From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0BF5FC433EF for ; Thu, 30 Sep 2021 08:29:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E4C226135E for ; Thu, 30 Sep 2021 08:29:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348144AbhI3IbF (ORCPT ); Thu, 30 Sep 2021 04:31:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35512 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348109AbhI3IbF (ORCPT ); Thu, 30 Sep 2021 04:31:05 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9B498C06161C; Thu, 30 Sep 2021 01:29:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=uzic4wxHiJzWES2wvMkJG4KWKCJ8cRQgvRjUfWYW4Ps=; b=ewkRNU2USMCgbxisCjb+/h4q8L Qf2cYr2N6uM0d0X4CTwysSaBsJEWBU0N2C5XNYyAodrNRcdNKyS+lZeVUzzOt31gh2jLXLRFNCs/6 i6dHQaQszHfrAzTn3DZEWgau4Vp4zbwAjmdgflWKFJNET4uTDCRvLeCP34W8ns639INEAoMFlTzaQ IRSyRbEEoew/RB/RwCfqVjbYSg7sElCh/9t/Ygveff5pIdTEe4/UKwlgzwXChRVbZvF15TlHKPBss Q1QaH2wPSBJrtuNsDx6VppZN0ynMlr6kcSixEx7CbJnQkHrxzSrmb3mKRzlVddeZ7b+hxpLdSwrwA SmwUMA0Q==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1mVrQj-006ump-LR; Thu, 30 Sep 2021 08:28:37 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 48ACE300268; Thu, 30 Sep 2021 10:28:37 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 361AB266411B0; Thu, 30 Sep 2021 10:28:37 +0200 (CEST) Date: Thu, 30 Sep 2021 10:28:37 +0200 From: Peter Zijlstra To: Kees Cook Cc: Ingo Molnar , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , kernel test robot , Vito Caputo , Jann Horn , Andrew Morton , Christian Brauner , Anand K Mistry , "Kenta.Tada@sony.com" , Alexey Gladkov , Michael =?iso-8859-1?Q?Wei=DF?= , Michal Hocko , Helge Deller , Qi Zheng , "Tobin C. Harding" , Tycho Andersen , Thomas Gleixner , Borislav Petkov , "H. Peter Anvin" , Mark Rutland , Jens Axboe , Stefan Metzmacher , Lai Jiangshan , Andy Lutomirski , Dave Hansen , "Eric W. Biederman" , Ohhoon Kwon , Kalesh Singh , YiFei Zhu , Josh Poimboeuf , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-hardening@vger.kernel.org, x86@kernel.org Subject: Re: [PATCH v2 2/6] sched: Add wrapper for get_wchan() to keep task blocked Message-ID: References: <20210929220218.691419-1-keescook@chromium.org> <20210929220218.691419-3-keescook@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org On Thu, Sep 30, 2021 at 10:27:07AM +0200, Peter Zijlstra wrote: > On Wed, Sep 29, 2021 at 03:02:14PM -0700, Kees Cook wrote: > > Having a stable wchan means the process must be blocked and for it to > > stay that way while performing stack unwinding. > > How's this instead? > On top of which we can do.. --- Subject: arch: __get_wchan || STACKTRACE_SUPPORT From: Peter Zijlstra Date: Thu Sep 30 10:08:13 CEST 2021 It's trivial to implement __get_wchan() with CONFIG_STACKTRACE Signed-off-by: Peter Zijlstra (Intel) --- arch/arc/include/asm/processor.h | 2 - arch/arc/kernel/stacktrace.c | 17 -------------- arch/arm/include/asm/processor.h | 2 - arch/arm/kernel/process.c | 22 ------------------- arch/arm64/include/asm/processor.h | 2 - arch/arm64/kernel/process.c | 26 ---------------------- arch/csky/include/asm/processor.h | 2 - arch/csky/kernel/stacktrace.c | 18 --------------- arch/microblaze/include/asm/processor.h | 2 - arch/microblaze/kernel/process.c | 6 ----- arch/mips/include/asm/processor.h | 2 - arch/mips/kernel/process.c | 27 ----------------------- arch/nds32/include/asm/processor.h | 2 - arch/nds32/kernel/process.c | 23 ------------------- arch/openrisc/include/asm/processor.h | 1 arch/openrisc/kernel/process.c | 6 ----- arch/parisc/include/asm/processor.h | 2 - arch/parisc/kernel/process.c | 24 -------------------- arch/powerpc/include/asm/processor.h | 2 - arch/powerpc/kernel/process.c | 37 -------------------------------- arch/riscv/include/asm/processor.h | 3 -- arch/riscv/kernel/stacktrace.c | 21 ------------------ arch/s390/include/asm/processor.h | 1 arch/s390/kernel/process.c | 29 ------------------------- arch/sh/include/asm/processor_32.h | 2 - arch/sh/kernel/process_32.c | 19 ---------------- arch/sparc/include/asm/processor_64.h | 2 - arch/sparc/kernel/process_64.c | 28 ------------------------ arch/um/include/asm/processor-generic.h | 1 arch/um/kernel/process.c | 32 --------------------------- arch/x86/include/asm/processor.h | 2 - arch/x86/kernel/process.c | 14 ------------ arch/xtensa/include/asm/processor.h | 2 - arch/xtensa/kernel/process.c | 29 ------------------------- kernel/sched/core.c | 15 ++++++++++++ lib/Kconfig.debug | 7 ------ 36 files changed, 16 insertions(+), 416 deletions(-) --- a/arch/arc/include/asm/processor.h +++ b/arch/arc/include/asm/processor.h @@ -70,8 +70,6 @@ struct task_struct; extern void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long usp); -extern unsigned int __get_wchan(struct task_struct *p); - #endif /* !__ASSEMBLY__ */ /* --- a/arch/arc/kernel/stacktrace.c +++ b/arch/arc/kernel/stacktrace.c @@ -217,14 +217,6 @@ static int __collect_all_but_sched(unsig #endif -static int __get_first_nonsched(unsigned int address, void *unused) -{ - if (in_sched_functions(address)) - return 0; - - return -1; -} - /*------------------------------------------------------------------------- * APIs expected by various kernel sub-systems *------------------------------------------------------------------------- @@ -244,15 +236,6 @@ void show_stack(struct task_struct *tsk, show_stacktrace(tsk, NULL, loglvl); } -/* Another API expected by schedular, shows up in "ps" as Wait Channel - * Of course just returning schedule( ) would be pointless so unwind until - * the function is not in schedular code - */ -unsigned int __get_wchan(struct task_struct *tsk) -{ - return arc_unwind_core(tsk, NULL, __get_first_nonsched, NULL); -} - #ifdef CONFIG_STACKTRACE /* --- a/arch/arm/include/asm/processor.h +++ b/arch/arm/include/asm/processor.h @@ -84,8 +84,6 @@ struct task_struct; /* Free all resources held by a thread. */ extern void release_thread(struct task_struct *); -unsigned long __get_wchan(struct task_struct *p); - #define task_pt_regs(p) \ ((struct pt_regs *)(THREAD_START_SP + task_stack_page(p)) - 1) --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -276,28 +276,6 @@ int copy_thread(unsigned long clone_flag return 0; } -unsigned long __get_wchan(struct task_struct *p) -{ - struct stackframe frame; - unsigned long stack_page; - int count = 0; - - frame.fp = thread_saved_fp(p); - frame.sp = thread_saved_sp(p); - frame.lr = 0; /* recovered from the stack */ - frame.pc = thread_saved_pc(p); - stack_page = (unsigned long)task_stack_page(p); - do { - if (frame.sp < stack_page || - frame.sp >= stack_page + THREAD_SIZE || - unwind_frame(&frame) < 0) - return 0; - if (!in_sched_functions(frame.pc)) - return frame.pc; - } while (count ++ < 16); - return 0; -} - #ifdef CONFIG_MMU #ifdef CONFIG_KUSER_HELPERS /* --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -257,8 +257,6 @@ struct task_struct; /* Free all resources held by a thread. */ extern void release_thread(struct task_struct *); -unsigned long __get_wchan(struct task_struct *p); - void update_sctlr_el1(u64 sctlr); /* Thread switching */ --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -528,32 +528,6 @@ __notrace_funcgraph struct task_struct * return last; } -unsigned long __get_wchan(struct task_struct *p) -{ - struct stackframe frame; - unsigned long stack_page, ret = 0; - int count = 0; - - stack_page = (unsigned long)try_get_task_stack(p); - if (!stack_page) - return 0; - - start_backtrace(&frame, thread_saved_fp(p), thread_saved_pc(p)); - - do { - if (unwind_frame(p, &frame)) - goto out; - if (!in_sched_functions(frame.pc)) { - ret = frame.pc; - goto out; - } - } while (count++ < 16); - -out: - put_task_stack(p); - return ret; -} - unsigned long arch_align_stack(unsigned long sp) { if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) --- a/arch/csky/include/asm/processor.h +++ b/arch/csky/include/asm/processor.h @@ -81,8 +81,6 @@ static inline void release_thread(struct extern int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags); -unsigned long __get_wchan(struct task_struct *p); - #define KSTK_EIP(tsk) (task_pt_regs(tsk)->pc) #define KSTK_ESP(tsk) (task_pt_regs(tsk)->usp) --- a/arch/csky/kernel/stacktrace.c +++ b/arch/csky/kernel/stacktrace.c @@ -101,24 +101,6 @@ void show_stack(struct task_struct *task walk_stackframe(task, NULL, print_trace_address, (void *)loglvl); } -static bool save_wchan(unsigned long pc, void *arg) -{ - if (!in_sched_functions(pc)) { - unsigned long *p = arg; - *p = pc; - return true; - } - return false; -} - -unsigned long __get_wchan(struct task_struct *task) -{ - unsigned long pc = 0; - - walk_stackframe(task, NULL, save_wchan, &pc); - return pc; -} - #ifdef CONFIG_STACKTRACE static bool __save_trace(unsigned long pc, void *arg, bool nosched) { --- a/arch/microblaze/include/asm/processor.h +++ b/arch/microblaze/include/asm/processor.h @@ -68,8 +68,6 @@ static inline void release_thread(struct { } -unsigned long __get_wchan(struct task_struct *p); - /* The size allocated for kernel stacks. This _must_ be a power of two! */ # define KERNEL_STACK_SIZE 0x2000 --- a/arch/microblaze/kernel/process.c +++ b/arch/microblaze/kernel/process.c @@ -112,12 +112,6 @@ int copy_thread(unsigned long clone_flag return 0; } -unsigned long __get_wchan(struct task_struct *p) -{ -/* TBD (used by procfs) */ - return 0; -} - /* Set up a thread for executing a new program */ void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long usp) { --- a/arch/mips/include/asm/processor.h +++ b/arch/mips/include/asm/processor.h @@ -369,8 +369,6 @@ static inline void flush_thread(void) { } -unsigned long __get_wchan(struct task_struct *p); - #define __KSTK_TOS(tsk) ((unsigned long)task_stack_page(tsk) + \ THREAD_SIZE - 32 - sizeof(struct pt_regs)) #define task_pt_regs(tsk) ((struct pt_regs *)__KSTK_TOS(tsk)) --- a/arch/mips/kernel/process.c +++ b/arch/mips/kernel/process.c @@ -651,33 +651,6 @@ unsigned long unwind_stack(struct task_s } #endif -/* - * __get_wchan - a maintenance nightmare^W^Wpain in the ass ... - */ -unsigned long __get_wchan(struct task_struct *task) -{ - unsigned long pc = 0; -#ifdef CONFIG_KALLSYMS - unsigned long sp; - unsigned long ra = 0; -#endif - - if (!task_stack_page(task)) - goto out; - - pc = thread_saved_pc(task); - -#ifdef CONFIG_KALLSYMS - sp = task->thread.reg29 + schedule_mfi.frame_size; - - while (in_sched_functions(pc)) - pc = unwind_stack(task, &sp, pc, &ra); -#endif - -out: - return pc; -} - unsigned long mips_stack_top(void) { unsigned long top = TASK_SIZE & PAGE_MASK; --- a/arch/nds32/include/asm/processor.h +++ b/arch/nds32/include/asm/processor.h @@ -83,8 +83,6 @@ extern struct task_struct *last_task_use /* Prepare to copy thread state - unlazy all lazy status */ #define prepare_to_copy(tsk) do { } while (0) -unsigned long __get_wchan(struct task_struct *p); - #define cpu_relax() barrier() #define task_pt_regs(task) \ --- a/arch/nds32/kernel/process.c +++ b/arch/nds32/kernel/process.c @@ -232,26 +232,3 @@ int dump_fpu(struct pt_regs *regs, elf_f } EXPORT_SYMBOL(dump_fpu); - -unsigned long __get_wchan(struct task_struct *p) -{ - unsigned long fp, lr; - unsigned long stack_start, stack_end; - int count = 0; - - if (IS_ENABLED(CONFIG_FRAME_POINTER)) { - stack_start = (unsigned long)end_of_stack(p); - stack_end = (unsigned long)task_stack_page(p) + THREAD_SIZE; - - fp = thread_saved_fp(p); - do { - if (fp < stack_start || fp > stack_end) - return 0; - lr = ((unsigned long *)fp)[0]; - if (!in_sched_functions(lr)) - return