1. 30 Nov, 2017 9 commits
    • Viresh Kumar's avatar
      cpufreq: schedutil: Reset cached_raw_freq when not in sync with next_freq · b7997494
      Viresh Kumar authored
      commit 07458f6a upstream.
      
      'cached_raw_freq' is used to get the next frequency quickly but should
      always be in sync with sg_policy->next_freq. There is a case 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 see the CPU wasn't idle recently and choose to keep the next
         freq as 1.2 GHz.
       - Now we have cached_raw_freq is 780 MHz and sg_policy->next_freq is
         1.2 GHz.
       - Now if the utilization doesn't change in then next request, then the
         next target frequency will still be 780 MHz and it will match with
         cached_raw_freq. But we will choose 1.2 GHz instead of 800 MHz here.
      
      Fixes: b7eaf1aa (cpufreq: schedutil: Avoid reducing frequency of busy CPUs prematurely)
      Signed-off-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
      Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b7997494
    • Lv Zheng's avatar
      ACPI / EC: Fix regression related to triggering source of EC event handling · 3fe36d0c
      Lv Zheng authored
      commit 53c5eaab upstream.
      
      Originally the Samsung quirks removed by commit 4c237371 can be covered
      by commit e923e8e7 and ec_freeze_events=Y mode. But commit 9c40f956
      changed ec_freeze_events=Y back to N, making this problem re-surface.
      
      Actually, if commit e923e8e7 is robust enough, we can freely change
      ec_freeze_events mode, so this patch fixes the issue by improving
      commit e923e8e7.
      
      Related commits listed in the merged order:
      
       Commit: e923e8e7
       Subject: ACPI / EC: Fix an issue that SCI_EVT cannot be detected
                after event is enabled
      
       Commit: 4c237371
       Subject: ACPI / EC: Remove old CLEAR_ON_RESUME quirk
      
       Commit: 9c40f956
       Subject: Revert "ACPI / EC: Enable event freeze mode..." to fix
                a regression
      
      This patch not only fixes the reported post-resume EC event triggering
      source issue, but also fixes an unreported similar issue related to the
      driver bind by adding EC event triggering source in ec_install_handlers().
      
      Fixes: e923e8e7 (ACPI / EC: Fix an issue that SCI_EVT cannot be detected after event is enabled)
      Fixes: 4c237371 (ACPI / EC: Remove old CLEAR_ON_RESUME quirk)
      Fixes: 9c40f956 (Revert "ACPI / EC: Enable event freeze mode..." to fix a regression)
      Link: https://bugzilla.kernel.org/show_bug.cgi?id=196833Signed-off-by: default avatarLv Zheng <lv.zheng@intel.com>
      Reported-by: default avatarAlistair Hamilton <ahpatent@gmail.com>
      Tested-by: default avatarAlistair Hamilton <ahpatent@gmail.com>
      Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      3fe36d0c
    • Ville Syrjälä's avatar
      ACPI / PM: Fix acpi_pm_notifier_lock vs flush_workqueue() deadlock · ef2b11c0
      Ville Syrjälä authored
      commit ff165679 upstream.
      
      acpi_remove_pm_notifier() ends up calling flush_workqueue() while
      holding acpi_pm_notifier_lock, and that same lock is taken by
      by the work via acpi_pm_notify_handler(). This can deadlock.
      
      To fix the problem let's split the single lock into two: one to
      protect the dev->wakeup between the work vs. add/remove, and
      another one to handle notifier installation vs. removal.
      
      After commit a1d14934 "workqueue/lockdep: 'Fix' flush_work()
      annotation" I was able to kill the machine (Intel Braswell)
      very easily with 'powertop --auto-tune', runtime suspending i915,
      and trying to wake it up via the USB keyboard. The cases when
      it didn't die are presumably explained by lockdep getting disabled
      by something else (cpu hotplug locking issues usually).
      
