The poll() changes were not well thought out, and completely
unexplained. They also caused a huge performance regression, because
"->poll()" was no longer a trivial file operation that just called down
to the underlying file operations, but instead did at least two indirect
calls.
Indirect calls are sadly slow now with the Spectre mitigation, but the
performance problem could at least be largely mitigated by changing the
"->get_poll_head()" operation to just have a per-file-descriptor pointer
to the poll head instead. That gets rid of one of the new indirections.
But that doesn't fix the new complexity that is completely unwarranted
for the regular case. The (undocumented) reason for the poll() changes
was some alleged AIO poll race fixing, but we don't make the common case
slower and more complex for some uncommon special case, so this all
really needs way more explanations and most likely a fundamental
redesign.
[ This revert is a revert of about 30 different commits, not reverted
individually because that would just be unnecessarily messy - Linus ]
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch fixes the kernel oops when release net_device reference in
advance. In function raw_sendmsg(i think the dgram_sendmsg has the same
problem), there is a race condition between dev_put and dev_queue_xmit
when the device is gong that maybe lead to dev_queue_ximt to see
an illegal net_device pointer.
My test kernel is 3.13.0-32 and because i am not have a real 802154
device, so i change lowpan_newlink function to this:
/* find and hold real wpan device */
real_dev = dev_get_by_index(src_net, nla_get_u32(tb[IFLA_LINK]));
if (!real_dev)
return -ENODEV;
// if (real_dev->type != ARPHRD_IEEE802154) {
// dev_put(real_dev);
// return -EINVAL;
// }
lowpan_dev_info(dev)->real_dev = real_dev;
lowpan_dev_info(dev)->fragment_tag = 0;
mutex_init(&lowpan_dev_info(dev)->dev_list_mtx);
Also, in order to simulate preempt, i change the raw_sendmsg function
to this:
skb->dev = dev;
skb->sk = sk;
skb->protocol = htons(ETH_P_IEEE802154);
dev_put(dev);
//simulate preempt
schedule_timeout_uninterruptible(30 * HZ);
err = dev_queue_xmit(skb);
if (err > 0)
err = net_xmit_errno(err);
and this is my userspace test code named test_send_data:
int main(int argc, char **argv)
{
char buf[127];
int sockfd;
sockfd = socket(AF_IEEE802154, SOCK_RAW, 0);
if (sockfd < 0) {
printf("create sockfd error: %s\n", strerror(errno));
return -1;
}
send(sockfd, buf, sizeof(buf), 0);
return 0;
}
This is my test case:
root@zhanglin-x-computer:~/develop/802154# uname -a
Linux zhanglin-x-computer 3.13.0-32-generic #57-Ubuntu SMP Tue Jul 15
03:51:08 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
root@zhanglin-x-computer:~/develop/802154# ip link add link eth0 name
lowpan0 type lowpan
root@zhanglin-x-computer:~/develop/802154#
//keep the lowpan0 device down
root@zhanglin-x-computer:~/develop/802154# ./test_send_data &
//wait a while
root@zhanglin-x-computer:~/develop/802154# ip link del link dev lowpan0
//the device is gone
//oops
[381.303307] general protection fault: 0000 [#1]SMP
[381.303407] Modules linked in: af_802154 6lowpan bnep rfcomm
bluetooth nls_iso8859_1 snd_hda_codec_hdmi snd_hda_codec_realtek
rts5139(C) snd_hda_intel
snd_had_codec snd_hwdep snd_pcm snd_page_alloc snd_seq_midi
snd_seq_midi_event snd_rawmidi snd_req intel_rapl snd_seq_device
coretemp i915 kvm_intel
kvm snd_timer snd crct10dif_pclmul crc32_pclmul ghash_clmulni_intel
cypted drm_kms_helper drm i2c_algo_bit soundcore video mac_hid
parport_pc ppdev ip parport hid_generic
usbhid hid ahci r8169 mii libahdi
[381.304286] CPU:1 PID: 2524 Commm: 1 Tainted: G C 0 3.13.0-32-generic
[381.304409] Hardware name: Haier Haier DT Computer/Haier DT Codputer,
BIOS FIBT19H02_X64 06/09/2014
[381.304546] tasks: ffff000096965fc0 ti: ffffB0013779c000 task.ti:
ffffB8013779c000
