Linus Torvalds [Fri, 16 Jan 2015 01:28:01 +0000 (14:28 +1300)]
Merge tag 'powerpc-3.19-4' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux
Pull powerpc fixes from Michael Ellerman:
"A few powerpc fixes"
* tag 'powerpc-3.19-4' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux:
powerpc: Work around gcc bug in current_thread_info()
cxl: Fix issues when unmapping contexts
powernv: Fix OPAL tracepoint code
Also verified that there is no padding between errhdr.ee and
errhdr.offender that could leak additional kernel data. Acked-by: Eric Dumazet <[email protected]> Signed-off-by: David S. Miller <[email protected]>
David S. Miller [Fri, 16 Jan 2015 00:38:49 +0000 (19:38 -0500)]
Merge tag 'linux-can-fixes-for-3.19-20150115' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can
Marc Kleine-Budde says:
====================
pull-request: can 2015-01-15
this is a pull request of 8 patches.
Ahmed S. Darwish contributes 4 fixes for the kvaser_usb driver. The two patches
by Oliver Hartkopp mark the m_can driver as non-ISO, as the CANFD standard was
updated. Roger Quadros's patch for the c_can driver fixes the register access
during RAMINIT. And one patch by my, which updates the MAINTAINERS file, as we
moved the git repos to the kernel.org infrastructure.
====================
Or Gerlitz [Thu, 15 Jan 2015 13:28:54 +0000 (15:28 +0200)]
net/mlx4: Don't disable vxlan offloads under DMFS-A0 optimized steering
Except for VXLAN steering rules, all offloads should work as they were
under plain DMFS mode. Fix that by enabling all the offloads under
DMFS-A0 mode, except for VXLAN steering rules.
Fixes: d57febe1a478 "net/mlx4: Add A0 hybrid steering" Signed-off-by: Or Gerlitz <[email protected]> Signed-off-by: David S. Miller <[email protected]>
sh_eth: Fix addition of .trscer_err_mask to wrong SoC data
commit b284fbe3b3ef9cf8 ("sh_eth: Fix access to TRSCER register") wanted
to add a .trscer_err_mask value to the R-Car Gen2 family-specific data
structure (r8a779x_data), but it was accidentally added to the
SH7724-specific data structure (sh7724_data).
Presumably this happened due to a patch conflict with commit d407bc0203539031 ("sh-eth: Set fdr_value of R-Car SoCs"), which added
another field at the same position.
Move the field setting to fix this.
Signed-off-by: Geert Uytterhoeven <[email protected]> Fixes: b284fbe3b3ef9cf8 ("sh_eth: Fix access to TRSCER register") Signed-off-by: David S. Miller <[email protected]>
Mugunthan V N [Thu, 15 Jan 2015 09:29:28 +0000 (14:59 +0530)]
drivers: net: cpsw: fix cpsw hung with add vlan using vconfig
while adding vlan in dual EMAC mode, only specific ports should be
subscribed for the vlan, else it will lead to switching mode and
if both ports connected to same switch cpsw will hung as it creates
a network loop. Fixing this by adding only specific ports in case
of dual EMAC.
Johan Hovold [Tue, 13 Jan 2015 12:00:05 +0000 (13:00 +0100)]
gpio: sysfs: fix gpio device-attribute leak
The gpio device attributes were never destroyed when the gpio was
unexported (or on export failures).
Use device_create_with_groups() to create the default device attributes
of the gpio class device. Note that this also fixes the
attribute-creation race with userspace for these attributes.
Remove contingent attributes in export error path and on unexport.
can: kvaser_usb: Don't send a RESET_CHIP for non-existing channels
Recent Leaf firmware versions (>= 3.1.557) do not allow to send
commands for non-existing channels. If a command is sent for a
non-existing channel, the firmware crashes.
can: kvaser_usb: Reset all URB tx contexts upon channel close
Flooding the Kvaser CAN to USB dongle with multiple reads and
writes in very high frequency (*), closing the CAN channel while
all the transmissions are on (#), opening the device again (@),
then sending a small number of packets would make the driver
enter an almost infinite loop of:
_dragging the whole system down_ in the process due to the
excessive logging output.
Initially, this has caused random panics in the kernel due to a
buggy error recovery path. That got fixed in an earlier commit.(%)
This patch aims at solving the root cause. -->
16 tx URBs and contexts are allocated per CAN channel per USB
device. Such URBs are protected by:
a) A simple atomic counter, up to a value of MAX_TX_URBS (16)
b) A flag in each URB context, stating if it's free
c) The fact that ndo_start_xmit calls are themselves protected
by the networking layers higher above
After grabbing one of the tx URBs, if the driver noticed that all
of them are now taken, it stops the netif transmission queue.
Such queue is worken up again only if an acknowedgment was received
from the firmware on one of our earlier-sent frames.
Meanwhile, upon channel close (#), the driver sends a CMD_STOP_CHIP
to the firmware, effectively closing all further communication. In
the high traffic case, the atomic counter remains at MAX_TX_URBS,
and all the URB contexts remain marked as active. While opening
the channel again (@), it cannot send any further frames since no
more free tx URB contexts are available.
Reset all tx URB contexts upon CAN channel close.
(*) 50 parallel instances of `cangen0 -g 0 -ix`
(#) `ifconfig can0 down`
(@) `ifconfig can0 up`
(%) "can: kvaser_usb: Don't free packets when tight on URBs"
can: kvaser_usb: Don't free packets when tight on URBs
Flooding the Kvaser CAN to USB dongle with multiple reads and
writes in high frequency caused seemingly-random panics in the
kernel.
On further inspection, it seems the driver erroneously freed the
to-be-transmitted packet upon getting tight on URBs and returning
NETDEV_TX_BUSY, leading to invalid memory writes and double frees
at a later point in time.
Note:
Finding no more URBs/transmit-contexts and returning NETDEV_TX_BUSY
is a driver bug in and out of itself: it means that our start/stop
queue flow control is broken.
This patch only fixes the (buggy) error handling code; the root
cause shall be fixed in a later commit.
