Pablo Neira Ayuso says:
====================
Netfilter fix for net
The following patch reverts the ebtables chunk that enforces counters that was
introduced in the recently applied d26e2c9ffa ('Revert "netfilter: ensure
number of counters is >0 in do_replace()"') since this breaks ebtables.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
We currently rely on the PMTU discovery of xfrm.
However if a packet is localy sent, the PMTU mechanism
of xfrm tries to to local socket notification what
might not work for applications like ping that don't
check for this. So add pmtu handling to vti6_xmit to
report MTU changes immediately.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This reverts commit f96dee13b8.
It isn't right, ethtool is meant to manage one PHY instance
per netdevice at a time, and this is selected by the SET
command. Therefore by definition the GET command must only
return the settings for the configured and selected PHY.
Reported-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
This partially reverts commit 1086bbe97a ("netfilter: ensure number of
counters is >0 in do_replace()") in net/bridge/netfilter/ebtables.c.
Setting rules with ebtables does not work any more with 1086bbe97a place.
There is an error message and no rules set in the end.
e.g.
~# ebtables -t nat -A POSTROUTING --src 12:34:56:78:9a:bc -j DROP
Unable to update the kernel. Two possible causes:
1. Multiple ebtables programs were executing simultaneously. The ebtables
userspace tool doesn't by default support multiple ebtables programs
running
Reverting the ebtables part of 1086bbe97a makes this work again.
Signed-off-by: Bernhard Thaler <bernhard.thaler@wvnet.at>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
While shuffling some code around, dsa_switch_setup_one() was introduced,
and it was modified to return either an error code using ERR_PTR() or a
NULL pointer when running out of memory or failing to setup a switch.
This is a problem for its caler: dsa_switch_setup() which uses IS_ERR()
and expects to find an error code, not a NULL pointer, so we still try
to proceed with dsa_switch_setup() and operate on invalid memory
addresses. This can be easily reproduced by having e.g: the bcm_sf2
driver built-in, but having no such switch, such that drv->setup will
fail.
Fix this by using PTR_ERR() consistently which is both more informative
and avoids for the caller to use IS_ERR_OR_NULL().
Fixes: df197195a5 ("net: dsa: split dsa_switch_setup into two functions")
Reported-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Linux 3.17 and earlier are explicitly engineered so that if the app
doesn't specifically request a CC module on a listener before the SYN
arrives, then the child gets the system default CC when the connection
is established. See tcp_init_congestion_control() in 3.17 or earlier,
which says "if no choice made yet assign the current value set as
default". The change ("net: tcp: assign tcp cong_ops when tcp sk is
created") altered these semantics, so that children got their parent
listener's congestion control even if the system default had changed
after the listener was created.
This commit returns to those original semantics from 3.17 and earlier,
since they are the original semantics from 2007 in 4d4d3d1e8 ("[TCP]:
Congestion control initialization."), and some Linux congestion
control workflows depend on that.
In summary, if a listener socket specifically sets TCP_CONGESTION to
"x", or the route locks the CC module to "x", then the child gets
"x". Otherwise the child gets current system default from
net.ipv4.tcp_congestion_control. That's the behavior in 3.17 and
earlier, and this commit restores that.
Fixes: 55d8694fa8 ("net: tcp: assign tcp cong_ops when tcp sk is created")
Cc: Florian Westphal <fw@strlen.de>
Cc: Daniel Borkmann <dborkman@redhat.com>
Cc: Glenn Judd <glenn.judd@morganstanley.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
We have two problems in UDP stack related to bogus checksums :
1) We return -EAGAIN to application even if receive queue is not empty.
This breaks applications using edge trigger epoll()
2) Under UDP flood, we can loop forever without yielding to other
processes, potentially hanging the host, especially on non SMP.
This patch is an attempt to make things better.
We might in the future add extra support for rt applications
wanting to better control time spent doing a recv() in a hostile
environment. For example we could validate checksums before queuing
packets in socket receive queue.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
br_multicast_query_expired() querier argument is a pointer to
a struct bridge_mcast_querier :
struct bridge_mcast_querier {
struct br_ip addr;
struct net_bridge_port __rcu *port;
};
Intent of the code was to clear port field, not the pointer to querier.
