From patchwork Fri Dec 8 10:26:29 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Masami Hiramatsu (Google)" X-Patchwork-Id: 13485217 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DBE4B14297; Fri, 8 Dec 2023 10:26:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="KiT6MTUn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 58557C433C7; Fri, 8 Dec 2023 10:26:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1702031194; bh=TJdlXgVoOs1czXw3FLraoNo4e1qHiUrA0KJRNqTzl28=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KiT6MTUnXIitKHAslmL3c4I/TUZVj2ZMsl5+jO3PSwYBrNwn5BwJH7/KaGJ+lAr5j vxwKshOagbzby3sf1XurV3iMo11YGqeiYn0pgvJk9OKGiyvq5o9X0k7fj0eBTKzbDN uDTRHOzo9f3N6eO0tfZDYMHwzwGEpTJpJ3U3F6WOHarH3bYjYrarCCb/pH84YzmjY9 1ij1KDpjGcBb+TncXlunSE1Qdk5/uwOXkc/4GOxb+kbIlxjJp/ZINWIYNeVq10d9il b38sl5R/0hcn1eu5AKT6yx47avaDCRJR7VeHA31PEZQNz9cuxIqROBr42ITAzKTkzM rbgYMcgP3jXYw== From: "Masami Hiramatsu (Google)" To: Alexei Starovoitov , Steven Rostedt , Florent Revest Cc: linux-trace-kernel@vger.kernel.org, LKML , Martin KaFai Lau , bpf , Sven Schnelle , Alexei Starovoitov , Jiri Olsa , Arnaldo Carvalho de Melo , Daniel Borkmann , Alan Maguire , Mark Rutland , Peter Zijlstra , Thomas Gleixner , Guo Ren Subject: [PATCH v4 11/33] function_graph: Have the instances use their own ftrace_ops for filtering Date: Fri, 8 Dec 2023 19:26:29 +0900 Message-Id: <170203118875.579004.6433626598470720315.stgit@devnote2> X-Mailer: git-send-email 2.34.1 In-Reply-To: <170203105427.579004.8033550792660734570.stgit@devnote2> References: <170203105427.579004.8033550792660734570.stgit@devnote2> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Steven Rostedt (VMware) Allow for instances to have their own ftrace_ops part of the fgraph_ops that makes the funtion_graph tracer filter on the set_ftrace_filter file of the instance and not the top instance. This also change how the function_graph handles multiple instances on the shadow stack. Previously we use ARRAY type entries to record which one is enabled, and this makes it a bitmap of the fgraph_array's indexes. Previous function_graph_enter() expects calling back from prepare_ftrace_return() function which is called back only once if it is enabled. But this introduces different ftrace_ops for each fgraph instance and those are called from ftrace_graph_func() one by one. Thus we can not loop on the fgraph_array(), and need to reuse the ret_stack pushed by the previous instance. Finding the ret_stack is easy because we can check the ret_stack->func. But that is not enough for the self- recursive tail-call case. Thus fgraph uses the bitmap entry to find it is already set (this means that entry is for previous tail call). Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Masami Hiramatsu (Google) --- Changes in v4: - Simplify get_ret_stack() sanity check and use WARN_ON_ONCE() for obviously wrong value. - Do not check ret == return_to_handler but always read the previous ret_stack in ftrace_push_return_trace() to check it is reusable. - Set the bit 0 of the bitmap entry always in function_graph_enter() because it uses bit 0 to check re-usability. - Fix to ensure the ret_stack entry is bitmap type when checking the bitmap. Changes in v3: - Pass current fgraph_ops to the new entry handler (function_graph_enter_ops) if fgraph use ftrace. - Add fgraph_ops::idx in this patch. - Replace the array type with the bitmap type so that it can record which fgraph is called. - Fix some helper function to use passed task_struct instead of current. - Reduce the ret-index size to 1024 words. - Make the ret-index directly points the ret_stack. - Fix ftrace_graph_ret_addr() to handle tail-call case correctly. Changes in v2: - Use ftrace_graph_func and FTRACE_OPS_GRAPH_STUB instead of ftrace_stub and FTRACE_OPS_FL_STUB for new ftrace based fgraph. --- arch/arm64/kernel/ftrace.c | 