lr; - fp = *(unsigned long *)(fp + 4); - } while (count++ < 16); - } - return 0; -} --- a/arch/openrisc/include/asm/processor.h +++ b/arch/openrisc/include/asm/processor.h @@ -73,7 +73,6 @@ struct thread_struct { void start_thread(struct pt_regs *regs, unsigned long nip, unsigned long sp); void release_thread(struct task_struct *); -unsigned long __get_wchan(struct task_struct *p); #define cpu_relax() barrier() --- a/arch/openrisc/kernel/process.c +++ b/arch/openrisc/kernel/process.c @@ -263,9 +263,3 @@ void dump_elf_thread(elf_greg_t *dest, s dest[35] = 0; } -unsigned long __get_wchan(struct task_struct *p) -{ - /* TODO */ - - return 0; -} --- a/arch/parisc/include/asm/processor.h +++ b/arch/parisc/include/asm/processor.h @@ -273,8 +273,6 @@ struct mm_struct; /* Free all resources held by a thread. */ extern void release_thread(struct task_struct *); -extern unsigned long __get_wchan(struct task_struct *p); - #define KSTK_EIP(tsk) ((tsk)->thread.regs.iaoq[0]) #define KSTK_ESP(tsk) ((tsk)->thread.regs.gr[30]) --- a/arch/parisc/kernel/process.c +++ b/arch/parisc/kernel/process.c @@ -239,30 +239,6 @@ copy_thread(unsigned long clone_flags, u return 0; } -unsigned long -__get_wchan(struct task_struct *p) -{ - struct unwind_frame_info info; - unsigned long ip; - int count = 0; - - /* - * These bracket the sleeping functions.. - */ - - unwind_frame_init_from_blocked_task(&info, p); - do { - if (unwind_once(&info) < 0) - return 0; - if (task_is_running(p)) - return 0; - ip = info.ip; - if (!in_sched_functions(ip)) - return ip; - } while (count++ < MAX_UNWIND_ENTRIES); - return 0; -} - #ifdef CONFIG_64BIT void *dereference_function_descriptor(void *ptr) { --- a/arch/powerpc/include/asm/processor.h +++ b/arch/powerpc/include/asm/processor.h @@ -300,8 +300,6 @@ struct thread_struct { #define task_pt_regs(tsk) ((tsk)->thread.regs) -unsigned long __get_wchan(struct task_struct *p); - #define KSTK_EIP(tsk) ((tsk)->thread.regs? (tsk)->thread.regs->nip: 0) #define KSTK_ESP(tsk) ((tsk)->thread.regs? (tsk)->thread.regs->gpr[1]: 0) --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -2111,43 +2111,6 @@ int validate_sp(unsigned long sp, struct EXPORT_SYMBOL(validate_sp); -static unsigned long ___get_wchan(struct task_struct *p) -{ - unsigned long ip, sp; - int count = 0; - - sp = p->thread.ksp; - if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD)) - return 0; - - do { - sp = *(unsigned long *)sp; - if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD) || - task_is_running(p)) - return 0; - if (count > 0) { - ip = ((unsigned long *)sp)[STACK_FRAME_LR_SAVE]; - if (!in_sched_functions(ip)) - return ip; - } - } while (count++ < 16); - return 0; -} - -unsigned long __get_wchan(struct task_struct *p) -{ - unsigned long ret; - - if (!try_get_task_stack(p)) - return 0; - - ret = ___get_wchan(p); - - put_task_stack(p); - - return ret; -} - static int kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH; void __no_sanitize_address show_stack(struct task_struct *tsk, --- a/arch/riscv/include/asm/processor.h +++ b/arch/riscv/include/asm/processor.h @@ -66,9 +66,6 @@ static inline void release_thread(struct { } -extern unsigned long __get_wchan(struct task_struct *p); - - static inline void wait_for_interrupt(void) { __asm__ __volatile__ ("wfi"); --- a/arch/riscv/kernel/stacktrace.c +++ b/arch/riscv/kernel/stacktrace.c @@ -118,27 +118,6 @@ void show_stack(struct task_struct *task dump_backtrace(NULL, task, loglvl); } -static bool save_wchan(void *arg, unsigned long pc) -{ - if (!in_sched_functions(pc)) { - unsigned long *p = arg; - *p = pc; - return false; - } - return true; -} - -unsigned long __get_wchan(struct task_struct *task) -{ - unsigned long pc = 0; - - if (!try_get_task_stack(task)) - return 0; - walk_stackframe(task, NULL, save_wchan, &pc); - put_task_stack(task); - return