Messages in this thread | | | Subject | Re: [PATCH 0/2] locking/lockdep: Track number of zapped classes & report abuse | From | Waiman Long <> | Date | Fri, 30 Nov 2018 09:38:31 -0500 |
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On 11/29/2018 05:48 PM, Peter Zijlstra wrote: > On Thu, Nov 29, 2018 at 05:41:35PM -0500, Waiman Long wrote: >> When a kernel module is repeatedly load and unload, it will eventually >> exhaust the lockdep entries resulting in a bug message. This is a use >> case that the current lockdep code cannot support. >> >> This patchset tracks the number of zapped classes and print a warning if >> too many lockdep entries are wasted because of too many module unloading. >> For example, >> >> [ 2490.651531] BUG: MAX_LOCKDEP_KEYS too low! >> [ 2490.669925] turning off the locking correctness validator. >> [ 2490.669925] Please attach the output of /proc/lock_stat to the bug report >> [ 2490.669926] ======================================================== >> [ 2490.669927] WARNING: 6499 out of 8191 locks have been destroyed >> [ 2490.669927] through kernel module unload operations. >> [ 2490.669928] The corresponding lockdep entries are not reusable. >> [ 2490.669928] The system might have run out of lockdep entries because >> [ 2490.669929] of repeated kernel module load and unload operations. >> [ 2490.669929] Lockdep cannot support this particular use case. >> [ 2490.669930] -------------------------------------------------------- > Have a look here: > > https://lkml.kernel.org/r/20181128234325.110011-1-bvanassche@acm.org
Thanks for the pointer, I will take a look at that.
Cheers, Longman
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