diff options
| author | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2017-03-23 10:33:50 -0400 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2017-03-24 10:14:07 +0100 |
| commit | e6928e58d4d4a02f88838945f792c107623314ac (patch) | |
| tree | ab933b16e09edd0dc24772fb39df2a0011d91dd0 /arch/x86/kernel/ftrace_32.S | |
| parent | 3d82c59c6e3cb168284d9b0a1143415d9c98ae40 (diff) | |
| download | lwn-e6928e58d4d4a02f88838945f792c107623314ac.tar.gz lwn-e6928e58d4d4a02f88838945f792c107623314ac.zip | |
x86/ftrace: Add stack frame pointer to ftrace_caller
The function hook ftrace_caller does not create its own stack frame, and
this causes the ftrace stack trace to miss the first function when doing
stack traces.
# echo schedule:stacktrace > /sys/kernel/tracing/set_ftrace_filter
Before:
<idle>-0 [002] .N.. 29.865807: <stack trace>
=> cpu_startup_entry
=> start_secondary
=> startup_32_smp
<...>-7 [001] .... 29.866509: <stack trace>
=> kthread
=> ret_from_fork
<...>-1 [000] .... 29.865377: <stack trace>
=> poll_schedule_timeout
=> do_select
=> core_sys_select
=> SyS_select
=> do_fast_syscall_32
=> entry_SYSENTER_32
After:
<idle>-0 [002] .N.. 31.234853: <stack trace>
=> do_idle
=> cpu_startup_entry
=> start_secondary
=> startup_32_smp
<...>-7 [003] .... 31.235140: <stack trace>
=> rcu_gp_kthread
=> kthread
=> ret_from_fork
<...>-1819 [000] .... 31.264172: <stack trace>
=> schedule_hrtimeout_range
=> poll_schedule_timeout
=> do_sys_poll
=> SyS_ppoll
=> do_fast_syscall_32
=> entry_SYSENTER_32
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20170323143445.771707773@goodmis.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86/kernel/ftrace_32.S')
| -rw-r--r-- | arch/x86/kernel/ftrace_32.S | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/arch/x86/kernel/ftrace_32.S b/arch/x86/kernel/ftrace_32.S index 2b160f238a42..a4e2872971c0 100644 --- a/arch/x86/kernel/ftrace_32.S +++ b/arch/x86/kernel/ftrace_32.S @@ -16,12 +16,19 @@ ENTRY(mcount) END(mcount) ENTRY(ftrace_caller) + + pushl %ebp + movl %esp, %ebp + pushl %eax pushl %ecx pushl %edx pushl $0 /* Pass NULL as regs pointer */ - movl 4*4(%esp), %eax - movl 0x4(%ebp), %edx + movl 5*4(%esp), %eax + /* Copy original ebp into %edx */ + movl 4*4(%esp), %edx + /* Get the parent ip */ + movl 0x4(%edx), %edx movl function_trace_op, %ecx subl $MCOUNT_INSN_SIZE, %eax @@ -33,6 +40,7 @@ ftrace_call: popl %edx popl %ecx popl %eax + popl %ebp .Lftrace_ret: #ifdef CONFIG_FUNCTION_GRAPH_TRACER .globl ftrace_graph_call |