[sqlite] Re: sqlite 3.2.1 lock-2.8 test hangs

[Jolan Luff]

On Wed, Apr 27, 2005 at 04:55:00PM -0500, Jolan Luff wrote:
> hi,
> 
> when running the sqlite 3.2.1 regression tests, the lock-2.8 test hangs
> indefinitely.  if i disable that test, all others pass.
> 
> is this a bug in the regression test or is this something i should be
> concerned about?
> 
> thanks,
> 
> - jolan

i searched around on this and saw similar (ignored) reports.  there is
definitely a bug:

#0  0x08a1b915 in nanosleep () from /usr/lib/libc.so.35.1
#1  0x08a61727 in usleep () from /usr/lib/libc.so.35.1
#2  0x1c014349 in sqlite3OsSleep (ms=-32) at src/os_unix.c:1242
#3  0x0aa971c8 in sqliteDefaultBusyCallback (Timeout=0x190, count=0)
    at src/main.c:640

-32, ouch.

the code in question is:

  static const char delays[] =
     { 1, 2, 5, 10, 15, 20, 25, 25,  25,  50,  50,  50, 100};
  static const short int totals[] =
     { 0, 1, 3,  8, 18, 33, 53, 78, 103, 128, 178, 228, 287};
# define NDELAY (sizeof(delays)/sizeof(delays[0]))
  ptr timeout = (ptr)Timeout;
  ptr delay, prior;

  if( count <= NDELAY ){
    delay = delays[count-1];
    prior = totals[count-1];
  }else{
    delay = delays[NDELAY-1];
    prior = totals[NDELAY-1] + delay*(count-NDELAY-1);
  }
  if( prior + delay > timeout ){
    delay = timeout - prior;
    if( delay<=0 ) return 0;
  }
  sqlite3OsSleep(delay);

if count is 0:

delay = delays[0-1];

this is obviously an invalid array access which is causing the -32.

patch follows.

- jolan


Index: src/main.c
===================================================================
RCS file: /sqlite/sqlite/src/main.c,v
retrieving revision 1.285
diff -u -r1.285 main.c
--- src/main.c  29 Mar 2005 23:34:58 -0000      1.285
+++ src/main.c  28 Apr 2005 08:39:15 -0000
@@ -626,9 +626,9 @@
   ptr timeout = (ptr)Timeout;
   ptr delay, prior;
 
-  if( count <= NDELAY ){
-    delay = delays[count-1];
-    prior = totals[count-1];
+  if( count < NDELAY ){
+    delay = delays[count];
+    prior = totals[count];
   }else{
     delay = delays[NDELAY-1];
     prior = totals[NDELAY-1] + delay*(count-NDELAY-1);