[381.304659] RIP: 0010:[<ffffffff01621fe1>] [<ffffffff81621fe1>]
__dev_queue_ximt+0x61/0x500
[381.304798] RSP: 0018:ffffB8013779dca0 EFLAGS: 00010202
[381.304880] RAX: 272b031d57565351 RBX: 0000000000000000 RCX: ffff8800968f1a00
[381.304987] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8800968f1a00
[381.305095] RBP: ffff8e013773dce0 R08: 0000000000000266 R09: 0000000000000004
[381.305202] R10: 0000000000000004 R11: 0000000000000005 R12: ffff88013902e000
[381.305310] R13: 000000000000007f R14: 000000000000007f R15: ffff8800968f1a00
[381.305418] FS: 00007fc57f50f740(0000) GS: ffff88013fc80000(0000)
knlGS: 0000000000000000
[381.305540] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[381.305627] CR2: 00007fad0841c000 CR3: 00000001368dd000 CR4: 00000000001007e0
[361.905734] Stack:
[381.305768] 00000000002052d0 000000003facb30a ffff88013779dcc0
ffff880137764000
[381.305898] ffff88013779de70 000000000000007f 000000000000007f
ffff88013902e000
[381.306026] ffff88013779dcf0 ffffffff81622490 ffff88013779dd39
ffffffffa03af9f1
[381.306155] Call Trace:
[381.306202] [<ffffffff81622490>] dev_queue_xmit+0x10/0x20
[381.306294] [<ffffffffa03af9f1>] raw_sendmsg+0x1b1/0x270 [af_802154]
[381.306396] [<ffffffffa03af054>] ieee802154_sock_sendmsg+0x14/0x20 [af_802154]
[381.306512] [<ffffffff816079eb>] sock_sendmsg+0x8b/0xc0
[381.306600] [<ffffffff811d52a5>] ? __d_alloc+0x25/0x180
[381.306687] [<ffffffff811a1f56>] ? kmem_cache_alloc_trace+0x1c6/0x1f0
[381.306791] [<ffffffff81607b91>] SYSC_sendto+0x121/0x1c0
[381.306878] [<ffffffff8109ddf4>] ? vtime_account_user+x54/0x60
[381.306975] [<ffffffff81020d45>] ? syscall_trace_enter+0x145/0x250
[381.307073] [<ffffffff816086ae>] SyS_sendto+0xe/0x10
[381.307156] [<ffffffff8172c87f>] tracesys+0xe1/0xe6
[381.307233] Code: c6 a1 a4 ff 41 8b 57 78 49 8b 47 20 85 d2 48 8b 80
78 07 00 00 75 21 49 8b 57 18 48 85 d2 74 18 48 85 c0 74 13 8b 92 ac
01 00 00 <3b> 50 10 73 08 8b 44 90 14 41 89 47 78 41 f6 84 24 d5 00 00
00
[381.307801] RIP [<ffffffff81621fe1>] _dev_queue_xmit+0x61/0x500
[381.307901] RSP <ffff88013779dca0>
[381.347512] Kernel panic - not syncing: Fatal exception in interrupt
[381.347747] drm_kms_helper: panic occurred, switching back to text console
In my opinion, there is always exist a chance that the device is gong
before call dev_queue_xmit.
I think the latest kernel is have the same problem and that
dev_put should be behind of the dev_queue_xmit.
Signed-off-by: Lin Zhang <xiaolou4617@gmail.com>
Acked-by: Stefan Schmidt <stefan@osg.samsung.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Explicit set skb->sk is needless, sock_alloc_send_skb is already set it.
Signed-off-by: Lin Zhang <xiaolou4617@gmail.com>
Acked-by: Stefan Schmidt <stefan@osg.samsung.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Now that %z is standartised in C99 there is no reason to support %Z.
Unlike %L it doesn't even make format strings smaller.
Use BUILD_BUG_ON in a couple ATM drivers.
In case anyone didn't notice lib/vsprintf.o is about half of SLUB which
is in my opinion is quite an achievement. Hopefully this patch inspires
someone else to trim vsprintf.c more.
Link: http://lkml.kernel.org/r/20170103230126.GA30170@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In order to support fast reuseport lookups in TCP, the hash function
defined in struct proto must be capable of returning an error code.
This patch changes the function signature of all related hash functions
to return an integer and handles or propagates this return value at
all call sites.
Signed-off-by: Craig Gallek <kraig@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch changes the mtu size of 802.15.4 interfaces. The current
setting is the meaning of the maximum transport unit with mac header,
which is 127 bytes according 802.15.4. The linux meaning of the mtu size
field is the maximum payload of a mac frame. Like in ethernet, which is
1500 bytes.