pc; -} - #ifdef CONFIG_STACKTRACE noinline void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie, --- a/arch/s390/include/asm/processor.h +++ b/arch/s390/include/asm/processor.h @@ -192,7 +192,6 @@ static inline void release_thread(struct void guarded_storage_release(struct task_struct *tsk); void gs_load_bc_cb(struct pt_regs *regs); -unsigned long __get_wchan(struct task_struct *p); #define task_pt_regs(tsk) ((struct pt_regs *) \ (task_stack_page(tsk) + THREAD_SIZE) - 1) #define KSTK_EIP(tsk) (task_pt_regs(tsk)->psw.addr) --- a/arch/s390/kernel/process.c +++ b/arch/s390/kernel/process.c @@ -181,35 +181,6 @@ void execve_tail(void) asm volatile("sfpc %0" : : "d" (0)); } -unsigned long __get_wchan(struct task_struct *p) -{ - struct unwind_state state; - unsigned long ip = 0; - - if (!task_stack_page(p)) - return 0; - - if (!try_get_task_stack(p)) - return 0; - - unwind_for_each_frame(&state, p, NULL, 0) { - if (state.stack_info.type != STACK_TYPE_TASK) { - ip = 0; - break; - } - - ip = unwind_get_return_address(&state); - if (!ip) - break; - - if (!in_sched_functions(ip)) - break; - } - - put_task_stack(p); - return ip; -} - unsigned long arch_align_stack(unsigned long sp) { if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) --- a/arch/sh/include/asm/processor_32.h +++ b/arch/sh/include/asm/processor_32.h @@ -180,8 +180,6 @@ static inline void show_code(struct pt_r } #endif -extern unsigned long __get_wchan(struct task_struct *p); - #define KSTK_EIP(tsk) (task_pt_regs(tsk)->pc) #define KSTK_ESP(tsk) (task_pt_regs(tsk)->regs[15]) --- a/arch/sh/kernel/process_32.c +++ b/arch/sh/kernel/process_32.c @@ -181,22 +181,3 @@ __switch_to(struct task_struct *prev, st return prev; } - -unsigned long __get_wchan(struct task_struct *p) -{ - unsigned long pc; - - /* - * The same comment as on the Alpha applies here, too ... - */ - pc = thread_saved_pc(p); - -#ifdef CONFIG_FRAME_POINTER - if (in_sched_functions(pc)) { - unsigned long schedule_frame = (unsigned long)p->thread.sp; - return ((unsigned long *)schedule_frame)[21]; - } -#endif - - return pc; -} --- a/arch/sparc/include/asm/processor_64.h +++ b/arch/sparc/include/asm/processor_64.h @@ -183,8 +183,6 @@ do { \ /* Free all resources held by a thread. */ #define release_thread(tsk) do { } while (0) -unsigned long __get_wchan(struct task_struct *task); - #define task_pt_regs(tsk) (task_thread_info(tsk)->kregs) #define KSTK_EIP(tsk) (task_pt_regs(tsk)->tpc) #define KSTK_ESP(tsk) (task_pt_regs(tsk)->u_regs[UREG_FP]) --- a/arch/sparc/kernel/process_64.c +++ b/arch/sparc/kernel/process_64.c @@ -662,31 +662,3 @@ int arch_dup_task_struct(struct task_str *dst = *src; return 0; } - -unsigned long __get_wchan(struct task_struct *task) -{ - unsigned long pc, fp, bias = 0; - struct thread_info *tp; - struct reg_window *rw; - unsigned long ret = 0; - int count = 0; - - tp = task_thread_info(task); - bias = STACK_BIAS; - fp = task_thread_info(task)->ksp + bias; - - do { - if (!kstack_valid(tp, fp)) - break; - rw = (struct reg_window *) fp; - pc = rw->ins[7]; - if (!in_sched_functions(pc)) { - ret = pc; - goto out; - } - fp = rw->ins[6] + bias; - } while (++count < 16); - -out: - return ret; -} --- a/arch/um/include/asm/processor-generic.h +++ b/arch/um/include/asm/processor-generic.h @@ -106,6 +106,5 @@ extern struct cpuinfo_um boot_cpu_data; #define cache_line_size() (boot_cpu_data.cache_alignment) #define KSTK_REG(tsk, reg) get_thread_reg(reg, &tsk->thread.switch_buf) -extern unsigned long __get_wchan(struct task_struct *p); #endif --- a/arch/um/kernel/process.c +++ b/arch/um/kernel/process.c @@ -364,38 +364,6 @@ unsigned long arch_align_stack(unsigned } #endif -unsigned long __get_wchan(struct task_struct *p) -{ - unsigned long stack_page, sp, ip; - bool seen_sched = 0; - - stack_page = (unsigned