Commit Graph

32328 Commits

Author SHA1 Message Date
Linus Torvalds
f3cc24942e Merge tag 'irq-urgent-2020-02-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq fixes from Thomas Gleixner:
 "Two fixes for the irq core code which are follow ups to the recent MSI
  fixes:

   - The WARN_ON which was put into the MSI setaffinity callback for
     paranoia reasons actually triggered via a callchain which escaped
     when all the possible ways to reach that code were analyzed.

     The proc/irq/$N/*affinity interfaces have a quirk which came in
     when ALPHA moved to the generic interface: In case that the written
     affinity mask does not contain any online CPU it calls into ALPHAs
     magic auto affinity setting code.

     A few years later this mechanism was also made available to x86 for
     no good reasons and in a way which circumvents all sanity checks
     for interrupts which cannot have their affinity set from process
     context on X86 due to the way the X86 interrupt delivery works.

     It would be possible to make this work properly, but there is no
     point in doing so. If the interrupt is not yet started then the
     affinity setting has no effect and if it is started already then it
     is already assigned to an online CPU so there is no point to
     randomly move it to some other CPU. Just return EINVAL as the code
     has done before that change forever.

   - The new MSI quirk bit in the irq domain flags turned out to be
     already occupied, which escaped the author and the reviewers
     because the already in use bits were 0,6,2,3,4,5 listed in that
     order.

     That bit 6 was simply overlooked because the ordering was straight
     forward linear otherwise. So the new bit ended up being a
     duplicate.

     Fix it up by switching the oddball 6 to the obvious 1"

* tag 'irq-urgent-2020-02-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq/irqdomain: Make sure all irq domain flags are distinct
  genirq/proc: Reject invalid affinity masks (again)
2020-02-22 17:25:46 -08:00
Linus Torvalds
591dd4c101 Merge tag 's390-5.6-4' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 fixes from Vasily Gorbik:

 - Remove ieee_emulation_warnings sysctl which is a dead code.

 - Avoid triggering rebuild of the kernel during make install.

 - Enable protected virtualization guest support in default configs.

 - Fix cio_ignore seq_file .next function to increase position index.
   And use kobj_to_dev instead of container_of in cio code.

 - Fix storage block address lists to contain absolute addresses in qdio
   code.

 - Few clang warnings and spelling fixes.

* tag 's390-5.6-4' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/qdio: fill SBALEs with absolute addresses
  s390/qdio: fill SL with absolute addresses
  s390: remove obsolete ieee_emulation_warnings
  s390: make 'install' not depend on vmlinux
  s390/kaslr: Fix casts in get_random
  s390/mm: Explicitly compare PAGE_DEFAULT_KEY against zero in storage_key_init_range
  s390/pkey/zcrypt: spelling s/crytp/crypt/
  s390/cio: use kobj_to_dev() API
  s390/defconfig: enable CONFIG_PROTECTED_VIRTUALIZATION_GUEST
  s390/cio: cio_ignore_proc_seq_next should increase position index
2020-02-22 10:43:41 -08:00
Linus Torvalds
3dc55dba67 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from David Miller:

 1) Limit xt_hashlimit hash table size to avoid OOM or hung tasks, from
    Cong Wang.

 2) Fix deadlock in xsk by publishing global consumer pointers when NAPI
    is finished, from Magnus Karlsson.

 3) Set table field properly to RT_TABLE_COMPAT when necessary, from
    Jethro Beekman.

 4) NLA_STRING attributes are not necessary NULL terminated, deal wiht
    that in IFLA_ALT_IFNAME. From Eric Dumazet.

 5) Fix checksum handling in atlantic driver, from Dmitry Bezrukov.

 6) Handle mtu==0 devices properly in wireguard, from Jason A.
    Donenfeld.

 7) Fix several lockdep warnings in bonding, from Taehee Yoo.

 8) Fix cls_flower port blocking, from Jason Baron.

 9) Sanitize internal map names in libbpf, from Toke Høiland-Jørgensen.

10) Fix RDMA race in qede driver, from Michal Kalderon.

