From bf53de907dfdaac178c92d774aae7370d7b97d20 Mon Sep 17 00:00:00 2001 From: Markus Metzger Date: Fri, 19 Dec 2008 15:10:24 +0100 Subject: x86, bts: add fork and exit handling Impact: introduce new ptrace facility Add arch_ptrace_untrace() function that is called when the tracer detaches (either voluntarily or when the tracing task dies); ptrace_disable() is only called on a voluntary detach. Add ptrace_fork() and arch_ptrace_fork(). They are called when a traced task is forked. Clear DS and BTS related fields on fork. Release DS resources and reclaim memory in ptrace_untrace(). This releases resources already when the tracing task dies. We used to do that when the traced task dies. Signed-off-by: Markus Metzger Signed-off-by: Ingo Molnar --- arch/x86/include/asm/ds.h | 9 +++++++++ arch/x86/include/asm/ptrace.h | 7 +++++++ 2 files changed, 16 insertions(+) (limited to 'arch/x86/include/asm') diff --git a/arch/x86/include/asm/ds.h b/arch/x86/include/asm/ds.h index ee0ea3a96c1..a8f672ba100 100644 --- a/arch/x86/include/asm/ds.h +++ b/arch/x86/include/asm/ds.h @@ -252,12 +252,21 @@ extern void __cpuinit ds_init_intel(struct cpuinfo_x86 *); */ extern void ds_switch_to(struct task_struct *prev, struct task_struct *next); +/* + * Task clone/init and cleanup work + */ +extern void ds_copy_thread(struct task_struct *tsk, struct task_struct *father); +extern void ds_exit_thread(struct task_struct *tsk); + #else /* CONFIG_X86_DS */ struct cpuinfo_x86; static inline void __cpuinit ds_init_intel(struct cpuinfo_x86 *ignored) {} static inline void ds_switch_to(struct task_struct *prev, struct task_struct *next) {} +static inline void ds_copy_thread(struct task_struct *tsk, + struct task_struct *father) {} +static inline void ds_exit_thread(struct task_struct *tsk) {} #endif /* CONFIG_X86_DS */ #endif /* _ASM_X86_DS_H */ diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h index fbf74421591..6d34d954c22 100644 --- a/arch/x86/include/asm/ptrace.h +++ b/arch/x86/include/asm/ptrace.h @@ -235,6 +235,13 @@ extern int do_get_thread_area(struct task_struct *p, int idx, extern int do_set_thread_area(struct task_struct *p, int idx, struct user_desc __user *info, int can_allocate); +extern void x86_ptrace_untrace(struct task_struct *); +extern void x86_ptrace_fork(struct task_struct *child, + unsigned long clone_flags); + +#define arch_ptrace_untrace(tsk) x86_ptrace_untrace(tsk) +#define arch_ptrace_fork(child, flags) x86_ptrace_fork(child, flags) + #endif /* __KERNEL__ */ #endif /* !__ASSEMBLY__ */ -- cgit v1.2.3-70-g09d2 From 0ca59dd948a51c95d5a366d35f897bc5ef9df55d Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Wed, 24 Dec 2008 23:30:02 +0100 Subject: tracing/ftrace: don't trace on early stage of a secondary cpu boot, v3 Impact: fix a crash/hard-reboot on certain configs while enabling cpu runtime On some archs, the boot of a secondary cpu can have an early fragile state. On x86-64, the pda is not initialized on the first stage of a cpu boot but it is needed to get the cpu number and the current task pointer. This data is needed during tracing. As they were dereferenced at this stage, we got a crash while tracing a cpu being enabled at runtime. Some other archs like ia64 can have such kind of issue too. Changes on v2: We dropped the previous solution of a per-arch called function to guess the current state of a cpu. That could slow down the tracing. This patch removes the -pg flag on arch/x86/kernel/cpu/common.c where the low level cpu boot functions exist, on start_secondary() and a helper function used at this stage. Signed-off-by: Frederic Weisbecker Acked-by: Steven Rostedt Signed-off-by: Ingo Molnar --- arch/x86/include/asm/msr.h | 3 ++- arch/x86/kernel/cpu/Makefile | 5 +++++ arch/x86/kernel/smpboot.c | 2 +- 3 files changed, 8 insertions(+), 2 deletions(-) (limited to 'arch/x86/include/asm') diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h index c2a812ebde8..b8a1799ea87 100644 --- a/arch/x86/include/asm/msr.h +++ b/arch/x86/include/asm/msr.h @@ -85,7 +85,8 @@ static inline void native_write_msr(unsigned int msr, asm volatile("wrmsr" : : "c" (msr), "a"(low), "d" (high) : "memory"); } -static inline int native_write_msr_safe(unsigned int msr, +/* Can be uninlined because referenced by paravirt */ +notrace static inline int native_write_msr_safe(unsigned int msr, unsigned low, unsigned high) { int err; diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile index 82ec6075c05..4ae495a313f 100644 --- a/arch/x86/kernel/cpu/Makefile +++ b/arch/x86/kernel/cpu/Makefile @@ -2,6 +2,11 @@ # Makefile for x86-compatible CPU details and quirks # +# Don't trace early stages of a secondary CPU boot +ifdef CONFIG_FUNCTION_TRACER +CFLAGS_REMOVE_common.o = -pg +endif + obj-y := intel_cacheinfo.o addon_cpuid_features.o obj-y += proc.o capflags.o powerflags.o common.o diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index f71f96fc9e6..f6174d22902 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -287,7 +287,7 @@ static int __cpuinitdata unsafe_smp; /* * Activate a secondary processor. */ -static void __cpuinit start_secondary(void *unused) +notrace static void __cpuinit start_secondary(void *unused) { /* * Don't put *anything* before cpu_init(), SMP booting is too -- cgit v1.2.3-70-g09d2