Call the rseq_handle_notify_resume() function on return to userspace if TIF_NOTIFY_RESUME thread flag is set.
Perform fixup on the pre-signal frame when a signal is delivered on top of a restartable sequence critical section. Check that system calls are not invoked from within rseq critical sections by invoking rseq_signal() from syscall_return_slowpath(). With CONFIG_DEBUG_RSEQ, such behavior results in termination of the process with SIGSEGV. Signed-off-by: Mathieu Desnoyers <mathieu.desnoy...@efficios.com> Reviewed-by: Thomas Gleixner <t...@linutronix.de> CC: Russell King <li...@arm.linux.org.uk> CC: Catalin Marinas <catalin.mari...@arm.com> CC: Will Deacon <will.dea...@arm.com> CC: Paul Turner <p...@google.com> CC: Andrew Hunter <a...@google.com> CC: Peter Zijlstra <pet...@infradead.org> CC: Andy Lutomirski <l...@amacapital.net> CC: Andi Kleen <a...@firstfloor.org> CC: Dave Watson <davejwat...@fb.com> CC: Chris Lameter <c...@linux.com> CC: Ingo Molnar <mi...@redhat.com> CC: "H. Peter Anvin" <h...@zytor.com> CC: Ben Maurer <bmau...@fb.com> CC: Steven Rostedt <rost...@goodmis.org> CC: "Paul E. McKenney" <paul...@linux.vnet.ibm.com> CC: Josh Triplett <j...@joshtriplett.org> CC: Linus Torvalds <torva...@linux-foundation.org> CC: Andrew Morton <a...@linux-foundation.org> CC: Boqun Feng <boqun.f...@gmail.com> CC: linux-...@vger.kernel.org --- Changes since v1: - Call rseq_signal() when returning from a system call. --- arch/x86/Kconfig | 1 + arch/x86/entry/common.c | 3 +++ arch/x86/kernel/signal.c | 6 ++++++ 3 files changed, 10 insertions(+) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 0fa71a78ec99..47a2b14fcc7d 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -178,6 +178,7 @@ config X86 select HAVE_REGS_AND_STACK_ACCESS_API select HAVE_RELIABLE_STACKTRACE if X86_64 && UNWINDER_FRAME_POINTER && STACK_VALIDATION select HAVE_STACK_VALIDATION if X86_64 + select HAVE_RSEQ select HAVE_SYSCALL_TRACEPOINTS select HAVE_UNSTABLE_SCHED_CLOCK select HAVE_USER_RETURN_NOTIFIER diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c index 74f6eee15179..5bc9c9fe49c4 100644 --- a/arch/x86/entry/common.c +++ b/arch/x86/entry/common.c @@ -164,6 +164,7 @@ static void exit_to_usermode_loop(struct pt_regs *regs, u32 cached_flags) if (cached_flags & _TIF_NOTIFY_RESUME) { clear_thread_flag(TIF_NOTIFY_RESUME); tracehook_notify_resume(regs); + rseq_handle_notify_resume(regs); } if (cached_flags & _TIF_USER_RETURN_NOTIFY) @@ -254,6 +255,8 @@ __visible inline void syscall_return_slowpath(struct pt_regs *regs) WARN(irqs_disabled(), "syscall %ld left IRQs disabled", regs->orig_ax)) local_irq_enable(); + rseq_syscall(regs); + /* * First do one-time work. If these work items are enabled, we * want to run them exactly once per syscall exit with IRQs on. diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c index 4cdc0b27ec82..0f549cbd8b46 100644 --- a/arch/x86/kernel/signal.c +++ b/arch/x86/kernel/signal.c @@ -687,6 +687,12 @@ setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs) sigset_t *set = sigmask_to_save(); compat_sigset_t *cset = (compat_sigset_t *) set; + /* + * Increment event counter and perform fixup for the pre-signal + * frame. + */ + rseq_signal_deliver(regs); + /* Set up the stack frame */ if (is_ia32_frame(ksig)) { if (ksig->ka.sa.sa_flags & SA_SIGINFO) -- 2.11.0