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| author | Paul E. McKenney <paulmck@kernel.org> | 2024-12-31 08:47:43 -0800 |
|---|---|---|
| committer | Boqun Feng <boqun.feng@gmail.com> | 2025-02-04 21:50:06 -0800 |
| commit | bea1d19f03644b0eb7ac0b7d96f79a3af13f196b (patch) | |
| tree | 4f13a8e3eef29143af627bf81a65ff1d790e5f78 | |
| parent | 2014c95afecee3e76ca4a56956a936e23283f05b (diff) | |
doc: Add broken-timing possibility to stallwarn.rst
Currently, stallwarn.rst does not mention the fact that timer bugs can
result in false-positive RCU CPU stall warnings. This commit therefore
adds this to the list.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
| -rw-r--r-- | Documentation/RCU/stallwarn.rst | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/Documentation/RCU/stallwarn.rst b/Documentation/RCU/stallwarn.rst index 30080ff6f406..d1ccd6039a8c 100644 --- a/Documentation/RCU/stallwarn.rst +++ b/Documentation/RCU/stallwarn.rst @@ -96,6 +96,13 @@ warnings: the ``rcu_.*timer wakeup didn't happen for`` console-log message, which will include additional debugging information. +- A timer issue causes time to appear to jump forward, so that RCU + believes that the RCU CPU stall-warning timeout has been exceeded + when in fact much less time has passed. This could be due to + timer hardware bugs, timer driver bugs, or even corruption of + the "jiffies" global variable. These sorts of timer hardware + and driver bugs are not uncommon when testing new hardware. + - A low-level kernel issue that either fails to invoke one of the variants of rcu_eqs_enter(true), rcu_eqs_exit(true), ct_idle_enter(), ct_idle_exit(), ct_irq_enter(), or ct_irq_exit() on the one |