11) Fix several false lockdep warnings by adding conditions to
    list_for_each_entry_rcu(), from Madhuparna Bhowmik.

12) Fix sleep in atomic in mlx5 driver, from Huy Nguyen.

13) Fix potential deadlock in bpf_map_do_batch(), from Yonghong Song.

14) Hey, variables declared in switch statement before any case
    statements are not initialized. I learn something every day. Get
    rids of this stuff in several parts of the networking, from Kees
    Cook.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (99 commits)
  bnxt_en: Issue PCIe FLR in kdump kernel to cleanup pending DMAs.
  bnxt_en: Improve device shutdown method.
  net: netlink: cap max groups which will be considered in netlink_bind()
  net: thunderx: workaround BGX TX Underflow issue
  ionic: fix fw_status read
  net: disable BRIDGE_NETFILTER by default
  net: macb: Properly handle phylink on at91rm9200
  s390/qeth: fix off-by-one in RX copybreak check
  s390/qeth: don't warn for napi with 0 budget
  s390/qeth: vnicc Fix EOPNOTSUPP precedence
  openvswitch: Distribute switch variables for initialization
  net: ip6_gre: Distribute switch variables for initialization
  net: core: Distribute switch variables for initialization
  udp: rehash on disconnect
  net/tls: Fix to avoid gettig invalid tls record
  bpf: Fix a potential deadlock with bpf_map_do_batch
  bpf: Do not grab the bucket spinlock by default on htab batch ops
  ice: Wait for VF to be reset/ready before configuration
  ice: Don't tell the OS that link is going down
  ice: Don't reject odd values of usecs set by user
  ...
2020-02-21 11:59:51 -08:00
Arnd Bergmann
412c53a680 y2038: remove unused time32 interfaces
No users remain, so kill these off before we grow new ones.

Link: http://lkml.kernel.org/r/20200110154232.4104492-3-arnd@arndb.de
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Deepa Dinamani <deepa.kernel@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-02-21 11:22:15 -08:00
David S. Miller
41f57cfde1 Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Alexei Starovoitov says:

====================
pull-request: bpf 2020-02-19

The following pull-request contains BPF updates for your *net* tree.

We've added 10 non-merge commits during the last 10 day(s) which contain
a total of 10 files changed, 93 insertions(+), 31 deletions(-).

The main changes are:

1) batched bpf hashtab fixes from Brian and Yonghong.

2) various selftests and libbpf fixes.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2020-02-19 16:42:35 -08:00
Yonghong Song
b9aff38de2 bpf: Fix a potential deadlock with bpf_map_do_batch
Commit 057996380a ("bpf: Add batch ops to all htab bpf map")
added lookup_and_delete batch operation for hash table.
The current implementation has bpf_lru_push_free() inside
the bucket lock, which may cause a deadlock.

syzbot reports:
   -> #2 (&htab->buckets[i].lock#2){....}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:159
       htab_lru_map_delete_node+0xce/0x2f0 kernel/bpf/hashtab.c:593
       __bpf_lru_list_shrink_inactive kernel/bpf/bpf_lru_list.c:220 [inline]
       __bpf_lru_list_shrink+0xf9/0x470 kernel/bpf/bpf_lru_list.c:266
       bpf_lru_list_pop_free_to_local kernel/bpf/bpf_lru_list.c:340 [inline]
       bpf_common_lru_pop_free kernel/bpf/bpf_lru_list.c:447 [inline]
       bpf_lru_pop_free+0x87c/0x1670 kernel/bpf/bpf_lru_list.c:499
       prealloc_lru_pop+0x2c/0xa0 kernel/bpf/hashtab.c:132
       __htab_lru_percpu_map_update_elem+0x67e/0xa90 kernel/bpf/hashtab.c:1069
       bpf_percpu_hash_update+0x16e/0x210 kernel/bpf/hashtab.c:1585
       bpf_map_update_value.isra.0+0x2d7/0x8e0 kernel/bpf/syscall.c:181
       generic_map_update_batch+0x41f/0x610 kernel/bpf/syscall.c:1319
       bpf_map_do_batch+0x3f5/0x510 kernel/bpf/syscall.c:3348
       __do_sys_bpf+0x9b7/0x41e0 kernel/bpf/syscall.c:3460
       __se_sys_bpf kernel/bpf/syscall.c:3355 [inline]
       __x64_sys_bpf+0x73/0xb0 kernel/bpf/syscall.c:3355
       do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

