Author: markj Date: Fri Sep 11 03:54:37 2015 New Revision: 287645 URL: https://svnweb.freebsd.org/changeset/base/287645
Log: Add stack_save_td_running(), a function to trace the kernel stack of a running thread. It is currently implemented only on amd64 and i386; on these architectures, it is implemented by raising an NMI on the CPU on which the target thread is currently running. Unlike stack_save_td(), it may fail, for example if the thread is running in user mode. This change also modifies the kern.proc.kstack sysctl to use this function, so that stacks of running threads are shown in the output of "procstat -kk". This is handy for debugging threads that are stuck in a busy loop. Reviewed by: bdrewery, jhb, kib Sponsored by: EMC / Isilon Storage Division Differential Revision: https://reviews.freebsd.org/D3256 Modified: head/sys/amd64/amd64/trap.c head/sys/arm/arm/stack_machdep.c head/sys/arm64/arm64/stack_machdep.c head/sys/i386/i386/trap.c head/sys/kern/kern_proc.c head/sys/mips/mips/stack_machdep.c head/sys/powerpc/powerpc/stack_machdep.c head/sys/sparc64/sparc64/stack_machdep.c head/sys/sys/stack.h head/sys/x86/include/apicvar.h head/sys/x86/include/stack.h head/sys/x86/x86/local_apic.c head/sys/x86/x86/mp_x86.c head/sys/x86/x86/stack_machdep.c Modified: head/sys/amd64/amd64/trap.c ============================================================================== --- head/sys/amd64/amd64/trap.c Fri Sep 11 03:31:22 2015 (r287644) +++ head/sys/amd64/amd64/trap.c Fri Sep 11 03:54:37 2015 (r287645) @@ -49,6 +49,7 @@ __FBSDID("$FreeBSD$"); #include "opt_hwpmc_hooks.h" #include "opt_isa.h" #include "opt_kdb.h" +#include "opt_stack.h" #include <sys/param.h> #include <sys/bus.h> @@ -91,6 +92,7 @@ PMC_SOFT_DEFINE( , , page_fault, write); #ifdef SMP #include <machine/smp.h> #endif +#include <machine/stack.h> #include <machine/tss.h> #ifdef KDTRACE_HOOKS @@ -202,17 +204,24 @@ trap(struct trapframe *frame) goto out; } -#ifdef HWPMC_HOOKS - /* - * CPU PMCs interrupt using an NMI. If the PMC module is - * active, pass the 'rip' value to the PMC module's interrupt - * handler. A return value of '1' from the handler means that - * the NMI was handled by it and we can return immediately. - */ - if (type == T_NMI && pmc_intr && - (*pmc_intr)(PCPU_GET(cpuid), frame)) - goto out; + if (type == T_NMI) { +#ifdef HWPMC_HOOKS + /* + * CPU PMCs interrupt using an NMI. If the PMC module is + * active, pass the 'rip' value to the PMC module's interrupt + * handler. A non-zero return value from the handler means that + * the NMI was consumed by it and we can return immediately. + */ + if (pmc_intr != NULL && + (*pmc_intr)(PCPU_GET(cpuid), frame) != 0) + goto out; +#endif + +#ifdef STACK + if (stack_nmi_handler(frame) != 0) + goto out; #endif + } if (type == T_MCHK) { mca_intr(); Modified: head/sys/arm/arm/stack_machdep.c ============================================================================== --- head/sys/arm/arm/stack_machdep.c Fri Sep 11 03:31:22 2015 (r287644) +++ head/sys/arm/arm/stack_machdep.c Fri Sep 11 03:54:37 2015 (r287645) @@ -71,6 +71,13 @@ stack_save_td(struct stack *st, struct t stack_capture(st, frame); } +int +stack_save_td_running(struct stack *st, struct thread *td) +{ + + return (EOPNOTSUPP); +} + void stack_save(struct stack *st) { Modified: head/sys/arm64/arm64/stack_machdep.c ============================================================================== --- head/sys/arm64/arm64/stack_machdep.c Fri Sep 11 03:31:22 2015 (r287644) +++ head/sys/arm64/arm64/stack_machdep.c Fri Sep 11 03:54:37 2015 (r287645) @@ -72,6 +72,13 @@ stack_save_td(struct stack *st, struct t stack_capture(st, &frame); } +int +stack_save_td_running(struct stack *st, struct thread *td) +{ + + return (EOPNOTSUPP); +} + void stack_save(struct stack *st) { Modified: head/sys/i386/i386/trap.c ============================================================================== --- head/sys/i386/i386/trap.c Fri Sep 11 03:31:22 2015 (r287644) +++ head/sys/i386/i386/trap.c Fri Sep 11 03:54:37 2015 (r287645) @@ -50,6 +50,7 @@ __FBSDID("$FreeBSD$"); #include "opt_isa.h" #include "opt_kdb.h" #include "opt_npx.h" +#include "opt_stack.h" #include "opt_trap.h" #include <sys/param.h> @@ -94,6 +95,7 @@ PMC_SOFT_DEFINE( , , page_fault, write); #ifdef SMP #include <machine/smp.h> #endif +#include <machine/stack.h> #include <machine/tss.h> #include <machine/vm86.h> @@ -219,19 +221,26 @@ trap(struct trapframe *frame) goto out; } -#ifdef HWPMC_HOOKS - /* - * CPU PMCs interrupt using an NMI so we check for that first. - * If the HWPMC module is active, 'pmc_hook' will point to - * the function to be called. A return value of '1' from the - * hook means that the NMI was handled by it and that we can - * return immediately. - */ - if (type == T_NMI && pmc_intr && - (*pmc_intr)(PCPU_GET(cpuid), frame)) - goto out; + if (type == T_NMI) { +#ifdef HWPMC_HOOKS + /* + * CPU PMCs interrupt using an NMI so we check for that first. + * If the HWPMC module is active, 'pmc_hook' will point to + * the function to be called. A non-zero return value from the + * hook means that the NMI was consumed by it and that we can + * return immediately. + */ + if (pmc_intr != NULL && + (*pmc_intr)(PCPU_GET(cpuid), frame) != 0) + goto out; #endif +#ifdef STACK + if (stack_nmi_handler(frame) != 0) + goto out; +#endif + } + if (type == T_MCHK) { mca_intr(); goto out; Modified: head/sys/kern/kern_proc.c ============================================================================== --- head/sys/kern/kern_proc.c Fri Sep 11 03:31:22 2015 (r287644) +++ head/sys/kern/kern_proc.c Fri Sep 11 03:54:37 2015 (r287645) @@ -2517,11 +2517,14 @@ repeat: sizeof(kkstp->kkst_trace), SBUF_FIXEDLEN); thread_lock(td); kkstp->kkst_tid = td->td_tid; - if (TD_IS_SWAPPED(td)) + if (TD_IS_SWAPPED(td)) { kkstp->kkst_state = KKST_STATE_SWAPPED; - else if (TD_IS_RUNNING(td)) - kkstp->kkst_state = KKST_STATE_RUNNING; - else { + } else if (TD_IS_RUNNING(td)) { + if (stack_save_td_running(st, td) == 0) + kkstp->kkst_state = KKST_STATE_STACKOK; + else + kkstp->kkst_state = KKST_STATE_RUNNING; + } else { kkstp->kkst_state = KKST_STATE_STACKOK; stack_save_td(st, td); } Modified: head/sys/mips/mips/stack_machdep.c ============================================================================== --- head/sys/mips/mips/stack_machdep.c Fri Sep 11 03:31:22 2015 (r287644) +++ head/sys/mips/mips/stack_machdep.c Fri Sep 11 03:54:37 2015 (r287645) @@ -142,6 +142,13 @@ stack_save_td(struct stack *st, struct t stack_capture(st, pc, sp); } +int +stack_save_td_running(struct stack *st, struct thread *td) +{ + + return (EOPNOTSUPP); +} + void stack_save(struct stack *st) { Modified: head/sys/powerpc/powerpc/stack_machdep.c ============================================================================== --- head/sys/powerpc/powerpc/stack_machdep.c Fri Sep 11 03:31:22 2015 (r287644) +++ head/sys/powerpc/powerpc/stack_machdep.c Fri Sep 11 03:54:37 2015 (r287645) @@ -98,6 +98,13 @@ stack_save_td(struct stack *st, struct t stack_capture(st, frame); } +int +stack_save_td_running(struct stack *st, struct thread *td) +{ + + return (EOPNOTSUPP); +} + void stack_save(struct stack *st) { Modified: head/sys/sparc64/sparc64/stack_machdep.c ============================================================================== --- head/sys/sparc64/sparc64/stack_machdep.c Fri Sep 11 03:31:22 2015 (r287644) +++ head/sys/sparc64/sparc64/stack_machdep.c Fri Sep 11 03:54:37 2015 (r287645) @@ -82,6 +82,13 @@ stack_save_td(struct stack *st, struct t stack_capture(st, (struct frame *)(td->td_pcb->pcb_sp + SPOFF)); } +int +stack_save_td_running(struct stack *st, struct thread *td) +{ + + return (EOPNOTSUPP); +} + void stack_save(struct stack *st) { Modified: head/sys/sys/stack.h ============================================================================== --- head/sys/sys/stack.h Fri Sep 11 03:31:22 2015 (r287644) +++ head/sys/sys/stack.h Fri Sep 11 03:54:37 2015 (r287645) @@ -56,9 +56,10 @@ void stack_ktr(u_int, const char *, in #define CTRSTACK(m, st, depth, cheap) #endif -/* MD Routine. */ +/* MD Routines. */ struct thread; void stack_save(struct stack *); void stack_save_td(struct stack *, struct thread *); +int stack_save_td_running(struct stack *, struct thread *); #endif Modified: head/sys/x86/include/apicvar.h ============================================================================== --- head/sys/x86/include/apicvar.h Fri Sep 11 03:31:22 2015 (r287644) +++ head/sys/x86/include/apicvar.h Fri Sep 11 03:54:37 2015 (r287645) @@ -129,12 +129,14 @@ #else #define IPI_DYN_FIRST (APIC_IPI_INTS + 8) #endif -#define IPI_DYN_LAST (254) /* IPIs allocated at runtime */ +#define IPI_DYN_LAST (253) /* IPIs allocated at runtime */ /* * IPI_STOP_HARD does not need to occupy a slot in the IPI vector space since * it is delivered using an NMI anyways. */ +#define IPI_NMI_FIRST 254 +#define IPI_TRACE 254 /* Interrupt for tracing. */ #define IPI_STOP_HARD 255 /* Stop CPU with a NMI. */ /* Modified: head/sys/x86/include/stack.h ============================================================================== --- head/sys/x86/include/stack.h Fri Sep 11 03:31:22 2015 (r287644) +++ head/sys/x86/include/stack.h Fri Sep 11 03:54:37 2015 (r287645) @@ -54,4 +54,8 @@ struct i386_frame { }; #endif /* __amd64__ */ +#ifdef _KERNEL +int stack_nmi_handler(struct trapframe *); +#endif + #endif /* !_X86_STACK_H */ Modified: head/sys/x86/x86/local_apic.c ============================================================================== --- head/sys/x86/x86/local_apic.c Fri Sep 11 03:31:22 2015 (r287644) +++ head/sys/x86/x86/local_apic.c Fri Sep 11 03:54:37 2015 (r287645) @@ -1703,11 +1703,10 @@ native_lapic_ipi_vectored(u_int vector, icrlo = APIC_DESTMODE_PHY | APIC_TRIGMOD_EDGE | APIC_LEVEL_ASSERT; /* - * IPI_STOP_HARD is just a "fake" vector used to send a NMI. - * Use special rules regard NMI if passed, otherwise specify - * the vector. + * NMI IPIs are just fake vectors used to send a NMI. Use special rules + * regarding NMIs if passed, otherwise specify the vector. */ - if (vector == IPI_STOP_HARD) + if (vector >= IPI_NMI_FIRST) icrlo |= APIC_DELMODE_NMI; else icrlo |= vector | APIC_DELMODE_FIXED; Modified: head/sys/x86/x86/mp_x86.c ============================================================================== --- head/sys/x86/x86/mp_x86.c Fri Sep 11 03:31:22 2015 (r287644) +++ head/sys/x86/x86/mp_x86.c Fri Sep 11 03:54:37 2015 (r287645) @@ -120,7 +120,7 @@ struct cpu_ops cpu_ops; * Local data and functions. */ -static volatile cpuset_t ipi_nmi_pending; +static volatile cpuset_t ipi_stop_nmi_pending; /* used to hold the AP's until we are ready to release them */ struct mtx ap_boot_mtx; @@ -894,7 +894,7 @@ ipi_selected(cpuset_t cpus, u_int ipi) * Set the mask of receiving CPUs for this purpose. */ if (ipi == IPI_STOP_HARD) - CPU_OR_ATOMIC(&ipi_nmi_pending, &cpus); + CPU_OR_ATOMIC(&ipi_stop_nmi_pending, &cpus); while ((cpu = CPU_FFS(&cpus)) != 0) { cpu--; @@ -917,7 +917,7 @@ ipi_cpu(int cpu, u_int ipi) * Set the mask of receiving CPUs for this purpose. */ if (ipi == IPI_STOP_HARD) - CPU_SET_ATOMIC(cpu, &ipi_nmi_pending); + CPU_SET_ATOMIC(cpu, &ipi_stop_nmi_pending); CTR3(KTR_SMP, "%s: cpu: %d ipi: %x", __func__, cpu, ipi); ipi_send_cpu(cpu, ipi); @@ -944,7 +944,7 @@ ipi_all_but_self(u_int ipi) * Set the mask of receiving CPUs for this purpose. */ if (ipi == IPI_STOP_HARD) - CPU_OR_ATOMIC(&ipi_nmi_pending, &other_cpus); + CPU_OR_ATOMIC(&ipi_stop_nmi_pending, &other_cpus); CTR2(KTR_SMP, "%s: ipi: %x", __func__, ipi); lapic_ipi_vectored(ipi, APIC_IPI_DEST_OTHERS); @@ -962,10 +962,10 @@ ipi_nmi_handler() * and should be handled. */ cpuid = PCPU_GET(cpuid); - if (!CPU_ISSET(cpuid, &ipi_nmi_pending)) + if (!CPU_ISSET(cpuid, &ipi_stop_nmi_pending)) return (1); - CPU_CLR_ATOMIC(cpuid, &ipi_nmi_pending); + CPU_CLR_ATOMIC(cpuid, &ipi_stop_nmi_pending); cpustop_handler(); return (0); } Modified: head/sys/x86/x86/stack_machdep.c ============================================================================== --- head/sys/x86/x86/stack_machdep.c Fri Sep 11 03:31:22 2015 (r287644) +++ head/sys/x86/x86/stack_machdep.c Fri Sep 11 03:54:37 2015 (r287645) @@ -1,4 +1,5 @@ /*- + * Copyright (c) 2015 EMC Corporation * Copyright (c) 2005 Antoine Brodin * All rights reserved. * @@ -29,17 +30,21 @@ __FBSDID("$FreeBSD$"); #include <sys/param.h> #include <sys/systm.h> +#include <sys/kernel.h> +#include <sys/lock.h> +#include <sys/mutex.h> #include <sys/proc.h> #include <sys/stack.h> -#include <x86/stack.h> - #include <machine/pcb.h> +#include <machine/smp.h> #include <vm/vm.h> #include <vm/vm_param.h> #include <vm/pmap.h> +#include <x86/stack.h> + #ifdef __i386__ #define PCB_FP(pcb) ((pcb)->pcb_ebp) #define TF_FP(tf) ((tf)->tf_ebp) @@ -54,6 +59,14 @@ typedef struct i386_frame *x86_frame_t; typedef struct amd64_frame *x86_frame_t; #endif +static struct stack *nmi_stack; +static volatile struct thread *nmi_pending; + +#ifdef SMP +static struct mtx nmi_lock; +MTX_SYSINIT(nmi_lock, &nmi_lock, "stack_nmi", MTX_SPIN); +#endif + static void stack_capture(struct thread *td, struct stack *st, register_t fp) { @@ -78,6 +91,24 @@ stack_capture(struct thread *td, struct } } +int +stack_nmi_handler(struct trapframe *tf) +{ + + /* Don't consume an NMI that wasn't meant for us. */ + if (nmi_stack == NULL || curthread != nmi_pending) + return (0); + + if (INKERNEL(TF_PC(tf))) + stack_capture(curthread, nmi_stack, TF_FP(tf)); + else + /* We interrupted a thread in user mode. */ + nmi_stack->depth = 0; + + atomic_store_rel_ptr((long *)&nmi_pending, (long)NULL); + return (1); +} + void stack_save_td(struct stack *st, struct thread *td) { @@ -90,6 +121,39 @@ stack_save_td(struct stack *st, struct t stack_capture(td, st, PCB_FP(td->td_pcb)); } +int +stack_save_td_running(struct stack *st, struct thread *td) +{ + + THREAD_LOCK_ASSERT(td, MA_OWNED); + MPASS(TD_IS_RUNNING(td)); + + if (td == curthread) { + stack_save(st); + return (0); + } + +#ifdef SMP + mtx_lock_spin(&nmi_lock); + + nmi_stack = st; + nmi_pending = td; + ipi_cpu(td->td_oncpu, IPI_TRACE); + while ((void *)atomic_load_acq_ptr((long *)&nmi_pending) != NULL) + cpu_spinwait(); + nmi_stack = NULL; + + mtx_unlock_spin(&nmi_lock); + + if (st->depth == 0) + /* We interrupted a thread in user mode. */ + return (EAGAIN); +#else + KASSERT(0, ("curthread isn't running")); +#endif + return (0); +} + void stack_save(struct stack *st) { _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "[email protected]"
