mirror of https://github.com/torvalds/linux.git
function_graph: Enable funcgraph-args and funcgraph-retaddr to work simultaneously
Currently, the funcgraph-args and funcgraph-retaddr features are
mutually exclusive. This patch resolves this limitation by allowing
funcgraph-retaddr to have an args array.
To verify the change, use perf to trace vfs_write with both options
enabled:
Before:
# perf ftrace -G vfs_write --graph-opts args,retaddr
......
down_read() { /* <-n_tty_write+0xa3/0x540 */
__cond_resched(); /* <-down_read+0x12/0x160 */
preempt_count_add(); /* <-down_read+0x3b/0x160 */
preempt_count_sub(); /* <-down_read+0x8b/0x160 */
}
After:
# perf ftrace -G vfs_write --graph-opts args,retaddr
......
down_read(sem=0xffff8880100bea78) { /* <-n_tty_write+0xa3/0x540 */
__cond_resched(); /* <-down_read+0x12/0x160 */
preempt_count_add(val=1); /* <-down_read+0x3b/0x160 */
preempt_count_sub(val=1); /* <-down_read+0x8b/0x160 */
}
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Xiaoqin Zhang <zhangxiaoqin@xiaomi.com>
Link: https://patch.msgid.link/20251125093425.2563849-1-dolinux.peng@gmail.com
Signed-off-by: pengdonglin <pengdonglin@xiaomi.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit is contained in:
pengdonglin
Steven Rostedt (Google)
parent
20e7168326
commit
f83ac7544f
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@ -1126,17 +1126,14 @@ static inline void ftrace_init(void) { }
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*/
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struct ftrace_graph_ent {
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unsigned long func; /* Current function */
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int depth;
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unsigned long depth;
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} __packed;
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/*
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* Structure that defines an entry function trace with retaddr.
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* It's already packed but the attribute "packed" is needed
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* to remove extra padding at the end.
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*/
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struct fgraph_retaddr_ent {
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unsigned long func; /* Current function */
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int depth;
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struct ftrace_graph_ent ent;
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unsigned long retaddr; /* Return address */
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} __packed;
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@ -964,7 +964,8 @@ extern int __trace_graph_entry(struct trace_array *tr,
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extern int __trace_graph_retaddr_entry(struct trace_array *tr,
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struct ftrace_graph_ent *trace,
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unsigned int trace_ctx,
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unsigned long retaddr);
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unsigned long retaddr,
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struct ftrace_regs *fregs);
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extern void __trace_graph_return(struct trace_array *tr,
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struct ftrace_graph_ret *trace,
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unsigned int trace_ctx,
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@ -2276,4 +2277,25 @@ static inline int rv_init_interface(void)
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*/
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#define FTRACE_TRAMPOLINE_MARKER ((unsigned long) INT_MAX)
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/*
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* This is used to get the address of the args array based on
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* the type of the entry.
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*/
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#define FGRAPH_ENTRY_ARGS(e) \
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({ \
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unsigned long *_args; \
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struct ftrace_graph_ent_entry *_e = e; \
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\
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if (IS_ENABLED(CONFIG_FUNCTION_GRAPH_RETADDR) && \
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e->ent.type == TRACE_GRAPH_RETADDR_ENT) { \
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struct fgraph_retaddr_ent_entry *_re; \
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\
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_re = (typeof(_re))_e; \
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_args = _re->args; \
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} else { \
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_args = _e->args; \
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} \
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_args; \
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})
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#endif /* _LINUX_KERNEL_TRACE_H */
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@ -80,11 +80,11 @@ FTRACE_ENTRY(funcgraph_entry, ftrace_graph_ent_entry,
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F_STRUCT(
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__field_struct( struct ftrace_graph_ent, graph_ent )
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__field_packed( unsigned long, graph_ent, func )
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__field_packed( unsigned int, graph_ent, depth )
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__field_packed( unsigned long, graph_ent, depth )
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__dynamic_array(unsigned long, args )
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),
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F_printk("--> %ps (%u)", (void *)__entry->func, __entry->depth)
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F_printk("--> %ps (%lu)", (void *)__entry->func, __entry->depth)
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);
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#ifdef CONFIG_FUNCTION_GRAPH_RETADDR
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@ -95,13 +95,14 @@ FTRACE_ENTRY_PACKED(fgraph_retaddr_entry, fgraph_retaddr_ent_entry,
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TRACE_GRAPH_RETADDR_ENT,
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F_STRUCT(
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__field_struct( struct fgraph_retaddr_ent, graph_ent )
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__field_packed( unsigned long, graph_ent, func )
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__field_packed( unsigned int, graph_ent, depth )
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__field_packed( unsigned long, graph_ent, retaddr )
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__field_struct( struct fgraph_retaddr_ent, graph_rent )