   -> #0 (&loc_l->lock){....}:
       check_prev_add kernel/locking/lockdep.c:2475 [inline]
       check_prevs_add kernel/locking/lockdep.c:2580 [inline]
       validate_chain kernel/locking/lockdep.c:2970 [inline]
       __lock_acquire+0x2596/0x4a00 kernel/locking/lockdep.c:3954
       lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:159
       bpf_common_lru_push_free kernel/bpf/bpf_lru_list.c:516 [inline]
       bpf_lru_push_free+0x250/0x5b0 kernel/bpf/bpf_lru_list.c:555
       __htab_map_lookup_and_delete_batch+0x8d4/0x1540 kernel/bpf/hashtab.c:1374
       htab_lru_map_lookup_and_delete_batch+0x34/0x40 kernel/bpf/hashtab.c:1491
       bpf_map_do_batch+0x3f5/0x510 kernel/bpf/syscall.c:3348
       __do_sys_bpf+0x1f7d/0x41e0 kernel/bpf/syscall.c:3456
       __se_sys_bpf kernel/bpf/syscall.c:3355 [inline]
       __x64_sys_bpf+0x73/0xb0 kernel/bpf/syscall.c:3355
       do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

    Possible unsafe locking scenario:

          CPU0                    CPU2
          ----                    ----
     lock(&htab->buckets[i].lock#2);
                                  lock(&l->lock);
                                  lock(&htab->buckets[i].lock#2);
     lock(&loc_l->lock);

    *** DEADLOCK ***

To fix the issue, for htab_lru_map_lookup_and_delete_batch() in CPU0,
let us do bpf_lru_push_free() out of the htab bucket lock. This can
avoid the above deadlock scenario.

Fixes: 057996380a ("bpf: Add batch ops to all htab bpf map")
Reported-by: syzbot+a38ff3d9356388f2fb83@syzkaller.appspotmail.com
Reported-by: syzbot+122b5421d14e68f29cd1@syzkaller.appspotmail.com
Suggested-by: Hillf Danton <hdanton@sina.com>
Suggested-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Acked-by: Brian Vazquez <brianvv@google.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200219234757.3544014-1-yhs@fb.com
2020-02-19 16:01:25 -08:00
Brian Vazquez
492e0d0d6f bpf: Do not grab the bucket spinlock by default on htab batch ops
Grabbing the spinlock for every bucket even if it's empty, was causing
significant perfomance cost when traversing htab maps that have only a
few entries. This patch addresses the issue by checking first the
bucket_cnt, if the bucket has some entries then we go and grab the
spinlock and proceed with the batching.

Tested with a htab of size 50K and different value of populated entries.

Before:
  Benchmark             Time(ns)        CPU(ns)
  ---------------------------------------------
  BM_DumpHashMap/1       2759655        2752033
  BM_DumpHashMap/10      2933722        2930825
  BM_DumpHashMap/200     3171680        3170265
  BM_DumpHashMap/500     3639607        3635511
  BM_DumpHashMap/1000    4369008        4364981
  BM_DumpHashMap/5k     11171919       11134028
  BM_DumpHashMap/20k    69150080       69033496
  BM_DumpHashMap/39k   190501036      190226162

After:
  Benchmark             Time(ns)        CPU(ns)
  ---------------------------------------------
  BM_DumpHashMap/1        202707         200109
  BM_DumpHashMap/10       213441         210569
  BM_DumpHashMap/200      478641         472350
  BM_DumpHashMap/500      980061         967102
  BM_DumpHashMap/1000    1863835        1839575
  BM_DumpHashMap/5k      8961836        8902540
  BM_DumpHashMap/20k    69761497       69322756
  BM_DumpHashMap/39k   187437830      186551111