      Fortunately I still got a lockdep report over netconsole
      (trickling in very slowly), even though the machine was
      otherwise practically dead:
      
      [  112.179806] ======================================================
      [  114.670858] WARNING: possible circular locking dependency detected
      [  117.155663] 4.13.0-rc6-bsw-bisect-00169-ga1d14934 #119 Not tainted
      [  119.658101] ------------------------------------------------------
      [  121.310242] xhci_hcd 0000:00:14.0: xHCI host not responding to stop endpoint command.
      [  121.313294] xhci_hcd 0000:00:14.0: xHCI host controller not responding, assume dead
      [  121.313346] xhci_hcd 0000:00:14.0: HC died; cleaning up
      [  121.313485] usb 1-6: USB disconnect, device number 3
      [  121.313501] usb 1-6.2: USB disconnect, device number 4
      [  134.747383] kworker/0:2/47 is trying to acquire lock:
      [  137.220790]  (acpi_pm_notifier_lock){+.+.}, at: [<ffffffff813cafdf>] acpi_pm_notify_handler+0x2f/0x80
      [  139.721524]
      [  139.721524] but task is already holding lock:
      [  144.672922]  ((&dpc->work)){+.+.}, at: [<ffffffff8109ce90>] process_one_work+0x160/0x720
      [  147.184450]
      [  147.184450] which lock already depends on the new lock.
      [  147.184450]
      [  154.604711]
      [  154.604711] the existing dependency chain (in reverse order) is:
      [  159.447888]
      [  159.447888] -> #2 ((&dpc->work)){+.+.}:
      [  164.183486]        __lock_acquire+0x1255/0x13f0
      [  166.504313]        lock_acquire+0xb5/0x210
      [  168.778973]        process_one_work+0x1b9/0x720
      [  171.030316]        worker_thread+0x4c/0x440
      [  173.257184]        kthread+0x154/0x190
      [  175.456143]        ret_from_fork+0x27/0x40
      [  177.624348]
      [  177.624348] -> #1 ("kacpi_notify"){+.+.}:
      [  181.850351]        __lock_acquire+0x1255/0x13f0
      [  183.941695]        lock_acquire+0xb5/0x210
      [  186.046115]        flush_workqueue+0xdd/0x510
      [  190.408153]        acpi_os_wait_events_complete+0x31/0x40
      [  192.625303]        acpi_remove_notify_handler+0x133/0x188
      [  194.820829]        acpi_remove_pm_notifier+0x56/0x90
      [  196.989068]        acpi_dev_pm_detach+0x5f/0xa0
      [  199.145866]        dev_pm_domain_detach+0x27/0x30
      [  201.285614]        i2c_device_probe+0x100/0x210
      [  203.411118]        driver_probe_device+0x23e/0x310
      [  205.522425]        __driver_attach+0xa3/0xb0
      [  207.634268]        bus_for_each_dev+0x69/0xa0
      [  209.714797]        driver_attach+0x1e/0x20
      [  211.778258]        bus_add_driver+0x1bc/0x230
      [  213.837162]        driver_register+0x60/0xe0
      [  215.868162]        i2c_register_driver+0x42/0x70
      [  217.869551]        0xffffffffa0172017
      [  219.863009]        do_one_initcall+0x45/0x170
      [  221.843863]        do_init_module+0x5f/0x204
      [  223.817915]        load_module+0x225b/0x29b0
      [  225.757234]        SyS_finit_module+0xc6/0xd0
      [  227.661851]        do_syscall_64+0x5c/0x120
      [  229.536819]        return_from_SYSCALL_64+0x0/0x7a
      [  231.392444]
      [  231.392444] -> #0 (acpi_pm_notifier_lock){+.+.}:
      [  235.124914]        check_prev_add+0x44e/0x8a0
      [  237.024795]        __lock_acquire+0x1255/0x13f0
      [  238.937351]        lock_acquire+0xb5/0x210
      [  240.840799]        __mutex_lock+0x75/0x940
      [  242.709517]        mutex_lock_nested+0x1c/0x20
      [  244.551478]        acpi_pm_notify_handler+0x2f/0x80
      [  246.382052]        acpi_ev_notify_dispatch+0x44/0x5c
      [  248.194412]        acpi_os_execute_deferred+0x14/0x30
      [  250.003925]        process_one_work+0x1ec/0x720
      [  251.803191]        worker_thread+0x4c/0x440
      [  253.605307]        kthread+0x154/0x190
      [  255.387498]        ret_from_fork+0x27/0x40
      [  257.153175]
      [  257.153175] other info that might help us debug this:
      [  257.153175]
      [  262.324392] Chain exists of:
      [  262.324392]   acpi_pm_notifier_lock --> "kacpi_notify" --> (&dpc->work)
      [  262.324392]
      [  267.391997]  Possible unsafe locking scenario:
      [  267.391997]
      [  270.758262]        CPU0                    CPU1
      [  272.431713]        ----                    ----
      [  274.060756]   lock((&dpc->work));
      [  275.646532]                                lock("kacpi_notify");
      [  277.260772]                                lock((&dpc->work));
      [  278.839146]   lock(acpi_pm_notifier_lock);
      [  280.391902]
      [  280.391902]  *** DEADLOCK ***
      [  280.391902]
      [  284.986385] 2 locks held by kworker/0:2/47:
      [  286.524895]  #0:  ("kacpi_notify"){+.+.}, at: [<ffffffff8109ce90>] process_one_work+0x160/0x720
      [  288.112927]  #1:  ((&dpc->work)){+.+.}, at: [<ffffffff8109ce90>] process_one_work+0x160/0x720
      [  289.727725]
      