Fixes: 2cd4143192 ("bridge: memorize and export selected IGMP/MLD querier port")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Thadeu Lima de Souza Cascardo <cascardo@redhat.com>
Acked-by: Linus Lüssing <linus.luessing@c0d3.blue>
Cc: Linus Lüssing <linus.luessing@web.de>
Cc: Steinar H. Gunderson <sesse@samfundet.no>
Signed-off-by: David S. Miller <davem@davemloft.net>
Steffen Klassert says:
====================
pull request (net): ipsec 2015-05-28
1) Fix a race in xfrm_state_lookup_byspi, we need to take
the refcount before we release xfrm_state_lock.
From Li RongQing.
2) Fix IV generation on ESN state. We used just the
low order sequence numbers for IV generation on
ESN, as a result the IV can repeat on the same
state. Fix this by using the high order sequence
number bits too and make sure to always initialize
the high order bits with zero. These patches are
serious stable candidates. Fixes from Herbert Xu.
3) Fix the skb->mark handling on vti. We don't
reset skb->mark in skb_scrub_packet anymore,
so vti must care to restore the original
value back after it was used to lookup the
vti policy and state. Fixes from Alexander Duyck.
Please pull or let me know if there are problems.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
The vti6_rcv_cb and vti_rcv_cb calls were leaving the skb->mark modified
after completing the function. This resulted in the original skb->mark
value being lost. Since we only need skb->mark to be set for
xfrm_policy_check we can pull the assignment into the rcv_cb calls and then
just restore the original mark after xfrm_policy_check has been completed.
Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
This change makes it so that if a tunnel is defined we just use the mark
from the tunnel instead of the mark from the skb header. By doing this we
can avoid the need to set skb->mark inside of the tunnel receive functions.
Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Instead of modifying skb->mark we can simply modify the flowi_mark that is
generated as a result of the xfrm_decode_session. By doing this we don't
need to actually touch the skb->mark and it can be preserved as it passes
out through the tunnel.
Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Pull networking fixes from David Miller:
1) Don't use MMIO on certain iwlwifi devices otherwise we get a
firmware crash.
2) Don't corrupt the GRO lists of mac80211 contexts by doing sends via
timer interrupt, from Johannes Berg.
3) SKB tailroom is miscalculated in AP_VLAN crypto code, from Michal
Kazior.
4) Fix fw_status memory leak in iwlwifi, from Haim Dreyfuss.
5) Fix use after free in iwl_mvm_d0i3_enable_tx(), from Eliad Peller.
6) JIT'ing of large BPF programs is broken on x86, from Alexei
Starovoitov.
7) EMAC driver ethtool register dump size is miscalculated, from Ivan
Mikhaylov.
8) Fix PHY initial link mode when autonegotiation is disabled in
amd-xgbe, from Tom Lendacky.
9) Fix NULL deref on SOCK_DEAD socket in AF_UNIX and CAIF protocols,
from Mark Salyzyn.
10) credit_bytes not initialized properly in xen-netback, from Ross
Lagerwall.
11) Fallback from MSI-X to INTx interrupts not handled properly in mlx4
driver, fix from Benjamin Poirier.
12) Perform ->attach() after binding dev->qdisc in packet scheduler,
otherwise we can crash. From Cong WANG.
13) Don't clobber data in sctp_v4_map_v6(). From Jason Gunthorpe.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (30 commits)
sctp: Fix mangled IPv4 addresses on a IPv6 listening socket
net_sched: invoke ->attach() after setting dev->qdisc
xen-netfront: properly destroy queues when removing device
mlx4_core: Fix fallback from MSI-X to INTx
xen/netback: Properly initialize credit_bytes
net: netxen: correct sysfs bin attribute return code
tools: bpf_jit_disasm: fix segfault on disabled debugging log output
unix/caif: sk_socket can disappear when state is unlocked
amd-xgbe-phy: Fix initial mode when autoneg is disabled
net: dp83640: fix improper double spin locking.
