From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: Sean Christopherson <seanjc@google.com>
Cc: "Russell King, ARM Linux" <linux@armlinux.org.uk>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>, Guo Ren <guoren@kernel.org>,
Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
Michael Ellerman <mpe@ellerman.id.au>,
Heiko Carstens <hca@linux.ibm.com>, gor <gor@linux.ibm.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Oleg Nesterov <oleg@redhat.com>, rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Andy Lutomirski <luto@kernel.org>, paulmck <paulmck@kernel.org>,
Boqun Feng <boqun.feng@gmail.com>,
Paolo Bonzini <pbonzini@redhat.com>, shuah <shuah@kernel.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-csky <linux-csky@vger.kernel.org>,
linux-mips@vger.kernel.org,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
linux-s390@vger.kernel.org, KVM list <kvm@vger.kernel.org>,
linux-kselftest <linux-kselftest@vger.kernel.org>,
Peter Foley <pefoley@google.com>,
Shakeel Butt <shakeelb@google.com>,
Ben Gardon <bgardon@google.com>
Subject: Re: [PATCH 2/5] entry: rseq: Call rseq_handle_notify_resume() in tracehook_notify_resume()
Date: Thu, 19 Aug 2021 17:41:07 -0400 (EDT) [thread overview]
Message-ID: <1359319445.19723.1629409267434.JavaMail.zimbra@efficios.com> (raw)
In-Reply-To: <20210818001210.4073390-3-seanjc@google.com>
----- On Aug 17, 2021, at 8:12 PM, Sean Christopherson seanjc@google.com wrote:
> Invoke rseq_handle_notify_resume() from tracehook_notify_resume() now
> that the two function are always called back-to-back by architectures
> that have rseq. The rseq helper is stubbed out for architectures that
> don't support rseq, i.e. this is a nop across the board.
>
> Note, tracehook_notify_resume() is horribly named and arguably does not
> belong in tracehook.h as literally every line of code in it has nothing
> to do with tracing. But, that's been true since commit a42c6ded827d
> ("move key_repace_session_keyring() into tracehook_notify_resume()")
> first usurped tracehook_notify_resume() back in 2012. Punt cleaning that
> mess up to future patches.
>
> No functional change intended.
This will make it harder to introduce new code paths which consume the
NOTIFY_RESUME without calling the rseq callback, which introduces issues.
Agreed.
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
> arch/arm/kernel/signal.c | 1 -
> arch/arm64/kernel/signal.c | 1 -
> arch/csky/kernel/signal.c | 4 +---
> arch/mips/kernel/signal.c | 4 +---
> arch/powerpc/kernel/signal.c | 4 +---
> arch/s390/kernel/signal.c | 1 -
> include/linux/tracehook.h | 2 ++
> kernel/entry/common.c | 4 +---
> kernel/entry/kvm.c | 4 +---
> 9 files changed, 7 insertions(+), 18 deletions(-)
>
> diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
> index a3a38d0a4c85..9df68d139965 100644
> --- a/arch/arm/kernel/signal.c
> +++ b/arch/arm/kernel/signal.c
> @@ -670,7 +670,6 @@ do_work_pending(struct pt_regs *regs, unsigned int
> thread_flags, int syscall)
> uprobe_notify_resume(regs);
> } else {
> tracehook_notify_resume(regs);
> - rseq_handle_notify_resume(NULL, regs);
> }
> }
> local_irq_disable();
> diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
> index 23036334f4dc..22b55db13da6 100644
> --- a/arch/arm64/kernel/signal.c
> +++ b/arch/arm64/kernel/signal.c
> @@ -951,7 +951,6 @@ asmlinkage void do_notify_resume(struct pt_regs *regs,
>
> if (thread_flags & _TIF_NOTIFY_RESUME) {
> tracehook_notify_resume(regs);
> - rseq_handle_notify_resume(NULL, regs);
>
> /*
> * If we reschedule after checking the affinity
> diff --git a/arch/csky/kernel/signal.c b/arch/csky/kernel/signal.c
> index 312f046d452d..bc4238b9f709 100644
> --- a/arch/csky/kernel/signal.c
> +++ b/arch/csky/kernel/signal.c
> @@ -260,8 +260,6 @@ asmlinkage void do_notify_resume(struct pt_regs *regs,
> if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
> do_signal(regs);
>
> - if (thread_info_flags & _TIF_NOTIFY_RESUME) {
> + if (thread_info_flags & _TIF_NOTIFY_RESUME)
> tracehook_notify_resume(regs);
> - rseq_handle_notify_resume(NULL, regs);
> - }
> }
> diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c
> index f1e985109da0..c9b2a75563e1 100644
> --- a/arch/mips/kernel/signal.c
> +++ b/arch/mips/kernel/signal.c
> @@ -906,10 +906,8 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, void
> *unused,
> if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
> do_signal(regs);
>
> - if (thread_info_flags & _TIF_NOTIFY_RESUME) {
> + if (thread_info_flags & _TIF_NOTIFY_RESUME)
> tracehook_notify_resume(regs);
> - rseq_handle_notify_resume(NULL, regs);
> - }
>
> user_enter();
> }
> diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c
> index e600764a926c..b93b87df499d 100644
> --- a/arch/powerpc/kernel/signal.c
> +++ b/arch/powerpc/kernel/signal.c
