LSK 18.07 v4.4-android
* tag 'lsk-v4.4-18.07-android': (254 commits)
Linux 4.4.143
net/nfc: Avoid stalls when nfc_alloc_send_skb() returned NULL.
rds: avoid unenecessary cong_update in loop transport
KEYS: DNS: fix parsing multiple options
netfilter: ebtables: reject non-bridge targets
MIPS: Use async IPIs for arch_trigger_cpumask_backtrace()
MIPS: Call dump_stack() from show_regs()
rtlwifi: rtl8821ae: fix firmware is not ready to run
net: cxgb3_main: fix potential Spectre v1
net/mlx5: Fix command interface race in polling mode
net_sched: blackhole: tell upper qdisc about dropped packets
vhost_net: validate sock before trying to put its fd
tcp: prevent bogus FRTO undos with non-SACK flows
tcp: fix Fast Open key endianness
r8152: napi hangup fix after disconnect
qed: Limit msix vectors in kdump kernel to the minimum required count.
net: sungem: fix rx checksum support
net/mlx5: Fix incorrect raw command length parsing
net: dccp: switch rx_tstamp_last_feedback to monotonic clock
net: dccp: avoid crash in ccid3_hc_rx_send_feedback()
...
Fix wrong merge of include/linux/compiler-gcc.h
Change-Id: I1daae1251069d2791d2e29b65942d086fb8ad0ac
Every time _cpu_up() is called for a CPU, idle_thread_get() is called
which then re-initializes a CPU's idle thread that was already
previously created and cached in a global variable in
smpboot.c. idle_thread_get() calls init_idle() which then calls
__sched_fork(). __sched_fork() is where cpufreq_task_times_init() is,
and cpufreq_task_times_init() allocates memory for the task struct's
time_in_state array.
Since idle_thread_get() reuses a task struct instance that was already
previously created, this means that every time it calls init_idle(),
cpufreq_task_times_init() allocates this array again and overwrites
the existing allocation that the idle thread already had.
This causes memory to be leaked every time a CPU is onlined. In order
to fix this, move allocation of time_in_state into _do_fork to avoid
allocating it at all for idle threads. The cpufreq times interface is
intended to be used for tracking userspace tasks, so we can safely
remove it from the kernel's idle threads without killing any
functionality.
But that's not all!
Task structs can be freed outside of release_task(), which creates
another memory leak because a task struct can be freed without having
its cpufreq times allocation freed. To fix this, free the cpufreq
times allocation at the same time that task struct allocations are
freed, in free_task().
Since free_task() can also be called in error paths of copy_process()
after dup_task_struct(), set time_in_state to NULL immediately after
calling dup_task_struct() to avoid possible double free.
Bug description and fix adapted from patch submitted by
Sultan Alsawaf <sultanxda@gmail.com> at
https://android-review.googlesource.com/c/kernel/msm/+/700134
Bug: 110044919
Test: Hikey960 builds, boots & reports /proc/<pid>/time_in_state
correctly
Change-Id: I12fe7611fc88eb7f6c39f8f7629ad27b6ec4722c
Signed-off-by: Connor O'Brien <connoro@google.com>
Add empty versions of functions to cpufreq_times.h to cut down on use
of #ifdef in .c files.
Test: kernel builds with and without CONFIG_CPU_FREQ_TIMES=y
Change-Id: I49ac364fac3d42bba0ca1801e23b15081094fb12
Signed-off-by: Connor O'Brien <connoro@google.com>
* linux-linaro-lsk-v4.4: (361 commits)
Linux 4.4.135
Revert "vti4: Don't override MTU passed on link creation via IFLA_MTU"
Linux 4.4.134
s390/ftrace: use expoline for indirect branches
kdb: make "mdr" command repeat
Bluetooth: btusb: Add device ID for RTL8822BE
ASoC: samsung: i2s: Ensure the RCLK rate is properly determined
regulator: of: Add a missing 'of_node_put()' in an error handling path of 'of_regulator_match()'
scsi: lpfc: Fix frequency of Release WQE CQEs
scsi: lpfc: Fix soft lockup in lpfc worker thread during LIP testing
scsi: lpfc: Fix issue_lip if link is disabled
netlabel: If PF_INET6, check sk_buff ip header version
selftests/net: fixes psock_fanout eBPF test case
perf report: Fix memory corruption in --branch-history mode --branch-history
perf tests: Use arch__compare_symbol_names to compare symbols
x86/apic: Set up through-local-APIC mode on the boot CPU if 'noapic' specified
drm/rockchip: Respect page offset for PRIME mmap calls
MIPS: Octeon: Fix logging messages with spurious periods after newlines
audit: return on memory error to avoid null pointer dereference
crypto: sunxi-ss - Add MODULE_ALIAS to sun4i-ss
...
Conflicts:
arch/arm64/include/asm/assembler.h
Rebase LTS commit 348f043ab6
("arm64: Add work around for Arm Cortex-A55 Erratum 1024718").
fs/f2fs/namei.c
Rebase LTS commit 03bb758894
("do d_instantiate/unlock_new_inode combinations safely")
fs/proc/base.c
Trivial typo.
kernel/auditsc.c
Rebase LTS commit 9bb698bede
("audit: move calcs after alloc and check when logging set loginuid").
kernel/time/timekeeping.c
Rebase changes from AOSP commit 28850c79d0
("BACKPORT: time: Fix CLOCK_MONOTONIC_RAW sub-nanosecond accounting"), and
1d35c04386 ("BACKPORT: time: Clean up CLOCK_MONOTONIC_RAW time handling").
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
capacity_spare_wake in the slow path influences choice of idlest groups,
as we search for groups with maximum spare capacity. In scenarios where
RT pressure is high, a sub optimal group can be chosen and hurt
performance of the task being woken up.
Several tests with results are included below to show improvements with
this change.
1) Hackbench on Pixel 2 Android device (4x4 ARM64 Octa core)
------------------------------------------------------------
Here we have RT activity running on big CPU cluster induced with rt-app,
and running hackbench in parallel. The RT tasks are bound to 4 CPUs on
the big cluster (cpu 4,5,6,7) and have 100ms periodicity with
runtime=20ms sleep=80ms.
Hackbench shows big benefit (30%) improvement when number of tasks is 8
and 32: Note: data is completion time in seconds (lower is better).
Number of loops for 8 and 16 tasks is 50000, and for 32 tasks its 20000.
+--------+-----+-------+-------------------+---------------------------+
| groups | fds | tasks | Without Patch | With Patch |
+--------+-----+-------+---------+---------+-----------------+---------+
| | | | Mean | Stdev | Mean | Stdev |
| | | +-------------------+-----------------+---------+
| 1 | 8 | 8 | 1.0534 | 0.13722 | 0.7293 (+30.7%) | 0.02653 |
| 2 | 8 | 16 | 1.6219 | 0.16631 | 1.6391 (-1%) | 0.24001 |
| 4 | 8 | 32 | 1.2538 | 0.13086 | 1.1080 (+11.6%) | 0.16201 |
+--------+-----+-------+---------+---------+-----------------+---------+
2) Rohit ran barrier.c test (details below) with following improvements:
------------------------------------------------------------------------
This was Rohit's original use case for a patch he posted at [1] however
from his recent tests he showed my patch can replace his slow path
changes [1] and there's no need to selectively scan/skip CPUs in
find_idlest_group_cpu in the slow path to get the improvement he sees.
barrier.c (open_mp code) as a micro-benchmark. It does a number of
iterations and barrier sync at the end of each for loop.
