diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2014-04-13 20:59:18 +0200 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2014-06-21 06:15:25 +0200 |
| commit | 8063e41d2ffc0b0ce974ea802158be35902072f3 (patch) | |
| tree | 27787dcbf46b42a1737c4668673eb249b9304038 /kernel/tracepoint.c | |
| parent | tracing: Fix syscall_*regfunc() vs copy_process() race (diff) | |
| download | linux-8063e41d2ffc0b0ce974ea802158be35902072f3.tar.xz linux-8063e41d2ffc0b0ce974ea802158be35902072f3.zip | |
tracing: Change syscall_*regfunc() to check PF_KTHREAD and use for_each_process_thread()
1. Remove _irqsafe from syscall_regfunc/syscall_unregfunc,
read_lock(tasklist) doesn't need to disable irqs.
2. Change this code to avoid the deprecated do_each_thread()
and use for_each_process_thread() (stolen from the patch
from Frederic).
3. Change syscall_regfunc() to check PF_KTHREAD to skip
the kernel threads, ->mm != NULL is the common mistake.
Note: probably this check should be simply removed, needs
another patch.
[fweisbec@gmail.com: s/do_each_thread/for_each_process_thread/]
Link: http://lkml.kernel.org/p/20140413185918.GC20668@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/tracepoint.c')
| -rw-r--r-- | kernel/tracepoint.c | 24 |
1 files changed, 11 insertions, 13 deletions
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c index 33cbd8c203f8..9cf12640de5a 100644 --- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c @@ -492,33 +492,31 @@ static int sys_tracepoint_refcount; void syscall_regfunc(void) { - unsigned long flags; - struct task_struct *g, *t; + struct task_struct *p, *t; if (!sys_tracepoint_refcount) { - read_lock_irqsave(&tasklist_lock, flags); - do_each_thread(g, t) { + read_lock(&tasklist_lock); + for_each_process_thread(p, t) { /* Skip kernel threads. */ - if (t->mm) + if (!(t->flags & PF_KTHREAD)) set_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT); - } while_each_thread(g, t); - read_unlock_irqrestore(&tasklist_lock, flags); + } + read_unlock(&tasklist_lock); } sys_tracepoint_refcount++; } void syscall_unregfunc(void) { - unsigned long flags; - struct task_struct *g, *t; + struct task_struct *p, *t; sys_tracepoint_refcount--; if (!sys_tracepoint_refcount) { - read_lock_irqsave(&tasklist_lock, flags); - do_each_thread(g, t) { + read_lock(&tasklist_lock); + for_each_process_thread(p, t) { clear_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT); - } while_each_thread(g, t); - read_unlock_irqrestore(&tasklist_lock, flags); + } + read_unlock(&tasklist_lock); } } #endif |