Roger Quadros [Tue, 13 Jan 2015 14:23:11 +0000 (16:23 +0200)]
can: c_can: use regmap_update_bits() to modify RAMINIT register
use of regmap_read() and regmap_write() in c_can_hw_raminit_syscon()
is not safe as the RAMINIT register can be shared between different drivers
at least for TI SoCs.
To make the modification atomic we switch to using regmap_update_bits().
regmap_update_bits() skips writing to the register if it's read content is the
same as what is going to be written. This causes an issue for us when we
need to clear the DONE bit with the initial condition START:0, DONE:1 as
DONE bit must be written with 1 to clear it.
So we defer the clearing of DONE bit to later when we set the START bit.
There we are sure that START bit is changed from 0 to 1 so the write of
1 to already set DONE bit will happen.
Oliver Hartkopp [Mon, 5 Jan 2015 18:47:43 +0000 (19:47 +0100)]
can: m_can: tag current CAN FD controllers as non-ISO
During the CAN FD standardization process within the ISO it turned out that
the failure detection capability has to be improved.
The CAN in Automation organization (CiA) defined the already implemented CAN
FD controllers as 'non-ISO' and the upcoming improved CAN FD controllers as
'ISO' compliant. See at http://www.can-cia.com/index.php?id=1937
Finally there will be three types of CAN FD controllers in the future:
1. ISO compliant (fixed)
2. non-ISO compliant (fixed, like the M_CAN IP v3.0.1 in m_can.c)
3. ISO/non-ISO CAN FD controllers (switchable, like the PEAK USB FD)
So the current M_CAN driver for the M_CAN IP v3.0.1 has to expose its non-ISO
implementation by setting the CAN_CTRLMODE_FD_NON_ISO ctrlmode at startup.
As this bit cannot be switched at configuration time CAN_CTRLMODE_FD_NON_ISO
must not be set in ctrlmode_supported of the current M_CAN driver.
Oliver Hartkopp [Mon, 5 Jan 2015 17:40:15 +0000 (18:40 +0100)]
can: dev: fix crtlmode_supported check
When changing flags in the CAN drivers ctrlmode the provided new content has to
be checked whether the bits are allowed to be changed. The bits that are to be
changed are given as a bitfield in cm->mask. Therefore checking against
cm->flags is wrong as the content can hold any kind of values.
The iproute2 tool sets the bits in cm->mask and cm->flags depending on the
detected command line options. To be robust against bogus user space
applications additionally sanitize the provided flags with the provided mask.
tracing: Fix enabling of syscall events on the command line
Commit 5f893b2639b2 "tracing: Move enabling tracepoints to just after
rcu_init()" broke the enabling of system call events from the command
line. The reason was that the enabling of command line trace events
was moved before PID 1 started, and the syscall tracepoints require
that all tasks have the TIF_SYSCALL_TRACEPOINT flag set. But the
swapper task (pid 0) is not part of that. Since the swapper task is the
only task that is running at this early in boot, no task gets the
flag set, and the tracepoint never gets reached.
Instead of setting the swapper task flag (there should be no reason to
do that), re-enabled trace events again after the init thread (PID 1)
has been started. It requires disabling all command line events and
re-enabling them, as just enabling them again will not reset the logic
to set the TIF_SYSCALL_TRACEPOINT flag, as the syscall tracepoint will
be fooled into thinking that it was already set, and wont try setting
it again. For this reason, we must first disable it and re-enable it.
tracing: Remove extra call to init_ftrace_syscalls()
trace_init() calls init_ftrace_syscalls() and then calls trace_event_init()
which also calls init_ftrace_syscalls(). It makes more sense to only
call it from trace_event_init().
Calling it twice wastes memory, as it allocates the syscall events twice,
and loses the first copy of it.
ftrace/jprobes/x86: Fix conflict between jprobes and function graph tracing
If the function graph tracer traces a jprobe callback, the system will
crash. This can easily be demonstrated by compiling the jprobe
sample module that is in the kernel tree, loading it and running the
function graph tracer.
# modprobe jprobe_example.ko
# echo function_graph > /sys/kernel/debug/tracing/current_tracer
# ls
The first two commands end up in a nice crash after the first fork.
(do_fork has a jprobe attached to it, so "ls" just triggers that fork)
The problem is caused by the jprobe_return() that all jprobe callbacks
must end with. The way jprobes works is that the function a jprobe
is attached to has a breakpoint placed at the start of it (or it uses
ftrace if fentry is supported). The breakpoint handler (or ftrace callback)
will copy the stack frame and change the ip address to return to the
jprobe handler instead of the function. The jprobe handler must end
with jprobe_return() which swaps the stack and does an int3 (breakpoint).
This breakpoint handler will then put back the saved stack frame,
simulate the instruction at the beginning of the function it added
a breakpoint to, and then continue on.
For function tracing to work, it hijakes the return address from the
stack frame, and replaces it with a hook function that will trace
the end of the call. This hook function will restore the return
address of the function call.
If the function tracer traces the jprobe handler, the hook function
for that handler will not be called, and its saved return address
will be used for the next function. This will result in a kernel crash.
To solve this, pause function tracing before the jprobe handler is called
and unpause it before it returns back to the function it probed.
Some other updates:
Used a variable "saved_sp" to hold kcb->jprobe_saved_sp. This makes the
code look a bit cleaner and easier to understand (various tries to fix
this bug required this change).
Note, if fentry is being used, jprobes will change the ip address before
the function graph tracer runs and it will not be able to trace the
function that the jprobe is probing.
ftrace: Check both notrace and filter for old hash
Using just the filter for checking for trampolines or regs is not enough
when updating the code against the records that represent all functions.
Both the filter hash and the notrace hash need to be checked.
The trace-cmd record at the end clears the filter before it disables
function_graph tracing and then that causes the accounting of the
ftrace function records to become incorrect and causes ftrace to bug.
ftrace: Fix updating of filters for shared global_ops filters
As the set_ftrace_filter affects both the function tracer as well as the
function graph tracer, the ops that represent each have a shared
ftrace_ops_hash structure. This allows both to be updated when the filter
files are updated.
But if function graph is enabled and the global_ops (function tracing) ops
is not, then it is possible that the filter could be changed without the
update happening for the function graph ops. This will cause the changes
to not take place and may even cause a ftrace_bug to occur as it could mess
with the trampoline accounting.
