10 Sep, 2020
2 commits
-
[ Upstream commit 1d4adfaf65746203861c72d9d78de349eb97d528 ]
Fix rxrpc_kernel_get_srtt() to indicate the validity of the returned
smoothed RTT. If we haven't had any valid samples yet, the SRTT isn't
useful.Fixes: c410bf01933e ("rxrpc: Fix the excessive initial retransmission timeout")
Signed-off-by: David Howells
Signed-off-by: Sasha Levin -
[ Upstream commit 68528d937dcd675e79973061c1a314db598162d1 ]
Keep the ACK serial number in a variable in rxrpc_input_ack() as it's used
frequently.Signed-off-by: David Howells
Signed-off-by: Sasha Levin
11 Aug, 2020
1 commit
-
[ Upstream commit 65550098c1c4db528400c73acf3e46bfa78d9264 ]
There's a race between rxrpc_sendmsg setting up a call, but then failing to
send anything on it due to an error, and recvmsg() seeing the call
completion occur and trying to return the state to the user.An assertion fails in rxrpc_recvmsg() because the call has already been
released from the socket and is about to be released again as recvmsg deals
with it. (The recvmsg_q queue on the socket holds a ref, so there's no
problem with use-after-free.)We also have to be careful not to end up reporting an error twice, in such
a way that both returns indicate to userspace that the user ID supplied
with the call is no longer in use - which could cause the client to
malfunction if it recycles the user ID fast enough.Fix this by the following means:
(1) When sendmsg() creates a call after the point that the call has been
successfully added to the socket, don't return any errors through
sendmsg(), but rather complete the call and let recvmsg() retrieve
them. Make sendmsg() return 0 at this point. Further calls to
sendmsg() for that call will fail with ESHUTDOWN.Note that at this point, we haven't send any packets yet, so the
server doesn't yet know about the call.(2) If sendmsg() returns an error when it was expected to create a new
call, it means that the user ID wasn't used.(3) Mark the call disconnected before marking it completed to prevent an
oops in rxrpc_release_call().(4) recvmsg() will then retrieve the error and set MSG_EOR to indicate
that the user ID is no longer known by the kernel.An oops like the following is produced:
kernel BUG at net/rxrpc/recvmsg.c:605!
...
RIP: 0010:rxrpc_recvmsg+0x256/0x5ae
...
Call Trace:
? __init_waitqueue_head+0x2f/0x2f
____sys_recvmsg+0x8a/0x148
? import_iovec+0x69/0x9c
? copy_msghdr_from_user+0x5c/0x86
___sys_recvmsg+0x72/0xaa
? __fget_files+0x22/0x57
? __fget_light+0x46/0x51
? fdget+0x9/0x1b
do_recvmmsg+0x15e/0x232
? _raw_spin_unlock+0xa/0xb
? vtime_delta+0xf/0x25
__x64_sys_recvmmsg+0x2c/0x2f
do_syscall_64+0x4c/0x78
entry_SYSCALL_64_after_hwframe+0x44/0xa9Fixes: 357f5ef64628 ("rxrpc: Call rxrpc_release_call() on error in rxrpc_new_client_call()")
Reported-by: syzbot+b54969381df354936d96@syzkaller.appspotmail.com
Signed-off-by: David Howells
Reviewed-by: Marc Dionne
Signed-off-by: David S. Miller
Signed-off-by: Greg Kroah-Hartman
01 Aug, 2020
1 commit
-
[ Upstream commit 639f181f0ee20d3249dbc55f740f0167267180f0 ]
rxrpc_sendmsg() returns EPIPE if there's an outstanding error, such as if
rxrpc_recvmsg() indicating ENODATA if there's nothing for it to read.Change rxrpc_recvmsg() to return EAGAIN instead if there's nothing to read
as this particular error doesn't get stored in ->sk_err by the networking
core.Also change rxrpc_sendmsg() so that it doesn't fail with delayed receive
errors (there's no way for it to report which call, if any, the error was
caused by).Fixes: 17926a79320a ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both")
Signed-off-by: David Howells
Signed-off-by: David S. Miller
Signed-off-by: Greg Kroah-Hartman
09 Jul, 2020
2 commits
-
[ Upstream commit 02c28dffb13abbaaedece1e4a6493b48ad3f913a ]
Commit 2ad6691d988c, which moved the modification of the status annotation
for a packet in the Tx buffer prior to the retransmission moved the state
clearance, but managed to lose the bit that set it to UNACK.Consequently, if a retransmission occurs, the packet is accidentally
changed to the ACK state (ie. 0) by masking it off, which means that the
packet isn't counted towards the tally of newly-ACK'd packets if it gets
hard-ACK'd. This then prevents the congestion control algorithm from
recovering properly.Fix by reinstating the change of state to UNACK.
Spotted by the generic/460 xfstest.
Fixes: 2ad6691d988c ("rxrpc: Fix race between incoming ACK parser and retransmitter")
Signed-off-by: David Howells
Signed-off-by: Sasha Levin -
[ Upstream commit 2ad6691d988c0c611362ddc2aad89e0fb50e3261 ]
There's a race between the retransmission code and the received ACK parser.
The problem is that the retransmission loop has to drop the lock under
which it is iterating through the transmission buffer in order to transmit
a packet, but whilst the lock is dropped, the ACK parser can crank the Tx
window round and discard the packets from the buffer.The retransmission code then updated the annotations for the wrong packet
and a later retransmission thought it had to retransmit a packet that
wasn't there, leading to a NULL pointer dereference.Fix this by:
(1) Moving the annotation change to before we drop the lock prior to
transmission. This means we can't vary the annotation depending on
the outcome of the transmission, but that's fine - we'll retransmit
again later if it failed now.(2) Skipping the packet if the skb pointer is NULL.
The following oops was seen:
BUG: kernel NULL pointer dereference, address: 000000000000002d
Workqueue: krxrpcd rxrpc_process_call
RIP: 0010:rxrpc_get_skb+0x14/0x8a
...
