From a489ca355efaf9efa4990b0f8f30ab650a206273 Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Mon, 2 Nov 2009 16:59:15 -0800 Subject: x86: Make sure we also print a Code: line for show_regs() show_regs() is called as a mini BUG() equivalent in some places, specifically for the "scheduling while atomic" case. Unfortunately right now it does not print a Code: line unlike a real bug/oops. This patch changes the x86 implementation of show_regs() so that it calls the same function as oopses do to print the registers as well as the Code: line. Signed-off-by: Arjan van de Ven LKML-Reference: <20091102165915.4a980fc0@infradead.org> Signed-off-by: Ingo Molnar --- arch/x86/kernel/process_32.c | 2 +- arch/x86/kernel/process_64.c | 3 +-- 2 files changed, 2 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index 4cf79567cdab..e658331edb6d 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -187,7 +187,7 @@ void __show_regs(struct pt_regs *regs, int all) void show_regs(struct pt_regs *regs) { - __show_regs(regs, 1); + show_registers(regs); show_trace(NULL, regs, ®s->sp, regs->bp); } diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index ad535b683170..2386999bfcd2 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -226,8 +226,7 @@ void __show_regs(struct pt_regs *regs, int all) void show_regs(struct pt_regs *regs) { - printk(KERN_INFO "CPU %d:", smp_processor_id()); - __show_regs(regs, 1); + show_registers(regs); show_trace(NULL, regs, (void *)(regs + 1), regs->bp); } -- cgit v1.2.2 From ce7c42710e2dd133f10b7fc9ed9c73bdd2435f7a Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Tue, 3 Nov 2009 14:53:52 +1030 Subject: cpumask: Avoid cpumask_t in arch/x86/kernel/apic/nmi.c Ingo wants the certainty of a static cpumask (rather than a cpumask_var_t), but cpumask_t will some day be undefined to avoid on-stack declarations. This is what DECLARE_BITMAP/to_cpumask() is for. Signed-off-by: Rusty Russell LKML-Reference: <200911031453.52394.rusty@rustcorp.com.au> Signed-off-by: Ingo Molnar --- arch/x86/kernel/apic/nmi.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/arch/x86/kernel/apic/nmi.c b/arch/x86/kernel/apic/nmi.c index 7ff61d6a188a..6389432a9dbf 100644 --- a/arch/x86/kernel/apic/nmi.c +++ b/arch/x86/kernel/apic/nmi.c @@ -39,7 +39,8 @@ int unknown_nmi_panic; int nmi_watchdog_enabled; -static cpumask_t backtrace_mask __read_mostly; +/* For reliability, we're prepared to waste bits here. */ +static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly; /* nmi_active: * >0: the lapic NMI watchdog is active, but can be disabled @@ -414,7 +415,7 @@ nmi_watchdog_tick(struct pt_regs *regs, unsigned reason) } /* We can be called before check_nmi_watchdog, hence NULL check. */ - if (cpumask_test_cpu(cpu, &backtrace_mask)) { + if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) { static DEFINE_SPINLOCK(lock); /* Serialise the printks */ spin_lock(&lock); @@ -422,7 +423,7 @@ nmi_watchdog_tick(struct pt_regs *regs, unsigned reason) show_regs(regs); dump_stack(); spin_unlock(&lock); - cpumask_clear_cpu(cpu, &backtrace_mask); + cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask)); rc = 1; } @@ -558,14 +559,14 @@ void arch_trigger_all_cpu_backtrace(void) { int i; - cpumask_copy(&backtrace_mask, cpu_online_mask); + cpumask_copy(to_cpumask(backtrace_mask), cpu_online_mask); printk(KERN_INFO "sending NMI to all CPUs:\n"); apic->send_IPI_all(NMI_VECTOR); /* Wait for up to 10 seconds for all CPUs to do the backtrace */ for (i = 0; i < 10 * 1000; i++) { - if (cpumask_empty(&backtrace_mask)) + if (cpumask_empty(to_cpumask(backtrace_mask))) break; mdelay(1); } -- cgit v1.2.2 From 