aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorJosh Poimboeuf <jpoimboe@redhat.com>2016-08-19 06:52:57 -0500
committerIngo Molnar <mingo@kernel.org>2016-08-24 12:15:14 +0200
commit9a7c348ba6a46f6270d4fe49577649dad5664fe7 (patch)
tree747a399fc9f6f3f1e234e27a164b9bb5e6ac015a
parentftrace: Only allocate the ret_stack 'fp' field when needed (diff)
downloadlinux-dev-9a7c348ba6a46f6270d4fe49577649dad5664fe7.tar.xz
linux-dev-9a7c348ba6a46f6270d4fe49577649dad5664fe7.zip
ftrace: Add return address pointer to ftrace_ret_stack
Storing this value will help prevent unwinders from getting out of sync with the function graph tracer ret_stack. Now instead of needing a stateful iterator, they can compare the return address pointer to find the right ret_stack entry. Note that an array of 50 ftrace_ret_stack structs is allocated for every task. So when an arch implements this, it will add either 200 or 400 bytes of memory usage per task (depending on whether it's a 32-bit or 64-bit platform). Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Byungchul Park <byungchul.park@lge.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nilay Vaish <nilayvaish@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/a95cfcc39e8f26b89a430c56926af0bb217bc0a1.1471607358.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat
-rw-r--r--Documentation/trace/ftrace-design.txt11
-rw-r--r--arch/arm/kernel/ftrace.c2
-rw-r--r--arch/arm64/kernel/ftrace.c2
-rw-r--r--arch/blackfin/kernel/ftrace.c2
-rw-r--r--arch/microblaze/kernel/ftrace.c2
-rw-r--r--arch/mips/kernel/ftrace.c4
-rw-r--r--arch/parisc/kernel/ftrace.c2
-rw-r--r--arch/powerpc/kernel/ftrace.c3
-rw-r--r--arch/s390/kernel/ftrace.c3
-rw-r--r--arch/sh/kernel/ftrace.c2
-rw-r--r--arch/sparc/kernel/ftrace.c2
-rw-r--r--arch/tile/kernel/ftrace.c2
-rw-r--r--arch/x86/kernel/ftrace.c2
-rw-r--r--include/linux/ftrace.h5
-rw-r--r--kernel/trace/trace_functions_graph.c5
15 files changed, 34 insertions, 15 deletions
diff --git a/Documentation/trace/ftrace-design.txt b/Documentation/trace/ftrace-design.txt
index dd5f916b351d..a273dd0bbaaa 100644
--- a/Documentation/trace/ftrace-design.txt
+++ b/Documentation/trace/ftrace-design.txt
@@ -203,6 +203,17 @@ along to ftrace_push_return_trace() instead of a stub value of 0.
Similarly, when you call ftrace_return_to_handler(), pass it the frame pointer.
+HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
+--------------------------------
+
+An arch may pass in a pointer to the return address on the stack. This
+prevents potential stack unwinding issues where the unwinder gets out of
+sync with ret_stack and the wrong addresses are reported by
+ftrace_graph_ret_addr().
+
+Adding support for it is easy: just define the macro in asm/ftrace.h and
+pass the return address pointer as the 'retp' argument to
+ftrace_push_return_trace().
HAVE_FTRACE_NMI_ENTER
---------------------
diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c
index 709ee1d6d4df..3f1759411d51 100644
--- a/arch/arm/kernel/ftrace.c
+++ b/arch/arm/kernel/ftrace.c
@@ -218,7 +218,7 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
}
err = ftrace_push_return_trace(old, self_addr, &trace.depth,
- frame_pointer);
+ frame_pointer, NULL);
if (err == -EBUSY) {
*parent = old;
return;
diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c
index ebecf9aa33d1..40ad08ac569a 100644
--- a/arch/arm64/kernel/ftrace.c
+++ b/arch/arm64/kernel/ftrace.c
@@ -138,7 +138,7 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
return;
err = ftrace_push_return_trace(old, self_addr, &trace.depth,
- frame_pointer);
+ frame_pointer, NULL);
if (err == -EBUSY)
return;
else
diff --git a/arch/blackfin/kernel/ftrace.c b/arch/blackfin/kernel/ftrace.c
index 095de0fa044d..8dad7589b843 100644
--- a/arch/blackfin/kernel/ftrace.c
+++ b/arch/blackfin/kernel/ftrace.c
@@ -107,7 +107,7 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
return;
if (ftrace_push_return_trace(*parent, self_addr, &trace.depth,
- frame_pointer) == -EBUSY)
+ frame_pointer, NULL) == -EBUSY)
return;
trace.func = self_addr;
diff --git a/arch/microblaze/kernel/ftrace.c b/arch/microblaze/kernel/ftrace.c
index fc7b48a52cd5..d57563c58a26 100644
--- a/arch/microblaze/kernel/ftrace.c
+++ b/arch/microblaze/kernel/ftrace.c
@@ -63,7 +63,7 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
return;
}
- err = ftrace_push_return_trace(old, self_addr, &trace.depth, 0);
+ err = ftrace_push_return_trace(old, self_addr, &trace.depth, 0, NULL);
if (err == -EBUSY) {
*parent = old;
return;
diff --git a/arch/mips/kernel/ftrace.c b/arch/mips/kernel/ftrace.c
index 937c54bc8ccc..30a3b75e88eb 100644
--- a/arch/mips/kernel/ftrace.c
+++ b/arch/mips/kernel/ftrace.c
@@ -382,8 +382,8 @@ void prepare_ftrace_return(unsigned long *parent_ra_addr, unsigned long self_ra,
