Considering that we explicitly forbid system calls in rseq critical sections, it is not valid to issue a fork or clone system call within a rseq critical section, so rseq_fork() is not required to restart an active rseq c.s. in the child process.

Signed-off-by: Mathieu Desnoyers mathieu.desnoyers@efficios.com Cc: Thomas Gleixner tglx@linutronix.de Cc: Joel Fernandes joelaf@google.com Cc: Peter Zijlstra peterz@infradead.org Cc: Catalin Marinas catalin.marinas@arm.com Cc: Dave Watson davejwatson@fb.com Cc: Will Deacon will.deacon@arm.com Cc: Shuah Khan shuahkh@osg.samsung.com Cc: Andi Kleen andi@firstfloor.org Cc: linux-kselftest@vger.kernel.org Cc: "H . Peter Anvin" hpa@zytor.com Cc: Chris Lameter cl@linux.com Cc: Russell King linux@arm.linux.org.uk Cc: Michael Kerrisk mtk.manpages@gmail.com Cc: "Paul E . McKenney" paulmck@linux.vnet.ibm.com Cc: Paul Turner pjt@google.com Cc: Boqun Feng boqun.feng@gmail.com Cc: Josh Triplett josh@joshtriplett.org Cc: Steven Rostedt rostedt@goodmis.org Cc: Ben Maurer bmaurer@fb.com Cc: linux-api@vger.kernel.org Cc: Andy Lutomirski luto@amacapital.net Cc: Andrew Morton akpm@linux-foundation.org Cc: Linus Torvalds torvalds@linux-foundation.org --- include/linux/sched.h | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h index 87bf02d93a27..c1882643d455 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1831,9 +1831,7 @@ static inline void rseq_migrate(struct task_struct *t)

/* * If parent process has a registered restartable sequences area, the - * child inherits. Only applies when forking a process, not a thread. In - * case a parent fork() in the middle of a restartable sequence, set the - * resume notifier to force the child to retry. + * child inherits. Only applies when forking a process, not a thread. */ static inline void rseq_fork(struct task_struct *t, unsigned long clone_flags) { @@ -1847,7 +1845,6 @@ static inline void rseq_fork(struct task_struct *t, unsigned long clone_flags) t->rseq_len = current->rseq_len; t->rseq_sig = current->rseq_sig; t->rseq_event_mask = current->rseq_event_mask; - rseq_preempt(t); } }