Call Trace:
rxrpc_resend+0x331/0x41e
? get_vtime_delta+0x13/0x20
rxrpc_process_call+0x3c0/0x4ac
process_one_work+0x18f/0x27f
worker_thread+0x1a3/0x247
? create_worker+0x17d/0x17d
kthread+0xe6/0xeb
? kthread_delayed_work_timer_fn+0x83/0x83
ret_from_fork+0x1f/0x30Fixes: 248f219cb8bc ("rxrpc: Rewrite the data and ack handling code")
Signed-off-by: David Howells
Signed-off-by: David S. Miller
Signed-off-by: Sasha Levin
01 Jul, 2020
2 commits
-
[ Upstream commit a2ad7c21ad8cf1ce4ad65e13df1c2a1c29b38ac5 ]
The handling of the receive window size (rwind) from a received ACK packet
is not correct. The rxrpc_input_ackinfo() function currently checks the
current Tx window size against the rwind from the ACK to see if it has
changed, but then limits the rwind size before storing it in the tx_winsize
member and, if it increased, wake up the transmitting process. This means
that if rwind > RXRPC_RXTX_BUFF_SIZE - 1, this path will always be
followed.Fix this by limiting rwind before we compare it to tx_winsize.
The effect of this can be seen by enabling the rxrpc_rx_rwind_change
tracepoint.Fixes: 702f2ac87a9a ("rxrpc: Wake up the transmitter if Rx window size increases on the peer")
Signed-off-by: David Howells
Signed-off-by: Sasha Levin -
[ Upstream commit 0041cd5a50442db6e456b145892a0eaf2dff061f ]
When preallocated service calls are being discarded, they're passed to
->discard_new_call() to have the caller clean up any attached higher-layer
preallocated pieces before being marked completed. However, the act of
marking them completed now invokes the call's notification function - which
causes a problem because that function might assume that the previously
freed pieces of memory are still there.Fix this by setting a dummy notification function on the socket after
calling ->discard_new_call().This results in the following kasan message when the kafs module is
removed.==================================================================
BUG: KASAN: use-after-free in afs_wake_up_async_call+0x6aa/0x770 fs/afs/rxrpc.c:707
Write of size 1 at addr ffff8880946c39e4 by task kworker/u4:1/21CPU: 0 PID: 21 Comm: kworker/u4:1 Not tainted 5.8.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x18f/0x20d lib/dump_stack.c:118
print_address_description.constprop.0.cold+0xd3/0x413 mm/kasan/report.c:383
__kasan_report mm/kasan/report.c:513 [inline]
kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
afs_wake_up_async_call+0x6aa/0x770 fs/afs/rxrpc.c:707
rxrpc_notify_socket+0x1db/0x5d0 net/rxrpc/recvmsg.c:40
__rxrpc_set_call_completion.part.0+0x172/0x410 net/rxrpc/recvmsg.c:76
__rxrpc_call_completed net/rxrpc/recvmsg.c:112 [inline]
rxrpc_call_completed+0xca/0xf0 net/rxrpc/recvmsg.c:111
rxrpc_discard_prealloc+0x781/0xab0 net/rxrpc/call_accept.c:233
rxrpc_listen+0x147/0x360 net/rxrpc/af_rxrpc.c:245
afs_close_socket+0x95/0x320 fs/afs/rxrpc.c:110
afs_net_exit+0x1bc/0x310 fs/afs/main.c:155
ops_exit_list.isra.0+0xa8/0x150 net/core/net_namespace.c:186
cleanup_net+0x511/0xa50 net/core/net_namespace.c:603
process_one_work+0x965/0x1690 kernel/workqueue.c:2269
worker_thread+0x96/0xe10 kernel/workqueue.c:2415
kthread+0x3b5/0x4a0 kernel/kthread.c:291
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293Allocated by task 6820:
save_stack+0x1b/0x40 mm/kasan/common.c:48
set_track mm/kasan/common.c:56 [inline]
__kasan_kmalloc mm/kasan/common.c:494 [inline]
__kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:467
kmem_cache_alloc_trace+0x153/0x7d0 mm/slab.c:3551
kmalloc include/linux/slab.h:555 [inline]
kzalloc include/linux/slab.h:669 [inline]
afs_alloc_call+0x55/0x630 fs/afs/rxrpc.c:141
afs_charge_preallocation+0xe9/0x2d0 fs/afs/rxrpc.c:757
afs_open_socket+0x292/0x360 fs/afs/rxrpc.c:92
afs_net_init+0xa6c/0xe30 fs/afs/main.c:125
ops_init+0xaf/0x420 net/core/net_namespace.c:151
setup_net+0x2de/0x860 net/core/net_namespace.c:341
copy_net_ns+0x293/0x590 net/core/net_namespace.c:482
create_new_namespaces+0x3fb/0xb30 kernel/nsproxy.c:110
unshare_nsproxy_namespaces+0xbd/0x1f0 kernel/nsproxy.c:231
ksys_unshare+0x43d/0x8e0 kernel/fork.c:2983
__do_sys_unshare kernel/fork.c:3051 [inline]
__se_sys_unshare kernel/fork.c:3049 [inline]
__x64_sys_unshare+0x2d/0x40 kernel/fork.c:3049
do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359
entry_SYSCALL_64_after_hwframe+0x44/0xa9Freed by task 21:
save_stack+0x1b/0x40 mm/kasan/common.c:48
set_track mm/kasan/common.c:56 [inline]
kasan_set_free_info mm/kasan/common.c:316 [inline]
__kasan_slab_free+0xf7/0x140 mm/kasan/common.c:455
__cache_free mm/slab.c:3426 [inline]
kfree+0x109/0x2b0 mm/slab.c:3757
afs_put_call+0x585/0xa40 fs/afs/rxrpc.c:190
rxrpc_discard_prealloc+0x764/0xab0 net/rxrpc/call_accept.c:230
rxrpc_listen+0x147/0x360 net/rxrpc/af_rxrpc.c:245
afs_close_socket+0x95/0x320 fs/afs/rxrpc.c:110
afs_net_exit+0x1bc/0x310 fs/afs/main.c:155
ops_exit_list.isra.0+0xa8/0x150 net/core/net_namespace.c:186
cleanup_net+0x511/0xa50 net/core/net_namespace.c:603
process_one_work+0x965/0x1690 kernel/workqueue.c:2269