Here barrier,c is running in along with ping on CPU 0 and 1 as:
'ping -l 10000 -q -s 10 -f hostX'
barrier.c can be found at:
http://www.spinics.net/lists/kernel/msg2506955.html
Following are the results for the iterations per second with this
micro-benchmark (higher is better), on a 44 core, 2 socket 88 Threads
Intel x86 machine:
+--------+------------------+---------------------------+
|Threads | Without patch | With patch |
| | | |
+--------+--------+---------+-----------------+---------+
| | Mean | Std Dev | Mean | Std Dev |
+--------+--------+---------+-----------------+---------+
|1 | 539.36 | 60.16 | 572.54 (+6.15%) | 40.95 |
|2 | 481.01 | 19.32 | 530.64 (+10.32%)| 56.16 |
|4 | 474.78 | 22.28 | 479.46 (+0.99%) | 18.89 |
|8 | 450.06 | 24.91 | 447.82 (-0.50%) | 12.36 |
|16 | 436.99 | 22.57 | 441.88 (+1.12%) | 7.39 |
|32 | 388.28 | 55.59 | 429.4 (+10.59%)| 31.14 |
|64 | 314.62 | 6.33 | 311.81 (-0.89%) | 11.99 |
+--------+--------+---------+-----------------+---------+
3) ping+hackbench test on bare-metal sever (Rohit ran this test)
----------------------------------------------------------------
Here hackbench is running in threaded mode along
with, running ping on CPU 0 and 1 as:
'ping -l 10000 -q -s 10 -f hostX'
This test is running on 2 socket, 20 core and 40 threads Intel x86
machine:
Number of loops is 10000 and runtime is in seconds (Lower is better).
+--------------+-----------------+--------------------------+
|Task Groups | Without patch | With patch |
| +-------+---------+----------------+---------+
|(Groups of 40)| Mean | Std Dev | Mean | Std Dev |
+--------------+-------+---------+----------------+---------+
|1 | 0.851 | 0.007 | 0.828 (+2.77%)| 0.032 |
|2 | 1.083 | 0.203 | 1.087 (-0.37%)| 0.246 |
|4 | 1.601 | 0.051 | 1.611 (-0.62%)| 0.055 |
|8 | 2.837 | 0.060 | 2.827 (+0.35%)| 0.031 |
|16 | 5.139 | 0.133 | 5.107 (+0.63%)| 0.085 |
|25 | 7.569 | 0.142 | 7.503 (+0.88%)| 0.143 |
+--------------+-------+---------+----------------+---------+
[1] https://patchwork.kernel.org/patch/9991635/
Matt Fleming also ran cyclictest and several different hackbench tests
on his test machines to santiy-check that the patch doesn't harm any
of his usecases.
Change-Id: Ibcedbb65273545ff2f4d1962b4eaca14072b1bd2
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Morten Ramussen <morten.rasmussen@arm.com>
Cc: Brendan Jackman <brendan.jackman@arm.com>
Tested-by: Rohit Jain <rohit.k.jain@oracle.com>
Tested-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Joel Fernandes <joelaf@google.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
LSK 18.05 v4.4-android
* tag 'lsk-v4.4-18.05-android': (605 commits)
ANDROID: sdcardfs: Don't d_drop in d_revalidate
goldfish: pipe: ANDROID: mark local functions static
UPSTREAM: ANDROID: binder: prevent transactions into own process.
goldfish: pipe: ANDROID: Add DMA support
UPSTREAM: f2fs: clear PageError on writepage - part 2
UPSTREAM: f2fs: avoid fsync() failure caused by EAGAIN in writepage()
ANDROID: x86_64_cuttlefish_defconfig: Disable KPTI
UPSTREAM: mac80211: ibss: Fix channel type enum in ieee80211_sta_join_ibss()
UPSTREAM: mac80211: Fix clang warning about constant operand in logical operation
UPSTREAM: nl80211: Fix enum type of variable in nl80211_put_sta_rate()
UPSTREAM: sysfs: remove signedness from sysfs_get_dirent
UPSTREAM: tracing: Use cpumask_available() to check if cpumask variable may be used
BACKPORT: clocksource: Use GENMASK_ULL in definition of CLOCKSOURCE_MASK
UPSTREAM: netpoll: Fix device name check in netpoll_setup()
FROMLIST: staging: Fix sparse warnings in vsoc driver.
FROMLIST: staging: vsoc: Fix a i386-randconfig warning.
FROMLIST: staging: vsoc: Create wc kernel mapping for region shm.
goldfish: pipe: ANDROID: Replace writel with gf_write_ptr
goldfish: pipe: ANDROID: Use dev_ logging instead of pr_
goldfish: pipe: ANDROID: fix checkpatch warnings
...
Conflicts:
fs/f2fs/node.c
scripts/Makefile.lib
Change-Id: Ib92d11938a383464249fe6f2dad3ab2a05bc4770
[ Upstream commit d29a20645d ]
While running rt-tests' pi_stress program I got the following splat:
rq->clock_update_flags < RQCF_ACT_SKIP
WARNING: CPU: 27 PID: 0 at kernel/sched/sched.h:960 assert_clock_updated.isra.38.part.39+0x13/0x20
[...]
<IRQ>
enqueue_top_rt_rq+0xf4/0x150
? cpufreq_dbs_governor_start+0x170/0x170
sched_rt_rq_enqueue+0x65/0x80
sched_rt_period_timer+0x156/0x360
? sched_rt_rq_enqueue+0x80/0x80
__hrtimer_run_queues+0xfa/0x260
hrtimer_interrupt+0xcb/0x220
smp_apic_timer_interrupt+0x62/0x120
apic_timer_interrupt+0xf/0x20
</IRQ>
[...]
do_idle+0x183/0x1e0
cpu_startup_entry+0x5f/0x70
start_secondary+0x192/0x1d0
secondary_startup_64+0xa5/0xb0
We can get rid of it be the "traditional" means of adding an
update_rq_clock() call after acquiring the rq->lock in
do_sched_rt_period_timer().
The case for the RT task throttling (which this workload also hits)
can be ignored in that the skip_update call is actually bogus and
quite the contrary (the request bits are removed/reverted).
By setting RQCF_UPDATED we really don't care if the skip is happening
or not and will therefore make the assert_clock_updated() check happy.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dave@stgolabs.net
Cc: linux-kernel@vger.kernel.org
Cc: rostedt@goodmis.org
Link: http://lkml.kernel.org/r/20180402164954.16255-1-dave@stgolabs.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add time in state data to task structs, and create
/proc/<pid>/time_in_state files to show how long each individual task
has run at each frequency.
Create a CONFIG_CPU_FREQ_TIMES option to enable/disable this tracking.
Signed-off-by: Connor O'Brien <connoro@google.com>
Bug: 72339335
Test: Read /proc/<pid>/time_in_state
Change-Id: Ia6456754f4cb1e83b2bc35efa8fbe9f8696febc8
* linux-linaro-lsk-v4.4: (515 commits)
Linux 4.4.132
perf/x86: Fix possible Spectre-v1 indexing for x86_pmu::event_map()
perf/core: Fix possible Spectre-v1 indexing for ->aux_pages[]
perf/x86/msr: Fix possible Spectre-v1 indexing in the MSR driver
perf/x86/cstate: Fix possible Spectre-v1 indexing for pkg_msr
perf/x86: Fix possible Spectre-v1 indexing for hw_perf_event cache_*
tracing/uprobe_event: Fix strncpy corner case
Revert "Bluetooth: btusb: Fix quirk for Atheros 1525/QCA6174"
atm: zatm: Fix potential Spectre v1
net: atm: Fix potential Spectre v1
can: kvaser_usb: Increase correct stats counter in kvaser_usb_rx_can_msg()
tracing: Fix regex_match_front() to not over compare the test string
libata: Apply NOLPM quirk for SanDisk SD7UB3Q*G1001 SSDs
rfkill: gpio: fix memory leak in probe error path
xfrm_user: fix return value from xfrm_user_rcv_msg
f2fs: fix a dead loop in f2fs_fiemap()
bdi: Fix oops in wb_workfn()
tcp: fix TCP_REPAIR_QUEUE bound checking
perf: Remove superfluous allocation error check
soreuseport: initialise timewait reuseport field
...
