Dan Carpenter contacted me with some notes regarding some smatch warnings in the
netpoll code, some of which I introduced with my recent netpoll locking fixes,
some which were there prior. Specifically they were:
net-next/net/core/netpoll.c:243 netpoll_poll_dev() warn: inconsistent
returns mutex:&ni->dev_lock: locked (213,217) unlocked (210,243)
net-next/net/core/netpoll.c:706 netpoll_neigh_reply() warn: potential
pointer math issue ('skb_transport_header(send_skb)' is a 128 bit pointer)
This patch corrects the locking imbalance (the first error), and adds some
parenthesis to correct the second error. Tested by myself. Applies to net-next
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: Dan Carpenter <dan.carpenter@oracle.com>
CC: "David S. Miller" <davem@davemloft.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
With my recent commit I introduced two sparse warnings. Looking closer there
were a few more in the same file, so I fixed them all up. Basic rcu pointer
dereferencing suff.
I've validated these changes using CONFIG_PROVE_RCU while starting and stopping
netconsole repeatedly in bonded and non-bonded configurations
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: fengguang.wu@intel.com
CC: David Miller <davem@davemloft.net>
CC: eric.dumazet@gmail.com
Signed-off-by: David S. Miller <davem@davemloft.net>
__netpoll_rcu_free is used to free netpoll structures when the rtnl_lock is
already held. The mechanism is used to asynchronously call __netpoll_cleanup
outside of the holding of the rtnl_lock, so as to avoid deadlock.
Unfortunately, __netpoll_cleanup modifies pointers (dev->np), which means the
rtnl_lock must be held while calling it. Further, it cannot be held, because
rcu callbacks may be issued in softirq contexts, which cannot sleep.
Fix this by converting the rcu callback to a work queue that is guaranteed to
get scheduled in process context, so that we can hold the rtnl properly while
calling __netpoll_cleanup
Tested successfully by myself.
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: Cong Wang <amwang@redhat.com>
CC: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Ivan Vercera was recently backporting commit
9c13cb8bb4 to a RHEL kernel, and I noticed that,
while this patch protects the tg3 driver from having its ndo_poll_controller
routine called during device initalization, it does nothing for the driver
during shutdown. I.e. it would be entirely possible to have the
ndo_poll_controller method (or subsequently the ndo_poll) routine called for a
driver in the netpoll path on CPU A while in parallel on CPU B, the ndo_close or
ndo_open routine could be called. Given that the two latter routines tend to
initizlize and free many data structures that the former two rely on, the result
can easily be data corruption or various other crashes. Furthermore, it seems
that this is potentially a problem with all net drivers that support netpoll,
and so this should ideally be fixed in a common path.
As Ben H Pointed out to me, we can't preform dev_open/dev_close in atomic
context, so I've come up with this solution. We can use a mutex to sleep in
open/close paths and just do a mutex_trylock in the napi poll path and abandon
the poll attempt if we're locked, as we'll just retry the poll on the next send
anyway.
I've tested this here by flooding netconsole with messages on a system whos nic
driver I modfied to periodically return NETDEV_TX_BUSY, so that the netpoll tx
workqueue would be forced to send frames and poll the device. While this was
going on I rapidly ifdown/up'ed the interface and watched for any problems.
I've not found any.
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: Ivan Vecera <ivecera@redhat.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: Ben Hutchings <bhutchings@solarflare.com>
CC: Francois Romieu <romieu@fr.zoreil.com>
CC: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fengguang reported:
net/core/netpoll.c: In function 'netpoll_setup':
net/core/netpoll.c:1049:6: warning: 'err' may be used uninitialized in this function [-Wmaybe-uninitialized]
in !CONFIG_IPV6 case, we may error out without initializing
'err'.
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
v4: hold rtnl lock for the whole netpoll_setup()
v3: remove the comment
v2: use RCU read lock
This patch fixes the following warning:
[ 72.013864] RTNL: assertion failed at net/core/dev.c (4955)
[ 72.017758] Pid: 668, comm: netpoll-prep-v6 Not tainted 3.8.0-rc1+ #474
[ 72.019582] Call Trace:
[ 72.020295] [<ffffffff8176653d>] netdev_master_upper_dev_get+0x35/0x58
[ 72.022545] [<ffffffff81784edd>] netpoll_setup+0x61/0x340
[ 72.024846] [<ffffffff815d837e>] store_enabled+0x82/0xc3
[ 72.027466] [<ffffffff815d7e51>] netconsole_target_attr_store+0x35/0x37
[ 72.029348] [<ffffffff811c3479>] configfs_write_file+0xe2/0x10c
[ 72.030959] [<ffffffff8115d239>] vfs_write+0xaf/0xf6
[ 72.032359] [<ffffffff81978a05>] ? sysret_check+0x22/0x5d
[ 72.033824] [<ffffffff8115d453>] sys_write+0x5c/0x84
[ 72.035328] [<ffffffff819789d9>] system_call_fastpath+0x16/0x1b
In case of other races, hold rtnl lock for the entire netpoll_setup() function.
