• Rafael J. Wysocki's avatar
    cpufreq: pcc-cpufreq: Fix wait_event() under spinlock · e65b5ddb
    Rafael J. Wysocki authored
    Fix the following bug introduced by commit 8fec051e (cpufreq:
    Convert existing drivers to use cpufreq_freq_transition_{begin|end})
    that forgot to move the spin_lock() in pcc_cpufreq_target() past
    cpufreq_freq_transition_begin() which calls wait_event():
    
    BUG: sleeping function called from invalid context at drivers/cpufreq/cpufreq.c:370
    in_atomic(): 1, irqs_disabled(): 0, pid: 2636, name: modprobe
    Preemption disabled at:[<ffffffffa04d74d7>] pcc_cpufreq_target+0x27/0x200 [pcc_cpufreq]
    [   51.025044]
    CPU: 57 PID: 2636 Comm: modprobe Tainted: G            E  3.17.0-default #7
    Hardware name: Hewlett-Packard ProLiant DL980 G7, BIOS P66 07/07/2010
     00000000ffffffff ffff88026c46b828 ffffffff81589dbd 0000000000000000
     ffff880037978090 ffff88026c46b848 ffffffff8108e1df ffff880037978090
     0000000000000000 ffff88026c46b878 ffffffff8108e298 ffff88026d73ec00
    Call Trace:
     [<ffffffff81589dbd>] dump_stack+0x4d/0x90
     [<ffffffff8108e1df>] ___might_sleep+0x10f/0x180
     [<ffffffff8108e298>] __might_sleep+0x48/0xd0
     [<ffffffff8145b905>] cpufreq_freq_transition_begin+0x75/0x140 drivers/cpufreq/cpufreq.c:370 wait_event(policy->transition_wait, !policy->transition_ongoing);
     [<ffffffff8108fc99>] ? preempt_count_add+0xb9/0xc0
     [<ffffffffa04d7513>] pcc_cpufreq_target+0x63/0x200 [pcc_cpufreq] drivers/cpufreq/pcc-cpufreq.c:207 spin_lock(&pcc_lock);
     [<ffffffff810e0d0f>] ? update_ts_time_stats+0x7f/0xb0
     [<ffffffff8145be55>] __cpufreq_driver_target+0x85/0x170
     [<ffffffff8145e4c8>] od_check_cpu+0xa8/0xb0
     [<ffffffff8145ef10>] dbs_check_cpu+0x180/0x1d0
     [<ffffffff8145f310>] cpufreq_governor_dbs+0x3b0/0x720
     [<ffffffff8145ebe3>] od_cpufreq_governor_dbs+0x33/0xe0
     [<ffffffff814593d9>] __cpufreq_governor+0xa9/0x210
     [<ffffffff81459fb2>] cpufreq_set_policy+0x1e2/0x2e0
     [<ffffffff8145a6cc>] cpufreq_init_policy+0x8c/0x110
     [<ffffffff8145c9a0>] ? cpufreq_update_policy+0x1b0/0x1b0
     [<ffffffff8108fb99>] ? preempt_count_sub+0xb9/0x100
     [<ffffffff8145c6c6>] __cpufreq_add_dev+0x596/0x6b0
     [<ffffffffa016c608>] ? pcc_cpufreq_probe+0x4b4/0x4b4 [pcc_cpufreq]
     [<ffffffff8145c7ee>] cpufreq_add_dev+0xe/0x10
     [<ffffffff81408e81>] subsys_interface_register+0xc1/0xf0
     [<ffffffff8108fb99>] ? preempt_count_sub+0xb9/0x100
     [<ffffffff8145b3d7>] cpufreq_register_driver+0x117/0x2a0
     [<ffffffffa016c65d>] pcc_cpufreq_init+0x55/0x9f8 [pcc_cpufreq]
     [<ffffffffa016c608>] ? pcc_cpufreq_probe+0x4b4/0x4b4 [pcc_cpufreq]
     [<ffffffff81000298>] do_one_initcall+0xc8/0x1f0
     [<ffffffff811a731d>] ? __vunmap+0x9d/0x100
     [<ffffffff810eb9a0>] do_init_module+0x30/0x1b0
     [<ffffffff810edfa6>] load_module+0x686/0x710
     [<ffffffff810ebb20>] ? do_init_module+0x1b0/0x1b0
     [<ffffffff810ee1db>] SyS_init_module+0x9b/0xc0
     [<ffffffff8158f7a9>] system_call_fastpath+0x16/0x1b
    
    Fixes: 8fec051e (cpufreq: Convert existing drivers to use cpufreq_freq_transition_{begin|end})
    Reported-and-tested-by: default avatarMike Galbraith <umgwanakikbuti@gmail.com>
    Cc: 3.15+ <stable@vger.kernel.org> # 3.15+
    Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
    e65b5ddb
pcc-cpufreq.c 15.1 KB