Fixes: 057996380a ("bpf: Add batch ops to all htab bpf map")
Signed-off-by: Brian Vazquez <brianvv@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200218172552.215077-1-brianvv@google.com
2020-02-19 15:59:30 -08:00
Stephen Kitt
140588bfed s390: remove obsolete ieee_emulation_warnings
s390 math emulation was removed with commit 5a79859ae0 ("s390:
remove 31 bit support"), rendering ieee_emulation_warnings useless.
The code still built because it was protected by CONFIG_MATHEMU, which
was no longer selectable.

This patch removes the sysctl_ieee_emulation_warnings declaration and
the sysctl entry declaration.

Link: https://lkml.kernel.org/r/20200214172628.3598516-1-steve@sk2.org
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Stephen Kitt <steve@sk2.org>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2020-02-19 13:51:46 +01:00
Linus Torvalds
0a44cac810 Merge tag 'dma-mapping-5.6' of git://git.infradead.org/users/hch/dma-mapping
Pull dma-mapping fixes from Christoph Hellwig:

 - give command line cma= precedence over the CONFIG_ option (Nicolas
   Saenz Julienne)

 - always allow 32-bit DMA, even for weirdly placed ZONE_DMA

 - improve the debug printks when memory is not addressable, to help
   find problems with swiotlb initialization

* tag 'dma-mapping-5.6' of git://git.infradead.org/users/hch/dma-mapping:
  dma-direct: improve DMA mask overflow reporting
  dma-direct: improve swiotlb error reporting
  dma-direct: relax addressability checks in dma_direct_supported
  dma-contiguous: CMA: give precedence to cmdline
2020-02-18 15:06:38 -08:00
Johannes Krude
e20d3a055a bpf, offload: Replace bitwise AND by logical AND in bpf_prog_offload_info_fill
This if guards whether user-space wants a copy of the offload-jited
bytecode and whether this bytecode exists. By erroneously doing a bitwise
AND instead of a logical AND on user- and kernel-space buffer-size can lead
to no data being copied to user-space especially when user-space size is a
power of two and bigger then the kernel-space buffer.

Fixes: fcfb126def ("bpf: add new jited info fields in bpf_dev_offload and bpf_prog_info")
Signed-off-by: Johannes Krude <johannes@krude.de>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/bpf/20200212193227.GA3769@phlox.h.transitiv.net
2020-02-17 16:53:49 +01:00
Linus Torvalds
ef78e5b7de Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
 "Misc fixes all over the place:

   - Fix NUMA over-balancing between lightly loaded nodes. This is
     fallout of the big load-balancer rewrite.

   - Fix the NOHZ remote loadavg update logic, which fixes anomalies
     like reported 150 loadavg on mostly idle CPUs.

   - Fix XFS performance/scalability

   - Fix throttled groups unbound task-execution bug

   - Fix PSI procfs boundary condition

   - Fix the cpu.uclamp.{min,max} cgroup configuration write checks

   - Fix DocBook annotations

   - Fix RCU annotations

   - Fix overly CPU-intensive housekeeper CPU logic loop on large CPU
     counts"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/fair: Fix kernel-doc warning in attach_entity_load_avg()
  sched/core: Annotate curr pointer in rq with __rcu
  sched/psi: Fix OOB write when writing 0 bytes to PSI files
  sched/fair: Allow a per-CPU kthread waking a task to stack on the same CPU, to fix XFS performance regression
  sched/fair: Prevent unlimited runtime on throttled group
  sched/nohz: Optimize get_nohz_timer_target()
  sched/uclamp: Reject negative values in cpu_uclamp_write()
  sched/fair: Allow a small load imbalance between low utilisation SD_NUMA domains
  timers/nohz: Update NOHZ load in remote tick
  sched/core: Don't skip remote tick for idle CPUs
2020-02-15 12:51:22 -08:00
Linus Torvalds
4e03e4e6d2 Merge tag 'pm-5.6-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management fixes from Rafael Wysocki:
 "Fix three issues related to the handling of wakeup events signaled
  through the ACPI SCI while suspended to idle (Rafael Wysocki) and
  unexport an internal cpufreq variable (Yangtao Li)"

