diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2014-04-13 22:58:54 +0400 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2014-06-21 08:15:12 +0400 |
| commit | 4af4206be2bd1933cae20c2b6fb2058dbc887f7c (patch) | |
| tree | a11266fc7f0eb38a6185698a899a914dda13ed57 /include | |
| parent | 7171511eaec5bf23fb06078f59784a3a0626b38f (diff) | |
| download | linux-4af4206be2bd1933cae20c2b6fb2058dbc887f7c.tar.xz | |
tracing: Fix syscall_*regfunc() vs copy_process() race
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
Cc: stable@vger.kernel.org # 2.6.33
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>
Diffstat (limited to 'include')
| -rw-r--r-- | include/trace/syscall.h | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/include/trace/syscall.h b/include/trace/syscall.h index fed853f3d7aa..9674145e2f6a 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> @@ -32,4 +33,18 @@ 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 */ |