[LU-7766] LNetEQAlloc() misuses roundup_pow_of_two() Created: 09/Feb/16  Updated: 06/Dec/16  Resolved: 21/Feb/16

Status: Resolved
Project: Lustre
Component/s: None
Affects Version/s: None
Fix Version/s: Lustre 2.8.0

Type: Bug Priority: Blocker
Reporter: John Hammond Assignee: Oleg Drokin
Resolution: Fixed Votes: 0
Labels: None

Severity: 3
Rank (Obsolete): 9223372036854775807

 Description   

After http://review.whamcloud.com/16914 we see the following when starting LNet:

[690112.179415] LNet: 8882:0:(lib-eq.c:87:LNetEQAlloc()) EQ callback is guaranteed to get every event, do you still want to set eqcount 1 for polling event which will have locking overhead? Please contact with developer to confirm

Here LNetEQAlloc() is being called with a count of 0 and passing that to roundup_pow_of_two(). This is undefined behavior according to http://lxr.free-electrons.com/source/tools/include/linux/log2.h#L161.



 Comments   
Comment by Joseph Gmitter (Inactive) [ 09/Feb/16 ]

Oleg is planning to submit a patch for this.

Comment by Gerrit Updater [ 09/Feb/16 ]

Oleg Drokin (oleg.drokin@intel.com) uploaded a new patch: http://review.whamcloud.com/18370
Subject: LU-7766 lnet: Don't call roundup_pow_of_two on zero in LNetEQAlloc
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: c0cd8205473d7198ca48278449dcdfb09110f2de

Comment by Oleg Drokin [ 09/Feb/16 ]

I submitted the same patch upstream a few days ago, but did not notice we imported this bug into our tree too.

Comment by Bob Glossman (Inactive) [ 16/Feb/16 ]

just noticed the annoying new lnet warning message today. talked about it on Skype. good to know there's already a patch in flight to fix it.

Comment by Gerrit Updater [ 20/Feb/16 ]

Oleg Drokin (oleg.drokin@intel.com) merged in patch http://review.whamcloud.com/18370/
Subject: LU-7766 lnet: Don't call roundup_pow_of_two on zero in LNetEQAlloc
Project: fs/lustre-release
Branch: master
Current Patch Set:
Commit: e3705effd8d94be11493da754c5678de5523c877

Comment by Peter Jones [ 21/Feb/16 ]

Landed for 2.8

Generated at Sat Feb 10 02:11:44 UTC 2024 using Jira 9.4.14#940014-sha1:734e6822bbf0d45eff9af51f82432957f73aa32c.