Install ocamlbuild as part of Travis checks#2
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gasche merged 1 commit intogasche:remove-ocamlbuildfrom Feb 1, 2016
Merged
Install ocamlbuild as part of Travis checks#2gasche merged 1 commit intogasche:remove-ocamlbuildfrom
gasche merged 1 commit intogasche:remove-ocamlbuildfrom
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gasche
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Install ocamlbuild as part of Travis checks
gasche
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Nov 11, 2017
Enable UTF-8 on Windows 10 Console (Mark #2)
yallop
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Aug 27, 2020
yallop
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Aug 27, 2020
gasche
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Oct 9, 2020
Let's try with a very short timeout, to make sure the job will exceed it.
gasche
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Jul 13, 2024
The toplevel printer detects cycles by keeping a hashtable of values
that it has already traversed.
However, some OCaml runtime types (at least bigarrays) may be
partially uninitialized, and hashing them at arbitrary program points
may read uninitialized memory. In particular, the OCaml testsuite
fails when running with a memory-sanitizer enabled, as bigarray
printing results in reads to uninitialized memory:
```
==133712==WARNING: MemorySanitizer: use-of-uninitialized-value
#0 0x4e6d11 in caml_ba_hash /var/home/edwin/git/ocaml/runtime/bigarray.c:486:45
#1 0x52474a in caml_hash /var/home/edwin/git/ocaml/runtime/hash.c:251:35
#2 0x599ebf in caml_interprete /var/home/edwin/git/ocaml/runtime/interp.c:1065:14
#3 0x5a909a in caml_main /var/home/edwin/git/ocaml/runtime/startup_byt.c:575:9
#4 0x540ccb in main /var/home/edwin/git/ocaml/runtime/main.c:37:3
#5 0x7f0910abb087 in __libc_start_call_main (/lib64/libc.so.6+0x2a087) (BuildId: 8f53abaad945a669f2bdcd25f471d80e077568ef)
#6 0x7f0910abb14a in __libc_start_main@GLIBC_2.2.5 (/lib64/libc.so.6+0x2a14a) (BuildId: 8f53abaad945a669f2bdcd25f471d80e077568ef)
#7 0x441804 in _start (/var/home/edwin/git/ocaml/runtime/ocamlrun+0x441804) (BuildId: 7a60eef57e1c2baf770bc38d10d6c227e60ead37)
Uninitialized value was created by a heap allocation
#0 0x47d306 in malloc (/var/home/edwin/git/ocaml/runtime/ocamlrun+0x47d306) (BuildId: 7a60eef57e1c2baf770bc38d10d6c227e60ead37)
#1 0x4e7960 in caml_ba_alloc /var/home/edwin/git/ocaml/runtime/bigarray.c:246:12
#2 0x4e801f in caml_ba_create /var/home/edwin/git/ocaml/runtime/bigarray.c:673:10
#3 0x59b8fc in caml_interprete /var/home/edwin/git/ocaml/runtime/interp.c:1058:14
#4 0x5a909a in caml_main /var/home/edwin/git/ocaml/runtime/startup_byt.c:575:9
#5 0x540ccb in main /var/home/edwin/git/ocaml/runtime/main.c:37:3
#6 0x7f0910abb087 in __libc_start_call_main (/lib64/libc.so.6+0x2a087) (BuildId: 8f53abaad945a669f2bdcd25f471d80e077568ef)
#7 0x7f0910abb14a in __libc_start_main@GLIBC_2.2.5 (/lib64/libc.so.6+0x2a14a) (BuildId: 8f53abaad945a669f2bdcd25f471d80e077568ef)
#8 0x441804 in _start (/var/home/edwin/git/ocaml/runtime/ocamlrun+0x441804) (BuildId: 7a60eef57e1c2baf770bc38d10d6c227e60ead37)
SUMMARY: MemorySanitizer: use-of-uninitialized-value /var/home/edwin/git/ocaml/runtime/bigarray.c:486:45 in caml_ba_hash
```
The only use of hashing in genprintval is to avoid cycles, that is, it
is only useful for OCaml values that contain other OCaml values
(including possibly themselves). Bigarrays cannot introduce cycles,
and they are always printed as "<abstr>" anyway.