* tag 'pm-5.6-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI: PM: s2idle: Prevent spurious SCIs from waking up the system
  ACPICA: Introduce acpi_any_gpe_status_set()
  ACPI: PM: s2idle: Avoid possible race related to the EC GPE
  ACPI: EC: Fix flushing of pending work
  cpufreq: Make cpufreq_global_kobject static
2020-02-14 12:34:30 -08:00
Thomas Gleixner
cba6437a18 genirq/proc: Reject invalid affinity masks (again)
Qian Cai reported that the WARN_ON() in the x86/msi affinity setting code,
which catches cases where the affinity setting is not done on the CPU which
is the current target of the interrupt, triggers during CPU hotplug stress
testing.

It turns out that the warning which was added with the commit addressing
the MSI affinity race unearthed yet another long standing bug.

If user space writes a bogus affinity mask, i.e. it contains no online CPUs,
then it calls irq_select_affinity_usr(). This was introduced for ALPHA in

  eee45269b0 ("[PATCH] Alpha: convert to generic irq framework (generic part)")

and subsequently made available for all architectures in

  1840475676 ("genirq: Expose default irq affinity mask (take 3)")

which introduced the circumvention of the affinity setting restrictions for
interrupt which cannot be moved in process context.

The whole exercise is bogus in various aspects:

  1) If the interrupt is already started up then there is absolutely
     no point to honour a bogus interrupt affinity setting from user
     space. The interrupt is already assigned to an online CPU and it
     does not make any sense to reassign it to some other randomly
     chosen online CPU.

  2) If the interupt is not yet started up then there is no point
     either. A subsequent startup of the interrupt will invoke
     irq_setup_affinity() anyway which will chose a valid target CPU.

So the only correct solution is to just return -EINVAL in case user space
wrote an affinity mask which does not contain any online CPUs, except for
ALPHA which has it's own magic sauce for this.

Fixes: 1840475676 ("genirq: Expose default irq affinity mask (take 3)")
Reported-by: Qian Cai <cai@lca.pw>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Qian Cai <cai@lca.pw>
Link: https://lkml.kernel.org/r/878sl8xdbm.fsf@nanos.tec.linutronix.de
2020-02-14 09:43:17 +01:00
Linus Torvalds
61a7595403 Merge tag 'trace-v5.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
 "Various fixes:

   - Fix an uninitialized variable

   - Fix compile bug to bootconfig userspace tool (in tools directory)

   - Suppress some error messages of bootconfig userspace tool

   - Remove unneded CONFIG_LIBXBC from bootconfig

   - Allocate bootconfig xbc_nodes dynamically. To ease complaints about
     taking up static memory at boot up

   - Use of parse_args() to parse bootconfig instead of strstr() usage
     Prevents issues of double quotes containing the interested string

   - Fix missing ring_buffer_nest_end() on synthetic event error path

   - Return zero not -EINVAL on soft disabled synthetic event (soft
     disabling must be the same as hard disabling, which returns zero)

   - Consolidate synthetic event code (remove duplicate code)"

* tag 'trace-v5.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Consolidate trace() functions
  tracing: Don't return -EINVAL when tracing soft disabled synth events
  tracing: Add missing nest end to synth_event_trace_start() error case
  tools/bootconfig: Suppress non-error messages
  bootconfig: Allocate xbc_nodes array dynamically
  bootconfig: Use parse_args() to find bootconfig and '--'
  tracing/kprobe: Fix uninitialized variable bug
  bootconfig: Remove unneeded CONFIG_LIBXBC
  tools/bootconfig: Fix wrong __VA_ARGS__ usage
2020-02-11 16:39:18 -08:00
Randy Dunlap
e9f5490c35 sched/fair: Fix kernel-doc warning in attach_entity_load_avg()
Fix kernel-doc warning in kernel/sched/fair.c, caused by a recent
function parameter removal:

