On Sun, Jul 3, 2011 at 1:21 PM, Emmanuel Dreyfus
<address@hidden> wrote:
Hi
I get a reprodcutbile crash of glusterfsd, running 3.2.1 code. I get it
by running multiple tar -xzf on a client, and after a while, a
glusterfsd on a brick crashes:
Program terminated with signal 11, Segmentation fault.
#0 0xba0d652e in server_rchecksum_cbk (frame=0xbad007d0,
cookie=0xbaf00300, this=0xba810000, op_ret=-1, op_errno=9,
weak_checksum=0, strong_checksum=0xb91ffc74 "") at
server3_1-fops.c:1305
Here is the offending code
if (op_ret == -1)
gf_log (this->name, GF_LOG_INFO,
"%"PRId64": RCHECKSUM %"PRId64" (%"PRId64") ==>
%"PRId32" (%s)",
frame->root->unique, state->resolve.fd_no,
state->fd ? state->fd->inode->ino : 0, op_ret,
strerror (op_errno));
The problem is state->fd->inode value:
(gdb) print *((server_state_t *)frame->root->state)->fd
$7 = {pid = 2610, flags = 2, refcount = 2, inode_list =
{next = 0xb9801088, prev = 0xb9801088}, inode = 0xaaaaaaaa,
lock = {pts_magic = 3735879687, pts_spin = 0 '\0', pts_flags =
0}, _ctx = 0xbb96b080, xl_count = 8}
inode = 0xaaaaaaaa is set in fd_destroy() to denote a stale object (It
is less fun than using 0xdeadbeef :-)
That suggests a race condition where a thread uses a fd that another
thread destroyed. Of course, the value could be checked at the beginning
of server_rchecksum_cbk(), but I suspect the problem is more widespread
that this. There are many other places in server3_1-fops.c where
state->fd->inode->ino is used.
And should the value be checked at the beginning of
server_rchecksum_cbk() and its friends, or in any gf_log() call, like
this:
if (op_ret == -1)
gf_log (this->name, GF_LOG_INFO,
"%"PRId64": RCHECKSUM %"PRId64" (%"PRId64") "
"==> %"PRId32" (%s)",
frame->root->unique, state->resolve.fd_no,
state->fd && (state->fd->inode != 0xaaaaaaaa) ?
state->fd->inode->ino : 0, op_ret,
strerror (op_errno));
FWIW this is a 2x2 replicated and distributed setup.
--
Emmanuel Dreyfus
http://hcpnet.free.fr/pubz
address@hidden
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