View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0000489 | LDMud | Runtime | public | 2006-10-05 02:50 | 2018-01-29 21:57 |
| Reporter | Gnomi | Assigned To | |||
| Priority | normal | Severity | crash | Reproducibility | always |
| Status | resolved | Resolution | fixed | ||
| Platform | i686 | OS | Debian GNU/Linux | OS Version | 3.1 |
| Summary | 0000489: assert_simul_efun_object() should check whether the simul_efun was loaded during the master apply | ||||
| Description | The get_simul_efun() in our master loads a backup simul_efun if the load of the original simul_efun failed. A failure can be a compile or runtime error during loading of the original simul_efun or a recursive call to get_simul_efun(). The last possibility isn't handled by the driver very well. If a new simul_efun object accidentally calls a simul_efun (eg. because of a forgotten prototype or efun:: prefix), the driver calls assert_simul_efun_object and thus get_simul_efun again. The master then switches to the backup and loads it. Hence also the compilation of the original simul_efun succeeds and the driver activates it as the new official simul_efun. Because of this procedure the simul_efun tables first contains all the functions from the backup simul efun and after that all the functions from the original simul_efun. So if a program, that was compiled before this simul_efun renewal, calls a simul_efun, it will get the function from the backup simul_efun, which will then be executed with the variables from the original simul_efun (because the last activated simul_efun will be in the simul_efun_object variable). This may lead to an error "Illegal variable access 42(33)." and thus to a crash: 2006.10.05 11:36:10 Illegal variable access 42(33). 2006.10.05 11:36:10 Current object was secure/simul_efun/simul_efun 2006.10.05 11:36:10 Dump of the call chain: ' modify_command' in ' i/player/tippse.c' (' obj/player#5') line 548 ' command_start' in 'secure/simul_efun/backup/simul_efun.c (/secure/simul_efun/backup/notify_fail.inc)' ('secure/simul_efun/simul_efun') line 55 (gdb) bt #0 0x081050db in dump_core () at simulate.c:586 0000001 0x080fcdde in fatal (fmt=0x812b4a0 "Illegal variable access %d(%d).\n") at simulate.c:649 0000002 0x080abf35 in find_value (num=42) at interpret.c:5834 0000003 0x0808fb76 in eval_instruction ( first_instruction=0x9358b66 "?<'\003?\003\"j4`", initial_sp=0x816fa80) at interpret.c:8137 0000004 0x0809eadc in eval_instruction ( first_instruction=0x917078a "`\001\ta?n?\017?b\\v\016$\022\036/js\017v\016)\002\016\b\r+\022\n1&Y?~", initial_sp=0x816fa78) at interpret.c:14589 0000005 0x080a1fc9 in apply_low (fun=0x8b2df6c, ob=0x91f2890, num_arg=1, b_ign_prot=0, allowRefs=0) at interpret.c:16623 0000006 0x080a2583 in int_apply (fun=0x8b2df6c, ob=0x91f2890, num_arg=1, b_ign_prot=0, b_use_default=1) at interpret.c:16814 0000007 0x080a29af in sapply_int (fun=0x8b2df6c, ob=0x91f2890, num_arg=1, b_find_static=0, b_use_default=1) at interpret.c:16975 0000008 0x0804ac7a in call_modify_command (buff=0xbff2c610 "s") at actions.c:540 0000009 0x0804bbfa in parse_command (buff=0xbff2c610 "s", from_efun=0) at actions.c:883 0000010 0x0804c784 in execute_command (str=0xbff2c610 "s", ob=0x91f2890) at actions.c:1258 0000011 0x0805445c in backend () at backend.c:697 0000012 0x080b8156 in main (argc=16, argv=0xbff2e034) at main.c:615 Even if this crash wouldn't happen, the backup simul_efuns could get the content of wrong variables or if the backup simul_efun would be destroyed the entries in the simul_efun table could point to random memory entries. So I think after the master apply assert_simul_efun_object() should verify that no other simul_efun object mysteriously appeared. I have submitted a patch for this. Greetings, Gnomi | ||||
| Tags | No tags attached. | ||||
| Attached Files | sefun.diff (534 bytes)
Index: trunk/src/simul_efun.c
===================================================================
--- trunk/src/simul_efun.c (Revision 2312)
+++ trunk/src/simul_efun.c (Arbeitskopie)
@@ -200,6 +200,12 @@
/* Get the name(s) of the simul_efun object. */
svp = apply_master(STR_GET_SEFUN, 0);
+ if (simul_efun_object)
+ {
+ printf("%s Simul_efun appeared while asking for it.\n", time_stamp());
+ return MY_TRUE;
+ }
+
if (svp == NULL)
{
printf("%s No simul_efun\n", time_stamp());
| ||||
| External Data (URL) | |||||
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2006-10-05 02:50 | Gnomi | New Issue | |
| 2006-10-05 02:50 | Gnomi | File Added: sefun.diff | |
| 2007-10-14 00:36 |
|
Status | new => resolved |
| 2007-10-14 00:36 |
|
Fixed in Version | => 3.3.716 |
| 2007-10-14 00:36 |
|
Resolution | open => fixed |
| 2007-10-14 00:36 |
|
Assigned To | => lars |
| 2007-10-14 00:36 |
|
Note Added: 0000572 | |
| 2010-11-16 09:42 |
|
Source_changeset_attached | => ldmud.git master 26df4a54 |
| 2018-01-29 18:59 |
|
Source_changeset_attached | => ldmud.git master 26df4a54 |
| 2018-01-29 21:57 |
|
Source_changeset_attached | => ldmud.git master 26df4a54 |
