While rewriting the function graph tracer, I discovered a design flaw that
was introduced by a patch that tried to fix one bug, but by doing so created another bug. As both bugs corrupt the output (but they do not crash the kernel), I decided to fix the design such that it could have both bugs fixed. The original fix, fixed time reporting of the function graph tracer when doing a max_depth of one. This was code that can test how much the kernel interferes with userspace. But in doing so, it could corrupt the time keeping of the function profiler. The issue is that the curr_ret_stack variable was being used for two different meanings. One was to keep track of the stack pointer on the ret_stack (shadow stack used by the function graph tracer), and the other use case was the graph call depth. Although, the two may be closely related, where they got updated was the issue that lead to the two different bugs that required the two use cases to be updated differently. The big issue with this fix is that it requires changing each architecture. The good news is, I was able to remove a lot of code that was duplicated within the architectures and place it into a single location. Then I could make the fix in one place. I pushed this code into linux-next to let it settle over a week, and before doing so, I cross compiled all the affected architectures to make sure that they built fine. In the mean time, I also pulled in a patch that fixes the sched_switch previous tasks state output, that was not actually correct. -----BEGIN PGP SIGNATURE----- iIoEABYIADIWIQRRSw7ePDh/lE+zeZMp5XQQmuv6qgUCW/4NPhQccm9zdGVkdEBn b29kbWlzLm9yZwAKCRAp5XQQmuv6qnWAAQCyUIRLgYImr81eTl52lxNRsULk+aiI U29kRFWWU0c40AEA1X9sDF0MgOItbRGfZtnHTZEousXRDaDf4Fge2kF7Egg= =liQ0 -----END PGP SIGNATURE----- Merge tag 'trace-v4.20-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing fixes from Steven Rostedt: "While rewriting the function graph tracer, I discovered a design flaw that was introduced by a patch that tried to fix one bug, but by doing so created another bug. As both bugs corrupt the output (but they do not crash the kernel), I decided to fix the design such that it could have both bugs fixed. The original fix, fixed time reporting of the function graph tracer when doing a max_depth of one. This was code that can test how much the kernel interferes with userspace. But in doing so, it could corrupt the time keeping of the function profiler. The issue is that the curr_ret_stack variable was being used for two different meanings. One was to keep track of the stack pointer on the ret_stack (shadow stack used by the function graph tracer), and the other use case was the graph call depth. Although, the two may be closely related, where they got updated was the issue that lead to the two different bugs that required the two use cases to be updated differently. The big issue with this fix is that it requires changing each architecture. The good news is, I was able to remove a lot of code that was duplicated within the architectures and place it into a single location. Then I could make the fix in one place. I pushed this code into linux-next to let it settle over a week, and before doing so, I cross compiled all the affected architectures to make sure that they built fine. In the mean time, I also pulled in a patch that fixes the sched_switch previous tasks state output, that was not actually correct" * tag 'trace-v4.20-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: sched, trace: Fix prev_state output in sched_switch tracepoint function_graph: Have profiler use curr_ret_stack and not depth function_graph: Reverse the order of pushing the ret_stack and the callback function_graph: Move return callback before update of curr_ret_stack function_graph: Use new curr_ret_depth to manage depth instead of curr_ret_stack function_graph: Make ftrace_push_return_trace() static sparc/function_graph: Simplify with function_graph_enter() sh/function_graph: Simplify with function_graph_enter() s390/function_graph: Simplify with function_graph_enter() riscv/function_graph: Simplify with function_graph_enter() powerpc/function_graph: Simplify with function_graph_enter() parisc: function_graph: Simplify with function_graph_enter() nds32: function_graph: Simplify with function_graph_enter() MIPS: function_graph: Simplify with function_graph_enter() microblaze: function_graph: Simplify with function_graph_enter() arm64: function_graph: Simplify with function_graph_enter() ARM: function_graph: Simplify with function_graph_enter() x86/function_graph: Simplify with function_graph_enter() function_graph: Create function_graph_enter() to consolidate architecture code
This commit is contained in:
commit
0f1f692375
|
@ -183,9 +183,7 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
|
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unsigned long frame_pointer)
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{
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unsigned long return_hooker = (unsigned long) &return_to_handler;
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struct ftrace_graph_ent trace;
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unsigned long old;
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int err;
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if (unlikely(atomic_read(¤t->tracing_graph_pause)))