net: dp83640: reinforce locking rules.
net: dp83640: fix broken calibration routine.
net: stmmac: create one debugfs dir per net-device
net/ibm/emac: fix size of emac dump memory areas
x86: bpf_jit: fix compilation of large bpf programs
net: phy: bcm7xxx: Fix 7425 PHY ID and flags
iwlwifi: mvm: avoid use-after-free on iwl_mvm_d0i3_enable_tx()
iwlwifi: mvm: clean net-detect info if device was reset during suspend
iwlwifi: mvm: take the UCODE_DOWN reference when resuming
iwlwifi: mvm: BT Coex - duplicate the command if sent ASYNC
...
For mq qdisc, we add per tx queue qdisc to root qdisc
for display purpose, however, that happens too early,
before the new dev->qdisc is finally set, this causes
q->list points to an old root qdisc which is going to be
freed right before assigning with a new one.
Fix this by moving ->attach() after setting dev->qdisc.
For the record, this fixes the following crash:
------------[ cut here ]------------
WARNING: CPU: 1 PID: 975 at lib/list_debug.c:59 __list_del_entry+0x5a/0x98()
list_del corruption. prev->next should be ffff8800d1998ae8, but was 6b6b6b6b6b6b6b6b
CPU: 1 PID: 975 Comm: tc Not tainted 4.1.0-rc4+ #1019
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
0000000000000009 ffff8800d73fb928 ffffffff81a44e7f 0000000047574756
ffff8800d73fb978 ffff8800d73fb968 ffffffff810790da ffff8800cfc4cd20
ffffffff814e725b ffff8800d1998ae8 ffffffff82381250 0000000000000000
Call Trace:
[<ffffffff81a44e7f>] dump_stack+0x4c/0x65
[<ffffffff810790da>] warn_slowpath_common+0x9c/0xb6
[<ffffffff814e725b>] ? __list_del_entry+0x5a/0x98
[<ffffffff81079162>] warn_slowpath_fmt+0x46/0x48
[<ffffffff81820eb0>] ? dev_graft_qdisc+0x5e/0x6a
[<ffffffff814e725b>] __list_del_entry+0x5a/0x98
[<ffffffff814e72a7>] list_del+0xe/0x2d
[<ffffffff81822f05>] qdisc_list_del+0x1e/0x20
[<ffffffff81820cd1>] qdisc_destroy+0x30/0xd6
[<ffffffff81822676>] qdisc_graft+0x11d/0x243
[<ffffffff818233c1>] tc_get_qdisc+0x1a6/0x1d4
[<ffffffff810b5eaf>] ? mark_lock+0x2e/0x226
[<ffffffff817ff8f5>] rtnetlink_rcv_msg+0x181/0x194
[<ffffffff817ff72e>] ? rtnl_lock+0x17/0x19
[<ffffffff817ff72e>] ? rtnl_lock+0x17/0x19
[<ffffffff817ff774>] ? __rtnl_unlock+0x17/0x17
[<ffffffff81855dc6>] netlink_rcv_skb+0x4d/0x93
[<ffffffff817ff756>] rtnetlink_rcv+0x26/0x2d
[<ffffffff818544b2>] netlink_unicast+0xcb/0x150
[<ffffffff81161db9>] ? might_fault+0x59/0xa9
[<ffffffff81854f78>] netlink_sendmsg+0x4fa/0x51c
[<ffffffff817d6e09>] sock_sendmsg_nosec+0x12/0x1d
[<ffffffff817d8967>] sock_sendmsg+0x29/0x2e
[<ffffffff817d8cf3>] ___sys_sendmsg+0x1b4/0x23a
[<ffffffff8100a1b8>] ? native_sched_clock+0x35/0x37
[<ffffffff810a1d83>] ? sched_clock_local+0x12/0x72
[<ffffffff810a1fd4>] ? sched_clock_cpu+0x9e/0xb7
[<ffffffff810def2a>] ? current_kernel_time+0xe/0x32
[<ffffffff810b4bc5>] ? lock_release_holdtime.part.29+0x71/0x7f
[<ffffffff810ddebf>] ? read_seqcount_begin.constprop.27+0x5f/0x76
[<ffffffff810b6292>] ? trace_hardirqs_on_caller+0x17d/0x199
[<ffffffff811b14d5>] ? __fget_light+0x50/0x78
[<ffffffff817d9808>] __sys_sendmsg+0x42/0x60
[<ffffffff817d9838>] SyS_sendmsg+0x12/0x1c
[<ffffffff81a50e97>] system_call_fastpath+0x12/0x6f
---[ end trace ef29d3fb28e97ae7 ]---
For long term, we probably need to clean up the qdisc_graft() code
in case it hides other bugs like this.