15cd8812ab2ce62a2f779e93a8398bdad752291a Mon Sep 17 00:00:00 2001 From: Dave Jones Date: Thu, 12 Nov 2009 18:15:43 -0500 Subject: x86: Remove the CPU cache size printk's They aren't really useful, and they pollute the dmesg output a lot (especially on machines with many cores). Also the same information can be trivially found out from userspace. Reported-by: Mike Travis Signed-off-by: Dave Jones Acked-by: H. Peter Anvin Cc: Andi Kleen Cc: Heiko Carstens Cc: Roland Dreier Cc: Randy Dunlap Cc: Tejun Heo Cc: Greg Kroah-Hartman Cc: Yinghai Lu Cc: David Rientjes Cc: Steven Rostedt Cc: Rusty Russell Cc: Hidetoshi Seto Cc: Jack Steiner Cc: Frederic Weisbecker LKML-Reference: <20091112231542.GA7129@redhat.com> Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/intel_cacheinfo.c | 16 ---------------- 1 file changed, 16 deletions(-) diff --git a/arch/x86/kernel/cpu/intel_cacheinfo.c b/arch/x86/kernel/cpu/intel_cacheinfo.c index 804c40e2bc3e..0df4c2b7107f 100644 --- a/arch/x86/kernel/cpu/intel_cacheinfo.c +++ b/arch/x86/kernel/cpu/intel_cacheinfo.c @@ -488,22 +488,6 @@ unsigned int __cpuinit init_intel_cacheinfo(struct cpuinfo_x86 *c) #endif } - if (trace) - printk(KERN_INFO "CPU: Trace cache: %dK uops", trace); - else if (l1i) - printk(KERN_INFO "CPU: L1 I cache: %dK", l1i); - - if (l1d) - printk(KERN_CONT ", L1 D cache: %dK\n", l1d); - else - printk(KERN_CONT "\n"); - - if (l2) - printk(KERN_INFO "CPU: L2 cache: %dK\n", l2); - - if (l3) - printk(KERN_INFO "CPU: L3 cache: %dK\n", l3); - c->x86_cache_size = l3 ? l3 : (l2 ? l2 : (l1i+l1d)); return l2; -- cgit v1.2.2 From 0388423dba2217b4e5b6c61690b0506d13b25a49 Mon Sep 17 00:00:00 2001 From: Dave Jones Date: Fri, 13 Nov 2009 15:30:00 -0500 Subject: x86: Minimise printk spew from per-vendor init code In the default case where the kernel supports all CPU vendors, we currently print out a bunch of not useful messages on every system. 32-bit: KERNEL supported cpus: Intel GenuineIntel AMD AuthenticAMD NSC Geode by NSC Cyrix CyrixInstead Centaur CentaurHauls Transmeta GenuineTMx86 Transmeta TransmetaCPU UMC UMC UMC UMC 64-bit: KERNEL supported cpus: Intel GenuineIntel AMD AuthenticAMD Centaur CentaurHauls Given that "what CPUs does the kernel support" isn't useful for the "support everything" case, we can suppress these printk's. Signed-off-by: Dave Jones LKML-Reference: <20091113203000.GA19160@redhat.com> Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/common.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index cc25c2b4a567..617a29f95b3c 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -656,6 +656,7 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c) void __init early_cpu_init(void) { +#ifdef PROCESSOR_SELECT const struct cpu_dev *const *cdev; int count = 0; @@ -676,7 +677,7 @@ void __init early_cpu_init(void) cpudev->c_ident[j]); } } - +#endif early_identify_cpu(&boot_cpu_data); } -- cgit v1.2.2 From b01c845f0f2e3f9e54e6a78d5d56895f5b95e818 Mon Sep 17 00:00:00 2001 From: Roland Dreier Date: Fri, 13 Nov 2009 14:38:26 -0800 Subject: x86: Remove CPU cache size output for non-Intel too As Dave Jones said about the output in intel_cacheinfo.c: "They aren't useful, and pollute the dmesg output a lot (especially on machines with many cores). Also the same information can be trivially found out from userspace." Give the generic display_cacheinfo() function the same treatment. Signed-off-by: Roland Dreier Acked-by: Dave Jones Cc: Mike Travis Cc: Andi Kleen Cc: Heiko Carstens Cc: Randy Dunlap Cc: Tejun Heo Cc: Greg Kroah-Hartman Cc: Yinghai Lu Cc: David Rientjes Cc: Steven Rostedt Cc: Rusty Russell Cc: Hidetoshi Seto Cc: Jack Steiner Cc: Frederic