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return;
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@ -193,21 +191,8 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
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old = *parent;
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*parent = return_hooker;
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trace.func = self_addr;
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trace.depth = current->curr_ret_stack + 1;
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/* Only trace if the calling function expects to */
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if (!ftrace_graph_entry(&trace)) {
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if (function_graph_enter(old, self_addr, frame_pointer, NULL))
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*parent = old;
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return;
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}
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err = ftrace_push_return_trace(old, self_addr, &trace.depth,
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frame_pointer, NULL);
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if (err == -EBUSY) {
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*parent = old;
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return;
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}
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}
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#ifdef CONFIG_DYNAMIC_FTRACE
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@ -216,8 +216,6 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
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{
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unsigned long return_hooker = (unsigned long)&return_to_handler;
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unsigned long old;
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struct ftrace_graph_ent trace;
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int err;
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if (unlikely(atomic_read(¤t->tracing_graph_pause)))
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return;
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@ -229,18 +227,7 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
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*/
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old = *parent;
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trace.func = self_addr;
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trace.depth = current->curr_ret_stack + 1;
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/* Only trace if the calling function expects to */
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if (!ftrace_graph_entry(&trace))
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return;
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err = ftrace_push_return_trace(old, self_addr, &trace.depth,
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frame_pointer, NULL);
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if (err == -EBUSY)
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return;
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else
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if (!function_graph_enter(old, self_addr, frame_pointer, NULL))
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*parent = return_hooker;
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}
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|
|
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@ -22,8 +22,7 @@
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void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
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{
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unsigned long old;
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int faulted, err;
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struct ftrace_graph_ent trace;
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int faulted;
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unsigned long return_hooker = (unsigned long)
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&return_to_handler;
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@ -63,18 +62,8 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
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return;
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}
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err = ftrace_push_return_trace(old, self_addr, &trace.depth, 0, NULL);
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if (err == -EBUSY) {
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if (function_graph_enter(old, self_addr, 0, NULL))
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*parent = old;
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return;
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}
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trace.func = self_addr;
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/* Only trace if the calling function expects to */
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if (!ftrace_graph_entry(&trace)) {
