[haiku-bugs] Re: [Haiku] #6034: BFS Panics
- From: "mmlr" <trac@xxxxxxxxxxxx>
- Date: Sat, 25 Oct 2014 09:42:23 -0000
#6034: BFS Panics
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Reporter: bryanv | Owner: axeld
Type: bug | Status: reopened
Priority: critical | Milestone: R1
Component: File Systems/BFS | Version: R1/alpha2
Resolution: | Keywords: Panics
Blocked By: | Blocking:
Has a Patch: 0 | Platform: x86
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Comment (by mmlr):
I'm not sure this is triggered by the attribute data itself. At least the
photo in the second attachement leaked the syslog output "error creating
kernel stack: out of memory" into the KDL output, followed by the panic
"could not allocate parent" (a block cache panic). So the circumstances
may be the same as in #10312, the block cache using up all the address
space (not the actual pages) after reading/writing enough blocks.
Outputting the low resource state in KDL at that point would verify this.
A theory I recently discussed with Rene would be that in such a situation
some allocations may fail, but those failures not properly leading to
aborting the transactions. In such a case incomplete or bogus transactions
might be written back.
I was not able to reproduce the out of address space errors when running
in a memory constrained VM, because there the low resource handler for
pages kicks in first and cleans out stuff so the situation is never
reached. When running checkfs on the real machine directly, I was easily
able to trigger the out of address space errors because there are enough
pages for the address space shortage to trigger first. It should be
possible to waste some address space by allocating big B_NO_LOCK areas,
which then should make these situations more easy to trigger and
investigate.
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Ticket URL: <https://dev.haiku-os.org/ticket/6034#comment:20>
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