19 ++ arch/x86/kernel/ftrace.c | 19 ++ include/linux/ftrace.h | 7 + kernel/trace/fgraph.c | 369 ++++++++++++++++++++-------------- kernel/trace/ftrace.c | 6 - kernel/trace/trace.h | 16 + kernel/trace/trace_functions.c | 2 kernel/trace/trace_functions_graph.c | 8 + 8 files changed, 277 insertions(+), 169 deletions(-) diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c index a650f5e11fc5..205937e04ece 100644 --- a/arch/arm64/kernel/ftrace.c +++ b/arch/arm64/kernel/ftrace.c @@ -481,7 +481,24 @@ void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent, void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *op, struct ftrace_regs *fregs) { - prepare_ftrace_return(ip, &fregs->lr, fregs->fp); + unsigned long *parent = &fregs->lr; + struct fgraph_ops *gops = container_of(op, struct fgraph_ops, ops); + int bit; + + if (unlikely(ftrace_graph_is_dead())) + return; + + if (unlikely(atomic_read(¤t->tracing_graph_pause))) + return; + + bit = ftrace_test_recursion_trylock(ip, *parent); + if (bit < 0) + return; + + if (!function_graph_enter_ops(*parent, ip, fregs->fp, parent, gops)) + *parent = (unsigned long)&return_to_handler; + + ftrace_test_recursion_unlock(bit); } #else /* diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index 12df54ff0e81..845e29b4254f 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -657,9 +657,24 @@ void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *op, struct ftrace_regs *fregs) { struct pt_regs *regs = &fregs->regs; - unsigned long *stack = (unsigned long *)kernel_stack_pointer(regs); + unsigned long *parent = (unsigned long *)kernel_stack_pointer(regs); + struct fgraph_ops *gops = container_of(op, struct fgraph_ops, ops); + int bit; + + if (unlikely(ftrace_graph_is_dead())) + return; + + if (unlikely(atomic_read(¤t->tracing_graph_pause))) + return; - prepare_ftrace_return(ip, (unsigned long *)stack, 0); + bit = ftrace_test_recursion_trylock(ip, *parent); + if (bit < 0) + return; + + if (!function_graph_enter_ops(*parent, ip, 0, parent, gops)) + *parent = (unsigned long)&return_to_handler; + + ftrace_test_recursion_unlock(bit); } #endif diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 7b08169aa51d..c431a33fe789 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -1070,7 +1070,9 @@ extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace, struct fgraph struct fgraph_ops { trace_func_graph_ent_t entryfunc; trace_func_graph_ret_t retfunc; + struct ftrace_ops ops; /* for the hash lists */ void *private; + int idx; }; /* @@ -1104,6 +1106,11 @@ extern int function_graph_enter(unsigned long ret, unsigned long func, unsigned long frame_pointer, unsigned long *retp); +extern int +function_graph_enter_ops(unsigned long ret, unsigned long func, + unsigned long frame_pointer, unsigned long *retp, + struct fgraph_ops *gops); + struct ftrace_ret_stack * ftrace_graph_get_ret_stack(struct task_struct *task, int idx); diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c index 62c35d6d95f9..6f537ebd3ed7 100644 --- a/kernel/trace/fgraph.c +++ b/kernel/trace/fgraph.c @@ -7,6 +7,7 @@ * * Highly modified by Steven Rostedt (VMware). */ +#include #include #include #include @@ -17,22 +18,15 @@ #include "ftrace_internal.h" #include "trace.h" -#ifdef CONFIG_DYNAMIC_FTRACE -#define ASSIGN_OPS_HASH(opsname, val) \ - .func_hash = val, \ - .