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current->curr_ret_stack--;
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*parent = old;
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}
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}
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#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
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|
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|
@ -322,7 +322,6 @@ void prepare_ftrace_return(unsigned long *parent_ra_addr, unsigned long self_ra,
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unsigned long fp)
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{
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unsigned long old_parent_ra;
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struct ftrace_graph_ent trace;
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unsigned long return_hooker = (unsigned long)
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&return_to_handler;
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int faulted, insns;
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|
@ -369,12 +368,6 @@ void prepare_ftrace_return(unsigned long *parent_ra_addr, unsigned long self_ra,
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if (unlikely(faulted))
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goto out;
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if (ftrace_push_return_trace(old_parent_ra, self_ra, &trace.depth, fp,
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NULL) == -EBUSY) {
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*parent_ra_addr = old_parent_ra;
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return;
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}
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/*
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* Get the recorded ip of the current mcount calling site in the
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* __mcount_loc section, which will be used to filter the function
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|
@ -382,13 +375,10 @@ void prepare_ftrace_return(unsigned long *parent_ra_addr, unsigned long self_ra,
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*/
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insns = core_kernel_text(self_ra) ? 2 : MCOUNT_OFFSET_INSNS + 1;
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trace.func = self_ra - (MCOUNT_INSN_SIZE * insns);
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self_ra -= (MCOUNT_INSN_SIZE * insns);
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/* Only trace if the calling function expects to */
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if (!ftrace_graph_entry(&trace)) {
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current->curr_ret_stack--;
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if (function_graph_enter(old_parent_ra, self_ra, fp, NULL))
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*parent_ra_addr = old_parent_ra;
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}
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return;
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out:
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ftrace_graph_stop();
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|
|
|
@ -211,28 +211,14 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
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unsigned long frame_pointer)
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||||
{
|
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unsigned long return_hooker = (unsigned long)&return_to_handler;
|
||||
struct ftrace_graph_ent trace;
|
||||
unsigned long old;
|
||||
int err;
|
||||
|
||||
if (unlikely(atomic_read(¤t->tracing_graph_pause)))
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return;
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||||
|
||||
old = *parent;
|
||||
|
||||
trace.func = self_addr;
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trace.depth = current->curr_ret_stack + 1;
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|
||||
/* Only trace if the calling function expects to */
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if (!ftrace_graph_entry(&trace))
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return;
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|
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err = ftrace_push_return_trace(old, self_addr, &trace.depth,
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frame_pointer, NULL);
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if (err == -EBUSY)
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return;
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if (!function_graph_enter(old, self_addr, frame_pointer, NULL))
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*parent = return_hooker;
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}
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||||
|
|
|
@ -30,7 +30,6 @@ static void __hot prepare_ftrace_return(unsigned long *parent,
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unsigned long self_addr)
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||||
{
|
||||
unsigned long old;
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||||
