[Caml-list] Unitialized values according to Valgrind

[Caml-list] Unitialized values according to Valgrind

[Mark Christiaens]

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I'm using OCaml 4.00.1 with (among others) LWT 2.3.2.  We have inexplicable
crashes of our server process.  I've been digging through our source code
looking but no success so far.  I've run our process with the Valgrind
memory checker and I get some unexpected warnings like:

==4181== Conditional jump or move depends on uninitialised value(s)
==4181==    at 0xECEDDA: camlWeak__loop_1164 (weak.ml:209)
==4181==    by 0xDC9A24: camlLwt_io__make_1212 (lwt_io.ml:544)
==4181==    by 0xD03E24: camlConnection_util__to_conn_1054 (
connection_util.ml:81)
==4181==    by 0xB514B5: camlLwt_server__fun_1894 (Lwt_server.ml:202)
==4181==    by 0xDD70B3: camlLwt__try_bind_1364 (lwt.ml:553)
==4181==    by 0xDD8945: camlLwt__with_value_1552 (lwt.ml:977)
==4181==    by 0xB51E9F: camlLwt_server__fun_1857 (Lwt_server.ml:197)
==4181==    by 0xB52CCA: camlLwt_server__fun_1758 (Lwt_server.ml:175)
==4181==    by 0xDD3C95: camlLwt__fun_2035 (lwt.ml:438)
==4181==    by 0xDD593D: camlLwt__run_waiters_1128 (lwt.ml:153)
==4181==    by 0xDD593D: camlLwt__run_waiters_1128 (lwt.ml:153)
==4181==    by 0xDD58AC: camlLwt__run_waiters_rec_1110 (lwt.ml:136)

and

==4181== Conditional jump or move depends on uninitialised value(s)
==4181==    at 0x10F605B: caml_page_table_lookup (in
/home/christim/tmp/DSS-buchla/target/debug/bin/dss.bin)
==4181==    by 0x10F6724: caml_modify (in
/home/christim/tmp/DSS-buchla/target/debug/bin/dss.bin)
==4181==    by 0xECEDB1: camlWeak__loop_1164 (weak.ml:208)
==4181==    by 0xDC9A24: camlLwt_io__make_1212 (lwt_io.ml:544)
==4181==    by 0xDCDCC8: camlLwt_io__entry (lwt_io.ml:1333)
==4181==    by 0xA660E8: caml_program (in
/home/christim/tmp/DSS-buchla/target/debug/bin/dss.bin)
==4181==    by 0x1103CFD: ??? (in
/home/christim/tmp/DSS-buchla/target/debug/bin/dss.bin)
==4181==    by 0x10F2964: caml_main (in
/home/christim/tmp/DSS-buchla/target/debug/bin/dss.bin)
==4181==    by 0x10F299F: main (in
/home/christim/tmp/DSS-buchla/target/debug/bin/dss.bin)


and

==4181== Use of uninitialised value of size 8
==4181==    at 0x10F5AA3: caml_empty_minor_heap (in
/home/christim/tmp/DSS-buchla/target/debug/bin/dss.bin)
==4181==    by 0x10F5BB6: caml_minor_collection (in
/home/christim/tmp/DSS-buchla/target/debug/bin/dss.bin)
==4181==    by 0x10F3E52: caml_garbage_collection (in
/home/christim/tmp/DSS-buchla/target/debug/bin/dss.bin)
==4181==    by 0x1103B1F: ??? (in
/home/christim/tmp/DSS-buchla/target/debug/bin/dss.bin)
==4181==    by 0xEB1148: camlPrintf__ac_of_format_1155 (printf.ml:306)
==4181==    by 0xEB11E4: camlPrintf__kapr_1179 (printf.ml:311)
==4181==    by 0xDA6201: camlLwt_logging__string_of_time_1072
(Lwt_logging.ml:137)
==4181==    by 0xDA6C40: camlLwt_logging__log_1193 (Lwt_logging.ml:206)
==4181==    by 0xD0304A: camlConnection_util__fun_1298 (
connection_util.ml:45)
==4181==    by 0xDD6B9F: camlLwt__catch_1315 (lwt.ml:470)
==4181==    by 0xEACB28: camlCamlinternalLazy__force_lazy_block_1010
(camlinternalLazy.ml:27)
==4181==    by 0xDD6B9F: camlLwt__catch_1315 (lwt.ml:470)

In particular, this last one worries me.  All evidence I find seems to
indicate a rogue "free" call freeing data structures are random.  Are these
unitialized values to be expected?

Mark

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