Hello, I have been working on the memory model for J (the programming language). J uses a fairly standard memory pool system for small allocations, with a number of pools which are allocated once needed and store small values.
My additions are shown here: https://github.com/iocane/unbox/commit/62a0e6dd0278a49398ec9de06f93896e32a25177 The J source is notoriously hard to read, so this is just intended as a way to check if I've done anything obviously wrong with Valgrind's client requests. When run, valgrind gives a reasonable number of invalid read and write errors. I haven't been able to verify any of them, so the output might not be correct. My problem is that they don't give an instance of free which caused the error like Valgrind does when working with only malloc/free. The error message only indicates that the address is in one of the memory pools. Valgrind states that the block is "recently re-allocated", a term which I don't understand and which doesn't seem to appear in any of the documentation. ==4888== Invalid write of size 8 ==4888== at 0x4C3117F: memset (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so) ==4888== by 0x607CE9F: jtexta (m.c:359) ==4888== by 0x623F2D9: jtpreparse (wc.c:268) ==4888== by 0x6060F1A: jtcolon (cx.c:295) ==4888== by 0x60209CB: jtdfs2 (au.c:32) ==4888== by 0x607F269: jtconj (p.c:62) ==4888== by 0x607FCFE: jtparsea (p.c:138) ==4888== by 0x607F986: jtparse (p.c:117) ==4888== by 0x6083349: jtimmex (px.c:37) ==4888== by 0x626B120: jtline (xs.c:52) ==4888== by 0x626B7E4: jtlinf (xs.c:86) ==4888== by 0x626B8FB: jtscm00 (xs.c:94) ==4888== Address 0x5c31230 is 4,368 bytes inside a recently re-allocated block of size 65,536 alloc'd ==4888== at 0x4C2ABD0: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so) ==4888== by 0x607AF72: jtma (m.c:182) ==4888== by 0x607C241: jtga (m.c:285) ==4888== by 0x6071756: jtevinit (i.c:81) ==4888== by 0x6071E10: jtjinit3 (i.c:154) ==4888== by 0x6071EAC: jtjinit2 (i.c:169) ==4888== by 0x60731D3: JInit (io.c:278) ==4888== by 0x4013DF: jeload (jeload.c:66) ==4888== by 0x4011BF: main (jconsole.c:133) What does this error mean? Am I using the memory pool functions correctly? How do I find when the memory in question was freed, or was it just never allocated? Thanks for your help, Marshall ------------------------------------------------------------------------------ Mobile security can be enabling, not merely restricting. Employees who bring their own devices (BYOD) to work are irked by the imposition of MDM restrictions. Mobile Device Manager Plus allows you to control only the apps on BYO-devices by containerizing them, leaving personal data untouched! https://ad.doubleclick.net/ddm/clk/304595813;131938128;j _______________________________________________ Valgrind-users mailing list Valgrind-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/valgrind-users
