memory leak (2): named reference

memory leak (2): named reference

[Jun T]

This is the second problem (related with the named reference).
In the following all the tests are run as

% valgrind --leak-check=full zsh -f test_n

% cat test1
typeset -n ptr
ptr=ptr

Invalid read of size 8
  at 0x1A498C: assignstrvalue (params.c:2814)

Address 0x4bd6120 is 48 bytes inside a block of size 80 free'd
  by 0x193DB1: zfree (mem.c:1871)
  by 0x1AE241: freeparamnode (params.c:5913)
  by 0x1AA4A1: unsetparam_pm (params.c:3871)
  by 0x1AF873: setscope (params.c:6374)
  by 0x1A4983: assignstrvalue (params.c:2813)

assignstrvalue() calls setscope(pm), and when it finds the self reference
(params.c:6374) it calls (indirectly) zfree(pm). But just after returning
from setscope() (params.c:2814) the freed pm is used.


% cat test2
typeset -n ptr
for ptr in foo
do; done

4 bytes in 1 blocks are definitely lost in loss record 20 of 384
   by 0x1935B9: zalloc (mem.c:966)
   by 0x1CEB5E: ztrdup (string.c:83)
   by 0x188FBE: execfor (loop.c:168)

This is simple. In execfor()
loop.c:168	setloopvar(name, ztrdup(str))
but in setloopvar(name, value)
params.c:6329	SETREFNAME(pm, ztrdup(value))
I think we don't need two ztrdup()'s here, and the problem can be fixed
by removing the second ztrdup().


% cat test3
typeset -n ref
for ref in one ref
do; done

Invalid read of size 4
  at 0x1AF3D9: setloopvar (params.c:6333)

Address 0x4bd5af0 is 16 bytes inside a block of size 80 free'd
  by 0x193DB1: zfree (mem.c:1871)
  by 0x1AE241: freeparamnode (params.c:5913)
  by 0x1AA4A1: unsetparam_pm (params.c:3871)
  by 0x1AFB27: setscope (params.c:6409)
  by 0x1AF3D4: setloopvar (params.c:6332)

This similar to test1. setscope(pm) (params.c:6332) calls zfree(pm),
but the pm used just after it.

test3 also causes two memory leaks.
One is the same as test2; 7 bytes ("aa" and "ref", allocated by
ztrdup() at loop.c:168) are lost.
In the other, 4 bytes ("ref", allocated by ztrdup() at params.c:6329)
are lost. This is caused by aborting the loop by the self reference
and can't be fixed by removing the ztrdup() from params.c:6329.