struct ftrace_graph_ent trace;
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||||
extern int parisc_return_to_handler;
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|
||||
if (unlikely(ftrace_graph_is_dead()))
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||||
|
@ -41,17 +40,7 @@ static void __hot prepare_ftrace_return(unsigned long *parent,
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|
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old = *parent;
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trace.func = self_addr;
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trace.depth = current->curr_ret_stack + 1;
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||||
|
||||
/* Only trace if the calling function expects to */
|
||||
if (!ftrace_graph_entry(&trace))
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return;
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||||
|
||||
if (ftrace_push_return_trace(old, self_addr, &trace.depth,
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0, NULL) == -EBUSY)
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return;
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||||
if (!function_graph_enter(old, self_addr, 0, NULL))
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/* activate parisc_return_to_handler() as return point */
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*parent = (unsigned long) &parisc_return_to_handler;
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}
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|
|
|
@ -950,7 +950,6 @@ int ftrace_disable_ftrace_graph_caller(void)
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*/
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||||
unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip)
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{
|
||||
struct ftrace_graph_ent trace;
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unsigned long return_hooker;
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||||
|
||||
if (unlikely(ftrace_graph_is_dead()))
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||||
|
@ -961,17 +960,7 @@ unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip)
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|||
|
||||
return_hooker = ppc_function_entry(return_to_handler);
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trace.func = ip;
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||||
trace.depth = current->curr_ret_stack + 1;
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||||
|
||||
/* Only trace if the calling function expects to */
|
||||
if (!ftrace_graph_entry(&trace))
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||||
goto out;
|
||||
|
||||
if (ftrace_push_return_trace(parent, ip, &trace.depth, 0,
|
||||
NULL) == -EBUSY)
|
||||
goto out;
|
||||
|
||||
if (!function_graph_enter(parent, ip, 0, NULL))
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||||
parent = return_hooker;
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||||
out:
|
||||
return parent;
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||||
|
|
|
@ -132,7 +132,6 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
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|||
{
|
||||
unsigned long return_hooker = (unsigned long)&return_to_handler;
|
||||
unsigned long old;
|
||||
struct ftrace_graph_ent trace;
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||||
int err;
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||||
|
||||
if (unlikely(atomic_read(¤t->tracing_graph_pause)))
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||||
|
@ -144,16 +143,7 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
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|||
*/
|
||||
old = *parent;
|
||||
|
||||
trace.func = self_addr;
|
||||
trace.depth = current->curr_ret_stack + 1;
|
||||
|
||||
if (!ftrace_graph_entry(&trace))
|
||||
return;
|
||||
|
||||
err = ftrace_push_return_trace(old, self_addr, &trace.depth,
|
||||
frame_pointer, parent);
|
||||
if (err == -EBUSY)
|
||||
return;
|
||||
if (function_graph_enter(old, self_addr, frame_pointer, parent))
|
||||
*parent = return_hooker;
|
||||
}
|
||||
|
||||
|
|
|
@ -203,21 +203,12 @@ device_initcall(ftrace_plt_init);
|
|||
*/
|
||||
unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip)
|
||||
{
|
||||
struct ftrace_graph_ent trace;
|
||||
|
||||
if (unlikely(ftrace_graph_is_dead()))
|
||||
goto out;
|
||||
if (unlikely(atomic_read(¤t->tracing_graph_pause)))
|
||||
goto out;
|
||||
ip -= MCOUNT_INSN_SIZE;
|
||||
trace.func = ip;
|
||||
trace.depth = current->curr_ret_stack + 1;
|
||||
/* 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,
|
||||
NULL) == -EBUSY)
|
||||
goto out;
|
||||
if (!function_graph_enter(parent, ip, 0, NULL))
|
||||
parent = (unsigned long) return_to_handler;
|
||||
out:
|
||||
return parent;
|
||||
|
|
|
@ -321,8 +321,7 @@ int ftrace_disable_ftrace_graph_caller(void)
|
|||
void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
|
||||
{
|
||||
unsigned long old;
|
||||
int faulted, err;
|
||||
struct ftrace_graph_ent trace;
|
||||
int faulted;
|
||||
unsigned long return_hooker = (unsigned long)&return_to_handler;
|
||||
|
||||
if (unlikely(ftrace_graph_is_dead()))
|
||||
|
@ -365,18 +364,7 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