The solution is to check if the ops uses the shared global_ops filter and
if the ops itself is not enabled, to check if there's another ops that is
enabled and also shares the global_ops filter. In that case, the
modification still needs to be executed.
be2net: Allow GRE to work concurrently while a VxLAN tunnel is configured
Other tunnels like GRE break while VxLAN offloads are enabled in Skyhawk-R. To
avoid this, we should restrict offload features on a per-packet basis in such
conditions.
Linus Torvalds [Thu, 15 Jan 2015 06:20:26 +0000 (19:20 +1300)]
Merge branch 'thermal-soc' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux
Pull thermal fixes from Zhang Rui:
"Specifics:
- bogus type qualifier fix in OF thermal code.
- Minor fixes on imx and rcar thermal drivers.
- Update TI SoC thermal maintainer entry.
- Updated documentation of OF cpufreq cooling register"
* 'thermal-soc' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux:
thermal: rcar: Spelling/grammar: s/drier use .../driver uses ...s/
thermal: rcar: change type of ctemp in rcar_thermal_update_temp()
thermal: rcar: fix ENR register value
Documentation: thermal: document of_cpufreq_cooling_register()
Thermal: imx: add clk disable/enable for suspend/resume
MAINTAINERS: update ti-soc-thermal status
MAINTAINERS: Add linux-omap to list of reviewers for TI Thermal
thermal: of: Remove bogus type qualifier for of_thermal_get_trip_points()
Merge tag 'fixes-for-v3.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/balbi/usb into usb-linus
Felipe writes:
usb: fixes for v3.19-rc6
The final set of fixes for v3.19. Two of the fixes are
related to dwc3 scatter/gather implementation when we have
more requests queued than available TRBs, while the other
is a build fix for mv-usb PHY.
Merge tag 'usb-serial-3.19-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/johan/usb-serial into usb-linus
Johan writes:
USB-serial fixes for v3.18-rc5
Here are a few fixes for reported problems including a possible
null-deref on probe with keyspan, a misbehaving modem, and a couple of
issues with the USB console.
1) Don't use uninitialized data in IPVS, from Dan Carpenter.
2) conntrack race fixes from Pablo Neira Ayuso.
3) Fix TX hangs with i40e, from Jesse Brandeburg.
4) Fix budget return from poll calls in dnet and alx, from Eric
Dumazet.
5) Fix bugus "if (unlikely(x) < 0)" test in AF_PACKET, from Christoph
Jaeger.
6) Fix bug introduced by conversion to list_head in TIPC retransmit
code, from Jon Paul Maloy.
7) Don't use GFP_NOIO under spinlock in USB kaweth driver, from Alexey
Khoroshilov.
8) Fix bridge build with INET disabled, from Arnd Bergmann.
9) Fix netlink array overrun for PROBE attributes in openvswitch, from
Thomas Graf.
10) Don't hold spinlock across synchronize_irq() in tg3 driver, from
Prashant Sreedharan.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (44 commits)
tg3: Release tp->lock before invoking synchronize_irq()
tg3: tg3_reset_task() needs to use rtnl_lock to synchronize
tg3: tg3_timer() should grab tp->lock before checking for tp->irq_sync
team: avoid possible underflow of count_pending value for notify_peers and mcast_rejoin
openvswitch: packet messages need their own probe attribtue
i40e: adds FCoE configure option
cxgb4vf: Fix queue allocation for 40G adapter
netdevice: Add missing parentheses in macro
bridge: only provide proxy ARP when CONFIG_INET is enabled
neighbour: fix base_reachable_time(_ms) not effective immediatly when changed
net: fec: fix MDIO bus assignement for dual fec SoC's
xen-netfront: use different locks for Rx and Tx stats
drivers: net: cpsw: fix multicast flush in dual emac mode
cxgb4vf: Initialize mdio_addr before using it
net: Corrected the comment describing the ndo operations to reflect the actual prototype for couple of operations
usb/kaweth: use GFP_ATOMIC under spin_lock in usb_start_wait_urb()
MAINTAINERS: add me as ibmveth maintainer
tipc: fix bug in broadcast retransmit code
update ip-sysctl.txt documentation (v2)
net/at91_ether: prepare and unprepare clock
...
tg3: tg3_reset_task() needs to use rtnl_lock to synchronize
Currently tg3_reset_task() uses only tp->lock for synchronizing with code
paths like tg3_open() etc. But since tp->lock is released before doing
synchronize_irq(), rtnl_lock should be taken in tg3_reset_task() to
synchronize it with other code paths.
tg3: tg3_timer() should grab tp->lock before checking for tp->irq_sync
This is to avoid the race between tg3_timer() and the execution paths
which does not invoke tg3_timer_stop() and releases tp->lock before
calling synchronize_irq()
Linus Torvalds [Wed, 14 Jan 2015 21:54:30 +0000 (10:54 +1300)]
Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull kvm fixes from Paolo Bonzini:
"Two bugfixes for arm64. I will have another pull request next week,
but otherwise things are calm"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
arm64: KVM: Fix HCR setting for 32bit guests
arm64: KVM: Fix TLB invalidation by IPA/VMID
Jiri Pirko [Wed, 14 Jan 2015 17:15:30 +0000 (18:15 +0100)]
team: avoid possible underflow of count_pending value for notify_peers and mcast_rejoin
This patch is fixing a race condition that may cause setting
count_pending to -1, which results in unwanted big bulk of arp messages
(in case of "notify peers").
Consider following scenario:
count_pending == 2
CPU0 CPU1
team_notify_peers_work
atomic_dec_and_test (dec count_pending to 1)
schedule_delayed_work
team_notify_peers
atomic_add (adding 1 to count_pending)
team_notify_peers_work
atomic_dec_and_test (dec count_pending to 1)
schedule_delayed_work
team_notify_peers_work
atomic_dec_and_test (dec count_pending to 0)
schedule_delayed_work
team_notify_peers_work
atomic_dec_and_test (dec count_pending to -1)
Fix this race by using atomic_dec_if_positive - that will prevent
count_pending running under 0.
