Messages in this thread Patch in this message | | | From | Frederic Weisbecker <> | Subject | [PATCH 6/6] x86: Exit RCU extended QS on notify resume | Date | Fri, 6 Jul 2012 14:00:18 +0200 |
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do_notify_resume() may be called on irq exit but it won't be protected between rcu_irq_enter() and rcu_irq_exit() and we don't call rcu_user_exit() on irq entry (unlike syscalls/exceptions entry).
Since it can use RCU read side critical section, we must call rcu_user_exit() before doing anything there.
This complete support for RCU userspace extended quiescent state in x86.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Alessio Igor Bogani <abogani@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Avi Kivity <avi@redhat.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Christoph Lameter <cl@linux.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Gilad Ben Yossef <gilad@benyossef.com> Cc: Hakan Akkan <hakanakkan@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Kevin Hilman <khilman@ti.com> Cc: Max Krasnyansky <maxk@qualcomm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephen Hemminger <shemminger@vyatta.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> --- arch/x86/Kconfig | 1 + arch/x86/kernel/signal.c | 2 ++ 2 files changed, 3 insertions(+), 0 deletions(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index c70684f..38dfcc2 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -95,6 +95,7 @@ config X86 select KTIME_SCALAR if X86_32 select GENERIC_STRNCPY_FROM_USER select GENERIC_STRNLEN_USER + select HAVE_RCU_USER_QS if X86_64 config INSTRUCTION_DECODER def_bool (KPROBES || PERF_EVENTS || UPROBES) diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c index 21af737..5af078e 100644 --- a/arch/x86/kernel/signal.c +++ b/arch/x86/kernel/signal.c @@ -776,6 +776,8 @@ static void do_signal(struct pt_regs *regs) void do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags) { + rcu_user_exit(); + #ifdef CONFIG_X86_MCE /* notify userspace of pending MCEs */ if (thread_info_flags & _TIF_MCE_NOTIFY) -- 1.7.5.4
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