Red Hat Bugzilla – Bug 170546
kernel_lock() problem through NFS mount
Last modified: 2007-11-30 17:07:21 EST
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Description of problem:
We have discovered a problem where the kernel lock is still being held by a process
when it returns to user mode. This results in other processes that are in the kernel
and want the kernel lock spinning inside of lock_kernel() and reacquire_kernel_lock()
even though the real lock holder is no longer in the kernel.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
2.mount a nfs filesystem
3.unlock a nfs mounted file
Actual Results: all sorts of weird behavior happens with kernel lock held and going to user space.. espeically on SMP systems, you can notice the slowness of the system since it renders other cpus useless during swapping to user space.
Expected Results: On smp kernel, there shouldn't be any slowness when a cpu goes into user space.
*** This bug has been marked as a duplicate of 170545 ***
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.