[LU-15819] Executables run from Lustre may receive spurious SIGBUS signals

• Type: Bug
• Resolution: Duplicate
• Priority: Blocker
• Affects Version/s: Upstream
• Severity: 3
• Assignee: Andrew Perepechko
• Reporter: Andrew Perepechko

Description

We received several reports about applications (IOR and other unrelated user-provided programs) started from Lustre receiving SIGBUS signals.

 

We were able to reproduce the issue with IOR, RHEL7 kernel on the client.

 

It seems that it is caused by LU-14541 and the mechanics is the following:

 

1) a major fault in the IOR code happens

2) ll_fault()>...>filemap_fault()

3) ll_readpage() is issued from filemap_fault()

4) wait_on_page_locked() is issued from filemap_fault()

5) the uptodate check in filemap_fault() fails due to a parallel ClearPageUptodate() called from a blocking AST handler

6) VM_FAULT_SIGBUS is returned

Issue Links

• duplicates: LU-15815 fast_read/stale data/reclaim workround causes SIGBUS
• is related to: LU-14541 Memory reclaim caused a stale data read