From 093f13e23137b9e5f7629dd5932ceea1419e2b61 Mon Sep 17 00:00:00 2001 From: "Pallipadi, Venkatesh" Date: Wed, 15 Apr 2009 10:37:33 -0700 Subject: [PATCH 1/4] x86, acpi_cpufreq: Fix the NULL pointer dereference in get_measured_perf Fix for a regression that was introduced by earlier commit 18b2646fe3babeb40b34a0c1751e0bf5adfdc64c on Mon Apr 6 11:26:08 2009 Regression resulted in the below error happened on systems with software coordination where per_cpu acpi data will not be initiated for secondary CPUs in a P-state domain. On Tue, 2009-04-14 at 23:01 -0700, Zhang, Yanmin wrote: My machine hanged with kernel 2.6.30-rc2 when script read > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor. > > opps happens in get_measured_perf: > > cur.aperf.whole = readin.aperf.whole - > per_cpu(drv_data, cpu)->saved_aperf; > > Because per_cpu(drv_data, cpu)=NULL. > > So function get_measured_perf should check if (per_cpu(drv_data, > cpu)==NULL) > and return 0 if it's NULL. --------------sys log------------------ BUG: unable to handle kernel NULL pointer dereference at 0000000000000020 IP: [] get_measured_perf+0x4a/0xf9 PGD a7dd88067 PUD a7ccf5067 PMD 0 Oops: 0000 [#1] SMP last sysfs file: /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor CPU 0 Modules linked in: video output Pid: 2091, comm: kondemand/0 Not tainted 2.6.30-rc2 #1 MP Server RIP: 0010:[] [] get_measured_perf+0x4a/0xf9 RSP: 0018:ffff880a7d56de20 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 00000046241a42b6 RCX: ffff88004d219000 RDX: 000000000000b660 RSI: 0000000000000020 RDI: 0000000000000001 RBP: ffff880a7f052000 R08: 00000046241a42b6 R09: ffffffff807639f0 R10: 00000000ffffffea R11: ffffffff802207f4 R12: ffff880a7f052000 R13: ffff88004d20e460 R14: 0000000000ddd5a6 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff88004d200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b CR2: 0000000000000020 CR3: 0000000a7f1bf000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process kondemand/0 (pid: 2091, threadinfo ffff880a7d56c000, task ffff880a7d4d18c0) Stack: ffff880a7f052078 ffffffff803efd54 00000046241a42b6 000000462ffa9e95 0000000000000001 0000000000000001 00000000ffffffea ffffffff8064f41a 0000000000000012 0000000000000012 ffff880a7f052000 ffffffff80650547 Call Trace: [] ? kobject_get+0x12/0x17 [] ? __cpufreq_driver_getavg+0x42/0x57 [] ? do_dbs_timer+0x147/0x272 [] ? do_dbs_timer+0x0/0x272 [] ? worker_thread+0x15b/0x1f5 [] ? autoremove_wake_function+0x0/0x2e [] ? worker_thread+0x0/0x1f5 [] ? kthread+0x54/0x83 [] ? child_rip+0xa/0x20 [] ? kthread+0x0/0x83 [] ? child_rip+0x0/0x20 Code: 99 a6 03 00 31 c9 85 c0 0f 85 c3 00 00 00 89 df 4c 8b 44 24 10 48 c7 c2 60 b6 00 00 48 8b 0c fd e0 30 a5 80 4c 89 c3 48 8b 04 0a <48> 2b 58 20 48 8b 44 24 18 48 89 1c 24 48 8b 34 0a 48 2b 46 28 RIP [] get_measured_perf+0x4a/0xf9 RSP CR2: 0000000000000020 ---[ end trace 2b8fac9a49e19ad4 ]--- Tested-by: "Zhang, Yanmin" Signed-off-by: Venkatesh Pallipadi Signed-off-by: Len Brown --- arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c index ecdb682ab516..dd0bd76d14c0 100644 --- a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c +++ b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c @@ -68,11 +68,16 @@ struct acpi_cpufreq_data { unsigned int max_freq; unsigned int resume; unsigned int cpu_feature; - u64 saved_aperf, saved_mperf; }; static DEFINE_PER_CPU(struct acpi_cpufreq_data *, drv_data); +struct acpi_msr_data { + u64 saved_aperf, saved_mperf; +}; + +static DEFINE_PER_CPU(struct acpi_msr_data, msr_data); + DEFINE_TRACE(power_mark); /* acpi_perf_data is a pointer to percpu data. */ @@ -287,11 +292,11 @@ static unsigned int get_measured_perf(struct cpufreq_policy *policy, return 0; cur.aperf.whole = readin.aperf.whole - - per_cpu(drv_data, cpu)->saved_aperf; + per_cpu(msr_data, cpu).saved_aperf; cur.mperf.whole = readin.mperf.whole - - per_cpu(drv_data, cpu)->saved_mperf; - per_cpu(drv_data, cpu)->saved_aperf = readin.aperf.whole; - per_cpu(drv_data, cpu)->saved_mperf = readin.mperf.whole; + per_cpu(msr_data, cpu).saved_mperf; + per_cpu(msr_data, cpu).saved_aperf = readin.aperf.whole; + per_cpu(msr_data, cpu).saved_mperf = readin.mperf.whole; #ifdef __i386__ /* From e0e8c4e512e92bc25c19bd8d4926de17d2f8fbf2 Mon Sep 17 00:00:00 2001 From: Thomas Renninger Date: Fri, 17 Apr 2009 16:22:06 +0200 Subject: [PATCH 2/4] acpi-cpufreq: Cleanup: Use printk_once Signed-off-by: Thomas Renninger Signed-off-by: Len Brown --- arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c index dd0bd76d14c0..4eab747a8966 100644 --- a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c +++ b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c @@ -693,13 +693,9 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy) /* Check for high latency (>20uS) from buggy BIOSes, like on T42 */ if (perf->control_register.space_id == ACPI_ADR_SPACE_FIXED_HARDWARE && policy->cpuinfo.transition_latency > 20 * 1000) { - static int print_once; policy->cpuinfo.transition_latency = 20 * 1000; - if (!print_once) { - print_once = 1; - printk(KERN_INFO "Capping off P-state tranision latency" - " at 20 uS\n"); - } + printk_once(KERN_INFO "Capping off P-state tranision" + " latency at 20 uS\n"); } data->max_freq = perf->states[0].core_frequency * 1000; From d91758f5ddb80e91176fa2cf80c88c1633950b3d Mon Sep 17 00:00:00 2001 From: Thomas Renninger Date: Fri, 17 Apr 2009 16:22:07 +0200 Subject: [PATCH 3/4] acpi-cpufreq: style-only: add parens to math expression Signed-off-by: Thomas Renninger Signed-off-by: Len Brown --- arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c index 4eab747a8966..aec3161abede 100644 --- a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c +++ b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c @@ -340,7 +340,7 @@ static unsigned int get_measured_perf(struct cpufreq_policy *policy, #endif - retval = per_cpu(drv_data, policy->cpu)->max_freq * perf_percent / 100; + retval = (per_cpu(drv_data, policy->cpu)->max_freq * perf_percent) / 100; return retval; } From d876dfbbf5c8728102fb4f683450fa9ae3259cda Mon Sep 17 00:00:00 2001 From: Thomas Renninger Date: Fri, 17 Apr 2009 16:22:08 +0200 Subject: [PATCH 4/4] acpi-cpufreq: Do not let get_measured perf depend on internal variable Take already available policy->cpuinfo.max_freq and get rid of acpi-cpufreq specific max_freq variable. This implies that P0 is always the highest frequency which should always be true as ACPI spec says: As a result, the zeroth entry describes the highest performance state Signed-off-by: Thomas Renninger Acked-by: Venkatesh Pallipadi Signed-off-by: Len Brown --- arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c index aec3161abede..208ecf6643df 100644 --- a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c +++ b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c @@ -65,7 +65,6 @@ enum { struct acpi_cpufreq_data { struct acpi_processor_performance *acpi_data; struct cpufreq_frequency_table *freq_table; - unsigned int max_freq; unsigned int resume; unsigned int cpu_feature; }; @@ -340,7 +339,7 @@ static unsigned int get_measured_perf(struct cpufreq_policy *policy, #endif - retval = (per_cpu(drv_data, policy->cpu)->max_freq * perf_percent) / 100; + retval = (policy->cpuinfo.max_freq * perf_percent) / 100; return retval; } @@ -698,7 +697,6 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy) " latency at 20 uS\n"); } - data->max_freq = perf->states[0].core_frequency * 1000; /* table init */ for (i = 0; i < perf->state_count; i++) { if (i > 0 && perf->states[i].core_frequency >= @@ -717,6 +715,9 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy) if (result) goto err_freqfree; + if (perf->states[0].core_frequency * 1000 != policy->cpuinfo.max_freq) + printk(KERN_WARNING FW_WARN "P-state 0 is not max freq\n"); + switch (perf->control_register.space_id) { case ACPI_ADR_SPACE_SYSTEM_IO: /* Current speed is unknown and not detectable by IO port */