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock), -#else -#define ASSIGN_OPS_HASH(opsname, val) -#endif - #define FGRAPH_RET_SIZE sizeof(struct ftrace_ret_stack) #define FGRAPH_RET_INDEX (FGRAPH_RET_SIZE / sizeof(long)) /* * On entry to a function (via function_graph_enter()), a new ftrace_ret_stack - * is allocated on the task's ret_stack, then each fgraph_ops on the - * fgraph_array[]'s entryfunc is called and if that returns non-zero, the - * index into the fgraph_array[] for that fgraph_ops is added to the ret_stack. + * is allocated on the task's ret_stack with indexes entry, then each + * fgraph_ops on the fgraph_array[]'s entryfunc is called and if that returns + * non-zero, the index into the fgraph_array[] for that fgraph_ops is recorded + * on the indexes entry as a bit flag. * As the associated ftrace_ret_stack saved for those fgraph_ops needs to * be found, the index to it is also added to the ret_stack along with the * index of the fgraph_array[] to each fgraph_ops that needs their retfunc @@ -42,61 +36,59 @@ * to the last ftrace_ret_stack saved. All references to the * ftrace_ret_stack has the format of: * - * bits: 0 - 13 Index in words from the previous ftrace_ret_stack - * bits: 14 - 15 Type of storage + * bits: 0 - 9 offset in words from the previous ftrace_ret_stack + * (bitmap type should have FGRAPH_RET_INDEX always) + * bits: 10 - 11 Type of storage * 0 - reserved - * 1 - fgraph_array index - * For fgraph_array_index: - * bits: 16 - 23 The fgraph_ops fgraph_array index + * 1 - bitmap of fgraph_array index + * + * For bitmap of fgraph_array index + * bits: 12 - 27 The bitmap of fgraph_ops fgraph_array index * * That is, at the end of function_graph_enter, if the first and forth * fgraph_ops on the fgraph_array[] (index 0 and 3) needs their retfunc called * on the return of the function being traced, this is what will be on the * task's shadow ret_stack: (the stack grows upward) * - * | | <- task->curr_ret_stack - * +----------------------------------+ - * | (3 << FGRAPH_ARRAY_SHIFT)|(2) | ( 3 for index of fourth fgraph_ops) - * +----------------------------------+ - * | (0 << FGRAPH_ARRAY_SHIFT)|(1) | ( 0 for index of first fgraph_ops) - * +----------------------------------+ - * | struct ftrace_ret_stack | - * | (stores the saved ret pointer) | - * +----------------------------------+ - * | (X) | (N) | ( N words away from previous ret_stack) - * | | + * | | <- task->curr_ret_stack + * +--------------------------------------------+ + * | bitmap_type(bitmap:(BIT(3)|BIT(0)), | + * | offset:FGRAPH_RET_INDEX) | <- the offset is from here + * +--------------------------------------------+ + * | struct ftrace_ret_stack | + * | (stores the saved ret pointer) | <- the offset points here + * +--------------------------------------------+ + * | (X) | (N) | ( N words away from + * | | previous ret_stack) * * If a backtrace is required, and the real return pointer needs to be * fetched, then it looks at the task's curr_ret_stack index, if it - * is greater than zero, it would subtact one, and then mask the value - * on the ret_stack by FGRAPH_RET_INDEX_MASK and subtract FGRAPH_RET_INDEX - * from that, to get the index of the ftrace_ret_stack structure stored - * on the shadow stack. + * is greater than zero (reserved, or right before poped), it would mask + * the value by FGRAPH_RET_INDEX_MASK to get the offset index of the + * ftrace_ret_stack structure stored on the shadow stack. */ -#define FGRAPH_RET_INDEX_SIZE 14 -#define FGRAPH_RET_INDEX_MASK ((1 << FGRAPH_RET_INDEX_SIZE) - 1) - +#define FGRAPH_RET_INDEX_SIZE 10 +#define FGRAPH_RET_INDEX_MASK GENMASK(FGRAPH_RET_INDEX_SIZE - 1, 0) #define FGRAPH_TYPE_SIZE 2 -#define FGRAPH_TYPE_MASK ((1 << FGRAPH_TYPE_SIZE) - 1) +#define FGRAPH_TYPE_MASK GENMASK(FGRAPH_TYPE_SIZE - 1, 0) #define FGRAPH_TYPE_SHIFT FGRAPH_RET_INDEX_SIZE enum { FGRAPH_TYPE_RESERVED = 0, - FGRAPH_TYPE_ARRAY = 1, + FGRAPH_TYPE_BITMAP = 1, }; -#define FGRAPH_ARRAY_SIZE 16 -#define FGRAPH_ARRAY_MASK ((1 << FGRAPH_ARRAY_SIZE) - 1) -#define FGRAPH_ARRAY_SHIFT (FGRAPH_TYPE_SHIFT + FGRAPH_TYPE_SIZE) +#define FGRAPH_INDEX_SIZE 16 +#define FGRAPH_INDEX_MASK GENMASK(FGRAPH_INDEX_SIZE - 1, 0) +#define FGRAPH_INDEX_SHIFT (FGRAPH_TYPE_SHIFT + FGRAPH_TYPE_SIZE) /* Currently the max stack index can't be more than register callers */ -#define FGRAPH_MAX_INDEX FGRAPH_ARRAY_SIZE +#define FGRAPH_MAX_INDEX (FGRAPH_INDEX_SIZE + FGRAPH_RET_INDEX) + +#define FGRAPH_ARRAY_SIZE FGRAPH_INDEX_SIZE -#define FGRAPH_FRAME_SIZE (FGRAPH_RET_SIZE + FGRAPH_ARRAY_SIZE * (sizeof(long))) -#define FGRAPH_FRAME_INDEX (ALIGN(FGRAPH_FRAME_SIZE, \ - sizeof(long)) / sizeof(long)) #define SHADOW_STACK_SIZE (PAGE_SIZE) #define SHADOW_STACK_INDEX (SHADOW_STACK_SIZE / sizeof(long)) /* Leave on a buffer at the end */ @@ -113,19 +105,36 @@ static struct fgraph_ops *fgraph_array[FGRAPH_ARRAY_SIZE]; static inline int get_ret_stack_index(struct task_struct *t, int offset) { - return current->ret_stack[offset] & FGRAPH_RET_INDEX_MASK; + return t->ret_stack[offset] & FGRAPH_RET_INDEX_MASK; } static inline int get_fgraph_type(struct task_struct *t, int offset) { - return (current->ret_stack[offset] >> FGRAPH_TYPE_SHIFT) & - FGRAPH_TYPE_MASK; + return (t->ret_stack[offset] >> FGRAPH_TYPE_SHIFT) & FGRAPH_TYPE_MASK; +} + +static inline unsigned long +get_fgraph_index_bitmap(struct task_struct *t, int offset) +{ + return (t->ret_stack[offset] >> FGRAPH_INDEX_SHIFT) & FGRAPH_INDEX_MASK; } -static inline int get_fgraph_array(struct task_struct *t, int offset) +static inline void +set_fgraph_index_bitmap(struct task_struct *t, int offset, unsigned long bitmap) { - return (current->ret_stack[offset] >> FGRAPH_ARRAY_SHIFT) & - FGRAPH_ARRAY_MASK; + t->ret_stack[offset] = (bitmap << FGRAPH_INDEX_SHIFT) | + (FGRAPH_TYPE_BITMAP << FGRAPH_TYPE_SHIFT) | FGRAPH_RET_INDEX; +} + +static inline bool is_fgraph_index_set(struct task_struct *t, int offset, int idx) +{ + return !!(get_fgraph_index_bitmap(t, offset) & BIT(idx)); +} + +static inline void +add_fgraph_index_bitmap(struct task_struct *t, int offset, unsigned long bitmap) +{ + t->ret_stack[offset] |= (bitmap << FGRAPH_INDEX_SHIFT); } /* ftrace_graph_entry set to this to tell some archs to run function graph */ @@ -160,17 +169,14 @@ get_ret_stack(struct task_struct *t, int offset, int *index) BUILD_BUG_ON(FGRAPH_RET_SIZE % sizeof(long)); - if (offset <= 0) + if (unlikely(offset <= 0)) return NULL; - idx = get_ret_stack_index(t, offset - 1); - - if (idx <= 0 || idx > FGRAPH_MAX_INDEX) + idx = get_ret_stack_index(t, --offset); + if (WARN_ON_ONCE(idx <= 0 || idx > offset)) return NULL; - offset -= idx + FGRAPH_RET_INDEX; - if (offset < 0) - return NULL; + offset -= idx; *index = offset; return RET_STACK(t, offset); @@ -231,10 +237,12 @@ void ftrace_graph_stop(void) /* Add a function return address to the trace stack on thread info.*/ static int ftrace_push_return_trace(unsigned long ret, unsigned long func, - unsigned long frame_pointer, unsigned long *retp) + unsigned long frame_pointer, unsigned long *retp, + int fgraph_idx) { struct ftrace_ret_stack *ret_stack; unsigned long long calltime; + unsigned long val; int index; if (unlikely(ftrace_graph_is_dead())) @@ -243,6 +251,21 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, if (!current->ret_stack) return -EBUSY; + /* + * At first, check whether the previous fgraph callback is pushed by + * the fgraph on the same function entry. + * But if @func is the self tail-call function, we also need to ensure + * the ret_stack is not for the previous call by checking whether the + * bit of @fgraph_idx is set or not. + */ + ret_stack = get_ret_stack(current, current->curr_ret_stack, &index); + if (ret_stack && ret_stack->func == func && + get_fgraph_type(current, index + FGRAPH_RET_INDEX) == FGRAPH_TYPE_BITMAP && + !is_fgraph_index_set(current, index + FGRAPH_RET_INDEX, fgraph_idx)) + return index + FGRAPH_RET_INDEX; + + val = (FGRAPH_TYPE_RESERVED << FGRAPH_TYPE_SHIFT) | FGRAPH_RET_INDEX; + BUILD_BUG_ON(SHADOW_STACK_SIZE % sizeof(long)); /* @@ -252,17 +275,19 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, smp_rmb(); /* The return trace stack is full */ - if (current->curr_ret_stack >= SHADOW_STACK_MAX_INDEX) { + if (current->curr_ret_stack + FGRAPH_RET_INDEX >= SHADOW_STACK_MAX_INDEX) { atomic_inc(¤t->trace_overrun); return -EBUSY; } calltime = trace_clock_local(); - index = current->curr_ret_stack; - /* ret offset = 1 ; type = reserved */ - current->ret_stack[index + FGRAPH_RET_INDEX] = 1; + index = READ_ONCE(current->curr_ret_stack); ret_stack = RET_STACK(current, index); + index += FGRAPH_RET_INDEX; + + /* ret offset = FGRAPH_RET_INDEX ; type = reserved */ + current->ret_stack[index] = val; ret_stack->ret = ret; /* * The unwinders expect curr_ret_stack to point to either zero @@ -278,7 +303,7 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, * at least a correct index! */ barrier(); - current->curr_ret_stack += FGRAPH_RET_INDEX + 1; + current->curr_ret_stack = index + 1; /* * This next barrier is to ensure that an interrupt coming in * will not corrupt what we are about to write. @@ -286,7 +311,7 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, barrier(); /* Still keep it reserved even if an interrupt came in */ - current->ret_stack[index + FGRAPH_RET_INDEX] = 1; + current->ret_stack[index] = val; ret_stack->ret = ret; ret_stack->func = func; @@ -297,7 +322,7 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, #ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR ret_stack->retp = retp; #endif - return 0; + return index; } /* @@ -314,15 +339,13 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, # define MCOUNT_INSN_SIZE 0 #endif +/* If the caller does not use ftrace, call this function. */ int function_graph_enter(unsigned long ret, unsigned long func, unsigned long frame_pointer, unsigned long *retp) { struct ftrace_graph_ent trace; - int offset; - int start; - int type; - int val; - int cnt = 0; + unsigned long bitmap = 0; + int index; int i; #ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS @@ -337,69 +360,33 @@ int function_graph_enter(unsigned long ret, unsigned long func, return -EBUSY; #endif - if (!ftrace_ops_test(&global_ops, func, NULL)) - return -EBUSY; - trace.func = func; trace.depth = ++current->curr_ret_depth; - if (ftrace_push_return_trace(ret, func, frame_pointer, retp)) + index = ftrace_push_return_trace(ret, func, frame_pointer, retp, 0); + if (index < 0) goto out; - /* Use start for the distance to ret_stack (skipping over reserve) */ - start = offset = current->curr_ret_stack - 2; - for (i = 0; i < fgraph_array_cnt; i++) { struct fgraph_ops *gops = fgraph_array[i]; if (gops == &fgraph_stub) continue; - if ((offset == start) && - (current->curr_ret_stack >= SHADOW_STACK_INDEX - 1)) { - atomic_inc(¤t->trace_overrun); - break; - } - if (fgraph_array[i]->entryfunc(&trace, fgraph_array[i])) { - offset = current->curr_ret_stack; - /* Check the top level stored word */ - type = get_fgraph_type(current, offset - 1); - - val = (i << FGRAPH_ARRAY_SHIFT) | - (FGRAPH_TYPE_ARRAY << FGRAPH_TYPE_SHIFT) | - ((offset - start) - 1); - - /* We can reuse the top word if it is reserved */ - if (type == FGRAPH_TYPE_RESERVED) { - current->ret_stack[offset - 1] = val; - cnt++; - continue; - } - val++; - - current->ret_stack[offset] = val; - /* - * Write the value before we increment, so that - * if an interrupt comes in after we increment - * it will still see the value and skip over - * this. - */ - barrier(); - current->curr_ret_stack++; - /* - * Have to write again, in case an interrupt - * came in before the increment and after we - * wrote the value. - */ - barrier(); - current->ret_stack[offset] = val; - cnt++; - } + if (ftrace_ops_test(&gops->ops, func, NULL) && + gops->entryfunc(&trace, gops)) + bitmap |= BIT(i); } - if (!cnt) + if (!bitmap) goto out_ret; + /* + * Since this function uses fgraph_idx = 0 as a tail-call checking + * flag, set that bit always. + */ + set_fgraph_index_bitmap(current, index, bitmap | BIT(0)); + return 0; out_ret: current->curr_ret_stack -= FGRAPH_RET_INDEX + 1; @@ -408,15 +395,51 @@ int function_graph_enter(unsigned long ret, unsigned long func, return -EBUSY; } +/* This is called from ftrace_graph_func() via ftrace */ +int function_graph_enter_ops(unsigned long ret, unsigned long func, + unsigned long frame_pointer, unsigned long *retp, + struct fgraph_ops *gops) +{ + struct ftrace_graph_ent trace; + int index; + int type; + + + /* Use start for the distance to ret_stack (skipping over reserve) */ + index = ftrace_push_return_trace(ret, func, frame_pointer, retp, gops->idx); + if (index < 0) + return index; + type = get_fgraph_type(current, index); + + /* This is the first ret_stack for this fentry */ + if (type == FGRAPH_TYPE_RESERVED) + ++current->curr_ret_depth; + + trace.func = func; + trace.depth = current->curr_ret_depth; + if (gops->entryfunc(&trace, gops)) { + if (type == FGRAPH_TYPE_RESERVED) + set_fgraph_index_bitmap(current, index, BIT(gops->idx)); + else + add_fgraph_index_bitmap(current, index, BIT(gops->idx)); + return 0; + } + + if (type == FGRAPH_TYPE_RESERVED) { + current->curr_ret_stack -= FGRAPH_RET_INDEX + 1; + current->curr_ret_depth--; + } + return -EBUSY; +} + /* Retrieve a function return address to the trace stack on thread info.*/ static struct ftrace_ret_stack * ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret, - unsigned long frame_pointer) + unsigned long frame_pointer, int *index) { struct ftrace_ret_stack *ret_stack; - int index; - ret_stack = get_ret_stack(current, current->curr_ret_stack, &index); + ret_stack = get_ret_stack(current, current->curr_ret_stack, index); if (unlikely(!ret_stack)) { ftrace_graph_stop(); @@ -455,6 +478,7 @@ ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret, } #endif + *index += FGRAPH_RET_INDEX; *ret = ret_stack->ret; trace->func = ret_stack->func; trace->calltime = ret_stack->calltime; @@ -507,13 +531,12 @@ static unsigned long __ftrace_return_to_handler(struct fgraph_ret_regs *ret_regs { struct ftrace_ret_stack *ret_stack; struct ftrace_graph_ret trace; + unsigned long bitmap; unsigned long ret; - int offset; int index; - int idx; int i; - ret_stack = ftrace_pop_return_trace(&trace, &ret, frame_pointer); + ret_stack = ftrace_pop_return_trace(&trace, &ret, frame_pointer, &index); if (unlikely(!ret_stack)) { ftrace_graph_stop(); @@ -527,16 +550,17 @@ static unsigned long __ftrace_return_to_handler(struct fgraph_ret_regs *ret_regs trace.retval = fgraph_ret_regs_return_value(ret_regs); #endif - offset = current->curr_ret_stack - 1; - index = get_ret_stack_index(current, offset); + bitmap = get_fgraph_index_bitmap(current, index); + for (i = 0; i < FGRAPH_ARRAY_SIZE; i++) { + struct fgraph_ops *gops = fgraph_array[i]; - /* index has to be at least one! Optimize for it */ - i = 0; - do { - idx = get_fgraph_array(current, offset - i); - fgraph_array[idx]->retfunc(&trace, fgraph_array[idx]); - i++; - } while (i < index); + if (!(bitmap & BIT(i))) + continue; + if (gops == &fgraph_stub) + continue; + + gops->retfunc(&trace, gops); + } /* * The ftrace_graph_return() may still access the current @@ -544,7 +568,7 @@ static unsigned long __ftrace_return_to_handler(struct fgraph_ret_regs *ret_regs * curr_ret_stack is after that. */ barrier(); - current->curr_ret_stack -= index + FGRAPH_RET_INDEX; + current->curr_ret_stack -= FGRAPH_RET_INDEX + 1; current->curr_ret_depth--; return ret; } @@ -622,7 +646,17 @@ unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx, ret_stack = get_ret_stack(current, i, &i); if (!ret_stack) break; - if (ret_stack->retp == retp) + /* + * For the tail-call, there would be 2 or more ftrace_ret_stacks on + * the ret_stack, which records "return_to_handler" as the return + * address excpt for the last one. + * But on the real stack, there should be 1 entry because tail-call + * reuses the return address on the stack and jump to the next function. + * Thus