI instances to be added as disabled.

This causes crashes during driver reconfiguration (enabling XDP,
changing the channel count) - if there is any printk() after
netif_napi_add() but before napi_enable().

To ensure memory ordering is correct we need to use RCU accessors.

Reported-by: Rob Sherwood 
Fixes: 2d8bff12699a ("netpoll: Close race condition between poll_one_napi and napi_disable")
Signed-off-by: Jakub Kicinski 
Signed-off-by: David S. Miller

netpoll: accept NULL np argument in netpoll_send_skb()

2020-05-08T01:11:07+00:00

netpoll_send_skb() callers seem to leak skb if
the np pointer is NULL. While this should not happen, we
can make the code more robust.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

netpoll: netpoll_send_skb() returns transmit status

2020-05-08T01:11:07+00:00

Some callers want to know if the packet has been sent or
dropped, to inform upper stacks.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

netpoll: move netpoll_send_skb() out of line

2020-05-08T01:11:07+00:00

There is no need to inline this helper, as we intend to add more
code in this function.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

netpoll: remove dev argument from netpoll_send_skb_on_dev()

2020-05-08T01:11:07+00:00

netpoll_send_skb_on_dev() can get the device pointer directly from np->dev

Rename it to __netpoll_send_skb()

Following patch will move netpoll_send_skb() out-of-line.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

netpoll: Fix use correct return type for ndo_start_xmit()

2020-04-29T18:47:16+00:00

The method ndo_start_xmit() returns a value of type netdev_tx_t. Fix
the ndo function to use the correct type.

Signed-off-by: Yunjian Wang 
Signed-off-by: David S. Miller

net: fix skb use after free in netpoll

2019-08-28T03:52:02+00:00

After commit baeababb5b85d5c4e6c917efe2a1504179438d3b
("tun: return NET_XMIT_DROP for dropped packets"),
when tun_net_xmit drop packets, it will free skb and return NET_XMIT_DROP,
netpoll_send_skb_on_dev will run into following use after free cases:
1. retry netpoll_start_xmit with freed skb;
2. queue freed skb in npinfo->txq.
queue_process will also run into use after free case.

hit netpoll_send_skb_on_dev first case with following kernel log:

[  117.864773] kernel BUG at mm/slub.c:306!
[  117.864773] invalid opcode: 0000 [#1] SMP PTI
[  117.864774] CPU: 3 PID: 2627 Comm: loop_printmsg Kdump: loaded Tainted: P           OE     5.3.0-050300rc5-generic #201908182231
[  117.864775] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
[  117.864775] RIP: 0010:kmem_cache_free+0x28d/0x2b0
[  117.864781] Call Trace:
[  117.864781]  ? tun_net_xmit+0x21c/0x460
[  117.864781]  kfree_skbmem+0x4e/0x60
[  117.864782]  kfree_skb+0x3a/0xa0
[  117.864782]  tun_net_xmit+0x21c/0x460
[  117.864782]  netpoll_start_xmit+0x11d/0x1b0
[  117.864788]  netpoll_send_skb_on_dev+0x1b8/0x200
[  117.864789]  __br_forward+0x1b9/0x1e0 [bridge]
[  117.864789]  ? skb_clone+0x53/0xd0
[  117.864790]  ? __skb_clone+0x2e/0x120
[  117.864790]  deliver_clone+0x37/0x50 [bridge]
[  117.864790]  maybe_deliver+0x89/0xc0 [bridge]
[  117.864791]  br_flood+0x6c/0x130 [bridge]
[  117.864791]  br_dev_xmit+0x315/0x3c0 [bridge]
[  117.864792]  netpoll_start_xmit+0x11d/0x1b0
[  117.864792]  netpoll_send_skb_on_dev+0x1b8/0x200
[  117.864792]  netpoll_send_udp+0x2c6/0x3e8
[  117.864793]  write_msg+0xd9/0xf0 [netconsole]
[  117.864793]  console_unlock+0x386/0x4e0
[  117.864793]  vprintk_emit+0x17e/0x280
[  117.864794]  vprintk_default+0x29/0x50
[  117.864794]  vprintk_func+0x4c/0xbc
[  117.864794]  printk+0x58/0x6f
[  117.864795]  loop_fun+0x24/0x41 [printmsg_loop]
[  117.864795]  kthread+0x104/0x140
[  117.864795]  ? 0xffffffffc05b1000
[  117.864796]  ? kthread_park+0x80/0x80
[  117.864796]  ret_from_fork+0x35/0x40

Signed-off-by: Feng Sun 
Signed-off-by: Xiaojun Zhao 
Signed-off-by: David S. Miller