Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
Clone this repository
For self-hosted knots, clone URLs may differ based on your setup.
Download tar.gz
Objtool reports:
drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o: warning: objtool: .altinstr_replacement+0x36: redundant UACCESS disable
__copy_from_user() already does both STAC and CLAC, so the
user_access_end() in its error path adds an extra unnecessary CLAC.
Fixes: 0b2c8f8b6b0c ("i915: fix missing user_access_end() in page fault exception case")
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://github.com/ClangBuiltLinux/linux/issues/617
Link: https://lkml.kernel.org/r/51a4155c5bc2ca847a9cbe85c1c11918bb193141.1564086017.git.jpoimboe@redhat.com
Pull networking fixes from David Miller:
"Yeah I should have sent a pull request last week, so there is a lot
more here than usual:
1) Fix memory leak in ebtables compat code, from Wenwen Wang.
2) Several kTLS bug fixes from Jakub Kicinski (circular close on
disconnect etc.)
3) Force slave speed check on link state recovery in bonding 802.3ad
mode, from Thomas Falcon.
4) Clear RX descriptor bits before assigning buffers to them in
stmmac, from Jose Abreu.
5) Several missing of_node_put() calls, mostly wrt. for_each_*() OF
loops, from Nishka Dasgupta.
6) Double kfree_skb() in peak_usb can driver, from Stephane Grosjean.
7) Need to hold sock across skb->destructor invocation, from Cong
Wang.
8) IP header length needs to be validated in ipip tunnel xmit, from
Haishuang Yan.
9) Use after free in ip6 tunnel driver, also from Haishuang Yan.
10) Do not use MSI interrupts on r8169 chips before RTL8168d, from
Heiner Kallweit.
11) Upon bridge device init failure, we need to delete the local fdb.
From Nikolay Aleksandrov.
12) Handle erros from of_get_mac_address() properly in stmmac, from
Martin Blumenstingl.
13) Handle concurrent rename vs. dump in netfilter ipset, from Jozsef
Kadlecsik.
14) Setting NETIF_F_LLTX on mac80211 causes complete breakage with
some devices, so revert. From Johannes Berg.
15) Fix deadlock in rxrpc, from David Howells.
16) Fix Kconfig deps of enetc driver, we must have PHYLIB. From Yue
Haibing.
17) Fix mvpp2 crash on module removal, from Matteo Croce.
18) Fix race in genphy_update_link, from Heiner Kallweit.
19) bpf_xdp_adjust_head() stopped working with generic XDP when we
fixes generic XDP to support stacked devices properly, fix from
Jesper Dangaard Brouer.
20) Unbalanced RCU locking in rt6_update_exception_stamp_rt(), from
David Ahern.
21) Several memory leaks in new sja1105 driver, from Vladimir Oltean"
* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (214 commits)
net: dsa: sja1105: Fix memory leak on meta state machine error path
net: dsa: sja1105: Fix memory leak on meta state machine normal path
net: dsa: sja1105: Really fix panic on unregistering PTP clock
net: dsa: sja1105: Use the LOCKEDS bit for SJA1105 E/T as well
net: dsa: sja1105: Fix broken learning with vlan_filtering disabled
net: dsa: qca8k: Add of_node_put() in qca8k_setup_mdio_bus()
net: sched: sample: allow accessing psample_group with rtnl
net: sched: police: allow accessing police->params with rtnl
net: hisilicon: Fix dma_map_single failed on arm64
net: hisilicon: fix hip04-xmit never return TX_BUSY
net: hisilicon: make hip04_tx_reclaim non-reentrant
tc-testing: updated vlan action tests with batch create/delete
net sched: update vlan action for batched events operations
net: stmmac: tc: Do not return a fragment entry
net: stmmac: Fix issues when number of Queues >= 4
net: stmmac: xgmac: Fix XGMAC selftests
be2net: disable bh with spin_lock in be_process_mcc
net: cxgb3_main: Fix a resource leak in a error path in 'init_one()'
net: ethernet: sun4i-emac: Support phy-handle property for finding PHYs
net: bridge: move default pvid init/deinit to NETDEV_REGISTER/UNREGISTER
...
Pull MIPS fixes from Paul Burton:
"A few MIPS fixes for 5.3:
- Various switch fall through annotations to fixup warnings & errors
resulting from -Wimplicit-fallthrough.
- A fix for systems (at least jazz) using an i8253 PIT as clocksource
when it's not suitably configured.
