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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2009-01-07 14:33:30 -0800
committerIngo Molnar <mingo@elte.hu>2009-01-07 23:36:25 +0100
commitc9d557c19f94df42db78d4a5de4d25feee694bad (patch)
treea52f75630be16e6abf0cc11b70c089fa49905453 /arch/arm
parent8903709b054a8dafe4e8c6d9a6444034d7aba36f (diff)
rcu: fix bug in rcutorture system-shutdown code
This patch fixes an rcutorture bug found by Eric Sesterhenn that resulted in oopses in response to "rmmod rcutorture". The problem was in some new code that attempted to handle the case where a system is shut down while rcutorture is still running, for example, when rcutorture is built into the kernel so that it cannot be removed. The fix causes the rcutorture threads to "park" in an schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT) rather than trying to get them to terminate cleanly. Concurrent shutdown and rmmod is illegal. I believe that this is 2.6.29 material, as it is used in some testing setups. For reference, here are the rcutorture operating modes: CONFIG_RCU_TORTURE_TEST=m This is the normal rcutorture build. Use "modprobe rcutorture" (with optional arguments) to start, and "rmmod rcutorture" to stop. If you shut the system down without doing the rmmod, you should see console output like: rcutorture thread rcu_torture_writer parking due to system shutdown One for each rcutorture kthread. CONFIG_RCU_TORTURE_TEST=y CONFIG_RCU_TORTURE_TEST_RUNNABLE=n Use this if you want rcutorture built in, but don't want the test to start running during early boot. To start the torturing: echo 1 > /proc/sys/kernel/rcutorture_runnable To stop the torturing, s/1/0/ You will get "parking" console messages as noted above when you shut the system down. CONFIG_RCU_TORTURE_TEST=y CONFIG_RCU_TORTURE_TEST_RUNNABLE=y Same as above, except that the torturing starts during early boot. Only for the stout of heart and strong of stomach. The same /proc entry noted above may be used to control the test. Located-by: Eric Sesterhenn <snakebyte@gmx.de> Tested-by: Eric Sesterhenn <snakebyte@gmx.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/arm')
0 files changed, 0 insertions, 0 deletions