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authorPaul E. McKenney <paulmck@kernel.org>2020-04-30 12:23:11 -0700
committerPaul E. McKenney <paulmck@kernel.org>2020-06-29 11:58:11 -0700
commitb81898e3d2133715e4475d25757595a3e18502ed (patch)
tree47f208af2c5c6110a79d043ae96ae045d91776bb /Documentation/RCU
parent2d9c318bfd15394da014737bee30e7b2e22c5eac (diff)
downloadlwn-b81898e3d2133715e4475d25757595a3e18502ed.tar.gz
lwn-b81898e3d2133715e4475d25757595a3e18502ed.zip
doc: Timer problems can cause RCU CPU stall warnings
Over the past few years, there have been several cases where timekeeping bugs have caused RCU CPU stall warnings, particularly during hardware bringup. This commit therefore adds such bugs to the list of things that can result in RCU CPU stall warnings. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'Documentation/RCU')
-rw-r--r--Documentation/RCU/stallwarn.rst7
1 files changed, 7 insertions, 0 deletions
diff --git a/Documentation/RCU/stallwarn.rst b/Documentation/RCU/stallwarn.rst
index 08bc9aec4606..c9ab6af4d3be 100644
--- a/Documentation/RCU/stallwarn.rst
+++ b/Documentation/RCU/stallwarn.rst
@@ -87,6 +87,13 @@ warnings:
problem really has happened, and seems to be most likely to
result in RCU CPU stall warnings for CONFIG_NO_HZ_COMMON=n kernels.
+- A hardware or software issue that prevents time-based wakeups
+ from occurring. These issues can range from misconfigured or
+ buggy timer hardware through bugs in the interrupt or exception
+ path (whether hardware, firmware, or software) through bugs
+ in Linux's timer subsystem through bugs in the scheduler, and,
+ yes, even including bugs in RCU itself.
+
- A bug in the RCU implementation.
- A hardware failure. This is quite unlikely, but has occurred