tracing: Fix syscall_*regfunc() vs copy_process() race
authorOleg Nesterov <oleg@redhat.com>
Sun, 13 Apr 2014 18:58:54 +0000 (20:58 +0200)
committerSteven Rostedt <rostedt@goodmis.org>
Sat, 21 Jun 2014 04:15:12 +0000 (00:15 -0400)
commit4af4206be2bd1933cae20c2b6fb2058dbc887f7c
treea11266fc7f0eb38a6185698a899a914dda13ed57
parent7171511eaec5bf23fb06078f59784a3a0626b38f
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>
include/trace/syscall.h
kernel/fork.c