|
|||
return;
|
||||
}
|
||||
|
||||
err = ftrace_push_return_trace(old, self_addr, &trace.depth, 0, NULL);
|
||||
if (err == -EBUSY) {
|
||||
if (function_graph_enter(old, self_addr, 0, NULL))
|
||||
__raw_writel(old, parent);
|
||||
return;
|
||||
}
|
||||
|
||||
trace.func = self_addr;
|
||||
|
||||
/* Only trace if the calling function expects to */
|
||||
if (!ftrace_graph_entry(&trace)) {
|
||||
current->curr_ret_stack--;
|
||||
__raw_writel(old, parent);
|
||||
}
|
||||
}
|
||||
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
|
||||
|
|
|
@ -126,20 +126,11 @@ unsigned long prepare_ftrace_return(unsigned long parent,
|
|||
unsigned long frame_pointer)
|
||||
{
|
||||
unsigned long return_hooker = (unsigned long) &return_to_handler;
|
||||
struct ftrace_graph_ent trace;
|
||||
|
||||
if (unlikely(atomic_read(¤t->tracing_graph_pause)))
|
||||
return parent + 8UL;
|
||||
|
||||
trace.func = self_addr;
|
||||
trace.depth = current->curr_ret_stack + 1;
|
||||
|
||||
/* Only trace if the calling function expects to */
|
||||
if (!ftrace_graph_entry(&trace))
|
||||
return parent + 8UL;
|
||||
|
||||
if (ftrace_push_return_trace(parent, self_addr, &trace.depth,
|
||||
frame_pointer, NULL) == -EBUSY)
|
||||
if (function_graph_enter(parent, self_addr, frame_pointer, NULL))
|
||||
return parent + 8UL;
|
||||
|
||||
return return_hooker;
|
||||
|
|
|
@ -994,7 +994,6 @@ void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent,
|
|||
{
|
||||
unsigned long old;
|
||||
int faulted;
|
||||
struct ftrace_graph_ent trace;
|
||||
unsigned long return_hooker = (unsigned long)
|
||||
&return_to_handler;
|
||||
|
||||
|
@ -1046,19 +1045,7 @@ void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent,
|
|||
return;
|
||||
}
|
||||
|
||||
trace.func = self_addr;
|
||||
trace.depth = current->curr_ret_stack + 1;
|
||||
|
||||
/* Only trace if the calling function expects to */
|
||||
if (!ftrace_graph_entry(&trace)) {
|
||||
if (function_graph_enter(old, self_addr, frame_pointer, parent))
|
||||
*parent = old;
|
||||
return;
|
||||
}
|
||||
|
||||
if (ftrace_push_return_trace(old, self_addr, &trace.depth,
|
||||
frame_pointer, parent) == -EBUSY) {
|
||||
*parent = old;
|
||||
return;
|
||||
}
|
||||
}
|
||||
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
|
||||
|
|
|
@ -777,7 +777,7 @@ struct ftrace_ret_stack {
|
|||
extern void return_to_handler(void);
|
||||
|
||||
extern int
|
||||
ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
|
||||
function_graph_enter(unsigned long ret, unsigned long func,
|
||||
unsigned long frame_pointer, unsigned long *retp);
|
||||
|
||||
unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
|
||||
|
|
|
@ -1116,6 +1116,7 @@ struct task_struct {
|
|||
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
|
||||
/* Index of current stored address in ret_stack: */
|
||||
int curr_ret_stack;
|
||||
int curr_ret_depth;
|
||||
|
||||
/* Stack of return addresses for return function tracing: */
|
||||
struct ftrace_ret_stack *ret_stack;
|
||||
|
|
|
@ -107,6 +107,8 @@ DEFINE_EVENT(sched_wakeup_template, sched_wakeup_new,
|
|||
#ifdef CREATE_TRACE_POINTS
|
||||
static inline long __trace_sched_switch_state(bool preempt, struct task_struct *p)
|
||||
{
|
||||
unsigned int state;
|
||||
|
||||
#ifdef CONFIG_SCHED_DEBUG
|
||||
BUG_ON(p != current);
|
||||
#endif /* CONFIG_SCHED_DEBUG */
|
||||
|
@ -118,7 +120,15 @@ static inline long __trace_sched_switch_state(bool preempt, struct task_struct *
|
|||
if (preempt)
|
||||
return TASK_REPORT_MAX;
|
||||
|
||||
return 1 << task_state_index(p);
|
||||
/*
|
||||
* task_state_index() uses fls() and returns a value from 0-8 range.
|
||||
* Decrement it by 1 (except TASK_RUNNING state i.e 0) before using
|
||||
* it for left shift operation to get the correct task->state
|
||||
* mapping.
|
||||
*/
|
||||
state = task_state_index(p);
|
||||
|
||||
return state ? (1 << (state - 1)) : state;
|
||||
}
|
||||
#endif /* CREATE_TRACE_POINTS */
|
||||
|
||||
|
|
|
@ -817,7 +817,7 @@ function_profile_call(unsigned long ip, unsigned long parent_ip,
|
|||
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
|
||||
static int profile_graph_entry(struct ftrace_graph_ent *trace)
|
||||
{
|
||||
int index = trace->depth;
|
||||
int index = current->curr_ret_stack;
|
||||
|
||||
function_profile_call(trace->func, 0, NULL, NULL);
|
||||
|
||||
|
@ -852,7 +852,7 @@ static void profile_graph_return(struct ftrace_graph_ret *trace)
|
|||
if (!fgraph_graph_time) {
|
||||
int index;
|
||||
|
||||
index = trace->depth;
|
||||
index = current->curr_ret_stack;
|
||||
|
||||
/* Append this call time to the parent time to subtract */
|
||||
if (index)
|
||||
|
@ -6814,6 +6814,7 @@ static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
|
|||
atomic_set(&t->tracing_graph_pause, 0);
|
||||
atomic_set(&t->trace_overrun, 0);
|
||||
t->curr_ret_stack = -1;
|
||||
t->curr_ret_depth = -1;
|
||||
/* Make sure the tasks see the -1 first: */
|
||||
smp_wmb();
|
||||
t->ret_stack = ret_stack_list[start++];
|
||||
|
@ -7038,6 +7039,7 @@ graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
|
|||
void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
|
||||
{
|
||||
t->curr_ret_stack = -1;
|
||||
t->curr_ret_depth = -1;
|
||||
/*
|
||||
* The idle task has no parent, it either has its own
|
||||
* stack or no stack at all.