Fixes: fc423ff00df3a1955441 ("team: add peer notification") Fixes: 492b200efdd20b8fcfd ("team: add support for sending multicast rejoins") Signed-off-by: Jiri Pirko <[email protected]> Signed-off-by: Jiri Benc <[email protected]> Signed-off-by: David S. Miller <[email protected]>
Linus Torvalds [Wed, 14 Jan 2015 21:50:29 +0000 (10:50 +1300)]
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 fixes from Martin Schwidefsky:
"Two small performance tweaks, the plumbing for the execveat system
call and a couple of bug fixes"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390/uprobes: fix user space PER events
s390/bpf: Fix JMP_JGE_X (A > X) and JMP_JGT_X (A >= X)
s390/bpf: Fix ALU_NEG (A = -A)
s390/mm: avoid using pmd_to_page for !USE_SPLIT_PMD_PTLOCKS
s390/timex: fix get_tod_clock_ext() inline assembly
s390: wire up execveat syscall
s390/kernel: use stnsm 255 instead of stosm 0
s390/vtime: Get rid of redundant WARN_ON
s390/zcrypt: kernel oops at insmod of the z90crypt device driver
Thomas Graf [Wed, 14 Jan 2015 13:56:19 +0000 (13:56 +0000)]
openvswitch: packet messages need their own probe attribtue
User space is currently sending a OVS_FLOW_ATTR_PROBE for both flow
and packet messages. This leads to an out-of-bounds access in
ovs_packet_cmd_execute() because OVS_FLOW_ATTR_PROBE >
OVS_PACKET_ATTR_MAX.
Introduce a new OVS_PACKET_ATTR_PROBE with the same numeric value
as OVS_FLOW_ATTR_PROBE to grow the range of accepted packet attributes
while maintaining to be binary compatible with existing OVS binaries.
Linus Torvalds [Wed, 14 Jan 2015 21:38:07 +0000 (10:38 +1300)]
Merge tag 'locks-v3.19-1' of git://git.samba.org/jlayton/linux
Pull file locking fix from Jeff Layton:
"Just a simple bugfix for a regression that I introduced into v3.18
with the internal lease API overhaul -- mea culpa. Kudos to Linda and
Neil for tracking this down and fixing it"
* tag 'locks-v3.19-1' of git://git.samba.org/jlayton/linux:
locks: fix NULL-deref in generic_delete_lease
Linus Torvalds [Wed, 14 Jan 2015 21:27:56 +0000 (10:27 +1300)]
Merge branch 'for-linus' of git://git.kernel.dk/linux-block
Pull block layer fixes from Jens Axboe:
"The major part is an update to the NVMe driver, fixing various issues
around surprise removal and hung controllers. Most of that is from
Keith, and parts are simple blk-mq fixes or exports/additions of minor
functions to aid this effort, and parts are changes directly to the
NVMe driver.
Apart from the above, this contains:
- Small blk-mq change from me, killing an unused member of the
hardware queue structure.
- Small fix from Ming Lei, fixing up a few drivers that didn't
properly check for ERR_PTR() returns from blk_mq_init_queue()"
* 'for-linus' of git://git.kernel.dk/linux-block:
NVMe: Fix locking on abort handling
NVMe: Start and stop h/w queues on reset
NVMe: Command abort handling fixes
NVMe: Admin queue removal handling
NVMe: Reference count admin queue usage
NVMe: Start all requests
blk-mq: End unstarted requests on a dying queue
blk-mq: Allow requests to never expire
blk-mq: Add helper to abort requeued requests
blk-mq: Let drivers cancel requeue_work
blk-mq: Export if requests were started
blk-mq: Wake tasks entering queue on dying
blk-mq: get rid of ->cmd_size in the hardware queue
block: fix checking return value of blk_mq_init_queue
block: wake up waiters when a queue is marked dying
NVMe: Fix double free irq
blk-mq: Export freeze/unfreeze functions
blk-mq: Exit queue on alloc failure
Arnd Bergmann [Tue, 13 Jan 2015 14:10:27 +0000 (15:10 +0100)]
bridge: only provide proxy ARP when CONFIG_INET is enabled
When IPV4 support is disabled, we cannot call arp_send from
the bridge code, which would result in a kernel link error:
net/built-in.o: In function `br_handle_frame_finish':
:(.text+0x59914): undefined reference to `arp_send'
:(.text+0x59a50): undefined reference to `arp_tbl'
This makes the newly added proxy ARP support in the bridge
code depend on the CONFIG_INET symbol and lets the compiler
optimize the code out to avoid the link error.
Signed-off-by: Arnd Bergmann <[email protected]> Fixes: 958501163ddd ("bridge: Add support for IEEE 802.11 Proxy ARP") Cc: Kyeyoon Park <[email protected]> Signed-off-by: David S. Miller <[email protected]>
Amit Virdi [Tue, 13 Jan 2015 08:57:21 +0000 (14:27 +0530)]
usb: dwc3: gadget: Stop TRB preparation after limit is reached
DWC3 gadget sets up a pool of 32 TRBs for each EP during initialization. This
means, the max TRBs that can be submitted for an EP is fixed to 32. Since the
request queue for an EP is a linked list, any number of requests can be queued
to it by the gadget layer. However, the dwc3 driver must not submit TRBs more
than the pool it has created for. This limit wasn't respected when SG was used
resulting in submitting more than the max TRBs, eventually leading to
non-transfer of the TRBs submitted over the max limit.
Root cause:
When SG is used, there are two loops iterating to prepare TRBs:
- Outer loop over the request_list
- Inner loop over the SG list
The code was missing break to get out of the outer loop.
Amit Virdi [Tue, 13 Jan 2015 08:57:20 +0000 (14:27 +0530)]
usb: dwc3: gadget: Fix TRB preparation during SG
When scatter gather (SG) is used, multiple TRBs are prepared from one DWC3
request (dwc3_request). So while preparing TRBs, the 'last' flag should be set
only when it is the last TRB being prepared from the last dwc3_request entry.
The current implementation uses list_is_last to check if the dwc3_request is the
last entry from the request_list. However, list_is_last returns false for the
last entry too. This is because, while preparing the first TRB from a request,
the function dwc3_prepare_one_trb modifies the request's next and prev pointers
while moving the URB to req_queued. Hence, list_is_last always returns false no
matter what.