      Fixes: c072530f (ACPI / PM: Revork the handling of ACPI device wakeup notifications)
      Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
      Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      ef2b11c0
    • Vasily Gorbik's avatar
      s390/disassembler: increase show_code buffer size · 60479800
      Vasily Gorbik authored
      commit b192571d upstream.
      
      Current buffer size of 64 is too small. objdump shows that there are
      instructions which would require up to 75 bytes buffer (with current
      formating). 128 bytes "ought to be enough for anybody".
      
      Also replaces 8 spaces with a single tab to reduce the memory footprint.
      
      Fixes the following KASAN finding:
      
      BUG: KASAN: stack-out-of-bounds in number+0x3fe/0x538
      Write of size 1 at addr 000000005a4a75a0 by task bash/1282
      
      CPU: 1 PID: 1282 Comm: bash Not tainted 4.14.0+ #215
      Hardware name: IBM 2964 N96 702 (z/VM 6.4.0)
      Call Trace:
      ([<000000000011eeb6>] show_stack+0x56/0x88)
       [<0000000000e1ce1a>] dump_stack+0x15a/0x1b0
       [<00000000004e2994>] print_address_description+0xf4/0x288
       [<00000000004e2cf2>] kasan_report+0x13a/0x230
       [<0000000000e38ae6>] number+0x3fe/0x538
       [<0000000000e3dfe4>] vsnprintf+0x194/0x948
       [<0000000000e3ea42>] sprintf+0xa2/0xb8
       [<00000000001198dc>] print_insn+0x374/0x500
       [<0000000000119346>] show_code+0x4ee/0x538
       [<000000000011f234>] show_registers+0x34c/0x388
       [<000000000011f2ae>] show_regs+0x3e/0xa8
       [<000000000011f502>] die+0x1ea/0x2e8
       [<0000000000138f0e>] do_no_context+0x106/0x168
       [<0000000000139a1a>] do_protection_exception+0x4da/0x7d0
       [<0000000000e55914>] pgm_check_handler+0x16c/0x1c0
       [<000000000090639e>] sysrq_handle_crash+0x46/0x58
      ([<0000000000000007>] 0x7)
       [<00000000009073fa>] __handle_sysrq+0x102/0x218
       [<0000000000907c06>] write_sysrq_trigger+0xd6/0x100
       [<000000000061d67a>] proc_reg_write+0xb2/0x128
       [<0000000000520be6>] __vfs_write+0xee/0x368
       [<0000000000521222>] vfs_write+0x21a/0x278
       [<000000000052156a>] SyS_write+0xda/0x178
       [<0000000000e555cc>] system_call+0xc4/0x270
      