The present commit proposes to be more conservative in which values
are hashed by the cycle detector to avoid this issue: we skip hashing
any value with tag above No_scan_tag -- which may not contain any
OCaml values.
Suggested-by: Gabriel Scherer <gabriel.scherer@gmail.com>
Signed-off-by: Edwin Török <edwin.torok@cloud.com>
gasche
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Jul 30, 2024
…l#13294) The toplevel printer detects cycles by keeping a hashtable of values that it has already traversed. However, some OCaml runtime types (at least bigarrays) may be partially uninitialized, and hashing them at arbitrary program points may read uninitialized memory. In particular, the OCaml testsuite fails when running with a memory-sanitizer enabled, as bigarray printing results in reads to uninitialized memory: ``` ==133712==WARNING: MemorySanitizer: use-of-uninitialized-value #0 0x4e6d11 in caml_ba_hash /var/home/edwin/git/ocaml/runtime/bigarray.c:486:45 #1 0x52474a in caml_hash /var/home/edwin/git/ocaml/runtime/hash.c:251:35 #2 0x599ebf in caml_interprete /var/home/edwin/git/ocaml/runtime/interp.c:1065:14 #3 0x5a909a in caml_main /var/home/edwin/git/ocaml/runtime/startup_byt.c:575:9 #4 0x540ccb in main /var/home/edwin/git/ocaml/runtime/main.c:37:3 #5 0x7f0910abb087 in __libc_start_call_main (/lib64/libc.so.6+0x2a087) (BuildId: 8f53abaad945a669f2bdcd25f471d80e077568ef) #6 0x7f0910abb14a in __libc_start_main@GLIBC_2.2.5 (/lib64/libc.so.6+0x2a14a) (BuildId: 8f53abaad945a669f2bdcd25f471d80e077568ef) #7 0x441804 in _start (/var/home/edwin/git/ocaml/runtime/ocamlrun+0x441804) (BuildId: 7a60eef57e1c2baf770bc38d10d6c227e60ead37) Uninitialized value was created by a heap allocation #0 0x47d306 in malloc (/var/home/edwin/git/ocaml/runtime/ocamlrun+0x47d306) (BuildId: 7a60eef57e1c2baf770bc38d10d6c227e60ead37) #1 0x4e7960 in caml_ba_alloc /var/home/edwin/git/ocaml/runtime/bigarray.c:246:12 #2 0x4e801f in caml_ba_create /var/home/edwin/git/ocaml/runtime/bigarray.c:673:10 #3 0x59b8fc in caml_interprete /var/home/edwin/git/ocaml/runtime/interp.c:1058:14 #4 0x5a909a in caml_main /var/home/edwin/git/ocaml/runtime/startup_byt.c:575:9 #5 0x540ccb in main /var/home/edwin/git/ocaml/runtime/main.c:37:3 #6 0x7f0910abb087 in __libc_start_call_main (/lib64/libc.so.6+0x2a087) (BuildId: 8f53abaad945a669f2bdcd25f471d80e077568ef) #7 0x7f0910abb14a in __libc_start_main@GLIBC_2.2.5 (/lib64/libc.so.6+0x2a14a) (BuildId: 8f53abaad945a669f2bdcd25f471d80e077568ef) #8 0x441804 in _start (/var/home/edwin/git/ocaml/runtime/ocamlrun+0x441804) (BuildId: 7a60eef57e1c2baf770bc38d10d6c227e60ead37) SUMMARY: MemorySanitizer: use-of-uninitialized-value /var/home/edwin/git/ocaml/runtime/bigarray.c:486:45 in caml_ba_hash ``` The only use of hashing in genprintval is to avoid cycles, that is, it is only useful for OCaml values that contain other OCaml values (including possibly themselves). Bigarrays cannot introduce cycles, and they are always printed as "<abstr>" anyway. The present commit proposes to be more conservative in which values are hashed by the cycle detector to avoid this issue: we skip hashing any value with tag above No_scan_tag -- which may not contain any OCaml values. Suggested-by: Gabriel Scherer <gabriel.scherer@gmail.com> Signed-off-by: Edwin Török <edwin.torok@cloud.com> Co-authored-by: Edwin Török <edwin.torok@cloud.com>
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This works ok on my local box.