|
||||
|
@ -7068,6 +7070,7 @@ void ftrace_graph_init_task(struct task_struct *t)
|
|||
/* Make sure we do not use the parent ret_stack */
|
||||
t->ret_stack = NULL;
|
||||
t->curr_ret_stack = -1;
|
||||
t->curr_ret_depth = -1;
|
||||
|
||||
if (ftrace_graph_active) {
|
||||
struct ftrace_ret_stack *ret_stack;
|
||||
|
|
|
@ -118,8 +118,8 @@ print_graph_duration(struct trace_array *tr, unsigned long long duration,
|
|||
struct trace_seq *s, u32 flags);
|
||||
|
||||
/* 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,
|
||||
static int
|
||||
ftrace_push_return_trace(unsigned long ret, unsigned long func,
|
||||
unsigned long frame_pointer, unsigned long *retp)
|
||||
{
|
||||
unsigned long long calltime;
|
||||
|
@ -177,9 +177,31 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
|
|||
#ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
|
||||
current->ret_stack[index].retp = retp;
|
||||
#endif
|
||||
*depth = current->curr_ret_stack;
|
||||
return 0;
|
||||
}
|
||||
|
||||
int function_graph_enter(unsigned long ret, unsigned long func,
|
||||
unsigned long frame_pointer, unsigned long *retp)
|
||||
{
|
||||
struct ftrace_graph_ent trace;
|
||||
|
||||
trace.func = func;
|
||||
trace.depth = ++current->curr_ret_depth;
|
||||
|
||||
if (ftrace_push_return_trace(ret, func,
|
||||
frame_pointer, retp))
|
||||
goto out;
|
||||
|
||||
/* Only trace if the calling function expects to */
|
||||
if (!ftrace_graph_entry(&trace))
|
||||
goto out_ret;
|
||||
|
||||
return 0;
|
||||
out_ret:
|
||||
current->curr_ret_stack--;
|
||||
out:
|
||||
current->curr_ret_depth--;
|
||||
return -EBUSY;
|
||||
}
|
||||
|
||||
/* Retrieve a function return address to the trace stack on thread info.*/
|
||||
|
@ -241,7 +263,13 @@ ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
|
|||
trace->func = current->ret_stack[index].func;
|
||||
trace->calltime = current->ret_stack[index].calltime;
|
||||
trace->overrun = atomic_read(¤t->trace_overrun);
|
||||
trace->depth = index;
|
||||
trace->depth = current->curr_ret_depth--;
|
||||
/*
|
||||
* We still want to trace interrupts coming in if
|
||||
* max_depth is set to 1. Make sure the decrement is
|
||||
* seen before ftrace_graph_return.
|
||||
*/
|
||||
barrier();
|
||||
}
|
||||
|
||||
/*
|
||||
|
@ -255,6 +283,12 @@ unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
|
|||
|
||||
ftrace_pop_return_trace(&trace, &ret, frame_pointer);
|
||||
trace.rettime = trace_clock_local();
|
||||
ftrace_graph_return(&trace);
|
||||
/*
|
||||
* The ftrace_graph_return() may still access the current
|
||||
* ret_stack structure, we need to make sure the update of
|
||||
* curr_ret_stack is after that.
|
||||
*/
|
||||
barrier();
|
||||
current->curr_ret_stack--;
|
||||
/*
|
||||
|
@ -267,13 +301,6 @@ unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
|
|||
return ret;
|
||||
}
|
||||
|
||||
/*
|
||||
* The trace should run after decrementing the ret counter
|
||||
* in case an interrupt were to come in. We don't want to
|
||||
* lose the interrupt if max_depth is set.
|
||||
*/
|
||||
ftrace_graph_return(&trace);
|
||||
|
||||
if (unlikely(!ret)) {
|
||||
ftrace_graph_stop();
|
||||
WARN_ON(1);
|
||||
|
|
Loading…
Reference in New Issue