Weisbecker LKML-Reference: Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/common.c | 5 ----- 1 file changed, 5 deletions(-) diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 617a29f95b3c..9db1e2425c27 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -391,8 +391,6 @@ void __cpuinit display_cacheinfo(struct cpuinfo_x86 *c) if (n >= 0x80000005) { cpuid(0x80000005, &dummy, &ebx, &ecx, &edx); - printk(KERN_INFO "CPU: L1 I Cache: %dK (%d bytes/line), D cache %dK (%d bytes/line)\n", - edx>>24, edx&0xFF, ecx>>24, ecx&0xFF); c->x86_cache_size = (ecx>>24) + (edx>>24); #ifdef CONFIG_X86_64 /* On K8 L1 TLB is inclusive, so don't count it */ @@ -422,9 +420,6 @@ void __cpuinit display_cacheinfo(struct cpuinfo_x86 *c) #endif c->x86_cache_size = l2size; - - printk(KERN_INFO "CPU: L2 Cache: %dK (%d bytes/line)\n", - l2size, ecx & 0xFF); } void __cpuinit detect_ht(struct cpuinfo_x86 *c) -- cgit v1.2.2 From 31c997cac76e62918858a432fff6e43fd48425f9 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Sat, 14 Nov 2009 10:34:41 +0100 Subject: x86: Fix cpu_devs[] initialization in early_cpu_init() Yinghai Lu noticed that this commit: 0388423: x86: Minimise printk spew from per-vendor init code mistakenly left out the initialization of cpu_devs[] in the !PROCESSOR_SELECT case. Fix it. Reported-by: Yinghai Lu Cc: Dave Jones LKML-Reference: <20091113203000.GA19160@redhat.com> Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/common.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 9db1e2425c27..61242a56c2d6 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -651,28 +651,34 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c) void __init early_cpu_init(void) { -#ifdef PROCESSOR_SELECT const struct cpu_dev *const *cdev; int count = 0; +#ifdef PROCESSOR_SELECT printk(KERN_INFO "KERNEL supported cpus:\n"); +#endif + for (cdev = __x86_cpu_dev_start; cdev < __x86_cpu_dev_end; cdev++) { const struct cpu_dev *cpudev = *cdev; - unsigned int j; if (count >= X86_VENDOR_NUM) break; cpu_devs[count] = cpudev; count++; - for (j = 0; j < 2; j++) { - if (!cpudev->c_ident[j]) - continue; - printk(KERN_INFO " %s %s\n", cpudev->c_vendor, - cpudev->c_ident[j]); +#ifdef PROCESSOR_SELECT + { + unsigned int j; + + for (j = 0; j < 2; j++) { + if (!cpudev->c_ident[j]) + continue; + printk(KERN_INFO " %s %s\n", cpudev->c_vendor, + cpudev->c_ident[j]); + } } - } #endif + } early_identify_cpu(&boot_cpu_data); } -- cgit v1.2.2 From 0e7810be30f66e9f430c4ce2cd3b14634211690f Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Fri, 20 Nov 2009 14:00:14 +0000 Subject: x86: Suppress stack overrun message for init_task init_task doesn't get its stack end location set to STACK_END_MAGIC, and hence the message is confusing rather than helpful in this case. Signed-off-by: Jan Beulich LKML-Reference: <4B06AEFE02000078000211F4@vpn.id2.novell.com> Signed-off-by: Ingo Molnar --- arch/x86/mm/fault.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index f4cee9028cf0..071eee604147 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -658,7 +658,7 @@ no_context(struct pt_regs *regs, unsigned long error_code, show_fault_oops(regs, error_code, address); stackend = end_of_stack(tsk); - if (*stackend != STACK_END_MAGIC) + if (tsk != &init_task && *stackend != STACK_END_MAGIC) printk(KERN_ALERT "Thread overran stack, or stack corrupted\n"); tsk->thread.cr2 = address; -- cgit v1.2.2 From 27c13ecec4d8856687b50b959e1146845b478f95 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Sat, 21 Nov 2009 14:01:45 +0100 Subject: x86, cpu: mv display_cacheinfo -> cpu_detect_cache_sizes display_cacheinfo() doesn't display anything anymore and it