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__field_packed( unsigned long, graph_rent.ent, func )
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__field_packed( unsigned long, graph_rent.ent, depth )
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__field_packed( unsigned long, graph_rent, retaddr )
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__dynamic_array(unsigned long, args )
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),
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F_printk("--> %ps (%u) <- %ps", (void *)__entry->func, __entry->depth,
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F_printk("--> %ps (%lu) <- %ps", (void *)__entry->func, __entry->depth,
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(void *)__entry->retaddr)
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);
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@ -36,14 +36,19 @@ struct fgraph_ent_args {
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unsigned long args[FTRACE_REGS_MAX_ARGS];
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};
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struct fgraph_retaddr_ent_args {
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struct fgraph_retaddr_ent_entry ent;
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/* Force the sizeof of args[] to have FTRACE_REGS_MAX_ARGS entries */
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unsigned long args[FTRACE_REGS_MAX_ARGS];
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};
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struct fgraph_data {
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struct fgraph_cpu_data __percpu *cpu_data;
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/* Place to preserve last processed entry. */
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union {
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struct fgraph_ent_args ent;
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/* TODO allow retaddr to have args */
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struct fgraph_retaddr_ent_entry rent;
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struct fgraph_retaddr_ent_args rent;
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};
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struct ftrace_graph_ret_entry ret;
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int failed;
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@ -160,20 +165,32 @@ int __trace_graph_entry(struct trace_array *tr,
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int __trace_graph_retaddr_entry(struct trace_array *tr,
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struct ftrace_graph_ent *trace,
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unsigned int trace_ctx,
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unsigned long retaddr)
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unsigned long retaddr,
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struct ftrace_regs *fregs)
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{
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struct ring_buffer_event *event;
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struct trace_buffer *buffer = tr->array_buffer.buffer;
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struct fgraph_retaddr_ent_entry *entry;
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int size;
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/* If fregs is defined, add FTRACE_REGS_MAX_ARGS long size words */
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size = sizeof(*entry) + (FTRACE_REGS_MAX_ARGS * !!fregs * sizeof(long));
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event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RETADDR_ENT,
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sizeof(*entry), trace_ctx);
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size, trace_ctx);
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if (!event)
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return 0;
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entry = ring_buffer_event_data(event);
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entry->graph_ent.func = trace->func;
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entry->graph_ent.depth = trace->depth;
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entry->graph_ent.retaddr = retaddr;
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entry->graph_rent.ent = *trace;
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entry->graph_rent.retaddr = retaddr;
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#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
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if (fregs) {
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for (int i = 0; i < FTRACE_REGS_MAX_ARGS; i++)
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entry->args[i] = ftrace_regs_get_argument(fregs, i);
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}
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#endif
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trace_buffer_unlock_commit_nostack(buffer, event);
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return 1;
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@ -182,7 +199,8 @@ int __trace_graph_retaddr_entry(struct trace_array *tr,
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int __trace_graph_retaddr_entry(struct trace_array *tr,
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struct ftrace_graph_ent *trace,
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unsigned int trace_ctx,
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unsigned long retaddr)
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unsigned long retaddr,
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struct ftrace_regs *fregs)
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{
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return 1;
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}
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@ -267,7 +285,8 @@ static int graph_entry(struct ftrace_graph_ent *trace,
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if (IS_ENABLED(CONFIG_FUNCTION_GRAPH_RETADDR) &&
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tracer_flags_is_set(tr, TRACE_GRAPH_PRINT_RETADDR)) {
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unsigned long retaddr = ftrace_graph_top_ret_addr(current);
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ret = __trace_graph_retaddr_entry(tr, trace, trace_ctx, retaddr);
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ret = __trace_graph_retaddr_entry(tr, trace, trace_ctx,
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retaddr, fregs);
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} else {
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ret = __graph_entry(tr, trace, trace_ctx, fregs);
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}
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@ -654,13 +673,9 @@ get_return_for_leaf(struct trace_iterator *iter,
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* Save current and next entries for later reference
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* if the output fails.