worker_thread+0x96/0xe10 kernel/workqueue.c:2415
kthread+0x3b5/0x4a0 kernel/kthread.c:291
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293The buggy address belongs to the object at ffff8880946c3800
which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 484 bytes inside of
1024-byte region [ffff8880946c3800, ffff8880946c3c00)
The buggy address belongs to the page:
page:ffffea000251b0c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea0002546508 ffffea00024fa248 ffff8880aa000c40
raw: 0000000000000000 ffff8880946c3000 0000000100000002 0000000000000000
page dumped because: kasan: bad access detectedMemory state around the buggy address:
ffff8880946c3880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880946c3900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880946c3980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880946c3a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880946c3a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================Reported-by: syzbot+d3eccef36ddbd02713e9@syzkaller.appspotmail.com
Fixes: 5ac0d62226a0 ("rxrpc: Fix missing notification")
Signed-off-by: David Howells
Signed-off-by: David S. Miller
Signed-off-by: Greg Kroah-Hartman
24 Jun, 2020
1 commit
-
[ Upstream commit 32f71aa497cfb23d37149c2ef16ad71fce2e45e2 ]
The user ID value isn't actually much use - and leaks a kernel pointer or a
userspace value - so replace it with the call debug ID, which appears in trace
points.Signed-off-by: David Howells
Signed-off-by: Sasha Levin
27 May, 2020
4 commits
-
[ Upstream commit 441fdee1eaf050ef0040bde0d7af075c1c6a6d8b ]
The Rx protocol has a "previousPacket" field in it that is not handled in
the same way by all protocol implementations. Sometimes it contains the
serial number of the last DATA packet received, sometimes the sequence
number of the last DATA packet received and sometimes the highest sequence
number so far received.AF_RXRPC is using this to weed out ACKs that are out of date (it's possible
for ACK packets to get reordered on the wire), but this does not work with
OpenAFS which will just stick the sequence number of the last packet seen
into previousPacket.The issue being seen is that big AFS FS.StoreData RPC (eg. of ~256MiB) are
timing out when partly sent. A trace was captured, with an additional
tracepoint to show ACKs being discarded in rxrpc_input_ack(). Here's an
excerpt showing the problem.52873.203230: rxrpc_tx_data: c=000004ae DATA ed1a3584:00000002 0002449c q=00024499 fl=09
A DATA packet with sequence number 00024499 has been transmitted (the "q="
field)....
52873.243296: rxrpc_rx_ack: c=000004ae 00012a2b DLY r=00024499 f=00024497 p=00024496 n=0
52873.243376: rxrpc_rx_ack: c=000004ae 00012a2c IDL r=0002449b f=00024499 p=00024498 n=0
52873.243383: rxrpc_rx_ack: c=000004ae 00012a2d OOS r=0002449d f=00024499 p=0002449a n=2The Out-Of-Sequence ACK indicates that the server didn't see DATA sequence
number 00024499, but did see seq 0002449a (previousPacket, shown as "p=",
skipped the number, but firstPacket, "f=", which shows the bottom of the
window is set at that point).52873.252663: rxrpc_retransmit: c=000004ae q=24499 a=02 xp=14581537
52873.252664: rxrpc_tx_data: c=000004ae DATA ed1a3584:00000002 000244bc q=00024499 fl=0b *RETRANS*The packet has been retransmitted. Retransmission recurs until the peer
says it got the packet.52873.271013: rxrpc_rx_ack: c=000004ae 00012a31 OOS r=000244a1 f=00024499 p=0002449e n=6
More OOS ACKs indicate that the other packets that are already in the
transmission pipeline are being received. The specific-ACK list is up to 6
ACKs and NAKs....
52873.284792: rxrpc_rx_ack: c=000004ae 00012a49 OOS r=000244b9 f=00024499 p=000244b6 n=30
52873.284802: rxrpc_retransmit: c=000004ae q=24499 a=0a xp=63505500
52873.284804: rxrpc_tx_data: c=000004ae DATA ed1a3584:00000002 000244c2 q=00024499 fl=0b *RETRANS*
52873.287468: rxrpc_rx_ack: c=000004ae 00012a4a OOS r=000244ba f=00024499 p=000244b7 n=31
52873.287478: rxrpc_rx_ack: c=000004ae 00012a4b OOS r=000244bb f=00024499 p=000244b8 n=32At this point, the server's receive window is full (n=32) with presumably 1
NAK'd packet and 31 ACK'd packets. We can't transmit any more packets.52873.287488: rxrpc_retransmit: c=000004ae q=24499 a=0a xp=61327980
52873.287489: rxrpc_tx_data: c=000004ae DATA ed1a3584:00000002 000244c3 q=00024499 fl=0b *RETRANS*
52873.293850: rxrpc_rx_ack: c=000004ae 00012a4c DLY r=000244bc f=000244a0 p=00024499 n=25And now we've received an ACK indicating that a DATA retransmission was
received. 7 packets have been processed (the occupied part of the window
moved, as indicated by f= and n=).52873.293853: rxrpc_rx_discard_ack: c=000004ae r=00012a4c 000244a0
Signed-off-by: David Howells
Signed-off-by: Sasha Levin -
[ Upstream commit d1f129470e6cb79b8b97fecd12689f6eb49e27fe ]
Add a tracepoint to track received ACKs that are discarded due to being
outside of the Tx window.Signed-off-by: David Howells
Signed-off-by: Sasha Levin -
commit f45d01f4f30b53c3a0a1c6c1c154acb7ff74ab9f upstream.