> @@ -293,10 +293,8 @@ void do_notify_resume(struct pt_regs *regs, unsigned long
> thread_info_flags)
> do_signal(current);
> }
>
> - if (thread_info_flags & _TIF_NOTIFY_RESUME) {
> + if (thread_info_flags & _TIF_NOTIFY_RESUME)
> tracehook_notify_resume(regs);
> - rseq_handle_notify_resume(NULL, regs);
> - }
> }
>
> static unsigned long get_tm_stackpointer(struct task_struct *tsk)
> diff --git a/arch/s390/kernel/signal.c b/arch/s390/kernel/signal.c
> index 78ef53b29958..b307db26bf2d 100644
> --- a/arch/s390/kernel/signal.c
> +++ b/arch/s390/kernel/signal.c
> @@ -537,5 +537,4 @@ void arch_do_signal_or_restart(struct pt_regs *regs, bool
> has_signal)
> void do_notify_resume(struct pt_regs *regs)
> {
> tracehook_notify_resume(regs);
> - rseq_handle_notify_resume(NULL, regs);
> }
> diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h
> index 3e80c4bc66f7..2564b7434b4d 100644
> --- a/include/linux/tracehook.h
> +++ b/include/linux/tracehook.h
> @@ -197,6 +197,8 @@ static inline void tracehook_notify_resume(struct pt_regs
> *regs)
>
> mem_cgroup_handle_over_high();
> blkcg_maybe_throttle_current();
> +
> + rseq_handle_notify_resume(NULL, regs);
> }
>
> /*
> diff --git a/kernel/entry/common.c b/kernel/entry/common.c
> index bf16395b9e13..d5a61d565ad5 100644
> --- a/kernel/entry/common.c
> +++ b/kernel/entry/common.c
> @@ -171,10 +171,8 @@ static unsigned long exit_to_user_mode_loop(struct pt_regs
> *regs,
> if (ti_work & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
> handle_signal_work(regs, ti_work);
>
> - if (ti_work & _TIF_NOTIFY_RESUME) {
> + if (ti_work & _TIF_NOTIFY_RESUME)
> tracehook_notify_resume(regs);
> - rseq_handle_notify_resume(NULL, regs);
> - }
>
> /* Architecture specific TIF work */
> arch_exit_to_user_mode_work(regs, ti_work);
> diff --git a/kernel/entry/kvm.c b/kernel/entry/kvm.c
> index 049fd06b4c3d..49972ee99aff 100644
> --- a/kernel/entry/kvm.c
> +++ b/kernel/entry/kvm.c
> @@ -19,10 +19,8 @@ static int xfer_to_guest_mode_work(struct kvm_vcpu *vcpu,
> unsigned long ti_work)
> if (ti_work & _TIF_NEED_RESCHED)
> schedule();
>
> - if (ti_work & _TIF_NOTIFY_RESUME) {
> + if (ti_work & _TIF_NOTIFY_RESUME)
> tracehook_notify_resume(NULL);
> - rseq_handle_notify_resume(NULL, NULL);
> - }
>
> ret = arch_xfer_to_guest_mode_handle_work(vcpu, ti_work);
> if (ret)
> --
> 2.33.0.rc1.237.g0d66db33f3-goog
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
next prev parent reply other threads:[~2021-08-19 21:41 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-18 0:12 [PATCH 0/5] KVM: rseq: Fix and a test for a KVM+rseq bug Sean Christopherson
2021-08-18 0:12 ` [PATCH 1/5] KVM: rseq: Update rseq when processing NOTIFY_RESUME on xfer to KVM guest Sean Christopherson
2021-08-19 21:39 ` Mathieu Desnoyers
2021-08-19 23:48 ` Sean Christopherson
2021-08-20 18:51 ` Mathieu Desnoyers
2021-08-20 22:26 ` Sean Christopherson
2021-09-06 10:28 ` Paolo Bonzini
2021-09-07 14:38 ` Sean Christopherson
2021-08-18 0:12 ` [PATCH 2/5] entry: rseq: Call rseq_handle_notify_resume() in tracehook_notify_resume() Sean Christopherson
2021-08-19 21:41 ` Mathieu Desnoyers [this message]
2021-08-18 0:12 ` [PATCH 3/5] tools: Move x86 syscall number fallbacks to .../uapi/ Sean Christopherson
2021-08-18 0:12 ` [PATCH 4/5] KVM: selftests: Add a test for KVM_RUN+rseq to detect task migration bugs Sean Christopherson
2021-08-19 21:52 ` Mathieu Desnoyers
2021-08-19 23:33 ` Sean Christopherson
2021-08-20 18:31 ` Mathieu Desnoyers
2021-08-20 22:25 ` Sean Christopherson
2021-08-18 0:12 ` [PATCH 5/5] KVM: selftests: Remove __NR_userfaultfd syscall fallback Sean Christopherson
2021-09-22 14:12 ` [PATCH 0/5] KVM: rseq: Fix and a test for a KVM+rseq bug Paolo Bonzini
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1359319445.19723.1629409267434.JavaMail.zimbra@efficios.com \
--to=mathieu.desnoyers@efficios.com \
--cc=benh@kernel.crashing.org \
--cc=bgardon@google.com \
--cc=boqun.feng@gmail.com \
--cc=borntraeger@de.ibm.com \
--cc=catalin.marinas@arm.com \
--cc=gor@linux.ibm.com \
--cc=guoren@kernel.org \
--cc=hca@linux.ibm.com \
--cc=kvm@vger.kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-csky@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-kselftest@vger.kernel.org \
--cc=linux-mips@vger.kernel.org \
--cc=linux-s390@vger.kernel.org \
--cc=linux@armlinux.org.uk \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=luto@kernel.org \
--cc=mingo@redhat.com \
--cc=mpe@ellerman.id.au \
--cc=oleg@redhat.com \
--cc=paulmck@kernel.org \
--cc=paulus@samba.org \
--cc=pbonzini@redhat.com \
--cc=pefoley@google.com \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=seanjc@google.com \
--cc=shakeelb@google.com \
--cc=shuah@kernel.org \
--cc=tglx@linutronix.de \
--cc=tsbogend@alpha.franken.de \
--cc=will@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).