| Message ID | 52F74EF8.9050407@redhat.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
On 02/09/2014 01:48 AM, Maurizio Lombardi wrote: > There is a race condition in the intel pstate driver initialization: > the cpufreq_register_driver() function creates a timer that makes use of the > energy_divisor variable (intel_pstate_timer_func), the problem is that energy_divisor is initialized > *after* the call to cpufreq_register_driver(). > > This patch fixes the bug by initializing energy_divisor before the > call to cpufreq_register_driver(). > > > [ 2.351047] Intel pstate controlling: cpu 2 > [ 2.355271] divide error: 0000 [#1] SMP > [ 2.359222] Modules linked in: > [ 2.362291] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.14.0-rc1-linux-mainline+ #7 > [ 2.369933] Hardware name: wortmann To be filled by O.E.M./P8B-M Series, BIOS 6103 12/06/2012 > [ 2.378441] task: ffff880223948000 ti: ffff880223944000 task.ti: ffff880223944000 > [ 2.385912] RIP: 0010:[<ffffffff81548b07>] [<ffffffff81548b07>] intel_pstate_timer_func+0x2b7/0x430 > [ 2.395060] RSP: 0000:ffff880226e03d58 EFLAGS: 00010246 > [ 2.400363] RAX: 0000000006130063 RBX: ffff88022191b800 RCX: 0000000000000199 > [ 2.407486] RDX: 0000000000000000 RSI: 0000000000002000 RDI: 0000000000000199 > [ 2.414608] RBP: ffff880226e03dd8 R08: ffff88022191b850 R09: ffff880223948cc8 > [ 2.421731] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000002 > [ 2.428854] R13: 0000000006130063 R14: 0000003b3a91a54e R15: ffff880226e03da4 > [ 2.435984] FS: 0000000000000000(0000) GS:ffff880226e00000(0000) knlGS:0000000000000000 > [ 2.444060] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 2.449794] CR2: ffff88022ffff000 CR3: 0000000001a0e000 CR4: 00000000000407f0 > [ 2.456917] Stack: > [ 2.458927] ffff880226e03dd8 0000000000000246 0000000000000000 ffffffff8108a0c0 > [ 2.466380] 0000000000000000 ffffffff82dc18d0 ffff880226e03d98 0000000000000246 > [ 2.473832] 0000000026e03da8 0000000026e03e08 0000000000000038 ffff88022191b848 > [ 2.481281] Call Trace: > [ 2.483725] <IRQ> > [ 2.485651] [<ffffffff8108a0c0>] ? cascade+0xb0/0xb0 > [ 2.490912] [<ffffffff81548850>] ? intel_pstate_platform_pwr_mgmt_exists+0x1e0/0x1e0 > [ 2.498736] [<ffffffff8108a158>] call_timer_fn+0x98/0x260 > [ 2.504218] [<ffffffff8108a0c0>] ? cascade+0xb0/0xb0 > [ 2.509263] [<ffffffff816de600>] ? _raw_spin_unlock_irq+0x30/0x50 > [ 2.515439] [<ffffffff8108bc78>] run_timer_softirq+0x298/0x310 > [ 2.521351] [<ffffffff81100eef>] ? rcu_irq_exit+0x8f/0xe0 > [ 2.526833] [<ffffffff816debf3>] ? retint_restore_args+0x13/0x13 > [ 2.532919] [<ffffffff81548850>] ? intel_pstate_platform_pwr_mgmt_exists+0x1e0/0x1e0 > [ 2.540741] [<ffffffff81082584>] __do_softirq+0x144/0x4f0 > [ 2.546217] [<ffffffff81082ebd>] irq_exit+0x14d/0x180 > [ 2.551346] [<ffffffff816eb2da>] smp_apic_timer_interrupt+0x4a/0x60 > [ 2.557688] [<ffffffff816e9bf2>] apic_timer_interrupt+0x72/0x80 > [ 