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*/
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if (unlikely(curr->ent.type == TRACE_GRAPH_RETADDR_ENT)) {
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data->rent = *(struct fgraph_retaddr_ent_entry *)curr;
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} else {
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int size = min((int)sizeof(data->ent), (int)iter->ent_size);
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int size = min_t(int, sizeof(data->rent), iter->ent_size);
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memcpy(&data->ent, curr, size);
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}
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memcpy(&data->rent, curr, size);
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/*
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* If the next event is not a return type, then
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* we only care about what type it is. Otherwise we can
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@ -838,7 +853,7 @@ static void print_graph_retaddr(struct trace_seq *s, struct fgraph_retaddr_ent_e
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trace_seq_puts(s, " /*");
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trace_seq_puts(s, " <-");
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seq_print_ip_sym_offset(s, entry->graph_ent.retaddr, trace_flags);
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seq_print_ip_sym_offset(s, entry->graph_rent.retaddr, trace_flags);
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if (comment)
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trace_seq_puts(s, " */");
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@ -984,7 +999,7 @@ print_graph_entry_leaf(struct trace_iterator *iter,
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trace_seq_printf(s, "%ps", (void *)ret_func);
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if (args_size >= FTRACE_REGS_MAX_ARGS * sizeof(long)) {
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print_function_args(s, entry->args, ret_func);
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print_function_args(s, FGRAPH_ENTRY_ARGS(entry), ret_func);
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trace_seq_putc(s, ';');
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} else
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trace_seq_puts(s, "();");
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@ -1036,7 +1051,7 @@ print_graph_entry_nested(struct trace_iterator *iter,
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args_size = iter->ent_size - offsetof(struct ftrace_graph_ent_entry, args);
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if (args_size >= FTRACE_REGS_MAX_ARGS * sizeof(long))
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print_function_args(s, entry->args, func);
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print_function_args(s, FGRAPH_ENTRY_ARGS(entry), func);
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else
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trace_seq_puts(s, "()");
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@ -1218,11 +1233,14 @@ print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
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/*
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* print_graph_entry() may consume the current event,
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* thus @field may become invalid, so we need to save it.
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* sizeof(struct ftrace_graph_ent_entry) is very small,
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* it can be safely saved at the stack.
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* This function is shared by ftrace_graph_ent_entry and
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* fgraph_retaddr_ent_entry, the size of the latter one
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* is larger, but it is very small and can be safely saved
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* at the stack.
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*/
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struct ftrace_graph_ent_entry *entry;
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u8 save_buf[sizeof(*entry) + FTRACE_REGS_MAX_ARGS * sizeof(long)];
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struct fgraph_retaddr_ent_entry *rentry;
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u8 save_buf[sizeof(*rentry) + FTRACE_REGS_MAX_ARGS * sizeof(long)];
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/* The ent_size is expected to be as big as the entry */
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if (iter->ent_size > sizeof(save_buf))
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@ -1451,12 +1469,17 @@ print_graph_function_flags(struct trace_iterator *iter, u32 flags)
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}
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#ifdef CONFIG_FUNCTION_GRAPH_RETADDR
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case TRACE_GRAPH_RETADDR_ENT: {
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struct fgraph_retaddr_ent_entry saved;
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/*
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* ftrace_graph_ent_entry and fgraph_retaddr_ent_entry have
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* similar functions and memory layouts. The only difference
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* is that the latter one has an extra retaddr member, so
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* they can share most of the logic.
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*/
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struct fgraph_retaddr_ent_entry *rfield;
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trace_assign_type(rfield, entry);
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saved = *rfield;
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return print_graph_entry((struct ftrace_graph_ent_entry *)&saved, s, iter, flags);
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return print_graph_entry((struct ftrace_graph_ent_entry *)rfield,
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s, iter, flags);
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}
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#endif
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case TRACE_GRAPH_RET: {
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