Messages in this thread | | | From | genjian zhang <> | Date | Mon, 9 Jan 2023 15:13:06 +0800 | Subject | Re: [PATCH] context_tracking: Use arch_atomic_*() in __ct_user_enter and __ct_user_exit |
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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.
Thanks,
Genjian.
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