A ticket was not released after a call of the function
"rxkad_decrypt_ticket" failed. Thus replace the jump target
"temporary_error_free_resp" by "temporary_error_free_ticket".Fixes: 8c2f826dc3631 ("rxrpc: Don't put crypto buffers on the stack")
Signed-off-by: Qiushi Wu
Signed-off-by: David Howells
cc: Markus Elfring
Signed-off-by: Greg Kroah-Hartman -
commit c410bf01933e5e09d142c66c3df9ad470a7eec13 upstream.
rxrpc currently uses a fixed 4s retransmission timeout until the RTT is
sufficiently sampled. This can cause problems with some fileservers with
calls to the cache manager in the afs filesystem being dropped from the
fileserver because a packet goes missing and the retransmission timeout is
greater than the call expiry timeout.Fix this by:
(1) Copying the RTT/RTO calculation code from Linux's TCP implementation
and altering it to fit rxrpc.(2) Altering the various users of the RTT to make use of the new SRTT
value.(3) Replacing the use of rxrpc_resend_timeout to use the calculated RTO
value instead (which is needed in jiffies), along with a backoff.Notes:
(1) rxrpc provides RTT samples by matching the serial numbers on outgoing
DATA packets that have the RXRPC_REQUEST_ACK set and PING ACK packets
against the reference serial number in incoming REQUESTED ACK and
PING-RESPONSE ACK packets.(2) Each packet that is transmitted on an rxrpc connection gets a new
per-connection serial number, even for retransmissions, so an ACK can
be cross-referenced to a specific trigger packet. This allows RTT
information to be drawn from retransmitted DATA packets also.(3) rxrpc maintains the RTT/RTO state on the rxrpc_peer record rather than
on an rxrpc_call because many RPC calls won't live long enough to
generate more than one sample.(4) The calculated SRTT value is in units of 8ths of a microsecond rather
than nanoseconds.The (S)RTT and RTO values are displayed in /proc/net/rxrpc/peers.
Fixes: 17926a79320a ([AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both"")
Signed-off-by: David Howells
Signed-off-by: Greg Kroah-Hartman
02 May, 2020
1 commit
-
commit 0e631eee17dcea576ab922fa70e4fdbd596ee452 upstream.
Fix the DATA packet transmission to disable nofrag for UDPv4 on an AF_INET6
socket as well as UDPv6 when trying to transmit fragmentably.Without this, packets filled to the normal size used by the kernel AFS
client of 1412 bytes be rejected by udp_sendmsg() with EMSGSIZE
immediately. The ->sk_error_report() notification hook is called, but
rxrpc doesn't generate a trace for it.This is a temporary fix; a more permanent solution needs to involve
changing the size of the packets being filled in accordance with the MTU,
which isn't currently done in AF_RXRPC. The reason for not doing so was
that, barring the last packet in an rx jumbo packet, jumbos can only be
assembled out of 1412-byte packets - and the plan was to construct jumbos
on the fly at transmission time.Also, there's no point turning on IPV6_MTU_DISCOVER, since IPv6 has to
engage in this anyway since fragmentation is only done by the sender. We
can then condense the switch-statement in rxrpc_send_data_packet().Fixes: 75b54cb57ca3 ("rxrpc: Add IPv6 support")
Signed-off-by: David Howells
Signed-off-by: David S. Miller
Signed-off-by: Greg Kroah-Hartman
23 Apr, 2020
1 commit
-
commit d3ec10aa95819bff18a0d936b18884c7816d0914 upstream.
A lockdep circular locking dependency report was seen when running a
keyutils test:[12537.027242] ======================================================
[12537.059309] WARNING: possible circular locking dependency detected
[12537.088148] 4.18.0-147.7.1.el8_1.x86_64+debug #1 Tainted: G OE --------- - -
[12537.125253] ------------------------------------------------------
[12537.153189] keyctl/25598 is trying to acquire lock:
[12537.175087] 000000007c39f96c (&mm->mmap_sem){++++}, at: __might_fault+0xc4/0x1b0
[12537.208365]
[12537.208365] but task is already holding lock:
[12537.234507] 000000003de5b58d (&type->lock_class){++++}, at: keyctl_read_key+0x15a/0x220
[12537.270476]
[12537.270476] which lock already depends on the new lock.
[12537.270476]
[12537.307209]
[12537.307209] the existing dependency chain (in reverse order) is:
[12537.340754]
[12537.340754] -> #3 (&type->lock_class){++++}:
[12537.367434] down_write+0x4d/0x110
[12537.385202] __key_link_begin+0x87/0x280
[12537.405232] request_key_and_link+0x483/0xf70
[12537.427221] request_key+0x3c/0x80
[12537.444839] dns_query+0x1db/0x5a5 [dns_resolver]
[12537.468445] dns_resolve_server_name_to_ip+0x1e1/0x4d0 [cifs]
[12537.496731] cifs_reconnect+0xe04/0x2500 [cifs]
[12537.519418] cifs_readv_from_socket+0x461/0x690 [cifs]
[12537.546263] cifs_read_from_socket+0xa0/0xe0 [cifs]
[12537.573551] cifs_demultiplex_thread+0x311/0x2db0 [cifs]
[12537.601045] kthread+0x30c/0x3d0
[12537.617906] ret_from_fork+0x3a/0x50
[12537.636225]
[12537.636225] -> #2 (root_key_user.cons_lock){+.+.}:
[12537.664525] __mutex_lock+0x105/0x11f0
[12537.683734] request_key_and_link+0x35a/0xf70
[12537.705640] request_key+0x3c/0x80
[12537.723304] dns_query+0x1db/0x5a5 [dns_resolver]
[12537.746773] dns_resolve_server_name_to_ip+0x1e1/0x4d0 [cifs]
[12537.775607] cifs_reconnect+0xe04/0x2500 [cifs]
[12537.798322] cifs_readv_from_socket+0x461/0x690 [cifs]
[12537.823369] cifs_read_from_socket+0xa0/0xe0 [cifs]
[12537.847262] cifs_demultiplex_thread+0x311/0x2db0 [cifs]
[12537.873477] kthread+0x30c/0x3d0
[12537.890281] ret_from_fork+0x3a/0x50
[12537.908649]
[12537.908649] -> #1 (&tcp_ses->srv_mutex){+.+.}:
[12537.935225] __mutex_lock+0x105/0x11f0