      The buggy address belongs to the page:
      page:000003d1016929c0 count:0 mapcount:0 mapping:          (null) index:0x0
      flags: 0x0()
      raw: 0000000000000000 0000000000000000 0000000000000000 ffffffff00000000
      raw: 0000000000000100 0000000000000200 0000000000000000 0000000000000000
      page dumped because: kasan: bad access detected
      
      Memory state around the buggy address:
       000000005a4a7480: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
       000000005a4a7500: 00 00 00 00 00 00 00 00 f2 f2 f2 f2 00 00 00 00
      >000000005a4a7580: 00 00 00 00 f3 f3 f3 f3 00 00 00 00 00 00 00 00
                                     ^
       000000005a4a7600: 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1 f8 f8
       000000005a4a7680: f2 f2 f2 f2 f2 f2 f8 f8 f2 f2 f3 f3 f3 f3 00 00
      ==================================================================
      Signed-off-by: default avatarVasily Gorbik <gor@linux.vnet.ibm.com>
      Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      60479800
    • Heiko Carstens's avatar
      s390/disassembler: add missing end marker for e7 table · 15e82cdb
      Heiko Carstens authored
      commit 5c505387 upstream.
      
      The e7 opcode table does not have an end marker. Hence when trying to
      find an unknown e7 instruction the code will access memory behind the
      table until it finds something that matches the opcode, or the kernel
      crashes, whatever comes first.
      
      This affects not only the in-kernel disassembler but also uprobes and
      kprobes which refuse to set a probe on unknown instructions, and
      therefore search the opcode tables to figure out if instructions are
      known or not.
      
      Fixes: 3585cb02 ("s390/disassembler: add vector instructions")
      Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
      Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      15e82cdb
    • Heiko Carstens's avatar
      s390/guarded storage: fix possible memory corruption · 7ee3f026
      Heiko Carstens authored
      commit fa1edf3f upstream.
      
      For PREEMPT enabled kernels the guarded storage (GS) code contains a
      possible use-after-free bug. If a task that makes use of GS exits, it
      will execute do_exit() while still enabled for preemption.
      
      That function will call exit_thread_runtime_instr() via exit_thread().
      If exit_thread_gs() gets preempted after the GS control block of the
      task has been freed but before the pointer to it is set to NULL, then
      save_gs_cb(), called from switch_to(), will write to already freed
      memory.
      
      Avoid this and simply disable preemption while freeing the control
      block and setting the pointer to NULL.
      
      Fixes: 916cda1a ("s390: add a system call for guarded storage")
      Reviewed-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
      Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
      Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      7ee3f026
    • Heiko Carstens's avatar
      s390/runtime instrumention: fix possible memory corruption · 27576413
      Heiko Carstens authored
      commit d6e646ad upstream.
      
      For PREEMPT enabled kernels the runtime instrumentation (RI) code
      contains a possible use-after-free bug. If a task that makes use of RI
      exits, it will execute do_exit() while still enabled for preemption.
      
      That function will call exit_thread_runtime_instr() via
      exit_thread(). If exit_thread_runtime_instr() gets preempted after the
      RI control block of the task has been freed but before the pointer to
      it is set to NULL, then save_ri_cb(), called from switch_to(), will
      write to already freed memory.
      
      Avoid this and simply disable preemption while freeing the control
      block and setting the pointer to NULL.
      
      Fixes: e4b8b3f3 ("s390: add support for runtime instrumentation")
      Reviewed-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
      Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
      Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      27576413
    • Heiko Carstens's avatar
      s390/noexec: execute kexec datamover without DAT · 21caac65
      Heiko Carstens authored
      commit d0e810ee upstream.
      
