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context_tracking: Fix noinstr vs KASAN 

[ Upstream commit 0e26e1de00 ]

Low level noinstr context-tracking code is calling out to instrumented
code on KASAN:

  vmlinux.o: warning: objtool: __ct_user_enter+0x72: call to __kasan_check_write() leaves .noinstr.text section
  vmlinux.o: warning: objtool: __ct_user_exit+0x47: call to __kasan_check_write() leaves .noinstr.text section

Use even lower level atomic methods to avoid the instrumentation.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230112195542.458034262@infradead.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Peter Zijlstra 2023-01-12 20:44:05 +01:00 committed by Greg Kroah-Hartman
parent 0f688febd5
commit 982f8ef8ec
1 changed files with 6 additions and 6 deletions
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12
kernel/context_tracking.c
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@ -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);
}
}
}