[12537.954450] cifs_call_async+0x102/0x7f0 [cifs]
[12537.977250] smb2_async_readv+0x6c3/0xc90 [cifs]
[12538.000659] cifs_readpages+0x120a/0x1e50 [cifs]
[12538.023920] read_pages+0xf5/0x560
[12538.041583] __do_page_cache_readahead+0x41d/0x4b0
[12538.067047] ondemand_readahead+0x44c/0xc10
[12538.092069] filemap_fault+0xec1/0x1830
[12538.111637] __do_fault+0x82/0x260
[12538.129216] do_fault+0x419/0xfb0
[12538.146390] __handle_mm_fault+0x862/0xdf0
[12538.167408] handle_mm_fault+0x154/0x550
[12538.187401] __do_page_fault+0x42f/0xa60
[12538.207395] do_page_fault+0x38/0x5e0
[12538.225777] page_fault+0x1e/0x30
[12538.243010]
[12538.243010] -> #0 (&mm->mmap_sem){++++}:
[12538.267875] lock_acquire+0x14c/0x420
[12538.286848] __might_fault+0x119/0x1b0
[12538.306006] keyring_read_iterator+0x7e/0x170
[12538.327936] assoc_array_subtree_iterate+0x97/0x280
[12538.352154] keyring_read+0xe9/0x110
[12538.370558] keyctl_read_key+0x1b9/0x220
[12538.391470] do_syscall_64+0xa5/0x4b0
[12538.410511] entry_SYSCALL_64_after_hwframe+0x6a/0xdf
[12538.435535]
[12538.435535] other info that might help us debug this:
[12538.435535]
[12538.472829] Chain exists of:
[12538.472829] &mm->mmap_sem --> root_key_user.cons_lock --> &type->lock_class
[12538.472829]
[12538.524820] Possible unsafe locking scenario:
[12538.524820]
[12538.551431] CPU0 CPU1
[12538.572654] ---- ----
[12538.595865] lock(&type->lock_class);
[12538.613737] lock(root_key_user.cons_lock);
[12538.644234] lock(&type->lock_class);
[12538.672410] lock(&mm->mmap_sem);
[12538.687758]
[12538.687758] *** DEADLOCK ***
[12538.687758]
[12538.714455] 1 lock held by keyctl/25598:
[12538.732097] #0: 000000003de5b58d (&type->lock_class){++++}, at: keyctl_read_key+0x15a/0x220
[12538.770573]
[12538.770573] stack backtrace:
[12538.790136] CPU: 2 PID: 25598 Comm: keyctl Kdump: loaded Tainted: G
[12538.844855] Hardware name: HP ProLiant DL360 Gen9/ProLiant DL360 Gen9, BIOS P89 12/27/2015
[12538.881963] Call Trace:
[12538.892897] dump_stack+0x9a/0xf0
[12538.907908] print_circular_bug.isra.25.cold.50+0x1bc/0x279
[12538.932891] ? save_trace+0xd6/0x250
[12538.948979] check_prev_add.constprop.32+0xc36/0x14f0
[12538.971643] ? keyring_compare_object+0x104/0x190
[12538.992738] ? check_usage+0x550/0x550
[12539.009845] ? sched_clock+0x5/0x10
[12539.025484] ? sched_clock_cpu+0x18/0x1e0
[12539.043555] __lock_acquire+0x1f12/0x38d0
[12539.061551] ? trace_hardirqs_on+0x10/0x10
[12539.080554] lock_acquire+0x14c/0x420
[12539.100330] ? __might_fault+0xc4/0x1b0
[12539.119079] __might_fault+0x119/0x1b0
[12539.135869] ? __might_fault+0xc4/0x1b0
[12539.153234] keyring_read_iterator+0x7e/0x170
[12539.172787] ? keyring_read+0x110/0x110
[12539.190059] assoc_array_subtree_iterate+0x97/0x280
[12539.211526] keyring_read+0xe9/0x110
[12539.227561] ? keyring_gc_check_iterator+0xc0/0xc0
[12539.249076] keyctl_read_key+0x1b9/0x220
[12539.266660] do_syscall_64+0xa5/0x4b0
[12539.283091] entry_SYSCALL_64_after_hwframe+0x6a/0xdfOne way to prevent this deadlock scenario from happening is to not
allow writing to userspace while holding the key semaphore. Instead,
an internal buffer is allocated for getting the keys out from the
read method first before copying them out to userspace without holding
the lock.That requires taking out the __user modifier from all the relevant
read methods as well as additional changes to not use any userspace
write helpers. That is,1) The put_user() call is replaced by a direct copy.
2) The copy_to_user() call is replaced by memcpy().
3) All the fault handling code is removed.Compiling on a x86-64 system, the size of the rxrpc_read() function is
reduced from 3795 bytes to 2384 bytes with this patch.Fixes: ^1da177e4c3f4 ("Linux-2.6.12-rc2")
Reviewed-by: Jarkko Sakkinen
Signed-off-by: Waiman Long
Signed-off-by: David Howells
Signed-off-by: Greg Kroah-Hartman
17 Apr, 2020
2 commits
-
[ Upstream commit e138aa7d3271ac1b0690ae2c9b04d51468dce1d6 ]
Fix the interruptibility of kernel-initiated client calls so that they're
either only interruptible when they're waiting for a call slot to come
available or they're not interruptible at all. Either way, they're not
interruptible during transmission.This should help prevent StoreData calls from being interrupted when
writeback is in progress. It doesn't, however, handle interruption during
the receive phase.Userspace-initiated calls are still interruptable. After the signal has
been handled, sendmsg() will return the amount of data copied out of the
buffer and userspace can perform another sendmsg() call to continue
transmission.Fixes: bc5e3a546d55 ("rxrpc: Use MSG_WAITALL to tell sendmsg() to temporarily ignore signals")
Signed-off-by: David Howells
Signed-off-by: Sasha Levin -
[ Upstream commit 158fe6665389964a1de212818b4a5c52b7f7aff4 ]
Abstract out the calculation of there being sufficient Tx buffer space.
This is reproduced several times in the rxrpc sendmsg code.Signed-off-by: David Howells
Signed-off-by: Sasha Levin
08 Apr, 2020
1 commit
-
commit 498b577660f08cef5d9e78e0ed6dcd4c0939e98c upstream.
Fix the handling of sendmsg() with MSG_WAITALL for userspace to round the
timeout for when a signal occurs up to at least two jiffies as a 1 jiffy
timeout may end up being effectively 0 if jiffies wraps at the wrong time.Fixes: bc5e3a546d55 ("rxrpc: Use MSG_WAITALL to tell sendmsg() to temporarily ignore signals")
Signed-off-by: David Howells
Signed-off-by: Greg Kroah-Hartman
01 Apr, 2020
1 commit
-
commit 7d7587db0d7fd1138f2afcffdc46a8e15630b944 upstream.