We have dynamic length of mac frames in 802.15.4, this is why we assume
the minimum header length which is hard_header_len. This contains fc and
sequence fields. These can evaluated by driver layer without additional
checks. We currently don't support to set the FCS from userspace, so we
need to subtract this from mtu size as well.
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
The current header_ops callback structure of net device are used mostly
from 802.15.4 upper-layers. Because this callback structure is a very
generic one, which is also used by e.g. DGRAM AF_PACKET sockets, we
can't make this callback structure 802.15.4 specific which is currently
is.
I saw the smallest "constraint" for calling this callback with
dev_hard_header/dev_parse_header by AF_PACKET which assign a 8 byte
array for address void pointers. Currently 802.15.4 specific protocols
like af802154 and 6LoWPAN will assign the "struct ieee802154_addr" as
these parameters which is greater than 8 bytes. The current callback
implementation for header_ops.create assumes always a complete
"struct ieee802154_addr" which AF_PACKET can't never handled and is
greater than 8 bytes.
For that reason we introduce now a "generic" create/parse header_ops
callback which allows handling with intra-pan extended addresses only.
This allows a small use-case with AF_PACKET to send "somehow" a valid
dataframe over DGRAM.
To keeping the current dev_hard_header behaviour we introduce a similar
callback structure "wpan_dev_header_ops" which contains 802.15.4 specific
upper-layer header creation functionality, which can be called by
wpan_dev_hard_header.
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
The AF_IEEE802154 sockaddr looks like this:
struct sockaddr_ieee802154 {
sa_family_t family; /* AF_IEEE802154 */
struct ieee802154_addr_sa addr;
};
struct ieee802154_addr_sa {
int addr_type;
u16 pan_id;
union {
u8 hwaddr[IEEE802154_ADDR_LEN];
u16 short_addr;
};
};
On most architectures there will be implicit structure padding here,
in two different places:
* In struct sockaddr_ieee802154, two bytes of padding between 'family'
(unsigned short) and 'addr', so that 'addr' starts on a four byte
boundary.
* In struct ieee802154_addr_sa, two bytes at the end of the structure,
to make the structure 16 bytes.
When calling recvmsg(2) on a PF_IEEE802154 SOCK_DGRAM socket, the
ieee802154 stack constructs a struct sockaddr_ieee802154 on the
kernel stack without clearing these padding fields, and, depending
on the addr_type, between four and ten bytes of uncleared kernel
stack will be copied to userspace.
We can't just insert two 'u16 __pad's in the right places and zero
those before copying an address to userspace, as not all architectures
insert this implicit padding -- from a quick test it seems that avr32,
cris and m68k don't insert this padding, while every other architecture
that I have cross compilers for does insert this padding.
The easiest way to plug the leak is to just memset the whole struct
sockaddr_ieee802154 before filling in the fields we want to fill in,
and that's what this patch does.
Cc: stable@vger.kernel.org
Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Acked-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
ieee802154_get_dev() only returns devices that have dev->type ==
ARPHRD_IEEE802154, therefore, there is no need to check this again
in raw_bind().
Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Acked-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
The proper return code for trying to send a packet that exceeds the
outgoing interface's MTU is EMSGSIZE, not EINVAL, so patch ieee802154's
raw_sendmsg() to do the right thing. (Its dgram_sendmsg() was already
returning EMSGSIZE for this case.)
Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Acked-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
This patch removes the mib lock. The new locking mechanism is to protect
the mib values with the rtnl lock. Note that this isn't always necessary
if we have an interface up the most mib values are readonly (e.g.
address settings). With this behaviour we can remove locking in
hotpath like frame parsing completely. It depends on context if we need
to hold the rtnl lock or not, this makes the callbacks of
ieee802154_mlme_ops unnecessary because these callbacks hols always the
locks.
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Reviewed-by: Stefan Schmidt <stefan@osg.samsung.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
In preparation for changing how struct net is refcounted
on kernel sockets pass the knowledge that we are creating
a kernel socket from sock_create_kern through to sk_alloc.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
After TIPC doesn't depend on iocb argument in its internal
implementations of sendmsg() and recvmsg() hooks defined in proto
structure, no any user is using iocb argument in them at all now.
Then we can drop the redundant iocb argument completely from kinds of
implementations of both sendmsg() and recvmsg() in the entire
networking stack.
Cc: Christoph Hellwig <hch@lst.de>
Suggested-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch renames the "af_ieee802154.c" to "socket.c". This is just a
cleanup to have a short name for it which describes the implementationm
stuff more human understandable.
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Linus Torvalds