From 4efec6c0919d9081a52be50d5b5bfa32bf489c75 Mon Sep 17 00:00:00 2001 From: Zi Li Date: Fri, 27 Jun 2025 15:29:24 +0800 Subject: samples: enhance hung_task detector test with read-write semaphore support Extend the hung_task detector test module to include read-write semaphore support alongside existing mutex and semaphore tests. This module now creates additional debugfs files under /hung_task, namely 'rw_semaphore_read' and 'rw_semaphore_write', in addition to 'mutex' and 'semaphore'. Reading these files with multiple processes triggers a prolonged sleep (256 seconds) while holding the respective lock, enabling hung_task detector testing for various locking mechanisms. This change builds on the extensible hung_task_tests module, adding read-write semaphore functionality to improve test coverage for kernel locking primitives. The implementation ensures proper lock handling and includes checks to prevent redundant data reads. Usage is: > cd /sys/kernel/debug/hung_task > cat mutex & cat mutex # Test mutex blocking > cat semaphore & cat semaphore # Test semaphore blocking > cat rw_semaphore_write \ & cat rw_semaphore_read # Test rwsem blocking > cat rw_semaphore_write \ & cat rw_semaphore_write # Test rwsem blocking Update the Kconfig description to reflect the addition of read-write semaphore debugfs files. Link: https://lkml.kernel.org/r/20250627072924.36567-4-lance.yang@linux.dev Signed-off-by: Zi Li Suggested-by: Masami Hiramatsu (Google) Cc: Anna Schumaker Cc: Boqun Feng Cc: Ingo Molnar Cc: Joel Granados Cc: John Stultz Cc: Kent Overstreet Cc: Mingzhe Yang Cc: Peter Zijlstra Cc: Sergey Senozhatsky Cc: Steven Rostedt Cc: Tomasz Figa Cc: Waiman Long Cc: Will Deacon Cc: Yongliang Gao Signed-off-by: Andrew Morton --- samples/Kconfig | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'samples/Kconfig') diff --git a/samples/Kconfig b/samples/Kconfig index ffef99950206..a8880c62d4c8 100644 --- a/samples/Kconfig +++ b/samples/Kconfig @@ -316,10 +316,9 @@ config SAMPLE_HUNG_TASK depends on DETECT_HUNG_TASK && DEBUG_FS help Build a module that provides debugfs files (e.g., mutex, semaphore, - etc.) under /hung_task. If user reads one of these files, - it will sleep long time (256 seconds) with holding a lock. Thus, - if 2 or more processes read the same file concurrently, it will - be detected by the hung_task watchdog. + rw_semaphore_read, rw_semaphore_write) under /hung_task. + Reading these files with multiple processes triggers hung task + detection by holding locks for a long time (256 seconds). source "samples/rust/Kconfig" -- cgit v1.2.3