Fix the handling of signals in client rxrpc calls made by the afs
filesystem. Ignore signals completely, leaving call abandonment or
connection loss to be detected by timeouts inside AF_RXRPC.Allowing a filesystem call to be interrupted after the entire request has
been transmitted and an abort sent means that the server may or may not
have done the action - and we don't know. It may even be worse than that
for older servers.Fixes: bc5e3a546d55 ("rxrpc: Use MSG_WAITALL to tell sendmsg() to temporarily ignore signals")
Signed-off-by: David Howells
Signed-off-by: Greg Kroah-Hartman
29 Feb, 2020
1 commit
-
commit 963485d436ccc2810177a7b08af22336ec2af67b upstream.
rxrpc_rcu_destroy_call(), which is called as an RCU callback to clean up a
put call, calls rxrpc_put_connection() which, deep in its bowels, takes a
number of spinlocks in a non-BH-safe way, including rxrpc_conn_id_lock and
local->client_conns_lock. RCU callbacks, however, are normally called from
softirq context, which can cause lockdep to notice the locking
inconsistency.To get lockdep to detect this, it's necessary to have the connection
cleaned up on the put at the end of the last of its calls, though normally
the clean up is deferred. This can be induced, however, by starting a call
on an AF_RXRPC socket and then closing the socket without reading the
reply.Fix this by having rxrpc_rcu_destroy_call() punt the destruction to a
workqueue if in softirq-mode and defer the destruction to process context.Note that another way to fix this could be to add a bunch of bh-disable
annotations to the spinlocks concerned - and there might be more than just
those two - but that means spending more time with BHs disabled.Note also that some of these places were covered by bh-disable spinlocks
belonging to the rxrpc_transport object, but these got removed without the
_bh annotation being retained on the next lock in.Fixes: 999b69f89241 ("rxrpc: Kill the client connection bundle concept")
Reported-by: syzbot+d82f3ac8d87e7ccbb2c9@syzkaller.appspotmail.com
Reported-by: syzbot+3f1fd6b8cbf8702d134e@syzkaller.appspotmail.com
Signed-off-by: David Howells
cc: Hillf Danton
Signed-off-by: David S. Miller
Signed-off-by: Greg Kroah-Hartman
11 Feb, 2020
5 commits
-
[ Upstream commit b39a934ec72fa2b5a74123891f25273a38378b90 ]
The recent patch that substituted a flag on an rxrpc_call for the
connection pointer being NULL as an indication that a call was disconnected
puts the set_bit in the wrong place for service calls. This is only a
problem if a call is implicitly terminated by a new call coming in on the
same connection channel instead of a terminating ACK packet.In such a case, rxrpc_input_implicit_end_call() calls
__rxrpc_disconnect_call(), which is now (incorrectly) setting the
disconnection bit, meaning that when rxrpc_release_call() is later called,
it doesn't call rxrpc_disconnect_call() and so the call isn't removed from
the peer's error distribution list and the list gets corrupted.KASAN finds the issue as an access after release on a call, but the
position at which it occurs is confusing as it appears to be related to a
different call (the call site is where the latter call is being removed
from the error distribution list and either the next or pprev pointer
points to a previously released call).Fix this by moving the setting of the flag from __rxrpc_disconnect_call()
to rxrpc_disconnect_call() in the same place that the connection pointer
was being cleared.Fixes: 5273a191dca6 ("rxrpc: Fix NULL pointer deref due to call->conn being cleared on disconnect")
Signed-off-by: David Howells
Signed-off-by: David S. Miller
Signed-off-by: Sasha Levin -
[ Upstream commit 5273a191dca65a675dc0bcf3909e59c6933e2831 ]
When a call is disconnected, the connection pointer from the call is
cleared to make sure it isn't used again and to prevent further attempted
transmission for the call. Unfortunately, there might be a daemon trying
to use it at the same time to transmit a packet.Fix this by keeping call->conn set, but setting a flag on the call to
indicate disconnection instead.Remove also the bits in the transmission functions where the conn pointer is
checked and a ref taken under spinlock as this is now redundant.Fixes: 8d94aa381dab ("rxrpc: Calls shouldn't hold socket refs")
Signed-off-by: David Howells
Signed-off-by: Greg Kroah-Hartman -
[ Upstream commit 04d36d748fac349b068ef621611f454010054c58 ]
The introduction of a split between the reference count on rxrpc_local
objects and the usage count didn't quite go far enough. A number of kernel
work items need to make use of the socket to perform transmission. These
also need to get an active count on the local object to prevent the socket
from being closed.Fix this by getting the active count in those places.
Also split out the raw active count get/put functions as these places tend
to hold refs on the rxrpc_local object already, so getting and putting an
extra object ref is just a waste of time.The problem can lead to symptoms like:
BUG: kernel NULL pointer dereference, address: 0000000000000018
..
CPU: 2 PID: 818 Comm: kworker/u9:0 Not tainted 5.5.0-fscache+ #51
...
RIP: 0010:selinux_socket_sendmsg+0x5/0x13
...
Call Trace:
security_socket_sendmsg+0x2c/0x3e
sock_sendmsg+0x1a/0x46
rxrpc_send_keepalive+0x131/0x1ae
rxrpc_peer_keepalive_worker+0x219/0x34b
process_one_work+0x18e/0x271
worker_thread+0x1a3/0x247
kthread+0xe6/0xeb
ret_from_fork+0x1f/0x30Fixes: 730c5fd42c1e ("rxrpc: Fix local endpoint refcounting")
Signed-off-by: David Howells
Signed-off-by: Greg Kroah-Hartman -
[ Upstream commit f71dbf2fb28489a79bde0dca1c8adfb9cdb20a6b ]
In rxrpc_input_data(), rxrpc_notify_socket() is called if the base sequence
number of the packet is immediately following the hard-ack point at the end
of the function. However, this isn't sufficient, since the recvmsg side
may have been advancing the window and then overrun the position in which
we're adding - at which point rx_hard_ack >= seq0 and no notification is
generated.Fix this by always generating a notification at the end of the input
function.Without this, a long call may stall, possibly indefinitely.
