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bug#27476: libguile/memoize.c is not thread safe, so syntax parameter ex
From: |
Ludovic Courtès |
Subject: |
bug#27476: libguile/memoize.c is not thread safe, so syntax parameter expansion is not thread-safe |
Date: |
Mon, 30 Apr 2018 23:39:05 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/25.3 (gnu/linux) |
address@hidden (Ludovic Courtès) skribis:
> With Guile 2.2.3 a similar program triggers a crash very quickly:
Even simpler:
--8<---------------cut here---------------start------------->8---
$ guile ../guile-debugging/syntax-parms.scm
;;; note: source file /home/ludo/src/guix/../guile-debugging/syntax-parms.scm
;;; newer than compiled
/home/ludo/.cache/guile/ccache/2.2-LE-8-3.A/home/ludo/src/guile-debugging/syntax-parms.scm.go
;;; note: auto-compilation is enabled, set GUILE_AUTO_COMPILE=0
;;; or pass the --no-auto-compile argument to disable.
;;; compiling /home/ludo/src/guix/../guile-debugging/syntax-parms.scm
;;; compiled
/home/ludo/.cache/guile/ccache/2.2-LE-8-3.A/home/ludo/src/guile-debugging/syntax-parms.scm.go
In /home/ludo/src/guix/../guile-debugging/syntax-parms.scm:
37:17 13 (_)
In system/base/compile.scm:
255:6 12 (compile _ #:from _ #:to _ #:env _ #:opts _)
183:32 11 (compile-fold (#f syntax-violation (#<tree-il (const #f)>
#<tree-il (const "source expression failed to match any pattern")> #<tree-il
(lexical tmp tmp-1dff1b…>)) # …)
In ice-9/boot-9.scm:
2312:4 10 (save-module-excursion #<procedure 57dd920 at
ice-9/psyntax.scm:1774:12 (a b)>)
In language/scheme/compile-tree-il.scm:
31:15 9 (_)
In ice-9/psyntax.scm:
1234:22 8 (expand-top-sequence (#<tree-il (primcall syntax-violation (const
#f) (const "source expression failed to match any pattern") (lexical tmp
tmp-1dff1b83541ce327-2…>) …)
In ice-9/boot-9.scm:
222:29 7 (map1 ((10 (3 #((0 . 0)) 2 (1 (11 0 . 0) (7 (3 #() 2 (10 (13 15 5
(guile) list . #f) (5 . #<syntax ->) (11 0 . 0) (11 0 . 1)) () 2) (11 0 . 0))
10 (. #) …) …) #) …))
222:17 6 (map1 (10 (3 #((0 . 0)) 2 (1 (11 0 . 0) (7 (3 #() 2 (10 (13 15 5
(guile) list . #f) (5 . #<syntax ->) (11 0 . 0) (11 0 . 1)) () 2) (11 0 . 0))
10 (13 # . #) …) …) …))
In ice-9/psyntax.scm:
2054:19 5 (_ _ (#<tree-il (const (_ any any))>) (param 1 2) ())
In ice-9/boot-9.scm:
222:17 4 (map1 (#<tree-il (const (_ any any))>))
In ice-9/psyntax.scm:
2057:27 3 (_ _)
289:10 2 (eval-local-transformer _ _)
In ice-9/eval.scm:
718:15 1 (primitive-eval _)
In unknown file:
0 (memoize-expression #<tree-il (lambda () (lambda-case (((() 1) #f
#f #f () ((11 0 . 0))) (call (lambda () (lambda-case ((((#f .
#(tmp-1dff1b83541ce327-248119)) (#t…>)
ERROR: In procedure memoize-expression:
In procedure vector: Wrong type argument in position 1: #(#<directory
(guile-user) cd8140>)
C-c C-c
$ cat ../guile-debugging/syntax-parms.scm
(use-modules (ice-9 threads)
(srfi srfi-1)
(system base compile))
(compile #f) ;load modules
(define-syntax-parameter param
(lambda (s)
(syntax-case s ()
((_ a b) #'(+ a b)))))
(define threads
(unfold (lambda (x) (> x 100))
(lambda (x)
(call-with-new-thread
(lambda ()
(while #t
(compile '(begin
(param 1 2)
(syntax-parameterize ((param (lambda (s)
(syntax-case s ()
((_ a b)
#'(- a b))))))
(param 1 2)))
#:env (current-module)
#:from 'scheme
#:to 'tree-il)))))
1+
0))
(for-each join-thread threads)
--8<---------------cut here---------------end--------------->8---
So the problem, AIUI, is that psyntax evaluates syntax parameters using
‘primitive-eval’ (via ‘eval-local-transformer’), but memoization in
(ice-9 eval) is not thread-safe, hence the random crashes.
Not sure what can be done. Thoughts?
Ludo’.