- Set struct cacheinfo's cpu_map_populated field to true, indicating
that we filled in cache info detected from cop0 registers &
avoiding complaints about that info being (intentionally) missing
in devicetree"
* tag 'mips_fixes_5.3_1' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux:
MIPS: BCM63XX: Mark expected switch fall-through
MIPS: OProfile: Mark expected switch fall-throughs
MIPS: Annotate fall-through in Cavium Octeon code
MIPS: Annotate fall-through in kvm/emulate.c
mips: fix cacheinfo
MIPS: kernel: only use i8253 clocksource with periodic clockevent
Vladimir Oltean says:
====================
Fixes for SJA1105 DSA: FDBs, Learning and PTP
This is an assortment of functional fixes for the sja1105 switch driver
targeted for the "net" tree (although they apply on net-next just as
well).
Patch 1/5 ("net: dsa: sja1105: Fix broken learning with vlan_filtering
disabled") repairs a breakage introduced in the early development stages
of the driver: support for traffic from the CPU has broken "normal"
frame forwarding (based on DMAC) - there is connectivity through the
switch only because all frames are flooded.
I debated whether this patch qualifies as a fix, since it puts the
switch into a mode it has never operated in before (aka SVL). But
"normal" forwarding did use to work before the "Traffic support for
SJA1105 DSA driver" patchset, and arguably this patch should have been
part of that.
Also, it would be strange for this feature to be broken in the 5.2 LTS.
Patch 2/5 ("net: dsa: sja1105: Use the LOCKEDS bit for SJA1105 E/T as
well") is a simplification of a previous FDB-related patch that is
currently in the 5.3 rc's.
Patches 3/5 - 5/5 fix various crashes found while running linuxptp over the
switch ports for extended periods of time, or in conjunction with other
error conditions. The fixed-up commits were all introduced in 5.2.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull HID fixes from Jiri Kosina:
- functional regression fix for some of the Logitech unifying devices,
from Hans de Goede
- race condition fix in hid-sony for bug severely affecting
Valve/Android deployments, from Roderick Colenbrander
- several fixes for issues found by syzbot/kasan, from Oliver Neukum
and Hillf Danton
- functional regression fix for Wacom Cintiq device, from Aaron
Armstrong Skomra
- a few other assorted device-specific quirks
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid:
HID: sony: Fix race condition between rumble and device remove.
HID: hiddev: do cleanup in failure of opening a device
HID: hiddev: avoid opening a disconnected device
HID: input: fix a4tech horizontal wheel custom usage
HID: Add quirk for HP X1200 PIXART OEM mouse
HID: holtek: test for sanity of intfdata
HID: wacom: fix bit shift for Cintiq Companion 2
HID: quirks: Set the INCREMENT_USAGE_ON_DUPLICATE quirk on Saitek X52
HID: logitech-dj: Really fix return value of logi_dj_recv_query_hidpp_devices
HID: Add 044f:b320 ThrustMaster, Inc. 2 in 1 DT
HID: logitech-dj: add the Powerplay receiver
HID: logitech-hidpp: add USB PID for a few more supported mice
HID: logitech-dj: rename "gaming" receiver to "lightspeed"
Mark switch cases where we are expecting to fall through.
This patch fixes the following warning (Building: bcm63xx_defconfig mips):
arch/mips/pci/ops-bcm63xx.c: In function ‘bcm63xx_pcie_can_access’:
arch/mips/pci/ops-bcm63xx.c:474:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
if (PCI_SLOT(devfn) == 0)
^
arch/mips/pci/ops-bcm63xx.c:477:2: note: here
default:
^~~~~~~
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: bcm-kernel-feedback-list@broadcom.com
Cc: linux-mips@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Each iteration of for_each_available_child_of_node() puts the previous
node, but in the case of a return from the middle of the loop, there
is no put, thus causing a memory leak. Hence add an of_node_put() before
the return.
Additionally, the local variable ports in the function
qca8k_setup_mdio_bus() takes the return value of of_get_child_by_name(),
which gets a node but does not put it. If the function returns without
putting ports, it may cause a memory leak. Hence put ports before the
mid-loop return statement, and also outside the loop after its last usage
in this function.
Issues found with Coccinelle.
Signed-off-by: Nishka Dasgupta <nishkadg.linux@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When RX timestamping is enabled and two link-local (non-meta) frames are
received in a row, this constitutes an error.
The tagger is always caching the last link-local frame, in an attempt to
merge it with the meta follow-up frame when that arrives. To recover
from the above error condition, the initial cached link-local frame is
dropped and the second frame in a row is cached (in expectance of the
second meta frame).
However, when dropping the initial link-local frame, its backing memory
was being leaked.
Fixes: f3097be21bf1 ("net: dsa: sja1105: Add a state machine for RX timestamping")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull pti updates from Thomas Gleixner:
"The performance deterioration departement is not proud at all to
present yet another set of speculation fences to mitigate the next
chapter in the 'what could possibly go wrong' story.
The new vulnerability belongs to the Spectre class and affects GS
based data accesses and has therefore been dubbed 'Grand Schemozzle'
for secret communication purposes. It's officially listed as
CVE-2019-1125.
