set_city_production() overflows

• Reporter: cazfi
• 소유자: (None)
• Type: Bugs
• Status: Open
• Component: General
• MileStone: (None)
• Priority: 5 - Medium
• Severity: 5 - Medium
• Resolution: None
• File: 3

Details Reply

From https://osdn.net/projects/freeciv/ticket/46286#comment:12505:46286:1679918727 reported by alain_bkr:

17 ../../common/city.c:2872:21: runtime error: signed integer overflow
17 ../../common/city.c:2879:25: runtime error: signed integer overflow
17 ../../common/city.c:2886:37: runtime error: signed integer overflow
4 ../../common/city.c:3156:33: runtime error: signed integer overflow

The last one might be unrelated to the others. This was with S3_1.

Ticket History (3/8 Histories)

2023-04-02 15:45 Updated by: cazfi

• New Ticket "set_city_production() overflows" created

2023-04-10 09:54 Updated by: alain_bkr

댓글 올리기 Reply

This one is robust and reproducible.

• It happens approximately in each game, and before turn 100 in my tests on small maps (<4k tiles) with 2~12 AI.
• I took one game where it occurs very early and rerun, but i had pulled latest, and recompiled (clang-15 with -fsanitize=undefined flag for compilers and linker)

I step on the bug each time at turn 25, from the attached game at turn 21 , modified to have endturn 30

common/city.c
inline void set_city_production(struct city *pcity)
...
 2872 :      pcity->prod[o] * pcity->bonus[o] / 100,
... 
 2879 :      pcity->prod[O_TRADE] * pcity->bonus[O_TRADE] / 100
...
 2886 :      pcity->prod[o] = pcity->prod[o] * pcity->bonus[o] / 100;

with always mostly the same value - 1 billion * 100

 ../../common/city.c:2872:21: runtime error: signed integer overflow: -999999978 * 100 cannot be represented in type 'int'
../../common/city.c:2879:25: runtime error: signed integer overflow: -999999984 * 100 cannot be represented in type 'int'
../../common/city.c:2886:37: runtime error: signed integer overflow: -999999978 * 100 cannot be represented in type 'int'

(Edited, 2023-04-10 10:53 Updated by: alain_bkr)

2023-04-10 09:57 Updated by: alain_bkr

• File Sz03-Ai012-Lm54-20230401-154838-T00021-manual.sav.xz (File ID: 12141) is attached

2023-04-10 09:59 Updated by: alain_bkr

• File Sz03-Ai012-Lm54-20230401-154838.serv (File ID: 12142) is attached

2023-04-10 11:55 Updated by: alain_bkr

댓글 올리기 Reply

need to check if this also happens in other cases :

several turns before our overflow we have index -1 out of bounds

> 
Game saved as Sz03-Ai012-Lm54-20230401-154838-T00021-auto.sav.xz
> ../../common/unit.c:2475:13: runtime error: index -1 out of bounds for type 'const struct unit_list_link *[5]'
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior ../../common/unit.c:2475:13 in 

Game saved as Sz03-Ai012-Lm54-20230401-154838-T00022-auto.sav.xz
> 
Game saved as Sz03-Ai012-Lm54-20230401-154838-T00023-auto.sav.xz
> 
Game saved as Sz03-Ai012-Lm54-20230401-154838-T00024-auto.sav.xz
> ../../common/city.c:2872:21: runtime error: signed integer overflow: -999999982 * 100 cannot be represented in type 'int'
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior ../../common/city.c:2872:21 in 
../../common/city.c:2879:25: runtime error: signed integer overflow: -999999985 * 100 cannot be represented in type 'int'
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior ../../common/city.c:2879:25 in 
../../common/city.c:2886:37: runtime error: signed integer overflow: -999999982 * 100 cannot be represented in type 'int'
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior ../../common/city.c:2886:37 in 

Game saved as Sz03-Ai012-Lm54-20230401-154838-T00025-auto.sav.xz
> 

2023-04-22 19:31 Updated by: cazfi

댓글 올리기 Reply

Reply To alain_bkr

need to check if this also happens in other cases : several turns before our overflow we have index -1 out of bounds {{{

Game saved as Sz03-Ai012-Lm54-20230401-154838-T00021-auto.sav.xz

../../common/unit.c:2475:13: runtime error: index -1 out of bounds for type 'const struct unit_list_link *5'

SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior ../../common/unit.c:2475:13 in

Very likely not the cause to the later overflow. I opened #47900 about this one.

2023-05-02 01:08 Updated by: alain_bkr

댓글 올리기 Reply

origin/S3_1 373049274

I have reproducible error directly at load time from Sz4-Ai001-Lm62-230409_184438-T00069-auto.sav.xz with only one AI alone

3: Savegame: 'ysize' has been set to 72.
3: Erminaz has been added as Cheating level AI-controlled player (classic).
../../common/city.c:2872:21: runtime error: signed integer overflow: -999999992 * 100 cannot be represented in type 'int'
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior ../../common/city.c:2872:21 in 
../../common/city.c:2879:25: runtime error: signed integer overflow: -999999997 * 100 cannot be represented in type 'int'
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior ../../common/city.c:2879:25 in 
../../common/city.c:2886:37: runtime error: signed integer overflow: -999999992 * 100 cannot be represented in type 'int'
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior ../../common/city.c:2886:37 in 
Console: 'savename' has been set to "reSz4-Ai001-Lm62-230409_184438-T%04T-%R".
Console: 'endturn' has been set to 69.
Game saved as reSz4-Ai001-Lm62-230409_184438-T0069-manual.sav.xz
Starting game.
------------------------------------------------------------------------------
All options with non-default values
------------------------------------------------------------------------------
In the column '##' the status of 

(Edited, 2023-05-02 01:14 Updated by: alain_bkr)

2023-05-02 01:09 Updated by: alain_bkr

• File Sz4-Ai001-Lm62-230409_184438-T00069-auto.sav.xz (File ID: 12333) is attached