Conflicts:
arch/s390/kernel/module.c
arch/x86/kernel/kprobes/core.c
fs/proc/task_mmu.c
net/ipv6/route.c
Trivial conflicts between AOSP/LSK and backported/rebased LTS changes.
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
I finally got around to creating trampolines for dynamically allocated
ftrace_ops with using synchronize_rcu_tasks(). For users of the ftrace
function hook callbacks, like perf, that allocate the ftrace_ops
descriptor via kmalloc() and friends, ftrace was not able to optimize
the functions being traced to use a trampoline because they would also
need to be allocated dynamically. The problem is that they cannot be
freed when CONFIG_PREEMPT is set, as there's no way to tell if a task
was preempted on the trampoline. That was before Paul McKenney
implemented synchronize_rcu_tasks() that would make sure all tasks
(except idle) have scheduled out or have entered user space.
While testing this, I triggered this bug:
BUG: unable to handle kernel paging request at ffffffffa0230077
...
RIP: 0010:0xffffffffa0230077
...
Call Trace:
schedule+0x5/0xe0
schedule_preempt_disabled+0x18/0x30
do_idle+0x172/0x220
What happened was that the idle task was preempted on the trampoline.
As synchronize_rcu_tasks() ignores the idle thread, there's nothing
that lets ftrace know that the idle task was preempted on a trampoline.
The idle task shouldn't need to ever enable preemption. The idle task
is simply a loop that calls schedule or places the cpu into idle mode.
In fact, having preemption enabled is inefficient, because it can
happen when idle is just about to call schedule anyway, which would
cause schedule to be called twice. Once for when the interrupt came in
and was returning back to normal context, and then again in the normal
path that the idle loop is running in, which would be pointless, as it
had already scheduled.
The only reason schedule_preempt_disable() enables preemption is to be
able to call sched_submit_work(), which requires preemption enabled. As
this is a nop when the task is in the RUNNING state, and idle is always
in the running state, there's no reason that idle needs to enable
preemption. But that means it cannot use schedule_preempt_disable() as
other callers of that function require calling sched_submit_work().
Adding a new function local to kernel/sched/ that allows idle to call
the scheduler without enabling preemption, fixes the
synchronize_rcu_tasks() issue, as well as removes the pointless spurious
schedule calls caused by interrupts happening in the brief window where
preemption is enabled just before it calls schedule.
Reviewed: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170414084809.3dacde2a@gandalf.local.home
Signed-off-by: Ingo Molnar <mingo@kernel.org>
-----Shawn: trace on 4.4 for RK3308 -------------------------
[ 151.389904] BUG: scheduling while atomic: swapper/0/0/0x00000000
[ 151.390478] Modules linked in:
[ 151.390813] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.126 #1327
[ 151.390830] Hardware name: Rockchip RK3308 evb digital-i2s mic board
(DT)
[ 151.390844] Call trace:
[ 151.390868] [<ffffff800808731c>] dump_backtrace+0x0/0x1c4
[ 151.390883] [<ffffff80080874f4>] show_stack+0x14/0x1c
[ 151.390900] [<ffffff80081e4274>] dump_stack+0x94/0xbc
[ 151.390919] [<ffffff80080b4c6c>] __schedule_bug+0x3c/0x54
[ 151.390938] [<ffffff800857e978>] __schedule+0x88/0x45c
[ 151.390953] [<ffffff800857edc0>] schedule+0x74/0x94
[ 151.390971] [<ffffff800857f118>] schedule_preempt_disabled+0x20/0x38
[ 151.390987] [<ffffff80080c9d74>] cpu_startup_entry+0x44/0x204
[ 151.391007] [<ffffff800857cda0>] rest_init+0x80/0x8c
[ 151.391025] [<ffffff8008750b04>] start_kernel+0x31c/0x330
[ 151.391040] [<ffffff80087501c4>] __primary_switched+0x30/0x6c
-------------------------------------------------------
Change-Id: I12971dfe9c2039920162326aabe1df0ecaf79804
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
(cherry-picked from 8663effb24)
[ Upstream commit 8655d54977 ]
A customer has reported a soft-lockup when running an intensive
memory stress test, where the trace on multiple CPU's looks like this:
RIP: 0010:[<ffffffff810c53fe>]
[<ffffffff810c53fe>] native_queued_spin_lock_slowpath+0x10e/0x190
...
Call Trace:
[<ffffffff81182d07>] queued_spin_lock_slowpath+0x7/0xa
[<ffffffff811bc331>] change_protection_range+0x3b1/0x930
[<ffffffff811d4be8>] change_prot_numa+0x18/0x30
[<ffffffff810adefe>] task_numa_work+0x1fe/0x310
[<ffffffff81098322>] task_work_run+0x72/0x90
Further investigation showed that the lock contention here is pmd_lock().
The task_numa_work() function makes sure that only one thread is let to perform
the work in a single scan period (via cmpxchg), but if there's a thread with
mmap_sem locked for writing for several periods, multiple threads in
task_numa_work() can build up a convoy waiting for mmap_sem for read and then
all get unblocked at once.
This patch changes the down_read() to the trylock version, which prevents the
build up. For a workload experiencing mmap_sem contention, it's probably better
to postpone the NUMA balancing work anyway. This seems to have fixed the soft
lockups involving pmd_lock(), which is in line with the convoy theory.
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170515131316.21909-1-vbabka@suse.cz
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* linux-linaro-lsk-v4.4-android: (395 commits)
Linux 4.4.126
net: systemport: Rewrite __bcm_sysport_tx_reclaim()
net: fec: Fix unbalanced PM runtime calls
ieee802154: 6lowpan: fix possible NULL deref in lowpan_device_event()
s390/qeth: on channel error, reject further cmd requests
s390/qeth: lock read device while queueing next buffer
s390/qeth: when thread completes, wake up all waiters
s390/qeth: free netdevice when removing a card
team: Fix double free in error path
skbuff: Fix not waking applications when errors are enqueued
net: Only honor ifindex in IP_PKTINFO if non-0
netlink: avoid a double skb free in genlmsg_mcast()
net/iucv: Free memory obtained by kzalloc
net: ethernet: ti: cpsw: add check for in-band mode setting with RGMII PHY interface
net: ethernet: arc: Fix a potential memory leak if an optional regulator is deferred
l2tp: do not accept arbitrary sockets
ipv6: fix access to non-linear packet in ndisc_fill_redirect_hdr_option()
dccp: check sk for closed state in dccp_sendmsg()
net: Fix hlist corruptions in inet_evict_bucket()
Revert "genirq: Use irqd_get_trigger_type to compare the trigger type for shared IRQs"
...