The correct way is not to access the modified pointers of dwc3_request but to
use list_empty macro instead.
Johan Hovold [Mon, 12 Jan 2015 16:12:27 +0000 (17:12 +0100)]
gpio: fix memory leak and sleep-while-atomic
Fix memory leak and sleep-while-atomic in gpiochip_remove.
The memory leak was introduced by afa82fab5e13 ("gpio / ACPI: Move event
handling registration to gpiolib irqchip helpers") that moved the
release of acpi interrupt resources to gpiochip_irqchip_remove, but by
then the resources are no longer accessible as the acpi_gpio_chip has
already been freed by acpi_gpiochip_remove.
Note that this also fixes a few potential sleep-while-atomics, which has
been around since 1425052097b5 ("gpio: add IRQ chip helpers in gpiolib")
when the call to gpiochip_irqchip_remove while holding a spinlock was
added (a couple of irq-domain paths can end up grabbing mutexes).
Johan Hovold [Mon, 12 Jan 2015 16:12:25 +0000 (17:12 +0100)]
gpio: fix gpio-chip list corruption
Fix potential corruption of gpio-chip list due to failure to remove the
chip from the list before returning in gpiochip_add error path.
The chip could be long gone when the global list is next traversed,
something which could lead to a null-pointer dereference. In the best
case (chip not deallocated) we are just leaking the gpio range.
Fixes: 14e85c0e69d5 ("gpio: remove gpio_descs global array") Signed-off-by: Johan Hovold <[email protected]> Signed-off-by: Linus Walleij <[email protected]>
Johan Hovold [Mon, 12 Jan 2015 16:12:24 +0000 (17:12 +0100)]
gpio: fix memory and reference leaks in gpiochip_add error path
Memory allocated and references taken by of_gpiochip_add and
acpi_gpiochip_add were never released on errors in gpiochip_add (e.g.
failure to find free gpio range).
Fixes: 391c970c0dd1 ("of/gpio: add default of_xlate function if device
has a node pointer") Fixes: 664e3e5ac64c ("gpio / ACPI: register to ACPI events
automatically") Cc: stable <[email protected]> Signed-off-by: Johan Hovold <[email protected]> Signed-off-by: Linus Walleij <[email protected]>
Jim Lin [Thu, 8 Jan 2015 12:25:05 +0000 (20:25 +0800)]
pinctrl: Fix two deadlocks
This patch is to fix two deadlock cases.
Deadlock 1:
CPU #1
pinctrl_register-> pinctrl_get ->
create_pinctrl
(Holding lock pinctrl_maps_mutex)
-> get_pinctrl_dev_from_devname
(Trying to acquire lock pinctrldev_list_mutex)
CPU #0
pinctrl_unregister
(Holding lock pinctrldev_list_mutex)
-> pinctrl_put ->> pinctrl_free ->
pinctrl_dt_free_maps -> pinctrl_unregister_map
(Trying to acquire lock pinctrl_maps_mutex)
Simply to say
CPU#1 is holding lock A and trying to acquire lock B,
CPU#0 is holding lock B and trying to acquire lock A.
Deadlock 2:
CPU #3
pinctrl_register-> pinctrl_get ->
create_pinctrl
(Holding lock pinctrl_maps_mutex)
-> get_pinctrl_dev_from_devname
(Trying to acquire lock pinctrldev_list_mutex)
CPU #2
pinctrl_unregister
(Holding lock pctldev->mutex)
-> pinctrl_put ->> pinctrl_free ->
pinctrl_dt_free_maps -> pinctrl_unregister_map
(Trying to acquire lock pinctrl_maps_mutex)
CPU #0
tegra_gpio_request
(Holding lock pinctrldev_list_mutex)
-> pinctrl_get_device_gpio_range
(Trying to acquire lock pctldev->mutex)
Simply to say
CPU#3 is holding lock A and trying to acquire lock D,
CPU#2 is holding lock B and trying to acquire lock A,
CPU#0 is holding lock D and trying to acquire lock B.
Doug Anderson [Mon, 22 Dec 2014 18:47:29 +0000 (10:47 -0800)]
pinctrl: rockchip: Avoid losing interrupts when supporting both edges
I was seeing cases where I was losing interrupts when inserting and
removing SD cards. Sometimes the card would get "stuck" in the
inserted state.
I believe that the problem was related to the code to handle the case
where we needed both rising and falling edges. This code would
disable the interrupt as the polarity was switched. If an interrupt
came at the wrong time it could be lost.
We'll match what the gpio-dwapb.c driver does upstream and change the
interrupt polarity without disabling things.
Aaron Lu [Mon, 12 Jan 2015 02:09:32 +0000 (10:09 +0800)]
gpio: crystalcove: use handle_nested_irq
The CrystalCove GPIO chip has can_sleep set so its demultiplexed irqs
will have IRQ_NESTED_THREAD flag set, thus we should use the nested
version handle_nested_irq in CrystalCove's irq handler instead of
handle_generic_irq, or the following warning will be hit and the
functionality is lost:
Tim Kryger [Wed, 14 Jan 2015 06:24:12 +0000 (07:24 +0100)]
mmc: sdhci: Set SDHCI_POWER_ON with external vmmc
Host controllers lacking the required internal vmmc regulator may still
follow the spec with regard to the LSB of SDHCI_POWER_CONTROL. Set the
SDHCI_POWER_ON bit when vmmc is enabled to encourage the controller to
to drive CMD, DAT, SDCLK.
This fixes a regression observed on some Qualcomm and Nvidia boards
caused by 5222161 mmc: sdhci: Improve external VDD regulator support.
neighbour: fix base_reachable_time(_ms) not effective immediatly when changed
When setting base_reachable_time or base_reachable_time_ms on a
specific interface through sysctl or netlink, the reachable_time
value is not updated.
This means that neighbour entries will continue to be updated using the
old value until it is recomputed in neigh_period_work (which
recomputes the value every 300*HZ).
On systems with HZ equal to 1000 for instance, it means 5mins before
the change is effective.
This patch changes this behavior by recomputing reachable_time after
each set on base_reachable_time or base_reachable_time_ms.
The new value will become effective the next time the neighbour's timer
is triggered.
