Messages in this thread Patch in this message | | | From | Mathieu Desnoyers <> | Subject | [RFC PATCH for 4.18] rseq: cleanup: no need to abort rseq c.s. in child on fork | Date | Sat, 16 Jun 2018 16:20:13 -0400 |
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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); } } -- 2.11.0
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