Conflicts:
include/linux/usb/quirks.h
Change-Id: I125065cef66846e4cdee799f4b34d07c309d353e
[ Upstream commit a0982dfa03 ]
The rcutorture test suite occasionally provokes a splat due to invoking
resched_cpu() on an offline CPU:
WARNING: CPU: 2 PID: 8 at /home/paulmck/public_git/linux-rcu/arch/x86/kernel/smp.c:128 native_smp_send_reschedule+0x37/0x40
Modules linked in:
CPU: 2 PID: 8 Comm: rcu_preempt Not tainted 4.14.0-rc4+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
task: ffff902ede9daf00 task.stack: ffff96c50010c000
RIP: 0010:native_smp_send_reschedule+0x37/0x40
RSP: 0018:ffff96c50010fdb8 EFLAGS: 00010096
RAX: 000000000000002e RBX: ffff902edaab4680 RCX: 0000000000000003
RDX: 0000000080000003 RSI: 0000000000000000 RDI: 00000000ffffffff
RBP: ffff96c50010fdb8 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: 00000000299f36ae R12: 0000000000000001
R13: ffffffff9de64240 R14: 0000000000000001 R15: ffffffff9de64240
FS: 0000000000000000(0000) GS:ffff902edfc80000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000f7d4c642 CR3: 000000001e0e2000 CR4: 00000000000006e0
Call Trace:
resched_curr+0x8f/0x1c0
resched_cpu+0x2c/0x40
rcu_implicit_dynticks_qs+0x152/0x220
force_qs_rnp+0x147/0x1d0
? sync_rcu_exp_select_cpus+0x450/0x450
rcu_gp_kthread+0x5a9/0x950
kthread+0x142/0x180
? force_qs_rnp+0x1d0/0x1d0
? kthread_create_on_node+0x40/0x40
ret_from_fork+0x27/0x40
Code: 14 01 0f 92 c0 84 c0 74 14 48 8b 05 14 4f f4 00 be fd 00 00 00 ff 90 a0 00 00 00 5d c3 89 fe 48 c7 c7 38 89 ca 9d e8 e5 56 08 00 <0f> ff 5d c3 0f 1f 44 00 00 8b 05 52 9e 37 02 85 c0 75 38 55 48
---[ end trace 26df9e5df4bba4ac ]---
This splat cannot be generated by expedited grace periods because they
always invoke resched_cpu() on the current CPU, which is good because
expedited grace periods require that resched_cpu() unconditionally
succeed. However, other parts of RCU can tolerate resched_cpu() acting
as a no-op, at least as long as it doesn't happen too often.
This commit therefore makes resched_cpu() invoke resched_curr() only if
the CPU is either online or is the current CPU.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 2fe2582649 ]
The rcutorture test suite occasionally provokes a splat due to invoking
rt_mutex_lock() which needs to boost the priority of a task currently
sitting on a runqueue that belongs to an offline CPU:
WARNING: CPU: 0 PID: 12 at /home/paulmck/public_git/linux-rcu/arch/x86/kernel/smp.c:128 native_smp_send_reschedule+0x37/0x40
Modules linked in:
CPU: 0 PID: 12 Comm: rcub/7 Not tainted 4.14.0-rc4+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
task: ffff9ed3de5f8cc0 task.stack: ffffbbf80012c000
RIP: 0010:native_smp_send_reschedule+0x37/0x40
RSP: 0018:ffffbbf80012fd10 EFLAGS: 00010082
RAX: 000000000000002f RBX: ffff9ed3dd9cb300 RCX: 0000000000000004
RDX: 0000000080000004 RSI: 0000000000000086 RDI: 00000000ffffffff
RBP: ffffbbf80012fd10 R08: 000000000009da7a R09: 0000000000007b9d
R10: 0000000000000001 R11: ffffffffbb57c2cd R12: 000000000000000d
R13: ffff9ed3de5f8cc0 R14: 0000000000000061 R15: ffff9ed3ded59200
FS: 0000000000000000(0000) GS:ffff9ed3dea00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000080686f0 CR3: 000000001b9e0000 CR4: 00000000000006f0
Call Trace:
resched_curr+0x61/0xd0
switched_to_rt+0x8f/0xa0
rt_mutex_setprio+0x25c/0x410
task_blocks_on_rt_mutex+0x1b3/0x1f0
rt_mutex_slowlock+0xa9/0x1e0
rt_mutex_lock+0x29/0x30
rcu_boost_kthread+0x127/0x3c0
kthread+0x104/0x140
? rcu_report_unblock_qs_rnp+0x90/0x90
? kthread_create_on_node+0x40/0x40
ret_from_fork+0x22/0x30
Code: f0 00 0f 92 c0 84 c0 74 14 48 8b 05 34 74 c5 00 be fd 00 00 00 ff 90 a0 00 00 00 5d c3 89 fe 48 c7 c7 a0 c6 fc b9 e8 d5 b5 06 00 <0f> ff 5d c3 0f 1f 44 00 00 8b 05 a2 d1 13 02 85 c0 75 38 55 48
But the target task's priority has already been adjusted, so the only
purpose of switched_to_rt() invoking resched_curr() is to wake up the
CPU running some task that needs to be preempted by the boosted task.
But the CPU is offline, which presumably means that the task must be
migrated to some other CPU, and that this other CPU will undertake any
needed preemption at the time of migration. Because the runqueue lock
is held when resched_curr() is invoked, we know that the boosted task
cannot go anywhere, so it is not necessary to invoke resched_curr()
in this particular case.
This commit therefore makes switched_to_rt() refrain from invoking
resched_curr() when the target CPU is offline.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
There is a race between hotplug and energy_diff which might result
in endless loop in sched_group_energy. When this happens, the end
condition cannot be detected.
We can store how many CPUs we need to visit at the beginning, and
bail out of the energy calculation if we visit more cpus than expected.
Bug: 72311797 72202633
Change-Id: I8dda75468ee1570da4071cd8165ef5131a8205d8
Signed-off-by: Chris Redpath <chris.redpath@arm.com>
Boosted RT tasks can be deboosted quickly, this makes boost usless
for RT tasks and causes lots of glitching. Use timers to prevent
de-boost too soon and wait for long enough such that next enqueue
happens after a threshold.
While this can be solved in the governor, there are following
advantages:
- The approach used is governor-independent
- Reduces boost group lock contention for frequently sleepers/wakers
Note:
Fixed build breakage due to schedfreq dependency which isn't used
for RT anymore.
Bug: 30210506
Change-Id: I428a2695cac06cc3458cdde0dea72315e4e66c00
Signed-off-by: Joel Fernandes <joelaf@google.com>
In up-migrate path, select_energy_cpu_brute() was called directly
without checking energy_aware(). This will make select_energy_cpu_brute()
always worked even disabling energy_aware() on the asymmetric cpu
capacity system.
Signed-off-by: Ke Wang <ke.wang@spreadtrum.com>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
Conflicts:
fs/f2fs/extent_cache.c
Pick changes from AOSP Change-Id: Icd8a85ac0c19a8aa25cd2591a12b4e9b85bdf1c5
("f2fs: catch up to v4.14-rc1")
fs/f2fs/namei.c
Pick changes from AOSP F2FS backport commit 7d5c08fd91
("f2fs: backport from (4c1fad64 - Merge tag 'for-f2fs-4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs)")
commit 364f566537 upstream.
When issuing an IPI RT push, where an IPI is sent to each CPU that has more
than one RT task scheduled on it, it references the root domain's rto_mask,
that contains all the CPUs within the root domain that has more than one RT
task in the runable state. The problem is, after the IPIs are initiated, the
rq->lock is released. This means that the root domain that is associated to
the run queue could be freed while the IPIs are going around.
Add a sched_get_rd() and a sched_put_rd() that will increment and decrement
the root domain's ref count respectively. This way when initiating the IPIs,
the scheduler will up the root domain's ref count before releasing the
rq->lock, ensuring that the root domain does not go away until the IPI round
is complete.
Reported-by: Pavan Kondeti <pkondeti@codeaurora.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 4bdced5c9a ("sched/rt: Simplify the IPI based RT balancing logic")
Link: http://lkml.kernel.org/r/CAEU1=PkiHO35Dzna8EQqNSKW1fr1y1zRQ5y66X117MG06sQtNA@mail.gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ad0f1d9d65 upstream.
When the rto_push_irq_work_func() is called, it looks at the RT overloaded
bitmask in the root domain via the runqueue (rq->rd). The problem is that
during CPU up and down, nothing here stops rq->rd from changing between
taking the rq->rd->rto_lock and releasing it. That means the lock that is
released is not the same lock that was taken.