we will continue to find real return address. + */ + if (ret_stack->retp == retp && + ret_stack->ret != + (unsigned long)dereference_kernel_function_descriptor(return_to_handler)) return ret_stack->ret; } @@ -645,6 +679,9 @@ unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx, i = *idx; do { ret_stack = get_ret_stack(task, task_idx, &task_idx); + if (ret_stack && ret_stack->ret == + (unsigned long)dereference_kernel_function_descriptor(return_to_handler)) + continue; i--; } while (i >= 0 && ret_stack); @@ -655,17 +692,25 @@ unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx, } #endif /* HAVE_FUNCTION_GRAPH_RET_ADDR_PTR */ -static struct ftrace_ops graph_ops = { - .func = ftrace_graph_func, - .flags = FTRACE_OPS_FL_INITIALIZED | - FTRACE_OPS_FL_PID | - FTRACE_OPS_GRAPH_STUB, +void fgraph_init_ops(struct ftrace_ops *dst_ops, + struct ftrace_ops *src_ops) +{ + dst_ops->func = ftrace_graph_func; + dst_ops->flags = FTRACE_OPS_FL_PID | FTRACE_OPS_GRAPH_STUB; + #ifdef FTRACE_GRAPH_TRAMP_ADDR - .trampoline = FTRACE_GRAPH_TRAMP_ADDR, + dst_ops->trampoline = FTRACE_GRAPH_TRAMP_ADDR; /* trampoline_size is only needed for dynamically allocated tramps */ #endif - ASSIGN_OPS_HASH(graph_ops, &global_ops.local_hash) -}; + +#ifdef CONFIG_DYNAMIC_FTRACE + if (src_ops) { + dst_ops->func_hash = &src_ops->local_hash; + mutex_init(&dst_ops->local_hash.regex_lock); + dst_ops->flags |= FTRACE_OPS_FL_INITIALIZED; + } +#endif +} void ftrace_graph_sleep_time_control(bool enable) { @@ -869,11 +914,20 @@ static int start_graph_tracing(void) int register_ftrace_graph(struct fgraph_ops *gops) { + int command = 0; int ret = 0; int i; mutex_lock(&ftrace_lock); + if (!gops->ops.func) { + gops->ops.flags |= FTRACE_OPS_GRAPH_STUB; + gops->ops.func = ftrace_graph_func; +#ifdef FTRACE_GRAPH_TRAMP_ADDR + gops->ops.trampoline = FTRACE_GRAPH_TRAMP_ADDR; +#endif + } + if (!fgraph_array[0]) { /* The array must always have real data on it */ for (i = 0; i < FGRAPH_ARRAY_SIZE; i++) @@ -893,6 +947,7 @@ int register_ftrace_graph(struct fgraph_ops *gops) fgraph_array[i] = gops; if (i + 1 > fgraph_array_cnt) fgraph_array_cnt = i + 1; + gops->idx = i; ftrace_graph_active++; @@ -909,9 +964,10 @@ int register_ftrace_graph(struct fgraph_ops *gops) */ ftrace_graph_return = return_run; ftrace_graph_entry = entry_run; - - ret = ftrace_startup(&graph_ops, FTRACE_START_FUNC_RET); + command = FTRACE_START_FUNC_RET; } + + ret = ftrace_startup(&gops->ops, command); out: mutex_unlock(&ftrace_lock); return ret; @@ -919,6 +975,7 @@ int register_ftrace_graph(struct fgraph_ops *gops) void unregister_ftrace_graph(struct fgraph_ops *gops) { + int command = 0; int i; mutex_lock(&ftrace_lock); @@ -926,25 +983,29 @@ void unregister_ftrace_graph(struct fgraph_ops *gops) if (unlikely(!ftrace_graph_active)) goto out; - for (i = 0; i < fgraph_array_cnt; i++) - if (gops == fgraph_array[i]) - break; - if (i >= fgraph_array_cnt) + if (unlikely(gops->idx < 0 || gops->idx >= fgraph_array_cnt)) goto out; - fgraph_array[i] = &fgraph_stub; - if (i + 1 == fgraph_array_cnt) { - for (; i >= 0; i--) - if (fgraph_array[i] != &fgraph_stub) - break; + WARN_ON_ONCE(fgraph_array[gops->idx] != gops); + + fgraph_array[gops->idx] = &fgraph_stub; + if (gops->idx + 1 == fgraph_array_cnt) { + i = gops->idx; + while (i >= 0 && fgraph_array[i] == &fgraph_stub) + i--; fgraph_array_cnt = i + 1; } ftrace_graph_active--; + + if (!ftrace_graph_active) + command = FTRACE_STOP_FUNC_RET; + + ftrace_shutdown(&gops->ops, command); + if (!ftrace_graph_active) { ftrace_graph_return = ftrace_stub_graph; ftrace_graph_entry = ftrace_graph_entry_stub; - ftrace_shutdown(&graph_ops, FTRACE_STOP_FUNC_RET); unregister_pm_notifier(&ftrace_suspend_notifier); unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL); } diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 83fbfb7b48f8..c4cc2a9d0047 