2.563685] <EOI> > [ 2.565608] [<ffffffff810e2ff0>] ? mark_held_locks+0x90/0x150 > [ 2.571639] [<ffffffff810f5070>] ? vprintk_emit+0x1c0/0x610 > [ 2.577299] [<ffffffff816de660>] ? _raw_spin_unlock_irqrestore+0x40/0x80 > [ 2.584083] [<ffffffff816d74ea>] printk+0x77/0x79 > [ 2.588873] [<ffffffff815479bc>] ? core_get_turbo_pstate+0x3c/0x60 > [ 2.595139] [<ffffffff815481a5>] intel_pstate_init_cpu+0x395/0x3a0 > [ 2.601404] [<ffffffff815481cb>] intel_pstate_cpu_init+0x1b/0x100 > [ 2.607580] [<ffffffff81543933>] __cpufreq_add_dev+0x213/0x780 > [ 2.613491] [<ffffffff816cd6fe>] ? klist_next+0x8e/0x120 > [ 2.618887] [<ffffffff81543eb0>] cpufreq_add_dev+0x10/0x20 > [ 2.624451] [<ffffffff8145d921>] subsys_interface_register+0xb1/0xe0 > [ 2.630880] [<ffffffff810e345d>] ? trace_hardirqs_on+0xd/0x10 > [ 2.636711] [<ffffffff81541a1e>] cpufreq_register_driver+0xfe/0x2a0 > [ 2.643055] [<ffffffff81ddd383>] intel_pstate_init+0x14a/0x310 > [ 2.648972] [<ffffffff816d9cbe>] ? mutex_unlock+0xe/0x10 > [ 2.654361] [<ffffffff81ddd239>] ? intel_pstate_setup+0x2e/0x2e > [ 2.660357] [<ffffffff810020da>] do_one_initcall+0xda/0x180 > [ 2.666008] [<ffffffff81d8ed9b>] ? kernel_init_freeable+0x31a/0x31a > [ 2.672357] [<ffffffff81d8ea5e>] do_basic_setup+0x9d/0xc0 > [ 2.677833] [<ffffffff81d8ed9b>] ? kernel_init_freeable+0x31a/0x31a > [ 2.684176] [<ffffffff81d8ed18>] kernel_init_freeable+0x297/0x31a > [ 2.690345] [<ffffffff816cddce>] ? kernel_init+0xe/0xf0 > [ 2.695648] [<ffffffff810e3385>] ? trace_hardirqs_on_caller+0x105/0x1d0 > [ 2.702339] [<ffffffff816cddc0>] ? rest_init+0x170/0x170 > [ 2.707734] [<ffffffff816cddce>] kernel_init+0xe/0xf0 > [ 2.712866] [<ffffffff816e8e3c>] ret_from_fork+0x7c/0xb0 > [ 2.718262] [<ffffffff816cddc0>] ? rest_init+0x170/0x170 > [ 2.723651] Code: c8 00 00 00 48 89 df 01 d6 e8 b6 f1 ff ff eb 0e 0f 1f 40 00 29 d6 48 89 df e8 a6 f1 ff ff 4b 8d 04 a4 31 d2 4c 8d 04 c3 4c 89 e8 <48> f7 35 fa 8d 9b 01 45 8b b8 40 01 00 00 41 89 c1 49 8b 80 28 > [ 2.743596] RIP [<ffffffff81548b07>] intel_pstate_timer_func+0x2b7/0x430 > [ 2.750390] RSP <ffff880226e03d58> > [ 2.751934] tsc: Refined TSC clocksource calibration: 3092.975 MHz > [ 2.760048] divide error: 0000 [#2] [ 2.760064] ---[ end trace b87c91b37801378a ]--- > [ 2.761931] Kernel panic - not syncing: Fatal exception in interrupt > > Signed-off-by: Maurizio Lombardi <mlombard@redhat.com> Acked-by: Dirk Brandewie <dirk.j.brandewie@intel.com> > --- > drivers/cpufreq/intel_pstate.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c > index 79606f4..bc04e73 100644 > --- a/drivers/cpufreq/intel_pstate.c > +++ b/drivers/cpufreq/intel_pstate.c > @@ -956,13 +956,13 @@ static int __init intel_pstate_init(void) > if (!all_cpu_data) > return -ENOMEM; > > + rdmsrl(MSR_RAPL_POWER_UNIT, units); > + energy_divisor = 1 << ((units >> 8) & 0x1f); /* bits{12:8} */ > + > rc = cpufreq_register_driver(&intel_pstate_driver); > if (rc) > goto