3.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: "zhangwei(Jovi)" <jovi.zhangwei@xxxxxxxxxx>
commit 11034ae9c20f4057a6127fc965906417978e69b2 upstream.
All syscall tracing irqs-off tags are wrong, the syscall enter entry doesn't
disable irqs.
[root@jovi tracing]#echo "syscalls:sys_enter_open" > set_event
[root@jovi tracing]# cat trace
# tracer: nop
#
# entries-in-buffer/entries-written: 13/13 #P:2
#
# _-----=> irqs-off
# / _----=> need-resched
# | / _---=> hardirq/softirq
# || / _--=> preempt-depth
# ||| / delay
# TASK-PID CPU# |||| TIMESTAMP FUNCTION
# | | | |||| | |
irqbalance-513 [000] d... 56115.496766: sys_open(filename: 804e1a6, flags: 0, mode: 1b6)
irqbalance-513 [000] d... 56115.497008: sys_open(filename: 804e1bb, flags: 0, mode: 1b6)
sendmail-771 [000] d... 56115.827982: sys_open(filename: b770e6d1, flags: 0, mode: 1b6)
The reason is syscall tracing doesn't record irq_flags into buffer.
The proper display is:
[root@jovi tracing]#echo "syscalls:sys_enter_open" > set_event
[root@jovi tracing]# cat trace
# tracer: nop
#
# entries-in-buffer/entries-written: 14/14 #P:2
#
# _-----=> irqs-off
# / _----=> need-resched
# | / _---=> hardirq/softirq
# || / _--=> preempt-depth
# ||| / delay
# TASK-PID CPU# |||| TIMESTAMP FUNCTION
# | | | |||| | |
irqbalance-514 [001] .... 46.213921: sys_open(filename: 804e1a6, flags: 0, mode: 1b6)
irqbalance-514 [001] .... 46.214160: sys_open(filename: 804e1bb, flags: 0, mode: 1b6)
<...>-920 [001] .... 47.307260: sys_open(filename: 4e82a0c5, flags: 80000, mode: 0)
Link: http://lkml.kernel.org/r/1365564393-10972-3-git-send-email-jovi.zhangwei@xxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx # 2.6.35
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@xxxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/trace/trace_syscalls.c | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -305,6 +305,8 @@ void ftrace_syscall_enter(void *ignore,
struct ring_buffer *buffer;
int size;
int syscall_nr;
+ unsigned long irq_flags;
+ int pc;
syscall_nr = syscall_get_nr(current, regs);
if (syscall_nr < 0)
@@ -318,8 +320,11 @@ void ftrace_syscall_enter(void *ignore,
size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args;
+ local_save_flags(irq_flags);
+ pc = preempt_count();
+
event = trace_current_buffer_lock_reserve(&buffer,
- sys_data->enter_event->event.type, size, 0, 0);
+ sys_data->enter_event->event.type, size, irq_flags, pc);
if (!event)
return;
@@ -329,7 +334,8 @@ void ftrace_syscall_enter(void *ignore,
if (!filter_current_check_discard(buffer, sys_data->enter_event,
entry, event))
- trace_current_buffer_unlock_commit(buffer, event, 0, 0);
+ trace_current_buffer_unlock_commit(buffer, event,
+ irq_flags, pc);
}
void ftrace_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
@@ -339,6 +345,8 @@ void ftrace_syscall_exit(void *ignore, s
struct ring_buffer_event *event;
struct ring_buffer *buffer;
int syscall_nr;
+ unsigned long irq_flags;
+ int pc;
syscall_nr = syscall_get_nr(current, regs);
if (syscall_nr < 0)
@@ -351,7 +359,8 @@ void ftrace_syscall_exit(void *ignore, s
return;
event = trace_current_buffer_lock_reserve(&buffer,
- sys_data->exit_event->event.type, sizeof(*entry), 0, 0);
+ sys_data->exit_event->event.type, sizeof(*entry),
+ irq_flags, pc);
if (!event)
return;
@@ -361,7 +370,8 @@ void ftrace_syscall_exit(void *ignore, s
if (!filter_current_check_discard(buffer, sys_data->exit_event,
entry, event))
- trace_current_buffer_unlock_commit(buffer, event, 0, 0);
+ trace_current_buffer_unlock_commit(buffer, event,
+ irq_flags, pc);
}
int reg_event_syscall_enter(struct ftrace_event_call *call)
--
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