Instead of using this_rq()->rd to get the root domain, as the irq work is
part of the root domain, we can simply get the root domain from the irq work
that is passed to the routine:
container_of(work, struct root_domain, rto_push_work)
This keeps the root domain consistent.
Reported-by: Pavan Kondeti <pkondeti@codeaurora.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 4bdced5c9a ("sched/rt: Simplify the IPI based RT balancing logic")
Link: http://lkml.kernel.org/r/CAEU1=PkiHO35Dzna8EQqNSKW1fr1y1zRQ5y66X117MG06sQtNA@mail.gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
LSK 18.02 v4.4-android
* tag 'lsk-v4.4-18.02-android': (131 commits)
Linux 4.4.114
nfsd: auth: Fix gid sorting when rootsquash enabled
net: tcp: close sock if net namespace is exiting
flow_dissector: properly cap thoff field
ipv4: Make neigh lookup keys for loopback/point-to-point devices be INADDR_ANY
net: Allow neigh contructor functions ability to modify the primary_key
vmxnet3: repair memory leak
sctp: return error if the asoc has been peeled off in sctp_wait_for_sndbuf
sctp: do not allow the v4 socket to bind a v4mapped v6 address
r8169: fix memory corruption on retrieval of hardware statistics.
pppoe: take ->needed_headroom of lower device into account on xmit
net: qdisc_pkt_len_init() should be more robust
tcp: __tcp_hdrlen() helper
net: igmp: fix source address check for IGMPv3 reports
lan78xx: Fix failure in USB Full Speed
ipv6: ip6_make_skb() needs to clear cork.base.dst
ipv6: fix udpv6 sendmsg crash caused by too small MTU
ipv6: Fix getsockopt() for sockets with default IPV6_AUTOFLOWLABEL
dccp: don't restart ccid2_hc_tx_rto_expire() if sk in closed state
hrtimer: Reset hrtimer cpu base proper on CPU hotplug
...
commit 3effcb4247 upstream.
We have been facing some problems with self-suspending constrained
deadline tasks. The main reason is that the original CBS was not
designed for such sort of tasks.
One problem reported by Xunlei Pang takes place when a task
suspends, and then is awakened before the deadline, but so close
to the deadline that its remaining runtime can cause the task
to have an absolute density higher than allowed. In such situation,
the original CBS assumes that the task is facing an early activation,
and so it replenishes the task and set another deadline, one deadline
in the future. This rule works fine for implicit deadline tasks.
Moreover, it allows the system to adapt the period of a task in which
the external event source suffered from a clock drift.
However, this opens the window for bandwidth leakage for constrained
deadline tasks. For instance, a task with the following parameters:
runtime = 5 ms
deadline = 7 ms
[density] = 5 / 7 = 0.71
period = 1000 ms
If the task runs for 1 ms, and then suspends for another 1ms,
it will be awakened with the following parameters:
remaining runtime = 4
laxity = 5
presenting a absolute density of 4 / 5 = 0.80.
In this case, the original CBS would assume the task had an early
wakeup. Then, CBS will reset the runtime, and the absolute deadline will
be postponed by one relative deadline, allowing the task to run.
The problem is that, if the task runs this pattern forever, it will keep
receiving bandwidth, being able to run 1ms every 2ms. Following this
behavior, the task would be able to run 500 ms in 1 sec. Thus running
more than the 5 ms / 1 sec the admission control allowed it to run.
Trying to address the self-suspending case, Luca Abeni, Giuseppe
Lipari, and Juri Lelli [1] revisited the CBS in order to deal with
self-suspending tasks. In the new approach, rather than
replenishing/postponing the absolute deadline, the revised wakeup rule
adjusts the remaining runtime, reducing it to fit into the allowed
density.
A revised version of the idea is:
At a given time t, the maximum absolute density of a task cannot be
higher than its relative density, that is:
runtime / (deadline - t) <= dl_runtime / dl_deadline
Knowing the laxity of a task (deadline - t), it is possible to move
it to the other side of the equality, thus enabling to define max
remaining runtime a task can use within the absolute deadline, without
over-running the allowed density:
runtime = (dl_runtime / dl_deadline) * (deadline - t)
For instance, in our previous example, the task could still run:
runtime = ( 5 / 7 ) * 5
runtime = 3.57 ms
Without causing damage for other deadline tasks. It is note worthy
that the laxity cannot be negative because that would cause a negative
runtime. Thus, this patch depends on the patch:
df8eac8caf ("sched/deadline: Throttle a constrained deadline task activated after the deadline")
Which throttles a constrained deadline task activated after the
deadline.
Finally, it is also possible to use the revised wakeup rule for
all other tasks, but that would require some more discussions
about pros and cons.
[The main difference from the original commit is that
the BW_SHIFT define was not present yet. As BW_SHIFT was
introduced in a new feature, I just used the value (20),
likewise we used to use before the #define.
Other changes were required because of comments. - bistrot]
Reported-by: Xunlei Pang <xpang@redhat.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
[peterz: replaced dl_is_constrained with dl_is_implicit]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luca Abeni <luca.abeni@santannapisa.it>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Romulo Silva de Oliveira <romulo.deoliveira@ufsc.br>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tommaso Cucinotta <tommaso.cucinotta@sssup.it>
Link: http://lkml.kernel.org/r/5c800ab3a74a168a84ee5f3f84d12a02e11383be.1495803804.git.bristot@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
After applying up-migrate patches(dc626b2 sched: avoid pushing
tasks to an offline CPU, 2da014c sched: Extend active balance
to accept 'push_task' argument), leaving EAS disabled and doing
a stability test which includes some random cpu plugin/plugout.
There are two types crashes happened as below:
TYPE 1:
[ 2072.653091] c1 ------------[ cut here ]------------
[ 2072.653133] c1 WARNING: CPU: 1 PID: 13 at kernel/fork.c:252 __put_task_struct+0x30/0x124()
[ 2072.653173] c1 CPU: 1 PID: 13 Comm: migration/1 Tainted: G W O 4.4.83-01066-g04c5403-dirty #17
[ 2072.653215] c1 [<c011141c>] (unwind_backtrace) from [<c010ced8>] (show_stack+0x20/0x24)
[ 2072.653235] c1 [<c010ced8>] (show_stack) from [<c043d7f8>] (dump_stack+0xa8/0xe0)
[ 2072.653255] c1 [<c043d7f8>] (dump_stack) from [<c012be04>] (warn_slowpath_common+0x98/0xc4)
[ 2072.653273] c1 [<c012be04>] (warn_slowpath_common) from [<c012beec>] (warn_slowpath_null+0x2c/0x34)
[ 2072.653291] c1 [<c012beec>] (warn_slowpath_null) from [<c01293b4>] (__put_task_struct+0x30/0x124)
[ 2072.653310] c1 [<c01293b4>] (__put_task_struct) from [<c0166964>] (active_load_balance_cpu_stop+0x22c/0x314)
[ 2072.653331] c1 [<c0166964>] (active_load_balance_cpu_stop) from [<c01c2604>] (cpu_stopper_thread+0x90/0x144)
[ 2072.653352] c1 [<c01c2604>] (cpu_stopper_thread) from [<c014d80c>] (smpboot_thread_fn+0x258/0x270)
[ 2072.653370] c1 [<c014d80c>] (smpboot_thread_fn) from [<c0149ee4>] (kthread+0x118/0x12c)
[ 2072.653388] c1 [<c0149ee4>] (kthread) from [<c0108310>] (ret_from_fork+0x14/0x24)
[ 2072.653400] c1 ---[ end trace 49c3d154890763fc ]---
[ 2072.653418] c1 Unable to handle kernel NULL pointer dereference at virtual address 00000000
...
