Messages in this thread | | | Date | Mon, 9 Jan 2023 07:10:55 -0800 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH] context_tracking: Use arch_atomic_*() in __ct_user_enter and __ct_user_exit |
| |
On Mon, Jan 09, 2023 at 03:13:06PM +0800, genjian zhang wrote: > On Fri, Jan 6, 2023 at 10:53 PM Paul E. McKenney <paulmck@kernel.org> wrote: > > > > On Thu, Nov 10, 2022 at 04:24:43PM +0800, Genjian wrote: > > > From: Genjian Zhang <zhanggenjian@kylinos.cn> > > > > > > vmlinux.o: warning: objtool: __ct_user_enter+0x45: call to > > > __kasan_check_write() leaves .noinstr.text section > > > vmlinux.o: warning: objtool: __ct_user_exit+0x3f: call to > > > __kasan_check_write() leaves .noinstr.text section > > > > > > noinstr cannot have atomic_*() functions.because they have explicit > > > instrumentation.Switch to arch_ prefixed atomic operation functions to > > > avoid the explicit instrumentation. > > > > > > Reported-by: k2ci <kernel-bot@kylinos.cn> > > > Reported-by: kernel test robot <lkp@intel.com> > > > Signed-off-by: Genjian Zhang <zhanggenjian@kylinos.cn> > > > > Apologies for the delay, but finally queued, thank you! Frederic gave > > his ack off-list, which I have included in the wordsmithed version below. > > Could you please check to make sure that I did not mess anything up? > > > > Thanx, Paul > > > > ------------------------------------------------------------------------ > > > > commit 936acd859f4a7b2b0f9900e26bc972385286df6e > > Author: Genjian Zhang <zhanggenjian@kylinos.cn> > > Date: Thu Nov 10 16:24:43 2022 +0800 > > > > context_tracking: Use arch_atomic_*() in __ct_user_enter and __ct_user_exit > > > > The following diagnostics are issued by objtool: > > > > vmlinux.o: warning: objtool: __ct_user_enter+0x45: call to > > __kasan_check_write() leaves .noinstr.text section > > vmlinux.o: warning: objtool: __ct_user_exit+0x3f: call to > > __kasan_check_write() leaves .noinstr.text section > > > > The reason for these diagnostics is that code marked noinstr if prohibited > > from using atomic_*() functions, which have explicit instrumentation. > > Therefore, switch to arch_ prefixed atomic operation functions to avoid > > the explicit instrumentation. > > > > Reported-by: k2ci <kernel-bot@kylinos.cn> > > Reported-by: kernel test robot <lkp@intel.com> > > Signed-off-by: Genjian Zhang <zhanggenjian@kylinos.cn> > > Acked-by: Frederic Weisbecker <frederic@kernel.org> > > Signed-off-by: Paul E. McKenney <paulmck@kernel.org> > > > > diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c > > index 77978e3723771..a09f1c19336ae 100644 > > --- a/kernel/context_tracking.c > > +++ b/kernel/context_tracking.c > > @@ -510,7 +510,7 @@ void noinstr __ct_user_enter(enum ctx_state state) > > * In this we case we don't care about any concurrency/ordering. > > */ > > if (!IS_ENABLED(CONFIG_CONTEXT_TRACKING_IDLE)) > > - atomic_set(&ct->state, state); > > + arch_atomic_set(&ct->state, state); > > } else { > > /* > > * Even if context tracking is disabled on this CPU, because it's outside > > @@ -527,7 +527,7 @@ void noinstr __ct_user_enter(enum ctx_state state) > > */ > > if (!IS_ENABLED(CONFIG_CONTEXT_TRACKING_IDLE)) { > > /* Tracking for vtime only, no concurrent RCU EQS accounting */ > > - atomic_set(&ct->state, state); > > + arch_atomic_set(&ct->state, state); > > } else { > > /* > > * Tracking for vtime and RCU EQS. Make sure we don't race > > @@ -535,7 +535,7 @@ void noinstr __ct_user_enter(enum ctx_state state) > > * RCU only requires RCU_DYNTICKS_IDX increments to be fully > > * ordered. > > */ > > - atomic_add(state, &ct->state); > > + arch_atomic_add(state, &ct->state); > > } > > } > > } > > @@ -630,12 +630,12 @@ void noinstr __ct_user_exit(enum ctx_state state) > > * In this we case we don't care about any concurrency/ordering. > > */ > > if (!IS_ENABLED(CONFIG_CONTEXT_TRACKING_IDLE)) > > - atomic_set(&ct->state, CONTEXT_KERNEL); > > + arch_atomic_set(&ct->state, CONTEXT_KERNEL); > > > > } else { > > if (!IS_ENABLED(CONFIG_CONTEXT_TRACKING_IDLE)) { > > /* Tracking for vtime only, no concurrent RCU EQS accounting */ > > - atomic_set(&ct->state, CONTEXT_KERNEL); > > + arch_atomic_set(&ct->state, CONTEXT_KERNEL); > > } else { > > /* > > * Tracking for vtime and RCU EQS. Make sure we don't race > > @@ -643,7 +643,7 @@ void noinstr __ct_user_exit(enum ctx_state state) > > * RCU only requires RCU_DYNTICKS_IDX increments to be fully > > * ordered. > > */ > > - atomic_sub(state, &ct->state); > > + arch_atomic_sub(state, &ct->state); > > } > > } > > } > > Seems good to me.
Thank you for checking!
Thanx, Paul
| |