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, netpoll only supports IPv4. This patch adds IPv6
support to netpoll so that we can run netconsole over IPv6 network.
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch removes the redundant occurences of simple_strto<foo>
Signed-off-by: Abhijit Pawar <abhi.c.pawar@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In netpoll tx path, we miss the chance of calling ->ndo_select_queue(),
thus could cause problems when bonding is involved.
This patch makes dev_pick_tx() extern (and rename it to netdev_pick_tx())
to let netpoll call it in netpoll_send_skb_on_dev().
Reported-by: Sylvain Munaut <s.munaut@whatever-company.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Cong Wang <amwang@redhat.com>
Tested-by: Sylvain Munaut <s.munaut@whatever-company.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Merge the 'net' tree to get the recent set of netfilter bug fixes in
order to assist with some merge hassles Pablo is going to have to deal
with for upcoming changes.
Signed-off-by: David S. Miller <davem@davemloft.net>
Let's fill IP header ident field with a meaningful value,
it might help some setups.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Against -net.
In the patch "netpoll: re-enable irq in poll_napi()", I tried to
fix the following warning:
[100718.051041] ------------[ cut here ]------------
[100718.051048] WARNING: at kernel/softirq.c:159 local_bh_enable_ip+0x7d/0xb0()
(Not tainted)
[100718.051049] Hardware name: ProLiant BL460c G7
...
[100718.051068] Call Trace:
[100718.051073] [<ffffffff8106b747>] ? warn_slowpath_common+0x87/0xc0
[100718.051075] [<ffffffff8106b79a>] ? warn_slowpath_null+0x1a/0x20
[100718.051077] [<ffffffff810747ed>] ? local_bh_enable_ip+0x7d/0xb0
[100718.051080] [<ffffffff8150041b>] ? _spin_unlock_bh+0x1b/0x20
[100718.051085] [<ffffffffa00ee974>] ? be_process_mcc+0x74/0x230 [be2net]
[100718.051088] [<ffffffffa00ea68c>] ? be_poll_tx_mcc+0x16c/0x290 [be2net]
[100718.051090] [<ffffffff8144fe76>] ? netpoll_poll_dev+0xd6/0x490
[100718.051095] [<ffffffffa01d24a5>] ? bond_poll_controller+0x75/0x80 [bonding]
[100718.051097] [<ffffffff8144fde5>] ? netpoll_poll_dev+0x45/0x490
[100718.051100] [<ffffffff81161b19>] ? ksize+0x19/0x80
[100718.051102] [<ffffffff81450437>] ? netpoll_send_skb_on_dev+0x157/0x240
by reenabling IRQ before calling ->poll, but it seems more
problems are introduced after that patch:
http://ozlabs.org/~akpm/stuff/IMG_20120824_122054.jpghttp://marc.info/?l=linux-netdev&m=134563282530588&w=2
So it is safe to fix be2net driver code directly.
This patch reverts the offending commit and fixes be_poll() by
avoid disabling BH there, this is okay because be_poll()
can be called either by poll_napi() which already disables
IRQ, or by net_rx_action() which already disables BH.
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Reported-by: Sylvain Munaut <s.munaut@whatever-company.com>
Cc: Sylvain Munaut <s.munaut@whatever-company.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Miller <davem@davemloft.net>
Cc: Sathya Perla <sathya.perla@emulex.com>
Cc: Subbu Seetharaman <subbu.seetharaman@emulex.com>
Cc: Ajit Khaparde <ajit.khaparde@emulex.com>
Signed-off-by: Cong Wang <amwang@redhat.com>
Tested-by: Sylvain Munaut <s.munaut@whatever-company.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Without this patch, I can't get netconsole logs remotely over
vlan. The reason is probably we don't handle vlan tags in either
netpoll tx or rx path.
I am not sure if I use these vlan functions correctly, at
least this patch works.
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Patrick McHardy <kaber@trash.net>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch fixes several problems in the call path of
netpoll_send_skb_on_dev():
1. Disable IRQ's before calling netpoll_send_skb_on_dev().
2. All the callees of netpoll_send_skb_on_dev() should use
rcu_dereference_bh() to dereference ->npinfo.
3. Rename arp_reply() to netpoll_arp_reply(), the former is too generic.
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In __netpoll_rx(), it dereferences ->npinfo without rcu_dereference_bh(),
this patch fixes it by using the 'npinfo' passed from netpoll_rx()
where it is already dereferenced with rcu_dereference_bh().
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Like the previous patch, slave_disable_netpoll() and __netpoll_cleanup()
may be called with read_lock() held too, so we should make them
non-block, by moving the cleanup and kfree() to call_rcu_bh() callbacks.
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Neil Horman
Cong Wang
Jiri Pirko
Abhijit Pawar
David S. Miller
Eric Dumazet