Fixes: 95dc19299f ("pkt_sched: give visibility to mq slave qdiscs")
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
got a rare NULL pointer dereference in clear_bit
Signed-off-by: Mark Salyzyn <salyzyn@android.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
----
v2: switch to sock_flag(sk, SOCK_DEAD) and added net/caif/caif_socket.c
v3: return -ECONNRESET in upstream caller of wait function for SOCK_DEAD
Signed-off-by: David S. Miller <davem@davemloft.net>
Johannes Berg says:
====================
We have three more fixes:
* AP_VLAN tailroom calculation fix, the bug leads to warnings
along with dropped packets
* NAPI context issue, calling napi_gro_receive() from a timer
(obviously) can lead to crashes
* remain-on-channel combining leads to dropped requests and not
being able to finish certain operations, so remove it
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull two Ceph fixes from Sage Weil:
"These fix an issue with the RBD notifications when there are topology
changes in the cluster"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
Revert "libceph: clear r_req_lru_item in __unregister_linger_request()"
libceph: request a new osdmap if lingering request maps to no osd
When trying to configure the settings for PHY1, using commands
like 'ethtool -s eth0 phyad 1 speed 100', the 'ethtool' seems to
modify other settings apart from the speed of the PHY1, in the
above case.
The ethtool seems to query the settings for PHY0, and use this
as the base to apply the new settings to the PHY1. This is
causing the other settings of the PHY 1 to be wrongly
configured.
The issue is caused by the '_ethtool_get_settings()' API, which
gets called because of the 'ETHTOOL_GSET' command, is clearing
the 'cmd' pointer (of type 'struct ethtool_cmd') by calling
memset. This clears all the parameters (if any) passed for the
'ETHTOOL_GSET' cmd. So the driver's callback is always invoked
with 'cmd->phy_address' as '0'.
The '_ethtool_get_settings()' is called from other files in the
'net/core'. So the fix is applied to the 'ethtool_get_settings()'
which is only called in the context of the 'ethtool'.
Signed-off-by: Arun Parameswaran <aparames@broadcom.com>
Reviewed-by: Ray Jui <rjui@broadcom.com>
Reviewed-by: Scott Branden <sbranden@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When more than a multicast address is present in a MLDv2 report, all but
the first address is ignored, because the code breaks out of the loop if
there has not been an error adding that address.
This has caused failures when two guests connected through the bridge
tried to communicate using IPv6. Neighbor discoveries would not be
transmitted to the other guest when both used a link-local address and a
static address.
This only happens when there is a MLDv2 querier in the network.
The fix will only break out of the loop when there is a failure adding a
multicast address.
The mdb before the patch:
dev ovirtmgmt port vnet0 grp ff02::1:ff7d:6603 temp
dev ovirtmgmt port vnet1 grp ff02::1:ff7d:6604 temp
dev ovirtmgmt port bond0.86 grp ff02::2 temp
After the patch:
dev ovirtmgmt port vnet0 grp ff02::1:ff7d:6603 temp
dev ovirtmgmt port vnet1 grp ff02::1:ff7d:6604 temp
dev ovirtmgmt port bond0.86 grp ff02::fb temp
dev ovirtmgmt port bond0.86 grp ff02::2 temp
dev ovirtmgmt port bond0.86 grp ff02::d temp
dev ovirtmgmt port vnet0 grp ff02::1:ff00:76 temp
dev ovirtmgmt port bond0.86 grp ff02::16 temp
dev ovirtmgmt port vnet1 grp ff02::1:ff00:77 temp
dev ovirtmgmt port bond0.86 grp ff02::1:ff00:def temp
dev ovirtmgmt port bond0.86 grp ff02::1:ffa1:40bf temp
Fixes: 08b202b672 ("bridge br_multicast: IPv6 MLD support.")