  ../kernel/sched/fair.c:3526: warning: Excess function parameter 'flags' description in 'attach_entity_load_avg'

Fixes: a4f9a0e51b ("sched/fair: Remove redundant call to cpufreq_update_util()")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/cbe964e4-6879-fd08-41c9-ef1917414af4@infradead.org
2020-02-11 13:05:10 +01:00
Madhuparna Bhowmik
4104a562e0 sched/core: Annotate curr pointer in rq with __rcu
This patch fixes the following sparse warnings in sched/core.c
and sched/membarrier.c:

  kernel/sched/core.c:2372:27: error: incompatible types in comparison expression
  kernel/sched/core.c:4061:17: error: incompatible types in comparison expression
  kernel/sched/core.c:6067:9: error: incompatible types in comparison expression
  kernel/sched/membarrier.c:108:21: error: incompatible types in comparison expression
  kernel/sched/membarrier.c:177:21: error: incompatible types in comparison expression
  kernel/sched/membarrier.c:243:21: error: incompatible types in comparison expression

Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20200201125803.20245-1-madhuparnabhowmik10@gmail.com
2020-02-11 13:00:37 +01:00
Suren Baghdasaryan
6fcca0fa48 sched/psi: Fix OOB write when writing 0 bytes to PSI files
Issuing write() with count parameter set to 0 on any file under
/proc/pressure/ will cause an OOB write because of the access to
buf[buf_size-1] when NUL-termination is performed. Fix this by checking
for buf_size to be non-zero.

Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Link: https://lkml.kernel.org/r/20200203212216.7076-1-surenb@google.com
2020-02-11 13:00:02 +01:00
Rafael J. Wysocki
e3728b50cd ACPI: PM: s2idle: Avoid possible race related to the EC GPE
It is theoretically possible for the ACPI EC GPE to be set after the
s2idle_ops->wake() called from s2idle_loop() has returned and before
the subsequent pm_wakeup_pending() check is carried out.  If that
happens, the resulting wakeup event will cause the system to resume
even though it may be a spurious one.

To avoid that race, first make the ->wake() callback in struct
platform_s2idle_ops return a bool value indicating whether or not
to let the system resume and rearrange s2idle_loop() to use that
value instad of the direct pm_wakeup_pending() call if ->wake() is
present.

Next, rework acpi_s2idle_wake() to process EC events and check
pm_wakeup_pending() before re-arming the SCI for system wakeup
to prevent it from triggering prematurely and add comments to
that function to explain the rationale for the new code flow.

Fixes: 56b9918490 ("PM: sleep: Simplify suspend-to-idle control flow")
Cc: 5.4+ <stable@vger.kernel.org> # 5.4+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-02-11 10:11:02 +01:00
Tom Zanussi
7276531d40 tracing: Consolidate trace() functions
Move the checking, buffer reserve and buffer commit code in
synth_event_trace_start/end() into inline functions
__synth_event_trace_start/end() so they can also be used by
synth_event_trace() and synth_event_trace_array(), and then have all
those functions use them.

Also, change synth_event_trace_state.enabled to disabled so it only
needs to be set if the event is disabled, which is not normally the
case.

Link: http://lkml.kernel.org/r/b1f3108d0f450e58192955a300e31d0405ab4149.1581374549.git.zanussi@kernel.org

Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-02-10 22:00:21 -05:00
Tom Zanussi
0c62f6cd9e tracing: Don't return -EINVAL when tracing soft disabled synth events
There's no reason to return -EINVAL when tracing a synthetic event if
it's soft disabled - treat it the same as if it were hard disabled and
return normally.

Have synth_event_trace() and synth_event_trace_array() just return
normally, and have synth_event_trace_start set the trace state to
disabled and return.