[ 2072.832804] c1 [<c01ba00c>] (put_css_set) from [<c01be870>] (cgroup_free+0x6c/0x78)
[ 2072.832823] c1 [<c01be870>] (cgroup_free) from [<c01293f8>] (__put_task_struct+0x74/0x124)
[ 2072.832844] c1 [<c01293f8>] (__put_task_struct) from [<c0166964>] (active_load_balance_cpu_stop+0x22c/0x314)
[ 2072.832860] c1 [<c0166964>] (active_load_balance_cpu_stop) from [<c01c2604>] (cpu_stopper_thread+0x90/0x144)
[ 2072.832879] c1 [<c01c2604>] (cpu_stopper_thread) from [<c014d80c>] (smpboot_thread_fn+0x258/0x270)
[ 2072.832896] c1 [<c014d80c>] (smpboot_thread_fn) from [<c0149ee4>] (kthread+0x118/0x12c)
[ 2072.832914] c1 [<c0149ee4>] (kthread) from [<c0108310>] (ret_from_fork+0x14/0x24)
[ 2072.832930] c1 Code: f57ff05b f590f000 e3e02000 e3a03001 (e1941f9f)
[ 2072.839208] c1 ---[ end trace 49c3d154890763fd ]---
TYPE 2:
[ 214.742695] c1 ------------[ cut here ]------------
[ 214.742709] c1 kernel BUG at kernel/smpboot.c:136!
[ 214.742718] c1 Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
[ 214.748785] c1 CPU: 1 PID: 18 Comm: migration/2 Tainted: G W O 4.4.83-00912-g370f62c #1
[ 214.748805] c1 task: ef2d9680 task.stack: ee862000
[ 214.748821] c1 PC is at smpboot_thread_fn+0x168/0x270
[ 214.748832] c1 LR is at smpboot_thread_fn+0xe4/0x270
...
[ 214.821339] c1 [<c014d71c>] (smpboot_thread_fn) from [<c0149ee4>] (kthread+0x118/0x12c)
[ 214.821363] c1 [<c0149ee4>] (kthread) from [<c0108310>] (ret_from_fork+0x14/0x24)
[ 214.821378] c1 Code: e5950000 e5943010 e1500003 0a000000 (e7f001f2)
[ 214.827676] c1 ---[ end trace da87539f59bab8de ]---
For the first type crash, the root cause is the push_task pointer will be
used without initialization on the out_lock path. And maybe cpu hotplug in/out
make this happen more easily.
For the second type crash, it hits 'BUG_ON(td->cpu != smp_processor_id());' in
smpboot_thread_fn(). It seems that OOPS was caused by migration/2 which actually
running on cpu1. And I haven't found what actually happened.
However, after this fix, the second type crash seems gone too.
Signed-off-by: Ke Wang <ke.wang@spreadtrum.com>
kcov provides code coverage collection for coverage-guided fuzzing
(randomized testing). Coverage-guided fuzzing is a testing technique
that uses coverage feedback to determine new interesting inputs to a
system. A notable user-space example is AFL
(http://lcamtuf.coredump.cx/afl/). However, this technique is not
widely used for kernel testing due to missing compiler and kernel
support.
kcov does not aim to collect as much coverage as possible. It aims to
collect more or less stable coverage that is function of syscall inputs.
To achieve this goal it does not collect coverage in soft/hard
interrupts and instrumentation of some inherently non-deterministic or
non-interesting parts of kernel is disbled (e.g. scheduler, locking).
Currently there is a single coverage collection mode (tracing), but the
API anticipates additional collection modes. Initially I also
implemented a second mode which exposes coverage in a fixed-size hash
table of counters (what Quentin used in his original patch). I've
dropped the second mode for simplicity.
This patch adds the necessary support on kernel side. The complimentary
compiler support was added in gcc revision 231296.
We've used this support to build syzkaller system call fuzzer, which has
found 90 kernel bugs in just 2 months:
https://github.com/google/syzkaller/wiki/Found-Bugs
We've also found 30+ bugs in our internal systems with syzkaller.
Another (yet unexplored) direction where kcov coverage would greatly
help is more traditional "blob mutation". For example, mounting a
random blob as a filesystem, or receiving a random blob over wire.
Why not gcov. Typical fuzzing loop looks as follows: (1) reset
coverage, (2) execute a bit of code, (3) collect coverage, repeat. A
typical coverage can be just a dozen of basic blocks (e.g. an invalid
input). In such context gcov becomes prohibitively expensive as
reset/collect coverage steps depend on total number of basic
blocks/edges in program (in case of kernel it is about 2M). Cost of
kcov depends only on number of executed basic blocks/edges. On top of
that, kernel requires per-thread coverage because there are always
background threads and unrelated processes that also produce coverage.
With inlined gcov instrumentation per-thread coverage is not possible.
kcov exposes kernel PCs and control flow to user-space which is
insecure. But debugfs should not be mapped as user accessible.
Based on a patch by Quentin Casasnovas.
[akpm@linux-foundation.org: make task_struct.kcov_mode have type `enum kcov_mode']
[akpm@linux-foundation.org: unbreak allmodconfig]
[akpm@linux-foundation.org: follow x86 Makefile layout standards]
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: syzkaller <syzkaller@googlegroups.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Tavis Ormandy <taviso@google.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Kees Cook <keescook@google.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: David Drysdale <drysdale@google.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Bug: 64145065
(cherry-picked from 5c9a8750a6)
Change-Id: I17b5e04f6e89b241924e78ec32ead79c38b860ce
Signed-off-by: Paul Lawrence <paullawrence@google.com>
For upmigrating misfit running task case, the currently running
task's util has been counted into cpu_util(). Thus currently
__cpu_overutilized() which add task's uitl twice is overestimated.
Signed-off-by: Ke Wang <ke.wang@spreadtrum.com>
'cached_raw_freq' is used to get the next frequency quickly but should
always be in sync with sg_policy->next_freq. There are cases where it is
not and in such cases it should be reset to avoid switching to incorrect
frequencies.
Consider this case for example:
- policy->cur is 1.2 GHz (Max)
- New request comes for 780 MHz and we store that in cached_raw_freq.
- Based on 780 MHz, we calculate the effective frequency as 800 MHz.
- We then decide not to update the frequency as
sugov_up_down_rate_limit() return true.
- Here cached_raw_freq is 780 MHz and sg_policy->next_freq is 1.2 GHz.
- Now if the utilization doesn't change in next request, then the next
target frequency will still be 780 MHz and it will match with
cached_raw_freq and so we will directly return 1.2 GHz instead of 800
MHz.
BACKPORT of upstream commit 07458f6a51 ("cpufreq: schedutil: Reset
cached_raw_freq when not in sync with next_freq").
This also updates sugov_update_commit() for handling up/down tunables, which
aren't present in mainline.
Change-Id: I70bca2c5dfdb545a0471d1c9e4c5addb30ab5494
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
Conflicts:
kernel/fork.c
Conflict due to Kaiser implementation in LTS 4.4.110.
net/ipv4/raw.c
Minor conflict due to LTS commit
be27b620a8 ("net: ipv4: fix for a race condition in raw_sendmsg")
[ Upstream commit 2317d5f1c3 ]
I was testing Daniel's changes with his test case, and tweaked it a
little. Instead of having the runtime equal to the deadline, I
increased the deadline ten fold.
Daniel's test case had:
attr.sched_runtime = 2 * 1000 * 1000; /* 2 ms */
attr.sched_deadline = 2 * 1000 * 1000; /* 2 ms */
attr.sched_period = 2 * 1000 * 1000 * 1000; /* 2 s */
To make it more interesting, I changed it to:
attr.sched_runtime = 2 * 1000 * 1000; /* 2 ms */
attr.sched_deadline = 20 * 1000 * 1000; /* 20 ms */
attr.sched_period = 2 * 1000 * 1000 * 1000; /* 2 s */
The results were rather surprising. The behavior that Daniel's patch
was fixing came back. The task started using much more than .1% of the
CPU. More like 20%.