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -3050,6 +3050,8 @@ int ftrace_startup(struct ftrace_ops *ops, int command) if (unlikely(ftrace_disabled)) return -ENODEV; + ftrace_ops_init(ops); + ret = __register_ftrace_function(ops); if (ret) return ret; @@ -7319,7 +7321,7 @@ __init void ftrace_init_global_array_ops(struct trace_array *tr) tr->ops = &global_ops; tr->ops->private = tr; ftrace_init_trace_array(tr); - init_array_fgraph_ops(tr); + init_array_fgraph_ops(tr, tr->ops); } void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func) @@ -8051,7 +8053,7 @@ static int register_ftrace_function_nolock(struct ftrace_ops *ops) */ int register_ftrace_function(struct ftrace_ops *ops) { - int ret; + int ret = -1; lock_direct_mutex(); ret = prepare_direct_functions_for_ipmodify(ops); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 16948c0ed00a..02edfdb68933 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -890,8 +890,8 @@ extern int __trace_graph_entry(struct trace_array *tr, extern void __trace_graph_return(struct trace_array *tr, struct ftrace_graph_ret *trace, unsigned int trace_ctx); -extern void init_array_fgraph_ops(struct trace_array *tr); -extern int allocate_fgraph_ops(struct trace_array *tr); +extern void init_array_fgraph_ops(struct trace_array *tr, struct ftrace_ops *ops); +extern int allocate_fgraph_ops(struct trace_array *tr, struct ftrace_ops *ops); extern void free_fgraph_ops(struct trace_array *tr); #ifdef CONFIG_DYNAMIC_FTRACE @@ -974,6 +974,7 @@ static inline int ftrace_graph_notrace_addr(unsigned long addr) preempt_enable_notrace(); return ret; } + #else static inline int ftrace_graph_addr(struct ftrace_graph_ent *trace) { @@ -999,18 +1000,19 @@ static inline bool ftrace_graph_ignore_func(struct ftrace_graph_ent *trace) (fgraph_max_depth && trace->depth >= fgraph_max_depth); } +void fgraph_init_ops(struct ftrace_ops *dst_ops, + struct ftrace_ops *src_ops); + #else /* CONFIG_FUNCTION_GRAPH_TRACER */ static inline enum print_line_t print_graph_function_flags(struct trace_iterator *iter, u32 flags) { return TRACE_TYPE_UNHANDLED; } -static inline void init_array_fgraph_ops(struct trace_array *tr) { } -static inline int allocate_fgraph_ops(struct trace_array *tr) -{ - return 0; -} static inline void free_fgraph_ops(struct trace_array *tr) { } +/* ftrace_ops may not be defined */ +#define init_array_fgraph_ops(tr, ops) do { } while (0) +#define allocate_fgraph_ops(tr, ops) ({ 0; }) #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ extern struct list_head ftrace_pids; diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c index 8e8da0d0ee52..13bf2415245d 100644 --- a/kernel/trace/trace_functions.c +++ b/kernel/trace/trace_functions.c @@ -91,7 +91,7 @@ int ftrace_create_function_files(struct trace_array *tr, if (!tr->ops) return -EINVAL; - ret = allocate_fgraph_ops(tr); + ret = allocate_fgraph_ops(tr, tr->ops); if (ret) { kfree(tr->ops); return ret; diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index 9ccc904a7703..7f30652f0e97 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -288,7 +288,7 @@ static struct fgraph_ops funcgraph_ops = { .retfunc = &trace_graph_return, }; -int allocate_fgraph_ops(struct trace_array *tr) +int allocate_fgraph_ops(struct trace_array *tr, struct ftrace_ops *ops) { struct fgraph_ops *gops; @@ -301,6 +301,9 @@ int allocate_fgraph_ops(struct trace_array *tr) tr->gops = gops; gops->private = tr; + + fgraph_init_ops(&gops->ops, ops); + return 0; } @@ -309,10 +312,11 @@ void free_fgraph_ops(struct trace_array *tr) kfree(tr->gops); } -__init void init_array_fgraph_ops(struct trace_array *tr) +__init void init_array_fgraph_ops(struct trace_array *tr, struct ftrace_ops *ops) { tr->gops = &funcgraph_ops; funcgraph_ops.private = tr; + fgraph_init_ops(&tr->gops->ops, ops); } static int graph_trace_init(struct trace_array *tr)