Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754265AbYLSOKl (ORCPT ); Fri, 19 Dec 2008 09:10:41 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753263AbYLSOKd (ORCPT ); Fri, 19 Dec 2008 09:10:33 -0500 Received: from mga02.intel.com ([134.134.136.20]:22354 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753261AbYLSOKc (ORCPT ); Fri, 19 Dec 2008 09:10:32 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.36,249,1228118400"; d="scan'208";a="372294800" Date: Fri, 19 Dec 2008 15:10:24 +0100 From: Markus Metzger To: linux-kernel@vger.kernel.org, mingo@elte.hu, tglx@linutronix.de, hpa@zytor.com Cc: markus.t.metzger@intel.com, markus.t.metzger@gmail.com, roland@redhat.com, eranian@googlemail.com Subject: [patch 1/2] x86, bts: fork and exit handling Message-ID: <20081219151024.A4960@sedona.ch.intel.com> Mime-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.2.5i Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 10374 Lines: 343 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 --- Index: ftrace/arch/x86/kernel/process_32.c =================================================================== --- ftrace.orig/arch/x86/kernel/process_32.c 2008-12-19 12:28:23.000000000 +0100 +++ ftrace/arch/x86/kernel/process_32.c 2008-12-19 13:18:52.000000000 +0100 @@ -60,6 +60,7 @@ #include #include #include +#include asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); @@ -251,17 +252,8 @@ tss->x86_tss.io_bitmap_base = INVALID_IO_BITMAP_OFFSET; put_cpu(); } -#ifdef CONFIG_X86_DS - /* Free any BTS tracers that have not been properly released. */ - if (unlikely(current->bts)) { - ds_release_bts(current->bts); - current->bts = NULL; - - kfree(current->bts_buffer); - current->bts_buffer = NULL; - current->bts_size = 0; - } -#endif /* CONFIG_X86_DS */ + + ds_exit_thread(current); } void flush_thread(void) @@ -343,6 +335,12 @@ kfree(p->thread.io_bitmap_ptr); p->thread.io_bitmap_max = 0; } + + ds_copy_thread(p, current); + + clear_tsk_thread_flag(p, TIF_DEBUGCTLMSR); + p->thread.debugctlmsr = 0; + return err; } Index: ftrace/arch/x86/kernel/process_64.c =================================================================== --- ftrace.orig/arch/x86/kernel/process_64.c 2008-12-19 12:29:30.000000000 +0100 +++ ftrace/arch/x86/kernel/process_64.c 2008-12-19 12:29:41.000000000 +0100 @@ -54,6 +54,7 @@ #include #include #include +#include asmlinkage extern void ret_from_fork(void); @@ -248,17 +249,8 @@ t->io_bitmap_max = 0; put_cpu(); } -#ifdef CONFIG_X86_DS - /* Free any BTS tracers that have not been properly released. */ - if (unlikely(current->bts)) { - ds_release_bts(current->bts); - current->bts = NULL; - - kfree(current->bts_buffer); - current->bts_buffer = NULL; - current->bts_size = 0; - } -#endif /* CONFIG_X86_DS */ + + ds_exit_thread(current); } void flush_thread(void) @@ -388,6 +380,12 @@ if (err) goto out; } + + ds_copy_thread(p, me); + + clear_tsk_thread_flag(p, TIF_DEBUGCTLMSR); + p->thread.debugctlmsr = 0; + err = 0; out: if (err && p->thread.io_bitmap_ptr) { Index: ftrace/kernel/fork.c =================================================================== --- ftrace.orig/kernel/fork.c 2008-12-19 12:29:32.000000000 +0100 +++ ftrace/kernel/fork.c 2008-12-19 12:29:41.000000000 +0100 @@ -1102,6 +1102,8 @@ #ifdef CONFIG_DEBUG_MUTEXES p->blocked_on = NULL; /* not blocked yet */ #endif + if (unlikely(ptrace_reparented(current))) + ptrace_fork(p, clone_flags); /* Perform scheduler related setup. Assign this task to a CPU. */ sched_fork(p, clone_flags); Index: ftrace/arch/x86/include/asm/ds.h =================================================================== --- ftrace.orig/arch/x86/include/asm/ds.h 2008-12-19 12:28:23.000000000 +0100 +++ ftrace/arch/x86/include/asm/ds.h 2008-12-19 12:29:41.000000000 +0100 @@ -252,12 +252,21 @@ */ 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 */ Index: ftrace/arch/x86/kernel/ds.c =================================================================== --- ftrace.orig/arch/x86/kernel/ds.c 2008-12-19 12:29:30.000000000 +0100 +++ ftrace/arch/x86/kernel/ds.c 2008-12-19 12:29:41.000000000 +0100 @@ -1022,3 +1022,14 @@ update_debugctlmsr(next->thread.debugctlmsr); } + +void ds_copy_thread(struct task_struct *tsk, struct task_struct *father) +{ + clear_tsk_thread_flag(tsk, TIF_DS_AREA_MSR); + tsk->thread.ds_ctx = NULL; +} + +void ds_exit_thread(struct task_struct *tsk) +{ + WARN_ON(tsk->thread.ds_ctx); +} Index: ftrace/arch/x86/kernel/ptrace.c =================================================================== --- ftrace.orig/arch/x86/kernel/ptrace.c 2008-12-19 12:28:23.000000000 +0100 +++ ftrace/arch/x86/kernel/ptrace.c 2008-12-19 13:17:47.000000000 +0100 @@ -769,8 +769,47 @@ return (trace->ds.top - trace->ds.begin) / trace->ds.size; } + +static void ptrace_bts_fork(struct task_struct *tsk) +{ + tsk->bts = NULL; + tsk->bts_buffer = NULL; + tsk->bts_size = 0; + tsk->thread.bts_ovfl_signal = 0; +} + +static void ptrace_bts_untrace(struct task_struct *child) +{ + if (unlikely(child->bts)) { + ds_release_bts(child->bts); + child->bts = NULL; + + kfree(child->bts_buffer); + child->bts_buffer = NULL; + child->bts_size = 0; + } +} + +static void ptrace_bts_detach(struct task_struct *child) +{ + ptrace_bts_untrace(child); +} +#else +static inline void ptrace_bts_fork(struct task_struct *tsk) {} +static inline void ptrace_bts_detach(struct task_struct *child) {} +static inline void ptrace_bts_untrace(struct task_struct *child) {} #endif /* CONFIG_X86_PTRACE_BTS */ +void x86_ptrace_fork(struct task_struct *child, unsigned long clone_flags) +{ + ptrace_bts_fork(child); +} + +void x86_ptrace_untrace(struct task_struct *child) +{ + ptrace_bts_untrace(child); +} + /* * Called by kernel/ptrace.c when detaching.. * @@ -782,16 +821,7 @@ #ifdef TIF_SYSCALL_EMU clear_tsk_thread_flag(child, TIF_SYSCALL_EMU); #endif -#ifdef CONFIG_X86_PTRACE_BTS - if (child->bts) { - ds_release_bts(child->bts); - child->bts = NULL; - - kfree(child->bts_buffer); - child->bts_buffer = NULL; - child->bts_size = 0; - } -#endif /* CONFIG_X86_PTRACE_BTS */ + ptrace_bts_detach(child); } #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION Index: ftrace/include/linux/ptrace.h =================================================================== --- ftrace.orig/include/linux/ptrace.h 2008-12-19 12:28:23.000000000 +0100 +++ ftrace/include/linux/ptrace.h 2008-12-19 12:29:41.000000000 +0100 @@ -94,6 +94,7 @@ extern void __ptrace_link(struct task_struct *child, struct task_struct *new_parent); extern void __ptrace_unlink(struct task_struct *child); +extern void ptrace_fork(struct task_struct *task, unsigned long clone_flags); #define PTRACE_MODE_READ 1 #define PTRACE_MODE_ATTACH 2 /* Returns 0 on success, -errno on denial. */ @@ -313,6 +314,27 @@ #define arch_ptrace_stop(code, info) do { } while (0) #endif +#ifndef arch_ptrace_untrace +/* + * Do machine-specific work before untracing child. + * + * This is called for a normal detach as well as from ptrace_exit() + * when the tracing task dies. + * + * Called with write_lock(&tasklist_lock) held. + */ +#define arch_ptrace_untrace(task) do { } while (0) +#endif + +#ifndef arch_ptrace_fork +/* + * Do machine-specific work to initialize a new task. + * + * This is called from copy_process(). + */ +#define arch_ptrace_fork(child, clone_flags) do { } while (0) +#endif + extern int task_current_syscall(struct task_struct *target, long *callno, unsigned long args[6], unsigned int maxargs, unsigned long *sp, unsigned long *pc); Index: ftrace/kernel/ptrace.c =================================================================== --- ftrace.orig/kernel/ptrace.c 2008-12-19 12:28:23.000000000 +0100 +++ ftrace/kernel/ptrace.c 2008-12-19 12:29:41.000000000 +0100 @@ -25,6 +25,17 @@ #include #include + +/* + * Initialize a new task whose father had been ptraced. + * + * Called from copy_process(). + */ +void ptrace_fork(struct task_struct *child, unsigned long clone_flags) +{ + arch_ptrace_fork(child, clone_flags); +} + /* * ptrace a task: make the debugger its new parent and * move it to the ptrace list. @@ -72,6 +83,7 @@ child->parent = child->real_parent; list_del_init(&child->ptrace_entry); + arch_ptrace_untrace(child); if (task_is_traced(child)) ptrace_untrace(child); } Index: ftrace/arch/x86/include/asm/ptrace.h =================================================================== --- ftrace.orig/arch/x86/include/asm/ptrace.h 2008-12-19 12:28:23.000000000 +0100 +++ ftrace/arch/x86/include/asm/ptrace.h 2008-12-19 12:29:41.000000000 +0100 @@ -235,6 +235,13 @@ 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__ */ --------------------------------------------------------------------- Intel GmbH Dornacher Strasse 1 85622 Feldkirchen/Muenchen Germany Sitz der Gesellschaft: Feldkirchen bei Muenchen Geschaeftsfuehrer: Douglas Lusk, Peter Gleissner, Hannes Schwaderer Registergericht: Muenchen HRB 47456 Ust.-IdNr. 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