Fixes: 248f219cb8bc ("rxrpc: Rewrite the data and ack handling code")
Signed-off-by: David Howells
Signed-off-by: Greg Kroah-Hartman -
[ Upstream commit fac20b9e738523fc884ee3ea5be360a321cd8bad ]
Fix rxrpc_put_local() to not access local->debug_id after calling
atomic_dec_return() as, unless that returned n==0, we no longer have the
right to access the object.Fixes: 06d9532fa6b3 ("rxrpc: Fix read-after-free in rxrpc_queue_local()")
Signed-off-by: David Howells
Signed-off-by: Greg Kroah-Hartman
01 Feb, 2020
1 commit
-
[ Upstream commit 122d74fac84204b9a98263636f6f9a3b2e665639 ]
The subpacket scanning loop in rxrpc_receive_data() references the
subpacket count in the private data part of the sk_buff in the loop
termination condition. However, when the final subpacket is pasted into
the ring buffer, the function is no longer has a ref on the sk_buff and
should not be looking at sp->* any more. This point is actually marked in
the code when skb is cleared (but sp is not - which is an error).Fix this by caching sp->nr_subpackets in a local variable and using that
instead.Also clear 'sp' to catch accesses after that point.
This can show up as an oops in rxrpc_get_skb() if sp->nr_subpackets gets
trashed by the sk_buff getting freed and reused in the meantime.Fixes: e2de6c404898 ("rxrpc: Use info in skbuff instead of reparsing a jumbo packet")
Signed-off-by: David Howells
Signed-off-by: David S. Miller
Signed-off-by: Greg Kroah-Hartman
18 Jan, 2020
3 commits
-
[ Upstream commit 063c60d39180cec7c9317f5acfc3071f8fecd705 ]
Fix rxrpc_new_incoming_call() to check that we have a suitable service key
available for the combination of service ID and security class of a new
incoming call - and to reject calls for which we don't.This causes an assertion like the following to appear:
rxrpc: Assertion failed - 6(0x6) == 12(0xc) is false
kernel BUG at net/rxrpc/call_object.c:456!Where call->state is RXRPC_CALL_SERVER_SECURING (6) rather than
RXRPC_CALL_COMPLETE (12).Fixes: 248f219cb8bc ("rxrpc: Rewrite the data and ack handling code")
Reported-by: Marc Dionne
Signed-off-by: David Howells
Signed-off-by: Sasha Levin -
[ Upstream commit 13b7955a0252e15265386b229b814152f109b234 ]
Standard kernel mutexes cannot be used in any way from interrupt or softirq
context, so the user_mutex which manages access to a call cannot be a mutex
since on a new call the mutex must start off locked and be unlocked within
the softirq handler to prevent userspace interfering with a call we're
setting up.Commit a0855d24fc22d49cdc25664fb224caee16998683 ("locking/mutex: Complain
upon mutex API misuse in IRQ contexts") causes big warnings to be splashed
in dmesg for each a new call that comes in from the server. Whilst it
*seems* like it should be okay, since the accept path uses trylock, there
are issues with PI boosting and marking the wrong task as the owner.Fix this by not taking the mutex in the softirq path at all. It's not
obvious that there should be any need for it as the state is set before the
first notification is generated for the new call.There's also no particular reason why the link-assessing ping should be
triggered inside the mutex. It's not actually transmitted there anyway,
but rather it has to be deferred to a workqueue.Further, I don't think that there's any particular reason that the socket
notification needs to be done from within rx->incoming_lock, so the amount
of time that lock is held can be shortened too and the ping prepared before
the new call notification is sent.Fixes: 540b1c48c37a ("rxrpc: Fix deadlock between call creation and sendmsg/recvmsg")
Signed-off-by: David Howells
cc: Peter Zijlstra (Intel)
cc: Ingo Molnar
cc: Will Deacon
cc: Davidlohr Bueso
Signed-off-by: Sasha Levin -
[ Upstream commit f33121cbe91973a08e68e4bde8c3f7e6e4e351c1 ]
Move the unlock and the ping transmission for a new incoming call into
rxrpc_new_incoming_call() rather than doing it in the caller. This makes
it clearer to see what's going on.Suggested-by: Peter Zijlstra
Signed-off-by: David Howells
Acked-by: Peter Zijlstra (Intel)
cc: Ingo Molnar
cc: Will Deacon
cc: Davidlohr Bueso
Signed-off-by: Sasha Levin
01 Nov, 2019
1 commit
-
When rxrpc_recvmsg_data() sets the return value to 1 because it's drained
all the data for the last packet, it checks the last-packet flag on the
whole packet - but this is wrong, since the last-packet flag is only set on
the final subpacket of the last jumbo packet. This means that a call that
receives its last packet in a jumbo packet won't complete properly.Fix this by having rxrpc_locate_data() determine the last-packet state of
the subpacket it's looking at and passing that back to the caller rather
than having the caller look in the packet header. The caller then needs to
cache this in the rxrpc_call struct as rxrpc_locate_data() isn't then
called again for this packet.Fixes: 248f219cb8bc ("rxrpc: Rewrite the data and ack handling code")
Fixes: e2de6c404898 ("rxrpc: Use info in skbuff instead of reparsing a jumbo packet")
Signed-off-by: David Howells
Signed-off-by: David S. Miller
17 Oct, 2019
1 commit
-
We need to extend the rcu_read_lock() section in rxrpc_error_report()
and use rcu_dereference_sk_user_data() instead of plain access
to sk->sk_user_data to make sure all rules are respected.The compiler wont reload sk->sk_user_data at will, and RCU rules
prevent memory beeing freed too soon.Fixes: f0308fb07080 ("rxrpc: Fix possible NULL pointer access in ICMP handling")
Fixes: 17926a79320a ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both")
Signed-off-by: Eric Dumazet
Cc: David Howells
Signed-off-by: David S. Miller
12 Oct, 2019
1 commit
-
If an ICMP packet comes in on the UDP socket backing an AF_RXRPC socket as
the UDP socket is being shut down, rxrpc_error_report() may get called to
deal with it after sk_user_data on the UDP socket has been cleared, leading
to a NULL pointer access when this local endpoint record gets accessed.Fix this by just returning immediately if sk_user_data was NULL.
The oops looks like the following:
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
...
RIP: 0010:rxrpc_error_report+0x1bd/0x6a9
...