is used to detect CPU cache sizes. Rename it accordingly. Signed-off-by: Borislav Petkov LKML-Reference: <20091121130145.GA31357@liondog.tnic> Signed-off-by: H. Peter Anvin --- arch/x86/kernel/cpu/amd.c | 2 +- arch/x86/kernel/cpu/centaur.c | 2 +- arch/x86/kernel/cpu/common.c | 4 ++-- arch/x86/kernel/cpu/cpu.h | 2 +- arch/x86/kernel/cpu/cyrix.c | 2 +- arch/x86/kernel/cpu/transmeta.c | 2 +- 6 files changed, 7 insertions(+), 7 deletions(-) diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index c910a716a71c..7128b3799cec 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -535,7 +535,7 @@ static void __cpuinit init_amd(struct cpuinfo_x86 *c) } } - display_cacheinfo(c); + cpu_detect_cache_sizes(c); /* Multi core CPU? */ if (c->extended_cpuid_level >= 0x80000008) { diff --git a/arch/x86/kernel/cpu/centaur.c b/arch/x86/kernel/cpu/centaur.c index c95e831bb095..e58d978e0758 100644 --- a/arch/x86/kernel/cpu/centaur.c +++ b/arch/x86/kernel/cpu/centaur.c @@ -294,7 +294,7 @@ static void __cpuinit init_c3(struct cpuinfo_x86 *c) set_cpu_cap(c, X86_FEATURE_REP_GOOD); } - display_cacheinfo(c); + cpu_detect_cache_sizes(c); } enum { diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 61242a56c2d6..9bf845dc8055 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -61,7 +61,7 @@ void __init setup_cpu_local_masks(void) static void __cpuinit default_init(struct cpuinfo_x86 *c) { #ifdef CONFIG_X86_64 - display_cacheinfo(c); + cpu_detect_cache_sizes(c); #else /* Not much we can do here... */ /* Check if at least it has cpuid */ @@ -383,7 +383,7 @@ static void __cpuinit get_model_name(struct cpuinfo_x86 *c) } } -void __cpuinit display_cacheinfo(struct cpuinfo_x86 *c) +void __cpuinit cpu_detect_cache_sizes(struct cpuinfo_x86 *c) { unsigned int n, dummy, ebx, ecx, edx, l2size; diff --git a/arch/x86/kernel/cpu/cpu.h b/arch/x86/kernel/cpu/cpu.h index 6de9a908e400..3624e8a0f71b 100644 --- a/arch/x86/kernel/cpu/cpu.h +++ b/arch/x86/kernel/cpu/cpu.h @@ -32,6 +32,6 @@ struct cpu_dev { extern const struct cpu_dev *const __x86_cpu_dev_start[], *const __x86_cpu_dev_end[]; -extern void display_cacheinfo(struct cpuinfo_x86 *c); +extern void cpu_detect_cache_sizes(struct cpuinfo_x86 *c); #endif diff --git a/arch/x86/kernel/cpu/cyrix.c b/arch/x86/kernel/cpu/cyrix.c index 19807b89f058..4fbd384fb645 100644 --- a/arch/x86/kernel/cpu/cyrix.c +++ b/arch/x86/kernel/cpu/cyrix.c @@ -373,7 +373,7 @@ static void __cpuinit init_nsc(struct cpuinfo_x86 *c) /* Handle the GX (Formally known as the GX2) */ if (c->x86 == 5 && c->x86_model == 5) - display_cacheinfo(c); + cpu_detect_cache_sizes(c); else init_cyrix(c); } diff --git a/arch/x86/kernel/cpu/transmeta.c b/arch/x86/kernel/cpu/transmeta.c index bb62b3e5caad..28000743bbb0 100644 --- a/arch/x86/kernel/cpu/transmeta.c +++ b/arch/x86/kernel/cpu/transmeta.c @@ -26,7 +26,7 @@ static void __cpuinit init_transmeta(struct cpuinfo_x86 *c) early_init_transmeta(c); - display_cacheinfo(c); + cpu_detect_cache_sizes(c); /* Print CMS and CPU revision */ max = cpuid_eax(0x80860000); -- cgit v1.2.2 From b803090615ccec669681ff85ce28671e7bfefa3d Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Thu, 26 Nov 2009 08:17:31 +0100 Subject: x86: dumpstack: Clean up the x86_stack_ids[][] initalization and other details Make the initialization more readable, plus tidy up a few small visual details as well. No change in functionality. LKML-Reference: Signed-off-by: Ingo Molnar --- arch/x86/kernel/dumpstack_32.c | 9 ++++----- arch/x86/kernel/dumpstack_64.c | 25 +++++++++++++------------ 2 files changed, 17 insertions(+), 17 deletions(-) diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c index