Reported-by: Rik Theys <Rik.Theys@esat.kuleuven.be>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@redhat.com>
Tested-by: Rik Theys <Rik.Theys@esat.kuleuven.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
When replacing an IPv4 route, tb_id member of the new fib_alias
structure is not set in the replace code path so that the new route is
ignored.
Fixes: 0ddcf43d5d ("ipv4: FIB Local/MAIN table collapse")
Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Acked-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pablo Neira Ayuso says:
====================
Netfilter fixes for net
The following patchset contain Netfilter fixes for your net tree, they are:
1) Fix a race in nfnetlink_log and nfnetlink_queue that can lead to a crash.
This problem is due to wrong order in the per-net registration and netlink
socket events. Patch from Francesco Ruggeri.
2) Make sure that counters that userspace pass us are higher than 0 in all the
x_tables frontends. Discovered via Trinity, patch from Dave Jones.
3) Revert a patch for br_netfilter to rely on the conntrack status bits. This
breaks stateless IPv6 NAT transformations. Patch from Florian Westphal.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
ip_error does not check if in_dev is NULL before dereferencing it.
IThe following sequence of calls is possible:
CPU A CPU B
ip_rcv_finish
ip_route_input_noref()
ip_route_input_slow()
inetdev_destroy()
dst_input()
With the result that a network device can be destroyed while processing
an input packet.
A crash was triggered with only unicast packets in flight, and
forwarding enabled on the only network device. The error condition
was created by the removal of the network device.
As such it is likely the that error code was -EHOSTUNREACH, and the
action taken by ip_error (if in_dev had been accessible) would have
been to not increment any counters and to have tried and likely failed
to send an icmp error as the network device is going away.
Therefore handle this weird case by just dropping the packet if
!in_dev. It will result in dropping the packet sooner, and will not
result in an actual change of behavior.
Fixes: 251da41301 ("ipv4: Cache ip_error() routes even when not forwarding.")
Reported-by: Vittorio Gambaletta <linuxbugs@vittgam.net>
Tested-by: Vittorio Gambaletta <linuxbugs@vittgam.net>
Signed-off-by: Vittorio Gambaletta <linuxbugs@vittgam.net>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Taking socket spinlock in tcp_get_info() can deadlock, as
inet_diag_dump_icsk() holds the &hashinfo->ehash_locks[i],
while packet processing can use the reverse locking order.
We could avoid this locking for TCP_LISTEN states, but lockdep would
certainly get confused as all TCP sockets share same lockdep classes.
[ 523.722504] ======================================================
[ 523.728706] [ INFO: possible circular locking dependency detected ]
[ 523.734990] 4.1.0-dbg-DEV #1676 Not tainted
[ 523.739202] -------------------------------------------------------
[ 523.745474] ss/18032 is trying to acquire lock:
[ 523.750002] (slock-AF_INET){+.-...}, at: [<ffffffff81669d44>] tcp_get_info+0x2c4/0x360
[ 523.758129]
[ 523.758129] but task is already holding lock:
[ 523.763968] (&(&hashinfo->ehash_locks[i])->rlock){+.-...}, at: [<ffffffff816bcb75>] inet_diag_dump_icsk+0x1d5/0x6c0
[ 523.774661]
[ 523.774661] which lock already depends on the new lock.
