Hi all, I am working on a bug, which running PLR on HAWQ. The process hung and can't be terminated.
>From my investigation, it seems signal handler 'Rf_onsigusr1' trigger a malloc/free deadlock. The calling stack is below. Thread 1 (Thread 0x7f4c93af48e0 (LWP 431263)): #0 0x00007f4c9015805e in __lll_lock_wait_private () from /lib64/libc.so.6 #1 0x00007f4c900dd16b in _L_lock_9503 () from /lib64/libc.so.6 #2 0x00007f4c900da6a6 in malloc () from /lib64/libc.so.6 #3 0x00007f4c9008fb39 in _nl_make_l10nflist () from /lib64/libc.so.6 #4 0x00007f4c9008ddf5 in _nl_find_domain () from /lib64/libc.so.6 #5 0x00007f4c9008d6e0 in __dcigettext () from /lib64/libc.so.6 #6 0x00007f4c6fabcfe3 in Rf_onsigusr1 () from /usr/local/lib64/R/lib/libR.so #7 <signal handler called> #8 0x00007f4c9014079a in brk () from /lib64/libc.so.6 #9 0x00007f4c90140845 in sbrk () from /lib64/libc.so.6 #10 0x00007f4c900dd769 in __default_morecore () from /lib64/libc.so.6 #11 0x00007f4c900d87a2 in _int_free () from /lib64/libc.so.6 #12 0x0000000000b3ff24 in gp_free2 () #13 0x0000000000b356fc in AllocSetDelete () #14 0x0000000000b38391 in MemoryContextDeleteImpl () #15 0x000000000077c851 in ExecEndAgg () #16 0x00000000007592ad in ExecEndNode () #17 0x000000000075186c in ExecEndPlan () #18 0x000000000079dffa in ExecEndSubqueryScan () #19 0x000000000075921d in ExecEndNode () #20 0x000000000075186c in ExecEndPlan () #21 0x0000000000752565 in ExecutorEnd () #22 0x00000000006dd9bd in PortalCleanup () #23 0x0000000000b3f077 in AtCommit_Portals () #24 0x000000000051abe5 in CommitTransaction () #25 0x000000000051f1d5 in CommitTransactionCommand () #26 0x000000000099809e in PostgresMain () #27 0x00000000008f1031 in BackendStartup () #28 0x00000000008f70e0 in PostmasterMain () #29 0x00000000007f63da in main () I googled and found below info maybe useful to fix it: The best way to avoid this kind of deadlock is to Call only asynchronous-safe functions within signal handlers. https://www.securecoding.cert.org/confluence/display/c/SIG30-C.+Call+only+asynchronous-safe+functions+within+signal+handlers Thanks a lot. [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