f7dd2a7c3bf4..e0ed4c7abb62 100644 --- a/arch/x86/kernel/dumpstack_32.c +++ b/arch/x86/kernel/dumpstack_32.c @@ -10,9 +10,9 @@ #include #include #include +#include #include #include -#include #include @@ -35,6 +35,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs, if (!stack) { unsigned long dummy; + stack = &dummy; if (task && task != current) stack = (unsigned long *)task->thread.sp; @@ -57,8 +58,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs, context = (struct thread_info *) ((unsigned long)stack & (~(THREAD_SIZE - 1))); - bp = print_context_stack(context, stack, bp, ops, - data, NULL, &graph); + bp = print_context_stack(context, stack, bp, ops, data, NULL, &graph); stack = (unsigned long *)context->previous_esp; if (!stack) @@ -72,7 +72,7 @@ EXPORT_SYMBOL(dump_trace); void show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs, - unsigned long *sp, unsigned long bp, char *log_lvl) + unsigned long *sp, unsigned long bp, char *log_lvl) { unsigned long *stack; int i; @@ -156,4 +156,3 @@ int is_valid_bugaddr(unsigned long ip) return ud2 == 0x0b0f; } - diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c index a071e6be177e..cfec478a4e42 100644 --- a/arch/x86/kernel/dumpstack_64.c +++ b/arch/x86/kernel/dumpstack_64.c @@ -10,26 +10,28 @@ #include #include #include +#include #include #include -#include #include #include "dumpstack.h" +#define N_EXCEPTION_STACKS_END \ + (N_EXCEPTION_STACKS + DEBUG_STKSZ/EXCEPTION_STKSZ - 2) static char x86_stack_ids[][8] = { - [DEBUG_STACK - 1] = "#DB", - [NMI_STACK - 1] = "NMI", - [DOUBLEFAULT_STACK - 1] = "#DF", - [STACKFAULT_STACK - 1] = "#SS", - [MCE_STACK - 1] = "#MC", + [ DEBUG_STACK-1 ] = "#DB", + [ NMI_STACK-1 ] = "NMI", + [ DOUBLEFAULT_STACK-1 ] = "#DF", + [ STACKFAULT_STACK-1 ] = "#SS", + [ MCE_STACK-1 ] = "#MC", #if DEBUG_STKSZ > EXCEPTION_STKSZ - [N_EXCEPTION_STACKS ... - N_EXCEPTION_STACKS + DEBUG_STKSZ / EXCEPTION_STKSZ - 2] = "#DB[?]" + [ N_EXCEPTION_STACKS ... + N_EXCEPTION_STACKS_END ] = "#DB[?]" #endif - }; +}; int x86_is_stack_id(int id, char *name) { @@ -37,7 +39,7 @@ int x86_is_stack_id(int id, char *name) } static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack, - unsigned *usedp, char **idp) + unsigned *usedp, char **idp) { unsigned k; @@ -202,7 +204,7 @@ EXPORT_SYMBOL(dump_trace); void show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs, - unsigned long *sp, unsigned long bp, char *log_lvl) + unsigned long *sp, unsigned long bp, char *log_lvl) { unsigned long *stack; int i; @@ -303,4 +305,3 @@ int is_valid_bugaddr(unsigned long ip) return ud2 == 0x0b0f; } - -- cgit v1.2.2 From 67f2de0bf9141dd9fe9189d0caaa28d7ad21a523 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Thu, 26 Nov 2009 08:29:10 +0100 Subject: x86: dumpstack, 64-bit: Disable preemption when walking the IRQ/exception stacks This warning: [ 847.140022] rb_producer D 0000000000000000 5928 519 2 0x00000000 [ 847.203627] BUG: using smp_processor_id() in preemptible [00000000] code: khungtaskd/517 [ 847.207360] caller is show_stack_log_lvl+0x2e/0x241 [ 847.210364] Pid: 517, comm: khungtaskd Not tainted 2.6.32-rc8-tip+ #13761 [ 847.213395] Call Trace: [ 847.215847] [] debug_smp_processor_id+0x1f0/0x20a [ 847.216809] [] show_stack_log_lvl+0x2e/0x241 [ 847.220027] [] show_stack+0x1c/0x1e [ 847.223365] [] sched_show_task+0xe4/0xe9 [ 847.226694] [] check_hung_task+0x140/0x199 [ 847.230261] [] check_hung_uninterruptible_tasks+0x1b7/0x20f [ 847.233371] [] ? watchdog+0x0/0x50 [ 847.236683] [] watchdog+0x4e/0x50 [ 847.240034] [] kthread+0x97/0x9f [ 847.243372] [] child_rip+0xa/0x20 [ 847.246690] [] ? restore_args+0x0/0x30 [ 847.250019] [] ? _spin_lock+0xe/0x10 [ 847.253351] [] ? kthread+0x0/0x9f [ 847.256833] [] ? child_rip+0x0/0x20 Happens because on preempt-RCU, khungd calls show_stack() with preemption enabled. Make sure we are not preemptible while walking the IRQ and exception stacks on 64-bit. (32-bit stack dumping is preemption safe.) Signed-off-by: Ingo Molnar --- arch/x86/kernel/dumpstack_64.