[Bug 1423] New: - Crash when multiple threads call gethostbyname_r

[wine-bugs at wine.codeweavers.com]

http://bugs.winehq.com/show_bug.cgi?id=1423

           Summary: Crash when multiple threads call gethostbyname_r
           Product: Wine
           Version: CVS
          Platform: PC
               URL: http://www.proxomitron.org/
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: wine-loader
        AssignedTo: wine-bugs at winehq.com
        ReportedBy: prupe at myrealbox.com


I'm having trouble with this patch and Red Hat 9:  <http://www.
winehq.com/hypermail/wine-cvs/2003/04/0224.html>.  Multithreaded 
apps started crashing deep down in the guts of gethostbyname_r 
whenever it's called from multiple threads at once.  The crash 
typically looks like this:

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 1118186784 (LWP 27326)]
0x4206c909 in fgets_unlocked () from /lib/tls/libc.so.6
(gdb) bt
#0  0x4206c909 in fgets_unlocked () from /lib/tls/libc.so.6
#1  0x4023e1e4 in _nss_files_gethostbyname_r () from 
/lib/libnss_files.so.2
#2  0x420f2b3c in gethostbyname_r@@GLIBC_2.1.2 () from 
/lib/tls/libc.so.6
#3  0x40cf77c7 in __ws_gethostbyname (name=0x402900cf "media.
monster.com", 
    dup_flag=1) at socket.c:3044
#4  0x40cf78f4 in WS_gethostbyname (name=0x402900cf "media.
monster.com")
    at socket.c:3085
(gdb) info thr
* 8 Thread 1118186784 (LWP 27326)  0x4206c909 in fgets_unlocked 
()
   from /lib/tls/libc.so.6
  7 Thread 1115761952 (LWP 27325)  0xffffe002 in ?? ()
  6 Thread 1113337120 (LWP 27324)  0xffffe002 in ?? ()
  5 Thread 1110912288 (LWP 27323)  0x004168ff in ?? ()
  2 Thread 1100885280 (LWP 27314)  0xffffe002 in ?? ()
  1 Thread 1074023232 (LWP 27305)  0xffffe002 in ?? ()
(gdb) thr 7
[Switching to thread 7 (Thread 1115761952 (LWP 27325))]#0  
0xffffe002 in ?? ()
(gdb) bt
#0  0xffffe002 in ?? ()
#1  0x41c5f6d4 in send_dg () from /lib/libresolv.so.2
#2  0x41c5ecb5 in __libc_res_nsend () from /lib/libresolv.so.2
#3  0x41c5dc07 in __libc_res_nquery () from /lib/libresolv.so.2
#4  0x41c5e35b in __libc_res_nquerydomain () from /lib/libresolv.
so.2
#5  0x41c5df22 in __libc_res_nsearch () from /lib/libresolv.so.2
#6  0x40d0805f in _nss_dns_gethostbyname2_r () from 
/lib/libnss_dns.so.2
#7  0x40d08293 in _nss_dns_gethostbyname_r () from 
/lib/libnss_dns.so.2
#8  0x420f2b3c in gethostbyname_r@@GLIBC_2.1.2 () from 
/lib/tls/libc.so.6
#9  0x40cf77c7 in __ws_gethostbyname (name=0x40295b4f "media.
monster.com", 
    dup_flag=1) at socket.c:3044
#10 0x40cf78f4 in WS_gethostbyname (name=0x40295b4f "media.
monster.com")
    at socket.c:3085

Reversing patch #7969 seems to fix the problem.  To reproduce the 
crash, run the local web proxy Proxomitron <http://www.
proxomitron.org/> and try loading sites with lots of images.  I'm 
running Red Hat 9 with glibc 2.3.2-27.9 and the --with-nptl 
configure option (wine fully rebuilt after installing RH9).

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