[ 523.774661]
[ 523.782850]
[ 523.782850] the existing dependency chain (in reverse order) is:
[ 523.790326]
-> #1 (&(&hashinfo->ehash_locks[i])->rlock){+.-...}:
[ 523.796599] [<ffffffff811126bb>] lock_acquire+0xbb/0x270
[ 523.802565] [<ffffffff816f5868>] _raw_spin_lock+0x38/0x50
[ 523.808628] [<ffffffff81665af8>] __inet_hash_nolisten+0x78/0x110
[ 523.815273] [<ffffffff816819db>] tcp_v4_syn_recv_sock+0x24b/0x350
[ 523.822067] [<ffffffff81684d41>] tcp_check_req+0x3c1/0x500
[ 523.828199] [<ffffffff81682d09>] tcp_v4_do_rcv+0x239/0x3d0
[ 523.834331] [<ffffffff816842fe>] tcp_v4_rcv+0xa8e/0xc10
[ 523.840202] [<ffffffff81658fa3>] ip_local_deliver_finish+0x133/0x3e0
[ 523.847214] [<ffffffff81659a9a>] ip_local_deliver+0xaa/0xc0
[ 523.853440] [<ffffffff816593b8>] ip_rcv_finish+0x168/0x5c0
[ 523.859624] [<ffffffff81659db7>] ip_rcv+0x307/0x420
Lets use u64_sync infrastructure instead. As a bonus, 64bit
arches get optimized, as these are nop for them.
Fixes: 0df48c26d8 ("tcp: add tcpi_bytes_acked to tcp_info")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Vijay reported that a loop as simple as ...
while true; do
tc qdisc add dev foo root handle 1: prio
tc filter add dev foo parent 1: u32 match u32 0 0 flowid 1
tc qdisc del dev foo root
rmmod cls_u32
done
... will panic the kernel. Moreover, he bisected the change
apparently introducing it to 78fd1d0ab0 ("netlink: Re-add
locking to netlink_lookup() and seq walker").
The removal of synchronize_net() from the netlink socket
triggering the qdisc to be removed, seems to have uncovered
an RCU resp. module reference count race from the tc API.
Given that RCU conversion was done after e341694e3e ("netlink:
Convert netlink_lookup() to use RCU protected hash table")
which added the synchronize_net() originally, occasion of
hitting the bug was less likely (not impossible though):
When qdiscs that i) support attaching classifiers and,
ii) have at least one of them attached, get deleted, they
invoke tcf_destroy_chain(), and thus call into ->destroy()
handler from a classifier module.
After RCU conversion, all classifier that have an internal
prio list, unlink them and initiate freeing via call_rcu()
deferral.
Meanhile, tcf_destroy() releases already reference to the
tp->ops->owner module before the queued RCU callback handler
has been invoked.
Subsequent rmmod on the classifier module is then not prevented
since all module references are already dropped.
By the time, the kernel invokes the RCU callback handler from
the module, that function address is then invalid.
One way to fix it would be to add an rcu_barrier() to
unregister_tcf_proto_ops() to wait for all pending call_rcu()s
to complete.
synchronize_rcu() is not appropriate as under heavy RCU
callback load, registered call_rcu()s could be deferred
longer than a grace period. In case we don't have any pending
call_rcu()s, the barrier is allowed to return immediately.
Since we came here via unregister_tcf_proto_ops(), there
are no users of a given classifier anymore. Further nested
call_rcu()s pointing into the module space are not being
done anywhere.
Only cls_bpf_delete_prog() may schedule a work item, to
unlock pages eventually, but that is not in the range/context
of cls_bpf anymore.
Fixes: 25d8c0d55f ("net: rcu-ify tcf_proto")
Fixes: 9888faefe1 ("net: sched: cls_basic use RCU")
Reported-by: Vijay Subramanian <subramanian.vijay@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: John Fastabend <john.r.fastabend@intel.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Thomas Graf <tgraf@suug.ch>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Tested-by: Vijay Subramanian <subramanian.vijay@gmail.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
David S. Miller
Steffen Klassert
Bernhard Thaler
Florian Fainelli
Neal Cardwell
Eric Dumazet
Alexander Duyck
Linus Torvalds
WANG Cong
Mark Salyzyn
Arun Parameswaran
Thadeu Lima de Souza Cascardo
Michal Kubeček
Eric W. Biederman
Daniel Borkmann