Looking into this I found that it was due to the dl_entity_overflow()
constantly returning true. That's because it uses the relative period
against relative runtime vs the absolute deadline against absolute
runtime.
runtime / (deadline - t) > dl_runtime / dl_period
There's even a comment mentioning this, and saying that when relative
deadline equals relative period, that the equation is the same as using
deadline instead of period. That comment is backwards! What we really
want is:
runtime / (deadline - t) > dl_runtime / dl_deadline
We care about if the runtime can make its deadline, not its period. And
then we can say "when the deadline equals the period, the equation is
the same as using dl_period instead of dl_deadline".
After correcting this, now when the task gets enqueued, it can throttle
correctly, and Daniel's fix to the throttling of sleeping deadline
tasks works even when the runtime and deadline are not the same.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luca Abeni <luca.abeni@santannapisa.it>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Romulo Silva de Oliveira <romulo.deoliveira@ufsc.br>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tommaso Cucinotta <tommaso.cucinotta@sssup.it>
Link: http://lkml.kernel.org/r/02135a27f1ae3fe5fd032568a5a2f370e190e8d7.1488392936.git.bristot@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit df8eac8caf ]
During the activation, CBS checks if it can reuse the current task's
runtime and period. If the deadline of the task is in the past, CBS
cannot use the runtime, and so it replenishes the task. This rule
works fine for implicit deadline tasks (deadline == period), and the
CBS was designed for implicit deadline tasks. However, a task with
constrained deadline (deadine < period) might be awakened after the
deadline, but before the next period. In this case, replenishing the
task would allow it to run for runtime / deadline. As in this case
deadline < period, CBS enables a task to run for more than the
runtime / period. In a very loaded system, this can cause a domino
effect, making other tasks miss their deadlines.
To avoid this problem, in the activation of a constrained deadline
task after the deadline but before the next period, throttle the
task and set the replenishing timer to the begin of the next period,
unless it is boosted.
Reproducer:
--------------- %< ---------------
int main (int argc, char **argv)
{
int ret;
int flags = 0;
unsigned long l = 0;
struct timespec ts;
struct sched_attr attr;
memset(&attr, 0, sizeof(attr));
attr.size = sizeof(attr);
attr.sched_policy = SCHED_DEADLINE;
attr.sched_runtime = 2 * 1000 * 1000; /* 2 ms */
attr.sched_deadline = 2 * 1000 * 1000; /* 2 ms */
attr.sched_period = 2 * 1000 * 1000 * 1000; /* 2 s */
ts.tv_sec = 0;
ts.tv_nsec = 2000 * 1000; /* 2 ms */
ret = sched_setattr(0, &attr, flags);
if (ret < 0) {
perror("sched_setattr");
exit(-1);
}
for(;;) {
/* XXX: you may need to adjust the loop */
for (l = 0; l < 150000; l++);
/*
* The ideia is to go to sleep right before the deadline
* and then wake up before the next period to receive
* a new replenishment.
*/
nanosleep(&ts, NULL);
}
exit(0);
}
--------------- >% ---------------
On my box, this reproducer uses almost 50% of the CPU time, which is
obviously wrong for a task with 2/2000 reservation.
Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luca Abeni <luca.abeni@santannapisa.it>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Romulo Silva de Oliveira <romulo.deoliveira@ufsc.br>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tommaso Cucinotta <tommaso.cucinotta@sssup.it>
Link: http://lkml.kernel.org/r/edf58354e01db46bf42df8d2dd32418833f68c89.1488392936.git.bristot@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 5ac69d3778 ]
Currently, the replenishment timer is set to fire at the deadline
of a task. Although that works for implicit deadline tasks because the
deadline is equals to the begin of the next period, that is not correct
for constrained deadline tasks (deadline < period).
For instance:
f.c:
--------------- %< ---------------
int main (void)
{
for(;;);
}
--------------- >% ---------------
# gcc -o f f.c
# trace-cmd record -e sched:sched_switch \
-e syscalls:sys_exit_sched_setattr \
chrt -d --sched-runtime 490000000 \
--sched-deadline 500000000 \
--sched-period 1000000000 0 ./f
# trace-cmd report | grep "{pid of ./f}"
After setting parameters, the task is replenished and continue running
until being throttled:
f-11295 [003] 13322.113776: sys_exit_sched_setattr: 0x0
The task is throttled after running 492318 ms, as expected:
f-11295 [003] 13322.606094: sched_switch: f:11295 [-1] R ==> watchdog/3:32 [0]
But then, the task is replenished 500719 ms after the first
replenishment:
<idle>-0 [003] 13322.614495: sched_switch: swapper/3:0 [120] R ==> f:11295 [-1]
Running for 490277 ms:
f-11295 [003] 13323.104772: sched_switch: f:11295 [-1] R ==> swapper/3:0 [120]
Hence, in the first period, the task runs 2 * runtime, and that is a bug.
During the first replenishment, the next deadline is set one period away.
So the runtime / period starts to be respected. However, as the second
replenishment took place in the wrong instant, the next replenishment
will also be held in a wrong instant of time. Rather than occurring in
the nth period away from the first activation, it is taking place
in the (nth period - relative deadline).
Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Luca Abeni <luca.abeni@santannapisa.it>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Romulo Silva de Oliveira <romulo.deoliveira@ufsc.br>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tommaso Cucinotta <tommaso.cucinotta@sssup.it>
Link: http://lkml.kernel.org/r/ac50d89887c25285b47465638354b63362f8adff.1488392936.git.bristot@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f73c52a5bc upstream.
Daniel Wagner reported a crash on the BeagleBone Black SoC.
This is a single CPU architecture, and does not have a functional
arch_send_call_function_single_ipi() implementation which can crash
the kernel if that is called.
As it only has one CPU, it shouldn't be called, but if the kernel is
compiled for SMP, the push/pull RT scheduling logic now calls it for
irq_work if the one CPU is overloaded, it can use that function to call
itself and crash the kernel.
Ideally, we should disable the SCHED_FEAT(RT_PUSH_IPI) if the system
only has a single CPU. But SCHED_FEAT is a constant if sched debugging
is turned off. Another fix can also be used, and this should also help
with normal SMP machines. That is, do not initiate the pull code if
there's only one RT overloaded CPU, and that CPU happens to be the
current CPU that is scheduling in a lower priority task.
Even on a system with many CPUs, if there's many RT tasks waiting to
run on a single CPU, and that CPU schedules in another RT task of lower
priority, it will initiate the PULL logic in case there's a higher
priority RT task on another CPU that is waiting to run. But if there is
no other CPU with waiting RT tasks, it will initiate the RT pull logic
on itself (as it still has RT tasks waiting to run). This is a wasted
effort.
Not only does this help with SMP code where the current CPU is the only
one with RT overloaded tasks, it should also solve the issue that
Daniel encountered, because it will prevent the PULL logic from
executing, as there's only one CPU on the system, and the check added
here will cause it to exit the RT pull code.