      Rebooting into a new kernel with kexec fails (system dies) if tried on
      a machine that has no-execute support. Reason for this is that the so
      called datamover code gets executed with DAT on (MMU is active) and
      the page that contains the datamover is marked as non-executable.
      Therefore when branching into the datamover an unexpected program
      check happens and afterwards the machine is dead.
      
      This can be simply avoided by disabling DAT, which also disables any
      no-execute checks, just before the datamover gets executed.
      
      In fact the first thing done by the datamover is to disable DAT. The
      code in the datamover that disables DAT can be removed as well.
      
      Thanks to Michael Holzheu and Gerald Schaefer for tracking this down.
      Reviewed-by: default avatarMichael Holzheu <holzheu@linux.vnet.ibm.com>
      Reviewed-by: default avatarPhilipp Rudo <prudo@linux.vnet.ibm.com>
      Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Fixes: 57d7f939 ("s390: add no-execute support")
      Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      21caac65
    • Heiko Carstens's avatar
      s390: fix transactional execution control register handling · 236f6e72
      Heiko Carstens authored
      commit a1c5befc upstream.
      
      Dan Horák reported the following crash related to transactional execution:
      
      User process fault: interruption code 0013 ilc:3 in libpthread-2.26.so[3ff93c00000+1b000]
      CPU: 2 PID: 1 Comm: /init Not tainted 4.13.4-300.fc27.s390x #1
      Hardware name: IBM 2827 H43 400 (z/VM 6.4.0)
      task: 00000000fafc8000 task.stack: 00000000fafc4000
      User PSW : 0705200180000000 000003ff93c14e70
                 R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:1 AS:0 CC:2 PM:0 RI:0 EA:3
      User GPRS: 0000000000000077 000003ff00000000 000003ff93144d48 000003ff93144d5e
                 0000000000000000 0000000000000002 0000000000000000 000003ff00000000
                 0000000000000000 0000000000000418 0000000000000000 000003ffcc9fe770
                 000003ff93d28f50 000003ff9310acf0 000003ff92b0319a 000003ffcc9fe6d0
      User Code: 000003ff93c14e62: 60e0b030            std     %f14,48(%r11)
                 000003ff93c14e66: 60f0b038            std     %f15,56(%r11)
                #000003ff93c14e6a: e5600000ff0e        tbegin  0,65294
                >000003ff93c14e70: a7740006            brc     7,3ff93c14e7c
                 000003ff93c14e74: a7080000            lhi     %r0,0
                 000003ff93c14e78: a7f40023            brc     15,3ff93c14ebe
                 000003ff93c14e7c: b2220000            ipm     %r0
                 000003ff93c14e80: 8800001c            srl     %r0,28
      
      There are several bugs with control register handling with respect to
      transactional execution:
      
      - on task switch update_per_regs() is only called if the next task has
        an mm (is not a kernel thread). This however is incorrect. This
        breaks e.g. for user mode helper handling, where the kernel creates
        a kernel thread and then execve's a user space program. Control
        register contents related to transactional execution won't be
        updated on execve. If the previous task ran with transactional
        execution disabled then the new task will also run with
        transactional execution disabled, which is incorrect. Therefore call
        update_per_regs() unconditionally within switch_to().
      
      - on startup the transactional execution facility is not enabled for
        the idle thread. This is not really a bug, but an inconsistency to
        other facilities. Therefore enable the facility if it is available.
      
      - on fork the new thread's per_flags field is not cleared. This means
        that a child process inherits the PER_FLAG_NO_TE flag. This flag can
        be set with a ptrace request to disable transactional execution for
        the current process. It should not be inherited by new child
        processes in order to be consistent with the handling of all other
        PER related debugging options. Therefore clear the per_flags field in
        copy_thread_tls().
      Reported-and-tested-by: default avatarDan Horák <dan@danny.cz>
      Fixes: d35339a4 ("s390: add support for transactional memory")
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Reviewed-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
      Reviewed-by: default avatarHendrik Brueckner <brueckner@linux.vnet.ibm.com>
      Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      236f6e72
  2. 24 Nov, 2017 20 commits
  3. 21 Nov, 2017 11 commits