Messages in this thread Patch in this message | | | Date | Fri, 6 Jan 2023 06:53:31 -0800 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH] context_tracking: Use arch_atomic_*() in __ct_user_enter and __ct_user_exit |
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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
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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); } } }
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