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c index cfec478a4e42..8e740934bd1f 100644 --- a/arch/x86/kernel/dumpstack_64.c +++ b/arch/x86/kernel/dumpstack_64.c @@ -206,19 +206,22 @@ void show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs, unsigned long *sp, unsigned long bp, char *log_lvl) { + unsigned long *irq_stack_end; + unsigned long *irq_stack; unsigned long *stack; + int cpu; int i; - const int cpu = smp_processor_id(); - unsigned long *irq_stack_end = - (unsigned long *)(per_cpu(irq_stack_ptr, cpu)); - unsigned long *irq_stack = - (unsigned long *)(per_cpu(irq_stack_ptr, cpu) - IRQ_STACK_SIZE); + + preempt_disable(); + cpu = smp_processor_id(); + + irq_stack_end = (unsigned long *)(per_cpu(irq_stack_ptr, cpu)); + irq_stack = (unsigned long *)(per_cpu(irq_stack_ptr, cpu) - IRQ_STACK_SIZE); /* - * debugging aid: "show_stack(NULL, NULL);" prints the - * back trace for this cpu. + * Debugging aid: "show_stack(NULL, NULL);" prints the + * back trace for this cpu: */ - if (sp == NULL) { if (task) sp = (unsigned long *)task->thread.sp; @@ -242,6 +245,8 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs, printk(" %016lx", *stack++); touch_nmi_watchdog(); } + preempt_enable(); + printk("\n"); show_trace_log_lvl(task, regs, sp, bp, log_lvl); } -- cgit v1.2.2 From 9b3660a55a9052518c91cc7c62d89e22f3f6f490 Mon Sep 17 00:00:00 2001 From: Mike Travis Date: Tue, 17 Nov 2009 18:22:16 -0600 Subject: x86: Limit number of per cpu TSC sync messages Limit the number of per cpu TSC sync messages by only printing to the console if an error occurs, otherwise print as a DEBUG message. The info message "Skipping synchronization ..." is only printed after the last cpu has booted. Signed-off-by: Mike Travis Cc: Heiko Carstens Cc: Roland Dreier Cc: Randy Dunlap Cc: Tejun Heo Cc: Andi Kleen Cc: Greg Kroah-Hartman Cc: Yinghai Lu Cc: David Rientjes Cc: Steven Rostedt Cc: Rusty Russell Cc: Hidetoshi Seto Cc: Jack Steiner Cc: Frederic Weisbecker LKML-Reference: <20091118002222.181053000@alcatraz.americas.sgi.com> Signed-off-by: Ingo Molnar --- arch/x86/kernel/tsc_sync.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/arch/x86/kernel/tsc_sync.c b/arch/x86/kernel/tsc_sync.c index f37930954d15..eed156851f5d 100644 --- a/arch/x86/kernel/tsc_sync.c +++ b/arch/x86/kernel/tsc_sync.c @@ -114,13 +114,12 @@ void __cpuinit check_tsc_sync_source(int cpu) return; if (boot_cpu_has(X86_FEATURE_TSC_RELIABLE)) { - printk_once(KERN_INFO "Skipping synchronization checks as TSC is reliable.\n"); + if (cpu == (nr_cpu_ids-1) || system_state != SYSTEM_BOOTING) + pr_info( + "Skipped synchronization checks as TSC is reliable.\n"); return; } - pr_info("checking TSC synchronization [CPU#%d -> CPU#%d]:", - smp_processor_id(), cpu); - /* * Reset it - in case this is a second bootup: */ @@ -142,12 +141,14 @@ void __cpuinit check_tsc_sync_source(int cpu) cpu_relax(); if (nr_warps) { - printk("\n"); + pr_warning("TSC synchronization [CPU#%d -> CPU#%d]:\n", + smp_processor_id(), cpu); pr_warning("Measured %Ld cycles TSC warp between CPUs, " "turning off TSC clock.\n", max_warp); mark_tsc_unstable("check_tsc_sync_source failed"); } else { - printk(" passed.\n"); + pr_debug("TSC synchronization [CPU#%d -> CPU#%d]: passed\n", + smp_processor_id(), cpu); } /* -- cgit v1.2.2