out; > > - rdmsrl(MSR_RAPL_POWER_UNIT, units); > - energy_divisor = 1 << ((units >> 8) & 0x1f); /* bits{12:8} */ > - > intel_pstate_debug_expose_params(); > intel_pstate_sysfs_expose_params(); > -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index 79606f4..bc04e73 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -956,13 +956,13 @@ static int __init intel_pstate_init(void) if (!all_cpu_data) return -ENOMEM; + rdmsrl(MSR_RAPL_POWER_UNIT, units); + energy_divisor = 1 << ((units >> 8) & 0x1f); /* bits{12:8} */ + rc = cpufreq_register_driver(&intel_pstate_driver); if (rc) goto out; - rdmsrl(MSR_RAPL_POWER_UNIT, units); - energy_divisor = 1 << ((units >> 8) & 0x1f); /* bits{12:8} */ - intel_pstate_debug_expose_params(); intel_pstate_sysfs_expose_params();
There is a race condition in the intel pstate driver initialization: the cpufreq_register_driver() function creates a timer that makes use of the energy_divisor variable (intel_pstate_timer_func), the problem is that energy_divisor is initialized *after* the call to cpufreq_register_driver(). This patch fixes the bug by initializing energy_divisor before the call to cpufreq_register_driver(). [ 2.351047] Intel pstate controlling: cpu 2 [ 2.355271] divide error: 0000 [#1] SMP [ 2.359222] Modules linked in: [ 2.362291] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.14.0-rc1-linux-mainline+ #7 [ 2.369933] Hardware name: wortmann To be filled by O.E.M./P8B-M Series, BIOS 6103 12/06/2012 [ 2.378441] task: ffff880223948000 ti: ffff880223944000 task.ti: ffff880223944000 [ 2.385912] RIP: 0010:[<ffffffff81548b07>] [<ffffffff81548b07>] intel_pstate_timer_func+0x2b7/0x430 [ 2.395060] RSP: 0000:ffff880226e03d58 EFLAGS: 00010246 [ 2.400363] RAX: 0000000006130063 RBX: ffff88022191b800 RCX: 0000000000000199 [ 2.407486] RDX: 0000000000000000 RSI: 0000000000002000 RDI: 0000000000000199 [ 2.414608] RBP: ffff880226e03dd8 R08: ffff88022191b850 R09: ffff880223948cc8 [ 2.421731] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000002 [ 2.428854] R13: 0000000006130063 R14: 0000003b3a91a54e R15: ffff880226e03da4 [ 2.435984] FS: 0000000000000000(0000) GS:ffff880226e00000(0000) knlGS:0000000000000000 [ 2.444060] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 2.449794] CR2: ffff88022ffff000 CR3: 0000000001a0e000 CR4: 00000000000407f0 [ 2.456917] Stack: [ 2.458927] ffff880226e03dd8 0000000000000246 0000000000000000 ffffffff8108a0c0 [ 2.466380] 0000000000000000 ffffffff82dc18d0 ffff880226e03d98 0000000000000246 [ 2.473832] 0000000026e03da8 0000000026e03e08 0000000000000038 ffff88022191b848 [ 2.481281] Call Trace: [ 2.483725] <IRQ> [ 2.485651] [<ffffffff8108a0c0>] ? cascade+0xb0/0xb0 [ 2.490912] [<ffffffff81548850>] ? intel_pstate_platform_pwr_mgmt_exists+0x1e0/0x1e0 [ 2.498736] [<ffffffff8108a158>] call_timer_fn+0x98/0x260 [ 2.504218] [<ffffffff8108a0c0>] ? cascade+0xb0/0xb0 [ 2.509263] [<ffffffff816de600>] ? _raw_spin_unlock_irq+0x30/0x50 [ 2.515439] [<ffffffff8108bc78>] run_timer_softirq+0x298/0x310 [ 2.521351] [<ffffffff81100eef>] ? rcu_irq_exit+0x8f/0xe0 [ 2.526833] [<ffffffff816debf3>] ? retint_restore_args+0x13/0x13 [ 2.532919] [<ffffffff81548850>] ? intel_pstate_platform_pwr_mgmt_exists+0x1e0/0x1e0 [ 2.540741] [<ffffffff81082584>] __do_softirq+0x144/0x4f0 [ 2.546217] [<ffffffff81082ebd>] irq_exit+0x14d/0x180 [ 2.551346] [<ffffffff816eb2da>] smp_apic_timer_interrupt+0x4a/0x60 [ 2.557688] [<ffffffff816e9bf2>] apic_timer_interrupt+0x72/0x80 [ 2.563685] <EOI> [ 2.565608] [<ffffffff810e2ff0>] ? mark_held_locks+0x90/0x150 [ 2.571639] [<ffffffff810f5070>] ? vprintk_emit+0x1c0/0x610 [ 2.577299] [<ffffffff816de660>] ? _raw_spin_unlock_irqrestore+0x40/0x80 [ 2.584083] [<ffffffff816d74ea>] printk+0x77/0x79 [ 2.588873] [<ffffffff815479bc>] ? core_get_turbo_pstate+0x3c/0x60 [ 2.595139] [<ffffffff815481a5>] intel_pstate_init_cpu+0x395/0x3a0 [ 2.601404] [<ffffffff815481cb>] intel_pstate_cpu_init+0x1b/0x100 [ 2.607580] [<ffffffff81543933>] __cpufreq_add_dev+0x213/0x780 [ 2.613491] [<ffffffff816cd6fe>] ? klist_next+0x8e/0x120 [ 2.618887] [<ffffffff81543eb0>] cpufreq_add_dev+0x10/0x20 [ 2.624451] [<ffffffff8145d921>] subsys_interface_register+0xb1/0xe0 [ 2.630880] [<ffffffff810e345d>] ? trace_hardirqs_on+0xd/0x10 [ 2.636711] [<ffffffff81541a1e>] cpufreq_register_driver+0xfe/0x2a0 [ 2.643055] [<ffffffff81ddd383>] intel_pstate_init+0x14a/0x310 [ 2.648972] [<ffffffff816d9cbe>] ? mutex_unlock+0xe/0x10 [ 2.654361] [<ffffffff81ddd239>] ? intel_pstate_setup+0x2e/0x2e [ 2.660357] [<ffffffff810020da>] do_one_initcall+0xda/0x180 [ 2.666008] [<ffffffff81d8ed9b>] ? kernel_init_freeable+0x31a/0x31a [ 2.672357] [<ffffffff81d8ea5e>] do_basic_setup+0x9d/0xc0 [ 2.677833] [<ffffffff81d8ed9b>] ? kernel_init_freeable+0x31a/0x31a [ 2.684176] [<ffffffff81d8ed18>] kernel_init_freeable+0x297/0x31a [ 2.690345] [<ffffffff816cddce>] ? kernel_init+0xe/0xf0 [ 2.695648] [<ffffffff810e3385>] ? trace_hardirqs_on_caller+0x105/0x1d0 [ 2.702339] [<ffffffff816cddc0>] ? rest_init+0x170/0x170 [ 2.707734] [<ffffffff816cddce>] kernel_init+0xe/0xf0 [ 2.712866] [<ffffffff816e8e3c>] ret_from_fork+0x7c/0xb0 [ 2.718262] [<ffffffff816cddc0>] ? rest_init+0x170/0x170 [ 2.723651] Code: c8 00 00 00 48 89 df 01 d6 e8 b6 f1 ff ff eb 0e 0f 1f 40 00 29 d6 48 89 df e8 a6 f1 ff ff 4b 8d 04 a4 31 d2 4c 8d 04 c3 4c 89 e8 <48> f7 35 fa 8d 9b 01 45 8b b8 40 01 00 00 41 89 c1 49 8b 80 28 [ 2.743596] RIP [<ffffffff81548b07>] intel_pstate_timer_func+0x2b7/0x430 [ 2.750390] RSP <ffff880226e03d58> [ 2.751934] tsc: Refined TSC clocksource calibration: 3092.975 MHz [ 2.760048] divide error: 0000 [#2] [ 2.760064] ---[ end trace b87c91b37801378a ]--- [ 2.761931] Kernel panic - not syncing: Fatal exception in interrupt Signed-off-by: Maurizio Lombardi <mlombard@redhat.com> --- drivers/cpufreq/intel_pstate.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)