Call Trace:
? sock_queue_err_skb+0xbd/0xde
? __udp4_lib_err+0x313/0x34d
__udp4_lib_err+0x313/0x34d
icmp_unreach+0x1ee/0x207
icmp_rcv+0x25b/0x28f
ip_protocol_deliver_rcu+0x95/0x10e
ip_local_deliver+0xe9/0x148
__netif_receive_skb_one_core+0x52/0x6e
process_backlog+0xdc/0x177
net_rx_action+0xf9/0x270
__do_softirq+0x1b6/0x39a
? smpboot_register_percpu_thread+0xce/0xce
run_ksoftirqd+0x1d/0x42
smpboot_thread_fn+0x19e/0x1b3
kthread+0xf1/0xf6
? kthread_delayed_work_timer_fn+0x83/0x83
ret_from_fork+0x24/0x30Fixes: 17926a79320a ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both")
Reported-by: syzbot+611164843bd48cc2190c@syzkaller.appspotmail.com
Signed-off-by: David Howells
Signed-off-by: David S. Miller
07 Oct, 2019
6 commits
-
Fix the cleanup of the crypto state on a call after the call has been
disconnected. As the call has been disconnected, its connection ref has
been discarded and so we can't go through that to get to the security ops
table.Fix this by caching the security ops pointer in the rxrpc_call struct and
using that when freeing the call security state. Also use this in other
places we're dealing with call-specific security.The symptoms look like:
BUG: KASAN: use-after-free in rxrpc_release_call+0xb2d/0xb60
net/rxrpc/call_object.c:481
Read of size 8 at addr ffff888062ffeb50 by task syz-executor.5/4764Fixes: 1db88c534371 ("rxrpc: Fix -Wframe-larger-than= warnings from on-stack crypto")
Reported-by: syzbot+eed305768ece6682bb7f@syzkaller.appspotmail.com
Signed-off-by: David Howells -
The rxrpc_peer record needs to hold a reference on the rxrpc_local record
it points as the peer is used as a base to access information in the
rxrpc_local record.This can cause problems in __rxrpc_put_peer(), where we need the network
namespace pointer, and in rxrpc_send_keepalive(), where we need to access
the UDP socket, leading to symptoms like:BUG: KASAN: use-after-free in __rxrpc_put_peer net/rxrpc/peer_object.c:411
[inline]
BUG: KASAN: use-after-free in rxrpc_put_peer+0x685/0x6a0
net/rxrpc/peer_object.c:435
Read of size 8 at addr ffff888097ec0058 by task syz-executor823/24216Fix this by taking a ref on the local record for the peer record.
Fixes: ace45bec6d77 ("rxrpc: Fix firewall route keepalive")
Fixes: 2baec2c3f854 ("rxrpc: Support network namespacing")
Reported-by: syzbot+b9be979c55f2bea8ed30@syzkaller.appspotmail.com
Signed-off-by: David Howells -
rxrpc_put_call() calls trace_rxrpc_call() after it has done the decrement
of the refcount - which looks at the debug_id in the call record. But
unless the refcount was reduced to zero, we no longer have the right to
look in the record and, indeed, it may be deleted by some other thread.Fix this by getting the debug_id out before decrementing the refcount and
then passing that into the tracepoint.Fixes: e34d4234b0b7 ("rxrpc: Trace rxrpc_call usage")
Signed-off-by: David Howells -
rxrpc_put_*conn() calls trace_rxrpc_conn() after they have done the
decrement of the refcount - which looks at the debug_id in the connection
record. But unless the refcount was reduced to zero, we no longer have the
right to look in the record and, indeed, it may be deleted by some other
thread.Fix this by getting the debug_id out before decrementing the refcount and
then passing that into the tracepoint.Fixes: 363deeab6d0f ("rxrpc: Add connection tracepoint and client conn state tracepoint")
Signed-off-by: David Howells -
rxrpc_put_peer() calls trace_rxrpc_peer() after it has done the decrement
of the refcount - which looks at the debug_id in the peer record. But
unless the refcount was reduced to zero, we no longer have the right to
look in the record and, indeed, it may be deleted by some other thread.Fix this by getting the debug_id out before decrementing the refcount and
then passing that into the tracepoint.This can cause the following symptoms:
BUG: KASAN: use-after-free in __rxrpc_put_peer net/rxrpc/peer_object.c:411
[inline]
BUG: KASAN: use-after-free in rxrpc_put_peer+0x685/0x6a0
net/rxrpc/peer_object.c:435
Read of size 8 at addr ffff888097ec0058 by task syz-executor823/24216Fixes: 1159d4b496f5 ("rxrpc: Add a tracepoint to track rxrpc_peer refcounting")
Reported-by: syzbot+b9be979c55f2bea8ed30@syzkaller.appspotmail.com
Signed-off-by: David Howells -
When sendmsg() finds a call to continue on with, if the call is in an
inappropriate state, it doesn't release the ref it just got on that call
before returning an error.This causes the following symptom to show up with kasan:
BUG: KASAN: use-after-free in rxrpc_send_keepalive+0x8a2/0x940
net/rxrpc/output.c:635
Read of size 8 at addr ffff888064219698 by task kworker/0:3/11077where line 635 is:
whdr.epoch = htonl(peer->local->rxnet->epoch);
The local endpoint (which cannot be pinned by the call) has been released,
but not the peer (which is pinned by the call).Fix this by releasing the call in the error path.
Fixes: 37411cad633f ("rxrpc: Fix potential NULL-pointer exception")
Reported-by: syzbot+d850c266e3df14da1d31@syzkaller.appspotmail.com
Signed-off-by: David Howells
15 Sep, 2019
1 commit
-
Minor overlapping changes in the btusb and ixgbe drivers.
Signed-off-by: David S. Miller
05 Sep, 2019
1 commit
-
There's a misplaced traceline in rxrpc_input_packet() which is looking at a
packet that just got released rather than the replacement packet.Fix this by moving the traceline after the assignment that moves the new
packet pointer to the actual packet pointer.Fixes: d0d5c0cd1e71 ("rxrpc: Use skb_unshare() rather than skb_cow_data()")
Reported-by: Hillf Danton
Signed-off-by: David Howells
Signed-off-by: David S. Miller