Changes are made in two places: the netlink code for set and the sysctl
handling code. For sysctl, I use a proc_handler. The ipv6 network
code does provide its own handler but it already refreshes
reachable_time correctly so it's not an issue.
Any other user of neighbour which provide its own handlers must
refresh reachable_time.
Stefan Agner [Tue, 13 Jan 2015 23:20:21 +0000 (00:20 +0100)]
net: fec: fix MDIO bus assignement for dual fec SoC's
On i.MX28, the MDIO bus is shared between the two FEC instances.
The driver makes sure that the second FEC uses the MDIO bus of the
first FEC. This is done conditionally if FEC_QUIRK_ENET_MAC is set.
However, in newer designs, such as Vybrid or i.MX6SX, each FEC MAC
has its own MDIO bus. Simply removing the quirk FEC_QUIRK_ENET_MAC
is not an option since other logic, triggered by this quirk, is
still needed.
Furthermore, there are board designs which use the same MDIO bus
for both PHY's even though the second bus would be available on the
SoC side. Such layout are popular since it saves pins on SoC side.
Due to the above quirk, those boards currently do work fine. The
boards in the mainline tree with such a layout are:
- Freescale Vybrid Tower with TWR-SER2 (vf610-twr.dts)
- Freescale i.MX6 SoloX SDB Board (imx6sx-sdb.dts)
This patch adds a new quirk FEC_QUIRK_SINGLE_MDIO for i.MX28, which
makes sure that the MDIO bus of the first FEC is used in any case.
However, the boards above do have a SoC with a MDIO bus for each FEC
instance. But the PHY's are not connected in a 1:1 configuration. A
proper device tree description is needed to allow the driver to
figure out where to find its PHY. This patch fixes that shortcoming
by adding a MDIO bus child node to the first FEC instance, along
with the two PHY's on that bus, and making use of the phy-handle
property to add a reference to the PHY's.
Linus Torvalds [Tue, 13 Jan 2015 22:54:12 +0000 (11:54 +1300)]
Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/borntraeger/linux
Pull WRITE_ONCE argument order change from Christian Borntraeger:
"As discussed on LKML[1] it was agreed that WRITE_ONCE(x, val) is
better than ASSIGN_ONCE(val, x)
Lets change that for 3.19 as 3.19 has no user yet, but the first users
will hit linux-next soon"
David Vrabel [Tue, 13 Jan 2015 16:42:42 +0000 (16:42 +0000)]
xen-netfront: use different locks for Rx and Tx stats
In netfront the Rx and Tx path are independent and use different
locks. The Tx lock is held with hard irqs disabled, but Rx lock is
held with only BH disabled. Since both sides use the same stats lock,
a deadlock may occur.
[ INFO: possible irq lock inversion dependency detected ]
3.16.2 #16 Not tainted
---------------------------------------------------------
swapper/0/0 just changed the state of lock:
(&(&queue->tx_lock)->rlock){-.....}, at: [<c03adec8>]
xennet_tx_interrupt+0x14/0x34
but this lock took another, HARDIRQ-unsafe lock in the past:
(&stat->syncp.seq#2){+.-...}
and interrupts could create inverse lock ordering between them.
other info that might help us debug this:
Possible interrupt unsafe locking scenario:
Mugunthan V N [Tue, 13 Jan 2015 12:05:49 +0000 (17:35 +0530)]
drivers: net: cpsw: fix multicast flush in dual emac mode
Since ALE table is a common resource for both the interfaces in Dual EMAC
mode and while bringing up the second interface in cpsw_ndo_set_rx_mode()
all the multicast entries added by the first interface is flushed out and
only second interface multicast addresses are added. Fixing this by
flushing multicast addresses based on dual EMAC port vlans which will not
affect the other emac port multicast addresses.
Fixes: d9ba8f9 (driver: net: ethernet: cpsw: dual emac interface implementation) Cc: <[email protected]> # v3.9+ Signed-off-by: Mugunthan V N <[email protected]> Signed-off-by: David S. Miller <[email protected]>
Simon Guinot [Tue, 2 Dec 2014 15:32:10 +0000 (07:32 -0800)]
leds: netxbig: fix oops at probe time
This patch fixes a NULL pointer dereference on led_dat->mode_val. Due to
this bug, a kernel oops can be observed at probe time on the LaCie 2Big
and 5Big v2 boards:
Unable to handle kernel NULL pointer dereference at virtual address 00000008
[...]
[<c03f244c>] (netxbig_led_probe) from [<c02c8c6c>] (platform_drv_probe+0x4c/0x9c)
[<c02c8c6c>] (platform_drv_probe) from [<c02c72d0>] (driver_probe_device+0x98/0x25c)
[<c02c72d0>] (driver_probe_device) from [<c02c7520>] (__driver_attach+0x8c/0x90)
[<c02c7520>] (__driver_attach) from [<c02c5c24>] (bus_for_each_dev+0x68/0x94)
[<c02c5c24>] (bus_for_each_dev) from [<c02c6408>] (bus_add_driver+0x124/0x1dc)
[<c02c6408>] (bus_add_driver) from [<c02c7ac0>] (driver_register+0x78/0xf8)
[<c02c7ac0>] (driver_register) from [<c000888c>] (do_one_initcall+0x80/0x1cc)
[<c000888c>] (do_one_initcall) from [<c0733618>] (kernel_init_freeable+0xe4/0x1b4)
[<c0733618>] (kernel_init_freeable) from [<c058db9c>] (kernel_init+0xc/0xec)
[<c058db9c>] (kernel_init) from [<c0009850>] (ret_from_fork+0x14/0x24)
[...]
