diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2023-01-26 16:08:31 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-03-10 09:33:47 +0100 |
| commit | b78434f6eee0e6d7da3e301cfc33184a98edb08b (patch) | |
| tree | 00bdefbcb51a7c2086bc70676a1c403e995d0ea4 /include | |
| parent | 463ef209628e682b65b86e1b86945f0018cb358a (diff) | |
cpuidle: lib/bug: Disable rcu_is_watching() during WARN/BUG
[ Upstream commit 5a5d7e9badd2cb8065db171961bd30bd3595e4b6 ]
In order to avoid WARN/BUG from generating nested or even recursive
warnings, force rcu_is_watching() true during
WARN/lockdep_rcu_suspicious().
Notably things like unwinding the stack can trigger rcu_dereference()
warnings, which then triggers more unwinding which then triggers more
warnings etc..
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230126151323.408156109@infradead.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/context_tracking.h | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h index dcef4a9e4d63..d4afa8508a80 100644 --- a/include/linux/context_tracking.h +++ b/include/linux/context_tracking.h @@ -130,9 +130,36 @@ static __always_inline unsigned long ct_state_inc(int incby) return arch_atomic_add_return(incby, this_cpu_ptr(&context_tracking.state)); } +static __always_inline bool warn_rcu_enter(void) +{ + bool ret = false; + + /* + * Horrible hack to shut up recursive RCU isn't watching fail since + * lots of the actual reporting also relies on RCU. + */ + preempt_disable_notrace(); + if (rcu_dynticks_curr_cpu_in_eqs()) { + ret = true; + ct_state_inc(RCU_DYNTICKS_IDX); + } + + return ret; +} + +static __always_inline void warn_rcu_exit(bool rcu) +{ + if (rcu) + ct_state_inc(RCU_DYNTICKS_IDX); + preempt_enable_notrace(); +} + #else static inline void ct_idle_enter(void) { } static inline void ct_idle_exit(void) { } + +static __always_inline bool warn_rcu_enter(void) { return false; } +static __always_inline void warn_rcu_exit(bool rcu) { } #endif /* !CONFIG_CONTEXT_TRACKING_IDLE */ #endif |