diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2014-04-13 20:58:54 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-07-06 18:54:16 -0700 |
| commit | e6bc60b8fb412b38db86bc1351f2ce40ad31d0e0 (patch) | |
| tree | 7fa6f63114bf298bebe1833f5966a5d76d6d727f | |
| parent | c5bce73649b8a164990182b46185197f3d424f41 (diff) | |
tracing: Fix syscall_*regfunc() vs copy_process() race
commit 4af4206be2bd1933cae20c2b6fb2058dbc887f7c upstream.
syscall_regfunc() and syscall_unregfunc() should set/clear
TIF_SYSCALL_TRACEPOINT system-wide, but do_each_thread() can race
with copy_process() and miss the new child which was not added to
the process/thread lists yet.
Change copy_process() to update the child's TIF_SYSCALL_TRACEPOINT
under tasklist.
Link: http://lkml.kernel.org/p/20140413185854.GB20668@redhat.com
Fixes: a871bd33a6c0 "tracing: Add syscall tracepoints"
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | include/trace/syscall.h | 15 | ||||
| -rw-r--r-- | kernel/fork.c | 2 |
2 files changed, 17 insertions, 0 deletions
diff --git a/include/trace/syscall.h b/include/trace/syscall.h index 84bc4197e736..0a5b4952aa30 100644 --- a/include/trace/syscall.h +++ b/include/trace/syscall.h @@ -4,6 +4,7 @@ #include <linux/tracepoint.h> #include <linux/unistd.h> #include <linux/ftrace_event.h> +#include <linux/thread_info.h> #include <asm/ptrace.h> @@ -31,4 +32,18 @@ struct syscall_metadata { struct ftrace_event_call *exit_event; }; +#if defined(CONFIG_TRACEPOINTS) && defined(CONFIG_HAVE_SYSCALL_TRACEPOINTS) +static inline void syscall_tracepoint_update(struct task_struct *p) +{ + if (test_thread_flag(TIF_SYSCALL_TRACEPOINT)) + set_tsk_thread_flag(p, TIF_SYSCALL_TRACEPOINT); + else + clear_tsk_thread_flag(p, TIF_SYSCALL_TRACEPOINT); +} +#else +static inline void syscall_tracepoint_update(struct task_struct *p) +{ +} +#endif + #endif /* _TRACE_SYSCALL_H */ diff --git a/kernel/fork.c b/kernel/fork.c index 270c1dab674a..814363a69b80 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1479,7 +1479,9 @@ static struct task_struct *copy_process(unsigned long clone_flags, total_forks++; spin_unlock(¤t->sighand->siglock); + syscall_tracepoint_update(p); write_unlock_irq(&tasklist_lock); + proc_fork_connector(p); cgroup_post_fork(p); if (clone_flags & CLONE_THREAD) |