Server crash due to SIGBUS(Bus Error) when trying to access the memory created using dsm_create(). - Mailing list pgsql-hackers

From amul sul
Subject Server crash due to SIGBUS(Bus Error) when trying to access the memory created using dsm_create().
Date
Msg-id 1002664500.12301802.1471008223422.JavaMail.yahoo@mail.yahoo.com
Whole thread Raw
Responses Re: Server crash due to SIGBUS(Bus Error) when trying to access the memory created using dsm_create().  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Hi All,

When I am calling dsm_create on Linux using the POSIX DSM implementation can succeed, but result in SIGBUS when later try to access the memory.  This happens because of my system does not have enough shm space &  current allocation in dsm_impl_posix does not allocate disk blocks[1].
 
I wonder can we use fallocate system call (i.e. Zero-fill the file) to ensure that all the file space has really been allocated, so that we don't later seg fault when accessing the memory mapping. But here we will endup by loop calling ‘write’ squillions of times.

Thoughts/Suggestions ?

Similar post: 
 [1] http://uk.comp.os.linux.narkive.com/Ve44sO4i/shared-memory-problem-no-space-at-dev-shm-causes-sigbus 


Regards,
Amul Sul

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