Linus Torvalds [Tue, 13 Jan 2015 19:09:14 +0000 (08:09 +1300)]
Merge tag 'linux-kselftest-3.19-rc-5' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest
Pull kselftest fixes from Shuah Khan:
"This update contains three patches to fix one compile error, and two
run-time bugs. One of them fixes infinite loop on ARM"
* tag 'linux-kselftest-3.19-rc-5' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
selftests/vm: fix link error for transhuge-stress test
tools: testing: selftests: mq_perf_tests: Fix infinite loop on ARM
selftests/exec: allow shell return code of 126
Linus Torvalds [Tue, 13 Jan 2015 19:07:42 +0000 (08:07 +1300)]
Merge tag 'stable/for-linus-3.19-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen bug fixes from David Vrabel:
"Several critical linear p2m fixes that prevented some hosts from
booting"
* tag 'stable/for-linus-3.19-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
x86/xen: properly retrieve NMI reason
xen: check for zero sized area when invalidating memory
xen: use correct type for physical addresses
xen: correct race in alloc_p2m_pmd()
xen: correct error for building p2m list on 32 bits
x86/xen: avoid freeing static 'name' when kasprintf() fails
x86/xen: add extra memory for remapped frames during setup
x86/xen: don't count how many PFNs are identity mapped
x86/xen: Free bootmem in free_p2m_page() during early boot
x86/xen: Remove unnecessary BUG_ON(preemptible()) in xen_setup_timer()
The "smemc" clock is removed on BG2Q SoCs. In fact, bit19 of clkenable
register is for nfc. Current code use bit19 for non-exist "smemc"
incorrectly, this prevents eMMC from working due to the sdhci's
"core" clk is still gated.
Boris Brezillon [Tue, 13 Jan 2015 14:44:06 +0000 (15:44 +0100)]
clk: at91: keep slow clk enabled to prevent system hang
All slow clk users are not properly claiming it (get + prepare + enable)
before using it.
If all users properly claiming this clock release it, the clock is
disabled, but faulty users still depends on it, and the system hangs.
This fix prevents the slow clock from being disabled, and should solve the
hanging issue, but offending drivers should be patched to properly claim
this clock.
Linus Torvalds [Tue, 13 Jan 2015 18:53:51 +0000 (07:53 +1300)]
Merge branch 'for-rc' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux
Pull thermal management fixes from Zhang Rui:
"Specifics:
- Fix a problem that Intel SoC DTS thermal driver does not work when
CONFIG_THERMAL_INT340X is not set.
- Fix a NULL pointer dereference when processor_thermal_device driver
is loaded on a platform without ACPI support"
* 'for-rc' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux:
int340x_thermal/processor_thermal_device: return failure when
ACPI/int340x_thermal: enumerate INT3401 for Intel SoC DTS thermal driver
ACPI/int340x_thermal: enumerate INT340X devices even if they're not in _ART/_TRT
Andy Shevchenko [Tue, 13 Jan 2015 16:57:15 +0000 (18:57 +0200)]
dmaengine: dw: balance PM runtime calls
In case of PCI driver we will get a warning:
dw_dmac_pci 0000:00:18.0: Unbalanced pm_runtime_enable!
dw_dmac_pci 0000:00:18.0: DesignWare DMA Controller, 8 channels
This happens due to pm_runtime_enable() call from the driver when PM runtime is
enabled by core.
This patch moves that call to the platform driver where it might make sense.
Arnd Bergmann [Tue, 13 Jan 2015 14:25:11 +0000 (15:25 +0100)]
usb: phy: mv-usb: fix usb_phy build errors
The driver was recently adapted to a core API change, but the
change was incomplete, missing out the suspend helper and
leaving an extraneous local variable around:
usb/phy/phy-mv-usb.c: In function 'mv_otg_update_state':
usb/phy/phy-mv-usb.c:341:18: warning: unused variable 'phy' [-Wunused-variable]
usb/phy/phy-mv-usb.c: In function 'mv_otg_suspend':
usb/phy/phy-mv-usb.c:861:16: error: 'struct usb_phy' has no member named 'state'
Signed-off-by: Arnd Bergmann <[email protected]> Fixes: e47d92545c297 ("usb: move the OTG state from the USB PHY to the OTG structure") Signed-off-by: Felipe Balbi <[email protected]>
moves the call to fl->fl_lmops->lm_change() to a place in the
code where fl might be a non-lease lock.
When that happens, fl_lmops is NULL and an Oops ensures.
So add an extra test to restore correct functioning.
Mathias Krause [Sun, 11 Jan 2015 17:17:42 +0000 (18:17 +0100)]
crypto: add missing crypto module aliases
Commit 5d26a105b5a7 ("crypto: prefix module autoloading with "crypto-"")
changed the automatic module loading when requesting crypto algorithms
to prefix all module requests with "crypto-". This requires all crypto
modules to have a crypto specific module alias even if their file name
would otherwise match the requested crypto algorithm.
Even though commit 5d26a105b5a7 added those aliases for a vast amount of
modules, it was missing a few. Add the required MODULE_ALIAS_CRYPTO
annotations to those files to make them get loaded automatically, again.
This fixes, e.g., requesting 'ecb(blowfish-generic)', which used to work
with kernels v3.18 and below.
Also change MODULE_ALIAS() lines to MODULE_ALIAS_CRYPTO(). The former
won't work for crypto modules any more.
Hans de Goede [Mon, 5 Jan 2015 08:15:16 +0000 (09:15 +0100)]
simplefb: Fix build failure on Sparc
of_platform_device_create is only defined when CONFIG_OF_ADDRESS is set,
which is normally always the case when CONFIG_OF is defined, except on Sparc,
so explicitly check for CONFIG_OF_ADDRESS rather then for CONFIG_OF.
Jan Beulich [Tue, 13 Jan 2015 07:40:05 +0000 (07:40 +0000)]
x86/xen: properly retrieve NMI reason
Using the native code here can't work properly, as the hypervisor would
normally have cleared the two reason bits by the time Dom0 gets to see
the NMI (if passed to it at all). There's a shared info field for this,
and there's an existing hook to use - just fit the two together. This
is particularly relevant so that NMIs intended to be handled by APEI /
GHES actually make it to the respective handler.
Note that the hook can (and should) be used irrespective of whether
being in Dom0, as accessing port 0x61 in a DomU would be even worse,
while the shared info field would just hold zero all the time. Note
further that hardware NMI handling for PVH doesn't currently work
anyway due to missing code in the hypervisor (but it is expected to
work the native rather than the PV way).
if m_td1TD1.byTCR has TCR_EDP and TCR_STP are set, the interrupt handler will
try and complete the buffer before it is completed. Usually on the tail
of a burst of tx packets.
This results in a partially completed packet being transmitted or worse
sitll dead lock when skb is freed by the interrupt handler.