Reported-by: Daniel Wagner <wagi@monom.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-rt-users <linux-rt-users@vger.kernel.org>
Fixes: 4bdced5c9 ("sched/rt: Simplify the IPI based RT balancing logic")
Link: http://lkml.kernel.org/r/20171202130454.4cbbfe8d@vmware.local.home
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* linux-linaro-lsk-v4.4-android: (510 commits)
Linux 4.4.103
Revert "sctp: do not peel off an assoc from one netns to another one"
xen: xenbus driver must not accept invalid transaction ids
s390/kbuild: enable modversions for symbols exported from asm
ASoC: wm_adsp: Don't overrun firmware file buffer when reading region data
btrfs: return the actual error value from from btrfs_uuid_tree_iterate
ASoC: rsnd: don't double free kctrl
netfilter: nf_tables: fix oob access
netfilter: nft_queue: use raw_smp_processor_id()
spi: SPI_FSL_DSPI should depend on HAS_DMA
staging: iio: cdc: fix improper return value
iio: light: fix improper return value
mac80211: Suppress NEW_PEER_CANDIDATE event if no room
mac80211: Remove invalid flag operations in mesh TSF synchronization
drm: Apply range restriction after color adjustment when allocation
ALSA: hda - Apply ALC269_FIXUP_NO_SHUTUP on HDA_FIXUP_ACT_PROBE
ath10k: set CTS protection VDEV param only if VDEV is up
ath10k: fix potential memory leak in ath10k_wmi_tlv_op_pull_fw_stats()
ath10k: ignore configuring the incorrect board_id
ath10k: fix incorrect txpower set by P2P_DEVICE interface
...
Conflicts:
drivers/media/v4l2-core/v4l2-ctrls.c
kernel/sched/fair.c
Change-Id: I48152b2a0ab1f9f07e1da7823119b94f9b9e1751
commit 4bdced5c9a upstream.
When a CPU lowers its priority (schedules out a high priority task for a
lower priority one), a check is made to see if any other CPU has overloaded
RT tasks (more than one). It checks the rto_mask to determine this and if so
it will request to pull one of those tasks to itself if the non running RT
task is of higher priority than the new priority of the next task to run on
the current CPU.
When we deal with large number of CPUs, the original pull logic suffered
from large lock contention on a single CPU run queue, which caused a huge
latency across all CPUs. This was caused by only having one CPU having
overloaded RT tasks and a bunch of other CPUs lowering their priority. To
solve this issue, commit:
b6366f048e ("sched/rt: Use IPI to trigger RT task push migration instead of pulling")
changed the way to request a pull. Instead of grabbing the lock of the
overloaded CPU's runqueue, it simply sent an IPI to that CPU to do the work.
Although the IPI logic worked very well in removing the large latency build
up, it still could suffer from a large number of IPIs being sent to a single
CPU. On a 80 CPU box, I measured over 200us of processing IPIs. Worse yet,
when I tested this on a 120 CPU box, with a stress test that had lots of
RT tasks scheduling on all CPUs, it actually triggered the hard lockup
detector! One CPU had so many IPIs sent to it, and due to the restart
mechanism that is triggered when the source run queue has a priority status
change, the CPU spent minutes! processing the IPIs.
Thinking about this further, I realized there's no reason for each run queue
to send its own IPI. As all CPUs with overloaded tasks must be scanned
regardless if there's one or many CPUs lowering their priority, because
there's no current way to find the CPU with the highest priority task that
can schedule to one of these CPUs, there really only needs to be one IPI
being sent around at a time.
This greatly simplifies the code!
The new approach is to have each root domain have its own irq work, as the
rto_mask is per root domain. The root domain has the following fields
attached to it:
rto_push_work - the irq work to process each CPU set in rto_mask
rto_lock - the lock to protect some of the other rto fields
rto_loop_start - an atomic that keeps contention down on rto_lock
the first CPU scheduling in a lower priority task
is the one to kick off the process.
rto_loop_next - an atomic that gets incremented for each CPU that
schedules in a lower priority task.
rto_loop - a variable protected by rto_lock that is used to
compare against rto_loop_next
rto_cpu - The cpu to send the next IPI to, also protected by
the rto_lock.
When a CPU schedules in a lower priority task and wants to make sure
overloaded CPUs know about it. It increments the rto_loop_next. Then it
atomically sets rto_loop_start with a cmpxchg. If the old value is not "0",
then it is done, as another CPU is kicking off the IPI loop. If the old
value is "0", then it will take the rto_lock to synchronize with a possible
IPI being sent around to the overloaded CPUs.
If rto_cpu is greater than or equal to nr_cpu_ids, then there's either no
IPI being sent around, or one is about to finish. Then rto_cpu is set to the
first CPU in rto_mask and an IPI is sent to that CPU. If there's no CPUs set
in rto_mask, then there's nothing to be done.
When the CPU receives the IPI, it will first try to push any RT tasks that is
queued on the CPU but can't run because a higher priority RT task is
currently running on that CPU.
Then it takes the rto_lock and looks for the next CPU in the rto_mask. If it
finds one, it simply sends an IPI to that CPU and the process continues.
If there's no more CPUs in the rto_mask, then rto_loop is compared with
rto_loop_next. If they match, everything is done and the process is over. If
they do not match, then a CPU scheduled in a lower priority task as the IPI
was being passed around, and the process needs to start again. The first CPU
in rto_mask is sent the IPI.
This change removes this duplication of work in the IPI logic, and greatly
lowers the latency caused by the IPIs. This removed the lockup happening on
the 120 CPU machine. It also simplifies the code tremendously. What else
could anyone ask for?
Thanks to Peter Zijlstra for simplifying the rto_loop_start atomic logic and
supplying me with the rto_start_trylock() and rto_start_unlock() helper
functions.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Scott Wood <swood@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170424114732.1aac6dc4@gandalf.local.home
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7c2102e56a upstream.
The current implementation of synchronize_sched_expedited() incorrectly
assumes that resched_cpu() is unconditional, which it is not. This means
that synchronize_sched_expedited() can hang when resched_cpu()'s trylock
fails as follows (analysis by Neeraj Upadhyay):
o CPU1 is waiting for expedited wait to complete:
sync_rcu_exp_select_cpus
rdp->exp_dynticks_snap & 0x1 // returns 1 for CPU5
IPI sent to CPU5
synchronize_sched_expedited_wait
ret = swait_event_timeout(rsp->expedited_wq,
sync_rcu_preempt_exp_done(rnp_root),
jiffies_stall);
expmask = 0x20, CPU 5 in idle path (in cpuidle_enter())
o CPU5 handles IPI and fails to acquire rq lock.
Handles IPI
sync_sched_exp_handler
resched_cpu
returns while failing to try lock acquire rq->lock
need_resched is not set
o CPU5 calls rcu_idle_enter() and as need_resched is not set, goes to
idle (schedule() is not called).
o CPU 1 reports RCU stall.
Given that resched_cpu() is now used only by RCU, this commit fixes the
assumption by making resched_cpu() unconditional.
Reported-by: Neeraj Upadhyay <neeraju@codeaurora.org>
Suggested-by: Neeraj Upadhyay <neeraju@codeaurora.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Boosted RT tasks can be deboosted quickly, this makes boost usless
for RT tasks and causes lots of glitching. Use timers to prevent
de-boost too soon and wait for long enough such that next enqueue
happens after a threshold.
While this can be solved in the governor, there are following
advantages:
- The approach used is governor-independent
- Reduces boost group lock contention for frequently sleepers/wakers
- Works with schedfreq without any other schedfreq hacks.
Bug: 30210506
Change-Id: I41788b235586988be446505deb7c0529758a9898
Signed-off-by: Joel Fernandes <joelaf@google.com>
We all should be using (and improving) the schedutil governor now. Get
rid of the non-upstream governor.
Tested on Hikey.
Change-Id: Ic660756536e5da51952738c3c18b94e31f58cd57
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
This patch adds schedtune enqueue/dequeue to RT scheduling class.
Change-Id: If416e64319d62191f3aedd675d3e9a21fe2102fb
Signed-off-by: Joel Fernandes <joelaf@google.com>
util_delta becomes not zero in eenv_before, which will affect the
calculation of grp_util in group_idle_state(). Fix it under the
new condition.
Change-Id: Ic3853bb45876a8e388afcbe4e72d25fc42b1d7b0
Signed-off-by: Ke Wang <ke.wang@spreadtrum.com>
