Hi, I recently posted patches to integrate GlusterFS with QEMU. (http://lists.nongnu.org/archive/html/qemu-devel/2012-06/msg01745.html). While updating those patches to latest gluster git, I am seeing a problem and I tracked that down to this commit: e8eb0a9cb6539a7607d4c134daf331400a93d136 (Optimize for small dicts, and avoid an overrun). With this commit, I see an invalid memory reference in _dict_lookup(). Some details from gdb are shown below: [root@bharata qemu]# gdb ./x86_64-softmmu/qemu-system-x86_64 (gdb) set args --enable-kvm --nographic -m 1024 -smp 4 -drive file=gluster:/home/bharata/c-qemu-rpcbypass.vol:/dir1/F16,format=gluster,cache=none -net nic,model=virtio -net user -redir tcp:2000::22 (gdb) r Starting program: x86_64-softmmu/qemu-system-x86_64 --enable-kvm --nographic -m 1024 -smp 4 -drive file=gluster:/home/bharata/c-qemu-rpcbypass.vol:/dir1/F16,format=gluster,cache=none [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib64/libthread_db.so.1". Program received signal SIGSEGV, Segmentation fault. 0x00007ffff66e8ff6 in __strcmp_sse42 () from /lib64/libc.so.6 Missing separate debuginfos, use: debuginfo-install glib2-2.30.3-1.fc16.x86_64 glibc-2.14.90-24.fc16.7.x86_64 libuuid-2.20.1-2.3.fc16.x86_64 openssl-1.0.0j-1.fc16.x86_64 zlib-1.2.5-6.fc16.x86_64 (gdb) bt #0 0x00007ffff66e8ff6 in __strcmp_sse42 () from /lib64/libc.so.6 #1 0x00007ffff7241ab1 in _dict_lookup (key=0x5555564e11b0 "directory", this=<optimized out>) at dict.c:204 #2 _dict_lookup (this=<optimized out>, key=0x5555564e11b0 "directory") at dict.c:192 #3 0x00007ffff72427ae in _dict_set (value=0x7ffff534302c, key= 0x5555564e11b0 "directory", this=0x5555564c6c6c) at dict.c:254 #4 dict_set (value=0x7ffff534302c, key=<optimized out>, this=0x5555564c6c6c) at dict.c:327 #5 dict_set (this=0x5555564c6c6c, key=<optimized out>, value=0x7ffff534302c) at dict.c:313 #6 0x00007ffff728c2a8 in volume_option (value=0x5555564e2470 "/vm", key= 0x5555564e11b0 "directory") at ./graph.y:249 #7 yyparse () at ./graph.y:76 #8 0x00007ffff728cbbc in glusterfs_graph_construct (fp=0x5555564dcbe0) at ./graph.y:597 <snipped> (gdb) up #1 0x00007ffff7241ab1 in _dict_lookup (key=0x5555564e11b0 "directory", this=<optimized out>) at dict.c:204 204 if (pair->key && !strcmp (pair->key, key)) (gdb) p *pair $1 = {hash_next = 0x5555564c6ca4, prev = 0x5555564dbbfc, next = 0x3ff00000001, value = 0x1, key = 0x54 <Address 0x54 out of bounds>} You can see that pair->key has invalid address. I am using QEMU in RPC-bypass mode and the volume file looks like this: # cat c-qemu-rpcbypass.vol volume vm type storage/posix option directory /vm end-volume I am not familiar with this part of the code and hence will need time to debug this. Meanwhile if anyone else familiar with this part of the code could give some pointers, it will be useful. Regards, Bharata. -- http://bharata.sulekha.com/blog/posts.htm, http://raobharata.wordpress.com/