Set head_td->m_td1TD1.byTCR to 0 in first lock of vnt_tx_packet to stop
interrupt handler completing the buffer. Move Set TSR1 & ReqCount in
s_cbFillTxBufHead to the second lock.
cbReqCount is carried to the second lock in pTDInfo->dwReqCount without
the padding removed.
Linus Torvalds [Tue, 13 Jan 2015 02:29:42 +0000 (15:29 +1300)]
Merge tag 'gpio-v3.19-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio
Pull gpio fixes from Linus Walleij:
"Here are some GPIO fixes, mainly affecting the DLN2 IRQ handling.
Nothing special about them, just fixes:
- Three patches fixing IRQ handling for the DLN2
- Null pointer handling for grgpio"
* tag 'gpio-v3.19-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio:
gpio: dln2: use bus_sync_unlock instead of scheduling work
gpio: grgpio: Avoid potential NULL pointer dereference
gpio: dln2: Fix gpio output value in dln2_gpio_direction_output()
gpio: dln2: fix issue when an IRQ is unmasked then enabled
Linus Torvalds [Tue, 13 Jan 2015 02:25:23 +0000 (15:25 +1300)]
Merge tag 'mmc-v3.19-3' of git://git.linaro.org/people/ulf.hansson/mmc
Pull MMC fixes from Ulf Hansson:
"MMC host:
- sdhci-pci|acpi: Support some new IDs
- sdhci: Fix sleep from atomic context
- sdhci-pxav3: Prevent hang during ->probe()
- sdhci: Disable re-tuning for HS400"
* tag 'mmc-v3.19-3' of git://git.linaro.org/people/ulf.hansson/mmc:
mmc: sdhci-pci: Add support for Intel SPT
mmc: sdhci-acpi: Add ACPI HID INT344D
mmc: sdhci: Fix sleep in atomic after inserting SD card
mmc: sdhci-pxav3: do the mbus window configuration after enabling clocks
mmc: sdhci: Disable re-tuning for HS400
mmc: sdhci: Simplify use of tuning timer
mmc: sdhci: Add out_unlock to sdhci_execute_tuning
mmc: sdhci: Tuning should not change max_blk_count
Pull scsi target fixes from Nicholas Bellinger:
"Mostly minor fixes this time, including:
- Add missing virtio-scsi -> TCM attribute conversion in vhost-scsi.
- Fix persistent reservations write exclusive handling to allow
readers for all registered I_T nexuses.
- Drop arbitrary maximum I/O size limit in order to process I/Os
larger than 4 MB, required for initiators that don't honor block
limits EVPD.
- Drop the now left-over fabric_max_sectors attribute"
* git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending:
iscsi-target: Fix typos in enum cmd_flags_table
MAINTAINERS: Add entry for iSER target driver
target: Allow Write Exclusive non-reservation holders to READ
target: Drop left-over fabric_max_sectors attribute
target: Drop arbitrary maximum I/O size limit
Documentation/target: Update fabric_ops to latest code
vhost-scsi: Add missing virtio-scsi -> TCM attribute conversion
Will Deacon [Mon, 12 Jan 2015 19:10:55 +0000 (19:10 +0000)]
mm: mmu_gather: use tlb->end != 0 only for TLB invalidation
When batching up address ranges for TLB invalidation, we check tlb->end
!= 0 to indicate that some pages have actually been unmapped.
As of commit f045bbb9fa1b ("mmu_gather: fix over-eager
tlb_flush_mmu_free() calling"), we use the same check for freeing these
pages in order to avoid a performance regression where we call
free_pages_and_swap_cache even when no pages are actually queued up.
Unfortunately, the range could have been reset (tlb->end = 0) by
tlb_end_vma, which has been shown to cause memory leaks on arm64.
Furthermore, investigation into these leaks revealed that the fullmm
case on task exit no longer invalidates the TLB, by virtue of tlb->end
== 0 (in 3.18, need_flush would have been set).
This patch resolves the problem by reverting commit f045bbb9fa1b, using
instead tlb->local.nr as the predicate for page freeing in
tlb_flush_mmu_free and ensuring that tlb->end is initialised to a
non-zero value in the fullmm case.
Merge tag 'v3.19-rockhip-clkfixes1' of git://git.kernel.org/pub/scm/linux/kernel/git/mmind/linux-rockchip into clk-fixes
- two currently unused clocks that need to stay enabled
- fix the lock bit locations of the rk3066 plls
- fix rk3288 core divider values to the ones actually
specified by the soc vendor
usb/kaweth: use GFP_ATOMIC under spin_lock in usb_start_wait_urb()
Commit e4c7f259c5be ("USB: kaweth.c: use GFP_ATOMIC under spin_lock")
makes sure that kaweth_internal_control_msg() allocates memory with GFP_ATOMIC,
but kaweth_internal_control_msg() also calls usb_start_wait_urb()
that still allocates memory with GFP_NOIO.
The patch fixes usb_start_wait_urb() as well.
Found by Linux Driver Verification project (linuxtesting.org).
Jon Paul Maloy [Thu, 8 Jan 2015 17:27:27 +0000 (12:27 -0500)]
tipc: fix bug in broadcast retransmit code
In commit 58dc55f25631178ee74cd27185956a8f7dcb3e32 ("tipc: use generic
SKB list APIs to manage link transmission queue") we replace all list
traversal loops with the macros skb_queue_walk() or
skb_queue_walk_safe(). While the previous loops were based on the
assumption that the list was NULL-terminated, the standard macros
stop when the iterator reaches the list head, which is non-NULL.
In the function bclink_retransmit_pkt() this macro replacement has
lead to a bug. When we receive a BCAST STATE_MSG we unconditionally
call the function bclink_retransmit_pkt(), whether there really is
anything to retransmit or not, assuming that the sequence number
comparisons will lead to the correct behavior. However, if the
transmission queue is empty, or if there are no eligible buffers in
the transmission queue, we will by mistake pass the list head pointer
to the function tipc_link_retransmit(). Since the list head is not a
valid sk_buff, this leads to a crash.
In this commit we fix this by only calling tipc_link_retransmit()
if we actually found eligible buffers in the transmission queue.