Conditional branches in the entry paths which contain a SWAPGS
instruction (interrupts and exceptions) can be mis-speculated which
results in speculative accesses with a wrong GS base.
This can happen on entry from user mode through a mis-speculated
branch which takes the entry from kernel mode path and therefore does
not execute the SWAPGS instruction. The following speculative accesses
are done with user GS base.
On entry from kernel mode the mis-speculated branch executes the
SWAPGS instruction in the entry from user mode path which has the same
effect that the following GS based accesses are done with user GS
base.
If there is a disclosure gadget available in these code paths the
mis-speculated data access can be leaked through the usual side
channels.
The entry from user mode issue affects all CPUs which have speculative
execution. The entry from kernel mode issue affects only Intel CPUs
which can speculate through SWAPGS. On CPUs from other vendors SWAPGS
has semantics which prevent that.
SMAP migitates both problems but only when the CPU is not affected by
the Meltdown vulnerability.
The mitigation is to issue LFENCE instructions in the entry from
kernel mode path for all affected CPUs and on the affected Intel CPUs
also in the entry from user mode path unless PTI is enabled because
the CR3 write is serializing.
The fences are as usual enabled conditionally and can be completely
disabled on the kernel command line. The Spectre V1 documentation is
updated accordingly.
A big "Thank You!" goes to Josh for doing the heavy lifting for this
round of hardware misfeature 'repair'. Of course also "Thank You!" to
everybody else who contributed in one way or the other"
* 'x86/grand-schemozzle' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
Documentation: Add swapgs description to the Spectre v1 documentation
x86/speculation/swapgs: Exclude ATOMs from speculation through SWAPGS
x86/entry/64: Use JMP instead of JMPQ
x86/speculation: Enable Spectre v1 swapgs mitigations
x86/speculation: Prepare entry code for Spectre v1 swapgs mitigations
Valve reported a kernel crash on Ubuntu 18.04 when disconnecting a DS4
gamepad while rumble is enabled. This issue is reproducible with a
frequency of 1 in 3 times in the game Borderlands 2 when using an
automatic weapon, which triggers many rumble operations.
We found the issue to be a race condition between sony_remove and the
final device destruction by the HID / input system. The problem was
that sony_remove didn't clean some of its work_item state in
"struct sony_sc". After sony_remove work, the corresponding evdev
node was around for sufficient time for applications to still queue
rumble work after "sony_remove".
On pre-4.19 kernels the race condition caused a kernel crash due to a
NULL-pointer dereference as "sc->output_report_dmabuf" got freed during
sony_remove. On newer kernels this crash doesn't happen due the buffer
now being allocated using devm_kzalloc. However we can still queue work,
while the driver is an undefined state.
This patch fixes the described problem, by guarding the work_item
"state_worker" with an initialized variable, which we are setting back
to 0 on cleanup.
Signed-off-by: Roderick Colenbrander <roderick.colenbrander@sony.com>
CC: stable@vger.kernel.org
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Mark switch cases where we are expecting to fall through.
This patch fixes the following warning (Building: mips):
arch/mips/oprofile/op_model_mipsxx.c: In function ‘mipsxx_cpu_stop’:
arch/mips/oprofile/op_model_mipsxx.c:217:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
w_c0_perfctrl3(0);
^~~~~~~~~~~~~~~~~
arch/mips/oprofile/op_model_mipsxx.c:218:2: note: here
case 3:
^~~~
arch/mips/oprofile/op_model_mipsxx.c:219:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
w_c0_perfctrl2(0);
^~~~~~~~~~~~~~~~~
arch/mips/oprofile/op_model_mipsxx.c:220:2: note: here
case 2:
^~~~
arch/mips/oprofile/op_model_mipsxx.c:221:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
w_c0_perfctrl1(0);
^~~~~~~~~~~~~~~~~
arch/mips/oprofile/op_model_mipsxx.c:222:2: note: here
case 1:
^~~~
arch/mips/oprofile/op_model_mipsxx.c: In function ‘mipsxx_cpu_start’:
arch/mips/oprofile/op_model_mipsxx.c:197:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
w_c0_perfctrl3(WHAT | reg.control[3]);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/mips/oprofile/op_model_mipsxx.c:198:2: note: here
case 3:
^~~~
arch/mips/oprofile/op_model_mipsxx.c:199:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
w_c0_perfctrl2(WHAT | reg.control[2]);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/mips/oprofile/op_model_mipsxx.c:200:2: note: here
