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h-gethost-r-race-20030401

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FIXES 1308

Thanks to Chaskiel Grundman for explaining what was happening:
- the connection is old and pre-existing, but has no host structure.
- 2 calls come in
- the first one enters h_GetHost_r, and h_Lookup_r returns null (but identP is
non-null, since rx keeps it around until it gc's the connection)
  The first thread calls WhoAreYou, which succeeds, it then calls
InitCallBackState3 (after H_UNLOCK) note that the host has been inserted into
the hashtable
- the second thread enters h_GetHost_r, and calls rx_GetSpecific. it then
calls h_Lookup_r. h_Lookup_r will block (new host is locked), but eventually
returns the new host
- InitCallBackState3 returns, and the frees the old identP, replaces it, and
unlocks the host.
- the first thread returns from h_Lookup_r. boom.

the changes:
-call rx_GetSpecific after h_Lookup_r returns (and potentially slept)
-removes an if wrapping which always is true (since !interfValid is always
 true)
-don't realloc identP if it exists
-don't free an old one by calling rx_SetSpecific either
This commit is contained in:
Derrick Brashear 2003-04-02 01:22:16 +00:00
parent f14686ea2e
commit 5967b22698
1 changed files with 42 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

73
src/viced/host.c
View File

@ -943,8 +943,8 @@ retry:
caps.Capabilities_len = 0;
code = 0;
identP = (struct Identity *)rx_GetSpecific(tcon, rxcon_ident_key);
host = h_Lookup_r(haddr, hport, &held);
identP = (struct Identity *)rx_GetSpecific(tcon, rxcon_ident_key);
if (host && !identP && !(host->Console&1)) {
/* This is a new connection, and we already have a host
* structure for this address. Verify that the identity
@ -1069,39 +1069,50 @@ retry:
host = h_Alloc_r(tcon); /* returned held and locked */
h_gethostcps_r(host,FT_ApproxTime());
if (!(host->Console&1)) {
if (!identP || !interfValid) {
H_UNLOCK
code = RXAFSCB_TellMeAboutYourself(host->callback_rxcon,
&interf, &caps);
if ( code == RXGEN_OPCODE )
code = RXAFSCB_WhoAreYou(host->callback_rxcon, &interf);
H_LOCK
if ( code == RXGEN_OPCODE ) {
int pident = 0;
H_UNLOCK
code = RXAFSCB_TellMeAboutYourself(host->callback_rxcon,
&interf, &caps);
if ( code == RXGEN_OPCODE )
code = RXAFSCB_WhoAreYou(host->callback_rxcon, &interf);
H_LOCK
if ( code == RXGEN_OPCODE ) {
if (!identP)
identP = (struct Identity *)malloc(sizeof(struct Identity));
if (!identP) {
ViceLog(0, ("Failed malloc in h_GetHost_r\n"));
assert(0);
}
identP->valid = 0;
rx_SetSpecific(tcon, rxcon_ident_key, identP);
ViceLog(25,
("Host %s:%d does not support WhoAreYou.\n",
afs_inet_ntoa_r(host->host, hoststr), ntohs(host->port)));
code = 0;
} else if (code == 0) {
interfValid = 1;
identP = (struct Identity *)malloc(sizeof(struct Identity));
if (!identP) {
ViceLog(0, ("Failed malloc in h_GetHost_r\n"));
assert(0);
}
identP->valid = 1;
identP->uuid = interf.uuid;
rx_SetSpecific(tcon, rxcon_ident_key, identP);
ViceLog(25, ("WhoAreYou success on %s:%d\n",
afs_inet_ntoa_r(host->host, hoststr), ntohs(host->port)));
else
pident = 1;
if (!identP) {
ViceLog(0, ("Failed malloc in h_GetHost_r\n"));
assert(0);
}
identP->valid = 0;
if (!pident)
rx_SetSpecific(tcon, rxcon_ident_key, identP);
ViceLog(25,
("Host %s:%d does not support WhoAreYou.\n",
afs_inet_ntoa_r(host->host, hoststr),
ntohs(host->port)));
code = 0;
} else if (code == 0) {
if (!identP)
identP = (struct Identity *)malloc(sizeof(struct Identity));
else
pident = 1;
if (!identP) {
ViceLog(0, ("Failed malloc in h_GetHost_r\n"));
assert(0);
}
identP->valid = 1;
identP->uuid = interf.uuid;
if (!pident)
rx_SetSpecific(tcon, rxcon_ident_key, identP);
ViceLog(25, ("WhoAreYou success on %s:%d\n",
afs_inet_ntoa_r(host->host, hoststr),
ntohs(host->port)));
}
interfValid=identP->valid;
if (code == 0 && !identP->valid) {
H_UNLOCK
code = RXAFSCB_InitCallBackState(host->callback_rxcon);