#13731: Fix libsingular memory management
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Reporter: nbruin | Owner: rlm
Type: defect | Status: new
Priority: major | Milestone: sage-5.6
Component: memleak | Resolution:
Keywords: | Work issues:
Report Upstream: N/A | Reviewers:
Authors: | Merged in:
Dependencies: | Stopgaps:
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Comment (by nbruin):
We can also use ElectricFence as a malloc substitute:
{{{
$ export LD_PRELOAD=libefence.so
$ export EF_ALLOW_MALLOC_0=1 #apparently sage/python does a malloc(0)
somewhere
$ echo 512000 | sudo tee /proc/sys/vm/max_map_count #efence uses mprotect
A LOT
$ ./sage -t --gdb devel/sage/sage/libs/singular/function.pyx
}}}
This gives an error in a different location. Traceback:
{{{
#0 0x00007fffce9fb3f2 in
List<CanonicalForm>::isEmpty(this=0x7fffa515b000) at
./templates/ftmpl_list.cc:256
#1 0x00007fffce96a350 in multiFactorize (F=..., v=...) at
facFactorize.cc:710
#2 0x00007fffce905e9d in ratSqrfFactorize (v=..., G=...) at
facFactorize.h:45
#3 ratFactorize (G=..., v=..., substCheck=<optimized out>) at
facFactorize.h:125
#4 0x00007fffce90303c in factorize (f=..., issqrfree=false) at
cf_factor.cc:651
#5 0x00007fffce7a5b44 in singclap_factorize (f=0x7fff9e16dfd0,
v=0x7fffffffb548, with_exps=0) at clapsing.cc:835
#6 0x00007fffce720d50 in jjFAC_P (res=0x7fff9e16ffc0, u=0x7fff9ea7afc0)
at iparith.cc:3995
#7 0x00007fffce729c42 in iiExprArith1 (res=0x7fff9e16ffc0,
a=0x7fff9ea7afc0, op=424) at iparith.cc:7869
#8 0x00007fffce12df55 in
__pyx_f_4sage_4libs_8singular_8function_17KernelCallHandler_handle_call(__pyx_v_self=0x7fff9e967b48,
__pyx_v_argument_list=0x7fff9e975b40, __pyx_optional_args=<optimized out>)
at sage/lib/singular/function.cpp:11286
}}}
All these error point in the same direction, though: As soon as we start
interacting with the singular ''interpreter'' we get exposed to whatever
memory management it does and we're in big trouble. Use of libsingular on
more basic levels usually doesn't expose us to libsingular memory
management, so no problems arise.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/13731#comment:2>
Sage <http://www.sagemath.org>
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