if (unlikely(faulted))
goto out;
- if (ftrace_push_return_trace(old_parent_ra, self_ra, &trace.depth, fp)
- == -EBUSY) {
+ if (ftrace_push_return_trace(old_parent_ra, self_ra, &trace.depth, fp,
+ NULL) == -EBUSY) {
*parent_ra_addr = old_parent_ra;
return;
}
diff --git a/arch/parisc/kernel/ftrace.c b/arch/parisc/kernel/ftrace.c
index a828a0adf52c..5a5506a35395 100644
--- a/arch/parisc/kernel/ftrace.c
+++ b/arch/parisc/kernel/ftrace.c
@@ -48,7 +48,7 @@ static void __hot prepare_ftrace_return(unsigned long *parent,
return;
if (ftrace_push_return_trace(old, self_addr, &trace.depth,
- 0 ) == -EBUSY)
+ 0, NULL) == -EBUSY)
return;
/* activate parisc_return_to_handler() as return point */
diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c
index cc52d9795f88..a95639b8d4ac 100644
--- a/arch/powerpc/kernel/ftrace.c
+++ b/arch/powerpc/kernel/ftrace.c
@@ -593,7 +593,8 @@ unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip)
if (!ftrace_graph_entry(&trace))
goto out;
- if (ftrace_push_return_trace(parent, ip, &trace.depth, 0) == -EBUSY)
+ if (ftrace_push_return_trace(parent, ip, &trace.depth, 0,
+ NULL) == -EBUSY)
goto out;
parent = return_hooker;
diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c
index 0f7bfeba6da6..60a8a4e207ed 100644
--- a/arch/s390/kernel/ftrace.c
+++ b/arch/s390/kernel/ftrace.c
@@ -209,7 +209,8 @@ unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip)
/* Only trace if the calling function expects to. */
if (!ftrace_graph_entry(&trace))
goto out;
- if (ftrace_push_return_trace(parent, ip, &trace.depth, 0) == -EBUSY)
+ if (ftrace_push_return_trace(parent, ip, &trace.depth, 0,
+ NULL) == -EBUSY)
goto out;
parent = (unsigned long) return_to_handler;
out:
diff --git a/arch/sh/kernel/ftrace.c b/arch/sh/kernel/ftrace.c
index 38993e09ef03..95eccd49672f 100644
--- a/arch/sh/kernel/ftrace.c
+++ b/arch/sh/kernel/ftrace.c
@@ -382,7 +382,7 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
return;
}
- err = ftrace_push_return_trace(old, self_addr, &trace.depth, 0);
+ err = ftrace_push_return_trace(old, self_addr, &trace.depth, 0, NULL);
if (err == -EBUSY) {
__raw_writel(old, parent);
return;
diff --git a/arch/sparc/kernel/ftrace.c b/arch/sparc/kernel/ftrace.c
index 0a2d2ddff543..6bcff698069b 100644
--- a/arch/sparc/kernel/ftrace.c
+++ b/arch/sparc/kernel/ftrace.c
@@ -131,7 +131,7 @@ unsigned long prepare_ftrace_return(unsigned long parent,
return parent + 8UL;
if (ftrace_push_return_trace(parent, self_addr, &trace.depth,
- frame_pointer) == -EBUSY)
+ frame_pointer, NULL) == -EBUSY)
return parent + 8UL;
trace.func = self_addr;
diff --git a/arch/tile/kernel/ftrace.c b/arch/tile/kernel/ftrace.c
index 4a572088b270..b827a418b155 100644
--- a/arch/tile/kernel/ftrace.c
+++ b/arch/tile/kernel/ftrace.c
@@ -184,7 +184,7 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
*parent = return_hooker;
err = ftrace_push_return_trace(old, self_addr, &trace.depth,
- frame_pointer);
+ frame_pointer, NULL);
if (err == -EBUSY) {
*parent = old;
return;
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index d036cfb4495d..ae3b1fb2f582 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -1029,7 +1029,7 @@ void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent,
}
if (ftrace_push_return_trace(old, self_addr, &trace.depth,
- frame_pointer) == -EBUSY) {
+ frame_pointer, NULL) == -EBUSY) {
*parent = old;
return;
}
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 4ad9ccc60e38..483e02a50d37 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -798,6 +798,9 @@ struct ftrace_ret_stack {
#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
unsigned long fp;
#endif
+#ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
+ unsigned long *retp;
+#endif
};
/*
@@ -809,7 +812,7 @@ extern void return_to_handler(void);
extern int
ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
- unsigned long frame_pointer);
+ unsigned long frame_pointer, unsigned long *retp);
/*
* Sometimes we don't want to trace a function with the function
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 0e03ed0eac68..f7212ec643e2 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -119,7 +119,7 @@ print_graph_duration(struct trace_array *tr, unsigned long long duration,
/* Add a function return address to the trace stack on thread info.*/
int
ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
- unsigned long frame_pointer)
+ unsigned long frame_pointer, unsigned long *retp)
{
unsigned long long calltime;
int index;
@@ -174,6 +174,9 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
current->ret_stack[index].fp = frame_pointer;
#endif
+#ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
+ current->ret_stack[index].retp = retp;
+#endif
*depth = current->curr_ret_stack;
return 0;
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.