Link: http://lkml.kernel.org/r/df5d02a1625aff97c9866506c5bada6a069982ba.1581374549.git.zanussi@kernel.org

Fixes: 8dcc53ad95 ("tracing: Add synth_event_trace() and related functions")
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-02-10 22:00:13 -05:00
Tom Zanussi
d090409abb tracing: Add missing nest end to synth_event_trace_start() error case
If the ring_buffer reserve in synth_event_trace_start() fails, the
matching ring_buffer_nest_end() should be called in the error code,
since nothing else will ever call it in this case.

Link: http://lkml.kernel.org/r/20abc444b3eeff76425f895815380abe7aa53ff8.1581374549.git.zanussi@kernel.org

Fixes: 8dcc53ad95 ("tracing: Add synth_event_trace() and related functions")
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-02-10 21:58:19 -05:00
Linus Torvalds
0a679e13ea Merge branch 'for-5.6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fix from Tejun Heo:
 "I made a mistake while removing cgroup task list lazy init
  optimization making the root cgroup.procs show entries for the
  init_tasks. The zero entries doesn't cause critical failures but does
  make systemd print out warning messages during boot.

  Fix it by omitting init_tasks as they should be"

* 'for-5.6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: init_tasks shouldn't be linked to the root cgroup
2020-02-10 17:07:05 -08:00
Hongbo Yao
2bf0eb9b3b bpf: Make btf_check_func_type_match() static
Fix the following sparse warning:

kernel/bpf/btf.c:4131:5: warning: symbol 'btf_check_func_type_match' was
not declared. Should it be static?

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Hongbo Yao <yaohongbo@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200210011441.147102-1-yaohongbo@huawei.com
2020-02-11 00:22:47 +01:00
Gustavo A. R. Silva
10f129cb59 tracing/kprobe: Fix uninitialized variable bug
There is a potential execution path in which variable *ret* is returned
without being properly initialized, previously.

Fix this by initializing variable *ret* to 0.

Link: http://lkml.kernel.org/r/20200205223404.GA3379@embeddedor

Addresses-Coverity-ID: 1491142 ("Uninitialized scalar variable")
Fixes: 2a588dd1d5 ("tracing: Add kprobe event command generation functions")
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-02-10 12:07:42 -05:00
Mel Gorman
52262ee567 sched/fair: Allow a per-CPU kthread waking a task to stack on the same CPU, to fix XFS performance regression
The following XFS commit:

  8ab39f11d9 ("xfs: prevent CIL push holdoff in log recovery")

changed the logic from using bound workqueues to using unbound
workqueues. Functionally this makes sense but it was observed at the
time that the dbench performance dropped quite a lot and CPU migrations
were increased.

The current pattern of the task migration is straight-forward. With XFS,
an IO issuer delegates work to xlog_cil_push_work ()on an unbound kworker.
This runs on a nearby CPU and on completion, dbench wakes up on its old CPU
as it is still idle and no migration occurs. dbench then queues the real
IO on the blk_mq_requeue_work() work item which runs on a bound kworker
which is forced to run on the same CPU as dbench. When IO completes,
the bound kworker wakes dbench but as the kworker is a bound but,
real task, the CPU is not considered idle and dbench gets migrated by
select_idle_sibling() to a new CPU. dbench may ping-pong between two CPUs
for a while but ultimately it starts a round-robin of all CPUs sharing
the same LLC. High-frequency migration on each IO completion has poor
performance overall. It has negative implications both in commication
costs and power management. mpstat confirmed that at low thread counts
that all CPUs sharing an LLC has low level of activity.

Note that even if the CIL patch was reverted, there still would
be migrations but the impact is less noticeable. It turns out that
individually the scheduler, XFS, blk-mq and workqueues all made sensible
decisions but in combination, the overall effect was sub-optimal.

This patch special cases the IO issue/completion pattern and allows
a bound kworker waker and a task wakee to stack on the same CPU if
there is a strong chance they are directly related. The expectation
is that the kworker is likely going back to sleep shortly. This is not
guaranteed as the IO could be queued asynchronously but there is a very
strong relationship between the task and kworker in this case that would
justify stacking on the same CPU instead of migrating. There should be
few concerns about kworker starvation given that the special casing is
only when the kworker is the waker.