long) task_stack_page(p); - /* Bail if the process has no kernel stack for some reason */ - if (stack_page == 0) - return 0; - - sp = p->thread.switch_buf->JB_SP; - /* - * Bail if the stack pointer is below the bottom of the kernel - * stack for some reason - */ - if (sp < stack_page) - return 0; - - while (sp < stack_page + THREAD_SIZE) { - ip = *((unsigned long *) sp); - if (in_sched_functions(ip)) - /* Ignore everything until we're above the scheduler */ - seen_sched = 1; - else if (kernel_text_address(ip) && seen_sched) - return ip; - - sp += sizeof(unsigned long); - } - - return 0; -} - int elf_core_copy_fpregs(struct task_struct *t, elf_fpregset_t *fpu) { int cpu = current_thread_info()->cpu; --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -590,8 +590,6 @@ static inline void load_sp0(unsigned lon /* Free all resources held by a thread. */ extern void release_thread(struct task_struct *); -unsigned long __get_wchan(struct task_struct *p); - /* * Generic CPUID function * clear %ecx since some cpus (Cyrix MII) do not set or clear %ecx --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -937,20 +937,6 @@ unsigned long arch_randomize_brk(struct return randomize_page(mm->brk, 0x02000000); } -/* - * Called from fs/proc with a reference on @p to find the function - * which called into schedule(). This needs to be done carefully - * because the task might wake up and we might look at a stack - * changing under us. - */ -unsigned long __get_wchan(struct task_struct *p) -{ - unsigned long entry = 0; - - stack_trace_save_tsk(p, &entry, 1, 0); - return entry; -} - long do_arch_prctl_common(struct task_struct *task, int option, unsigned long cpuid_enabled) { --- a/arch/xtensa/include/asm/processor.h +++ b/arch/xtensa/include/asm/processor.h @@ -215,8 +215,6 @@ struct mm_struct; /* Free all resources held by a thread. */ #define release_thread(thread) do { } while(0) -extern unsigned long __get_wchan(struct task_struct *p); - #define KSTK_EIP(tsk) (task_pt_regs(tsk)->pc) #define KSTK_ESP(tsk) (task_pt_regs(tsk)->areg[1]) --- a/arch/xtensa/kernel/process.c +++ b/arch/xtensa/kernel/process.c @@ -293,32 +293,3 @@ int copy_thread(unsigned long clone_flag return 0; } - -/* - * These bracket the sleeping functions.. - */ - -unsigned long __get_wchan(struct task_struct *p) -{ - unsigned long sp, pc; - unsigned long stack_page = (unsigned long) task_stack_page(p); - int count = 0; - - sp = p->thread.sp; - pc = MAKE_PC_FROM_RA(p->thread.ra, p->thread.sp); - - do { - if (sp < stack_page + sizeof(struct task_struct) || - sp >= (stack_page + THREAD_SIZE) || - pc == 0) - return 0; - if (!in_sched_functions(pc)) - return pc; - - /* Stack layout: sp-4: ra, sp-3: sp' */ - - pc = MAKE_PC_FROM_RA(SPILL_SLOT(sp, 0), sp); - sp = SPILL_SLOT(sp, 1); - } while (count++ < 16); - return 0; -} --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1962,6 +1962,21 @@ bool sched_task_on_rq(struct task_struct return task_on_rq_queued(p); } +#ifdef CONFIG_STACKTRACE +static unsigned long __get_wchan(struct task_struct *p) +{ + unsigned long entry = 0; + + stack_trace_save_tsk(p, &entry, 1, 0); + + return entry; +} +#endif + +/* + * Called from fs/proc with a reference on @p to find the function + * which called into schedule(). + */ unsigned long get_wchan(struct task_struct *p) { unsigned long ip = 0; --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1531,13 +1531,8 @@ config DEBUG_IRQFLAGS are enabled. config STACKTRACE - bool "Stack backtrace support" + def_bool y depends on STACKTRACE_SUPPORT - help - This option causes the kernel to create a /proc/pid/stack for - every process, showing its current stack trace. - It is also used by various kernel debugging features that require - stack trace generation. config WARN_ALL_UNSEEDED_RANDOM bool "Warn for all uses of unseeded randomness"