case 2:
^~~~
arch/mips/oprofile/op_model_mipsxx.c:201:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
w_c0_perfctrl1(WHAT | reg.control[1]);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/mips/oprofile/op_model_mipsxx.c:202:2: note: here
case 1:
^~~~
arch/mips/oprofile/op_model_mipsxx.c: In function ‘reset_counters’:
arch/mips/oprofile/op_model_mipsxx.c:299:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
w_c0_perfcntr3(0);
^~~~~~~~~~~~~~~~~
arch/mips/oprofile/op_model_mipsxx.c:300:2: note: here
case 3:
^~~~
arch/mips/oprofile/op_model_mipsxx.c:302:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
w_c0_perfcntr2(0);
^~~~~~~~~~~~~~~~~
arch/mips/oprofile/op_model_mipsxx.c:303:2: note: here
case 2:
^~~~
arch/mips/oprofile/op_model_mipsxx.c:305:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
w_c0_perfcntr1(0);
^~~~~~~~~~~~~~~~~
arch/mips/oprofile/op_model_mipsxx.c:306:2: note: here
case 1:
^~~~
arch/mips/oprofile/op_model_mipsxx.c: In function ‘mipsxx_perfcount_handler’:
arch/mips/oprofile/op_model_mipsxx.c:242:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
if ((control & MIPS_PERFCTRL_IE) && \
^
arch/mips/oprofile/op_model_mipsxx.c:248:2: note: in expansion of macro ‘HANDLE_COUNTER’
HANDLE_COUNTER(3)
^~~~~~~~~~~~~~
arch/mips/oprofile/op_model_mipsxx.c:239:2: note: here
case n + 1: \
^
arch/mips/oprofile/op_model_mipsxx.c:249:2: note: in expansion of macro ‘HANDLE_COUNTER’
HANDLE_COUNTER(2)
^~~~~~~~~~~~~~
arch/mips/oprofile/op_model_mipsxx.c:242:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
if ((control & MIPS_PERFCTRL_IE) && \
^
arch/mips/oprofile/op_model_mipsxx.c:249:2: note: in expansion of macro ‘HANDLE_COUNTER’
HANDLE_COUNTER(2)
^~~~~~~~~~~~~~
arch/mips/oprofile/op_model_mipsxx.c:239:2: note: here
case n + 1: \
^
arch/mips/oprofile/op_model_mipsxx.c:250:2: note: in expansion of macro ‘HANDLE_COUNTER’
HANDLE_COUNTER(1)
^~~~~~~~~~~~~~
arch/mips/oprofile/op_model_mipsxx.c:242:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
if ((control & MIPS_PERFCTRL_IE) && \
^
arch/mips/oprofile/op_model_mipsxx.c:250:2: note: in expansion of macro ‘HANDLE_COUNTER’
HANDLE_COUNTER(1)
^~~~~~~~~~~~~~
arch/mips/oprofile/op_model_mipsxx.c:239:2: note: here
case n + 1: \
^
arch/mips/oprofile/op_model_mipsxx.c:251:2: note: in expansion of macro ‘HANDLE_COUNTER’
HANDLE_COUNTER(0)
^~~~~~~~~~~~~~
CC usr/include/linux/pmu.h.s
arch/mips/oprofile/op_model_mipsxx.c: In function ‘mipsxx_cpu_setup’:
arch/mips/oprofile/op_model_mipsxx.c:174:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
w_c0_perfcntr3(reg.counter[3]);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/mips/oprofile/op_model_mipsxx.c:175:2: note: here
case 3:
^~~~
arch/mips/oprofile/op_model_mipsxx.c:177:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
w_c0_perfcntr2(reg.counter[2]);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/mips/oprofile/op_model_mipsxx.c:178:2: note: here
case 2:
^~~~
arch/mips/oprofile/op_model_mipsxx.c:180:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
w_c0_perfcntr1(reg.counter[1]);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/mips/oprofile/op_model_mipsxx.c:181:2: note: here
case 1:
^~~~
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Robert Richter <rric@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: oprofile-list@lists.sf.net
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>
Vlad Buslov says:
====================
action fixes for flow_offload infra compatibility
Fix rcu warnings due to usage of action helpers that expect rcu read lock
protection from rtnl-protected context of flow_offload infra.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
After a meta frame is received, it is associated with the cached
sp->data->stampable_skb from the DSA tagger private structure.
Cached means its refcount is incremented with skb_get() in order for
dsa_switch_rcv() to not free it when the tagger .rcv returns NULL.
The mistake is that skb_unref() is not the correct function to use. It
will correctly decrement the refcount (which will go back to zero) but
the skb memory will not be freed. That is the job of kfree_skb(), which
also calls skb_unref().
But it turns out that freeing the cached stampable_skb is in fact not
necessary. It is still a perfectly valid skb, and now it is even
annotated with the partial RX timestamp. So remove the skb_copy()
altogether and simply pass the stampable_skb with a refcount of 1
(incremented by us, decremented by dsa_switch_rcv) up the stack.
Fixes: f3097be21bf1 ("net: dsa: sja1105: Add a state machine for RX timestamping")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>