DBench on XFS
MMTests config: io-dbench4-async modified to run on a fresh XFS filesystem

UMA machine with 8 cores sharing LLC
                          5.5.0-rc7              5.5.0-rc7
                  tipsched-20200124           kworkerstack
Amean     1        22.63 (   0.00%)       20.54 *   9.23%*
Amean     2        25.56 (   0.00%)       23.40 *   8.44%*
Amean     4        28.63 (   0.00%)       27.85 *   2.70%*
Amean     8        37.66 (   0.00%)       37.68 (  -0.05%)
Amean     64      469.47 (   0.00%)      468.26 (   0.26%)
Stddev    1         1.00 (   0.00%)        0.72 (  28.12%)
Stddev    2         1.62 (   0.00%)        1.97 ( -21.54%)
Stddev    4         2.53 (   0.00%)        3.58 ( -41.19%)
Stddev    8         5.30 (   0.00%)        5.20 (   1.92%)
Stddev    64       86.36 (   0.00%)       94.53 (  -9.46%)

NUMA machine, 48 CPUs total, 24 CPUs share cache
                           5.5.0-rc7              5.5.0-rc7
                   tipsched-20200124      kworkerstack-v1r2
Amean     1         58.69 (   0.00%)       30.21 *  48.53%*
Amean     2         60.90 (   0.00%)       35.29 *  42.05%*
Amean     4         66.77 (   0.00%)       46.55 *  30.28%*
Amean     8         81.41 (   0.00%)       68.46 *  15.91%*
Amean     16       113.29 (   0.00%)      107.79 *   4.85%*
Amean     32       199.10 (   0.00%)      198.22 *   0.44%*
Amean     64       478.99 (   0.00%)      477.06 *   0.40%*
Amean     128     1345.26 (   0.00%)     1372.64 *  -2.04%*
Stddev    1          2.64 (   0.00%)        4.17 ( -58.08%)
Stddev    2          4.35 (   0.00%)        5.38 ( -23.73%)
Stddev    4          6.77 (   0.00%)        6.56 (   3.00%)
Stddev    8         11.61 (   0.00%)       10.91 (   6.04%)
Stddev    16        18.63 (   0.00%)       19.19 (  -3.01%)
Stddev    32        38.71 (   0.00%)       38.30 (   1.06%)
Stddev    64       100.28 (   0.00%)       91.24 (   9.02%)
Stddev    128      186.87 (   0.00%)      160.34 (  14.20%)

Dbench has been modified to report the time to complete a single "load
file". This is a more meaningful metric for dbench that a throughput
metric as the benchmark makes many different system calls that are not
throughput-related

Patch shows a 9.23% and 48.53% reduction in the time to process a load
file with the difference partially explained by the number of CPUs sharing
a LLC. In a separate run, task migrations were almost eliminated by the
patch for low client counts. In case people have issue with the metric
used for the benchmark, this is a comparison of the throughputs as
reported by dbench on the NUMA machine.

dbench4 Throughput (misleading but traditional)
                           5.5.0-rc7              5.5.0-rc7
                   tipsched-20200124      kworkerstack-v1r2
Hmean     1        321.41 (   0.00%)      617.82 *  92.22%*
Hmean     2        622.87 (   0.00%)     1066.80 *  71.27%*
Hmean     4       1134.56 (   0.00%)     1623.74 *  43.12%*
Hmean     8       1869.96 (   0.00%)     2212.67 *  18.33%*
Hmean     16      2673.11 (   0.00%)     2806.13 *   4.98%*
Hmean     32      3032.74 (   0.00%)     3039.54 (   0.22%)
Hmean     64      2514.25 (   0.00%)     2498.96 *  -0.61%*
Hmean     128     1778.49 (   0.00%)     1746.05 *  -1.82%*

Note that this is somewhat specific to XFS and ext4 shows no performance
difference as it does not rely on kworkers in the same way. No major
problem was observed running other workloads on different machines although
not all tests have completed yet.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200128154006.GD3466@techsingularity.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-02-10 11:24:37 +01:00