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firewire: fw-sbp2: better fix for NULL pointer dereference in scsi_remove_device

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Patch "firewire: fw-sbp2: fix NULL pointer deref. in scsi_remove_device"
had the unintended effect that firewire-sbp2 could not be unloaded
anymore until all SBP-2 devices were unplugged.

We now fix the NULL pointer bug by reacquiring a reference to the sdev
instead of holding a reference to the sdev (and to the module) all the
time.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Tested-by: Jarod Wilson <jwilson@redhat.com>
This commit is contained in:
Stefan Richter 2008-02-26 23:30:02 +01:00
parent d395991c11
commit f8436158b1
1 changed files with 27 additions and 19 deletions
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46
drivers/firewire/fw-sbp2.c
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@ -122,7 +122,6 @@ static const char sbp2_driver_name[] = "sbp2";
struct sbp2_logical_unit {
struct sbp2_target *tgt;
struct list_head link;
struct scsi_device *sdev;
struct fw_address_handler address_handler;
struct list_head orb_list;
@ -139,6 +138,7 @@ struct sbp2_logical_unit {
int generation;
int retries;
struct delayed_work work;
bool has_sdev;
bool blocked;
};
@ -751,20 +751,33 @@ static void sbp2_unblock(struct sbp2_target *tgt)
scsi_unblock_requests(shost);
}
static int sbp2_lun2int(u16 lun)
{
struct scsi_lun eight_bytes_lun;
memset(&eight_bytes_lun, 0, sizeof(eight_bytes_lun));
eight_bytes_lun.scsi_lun[0] = (lun >> 8) & 0xff;
eight_bytes_lun.scsi_lun[1] = lun & 0xff;
return scsilun_to_int(&eight_bytes_lun);
}
static void sbp2_release_target(struct kref *kref)
{
struct sbp2_target *tgt = container_of(kref, struct sbp2_target, kref);
struct sbp2_logical_unit *lu, *next;
struct Scsi_Host *shost =
container_of((void *)tgt, struct Scsi_Host, hostdata[0]);
struct scsi_device *sdev;
/* prevent deadlocks */
sbp2_unblock(tgt);
list_for_each_entry_safe(lu, next, &tgt->lu_list, link) {
if (lu->sdev) {
scsi_remove_device(lu->sdev);
scsi_device_put(lu->sdev);
sdev = scsi_device_lookup(shost, 0, 0, sbp2_lun2int(lu->lun));
if (sdev) {
scsi_remove_device(sdev);
scsi_device_put(sdev);
}
sbp2_send_management_orb(lu, tgt->node_id, lu->generation,
SBP2_LOGOUT_REQUEST, lu->login_id, NULL);
@ -807,7 +820,6 @@ static void sbp2_login(struct work_struct *work)
struct fw_device *device = fw_device(tgt->unit->device.parent);
struct Scsi_Host *shost;
struct scsi_device *sdev;
struct scsi_lun eight_bytes_lun;
struct sbp2_login_response response;
int generation, node_id, local_node_id;
@ -820,7 +832,7 @@ static void sbp2_login(struct work_struct *work)
local_node_id = device->card->node_id;
/* If this is a re-login attempt, log out, or we might be rejected. */
if (lu->sdev)
if (lu->has_sdev)
sbp2_send_management_orb(lu, device->node_id, generation,
SBP2_LOGOUT_REQUEST, lu->login_id, NULL);
@ -859,7 +871,7 @@ static void sbp2_login(struct work_struct *work)
sbp2_agent_reset(lu);
/* This was a re-login. */
if (lu->sdev) {
if (lu->has_sdev) {
sbp2_cancel_orbs(lu);
sbp2_conditionally_unblock(lu);
goto out;
@ -868,13 +880,8 @@ static void sbp2_login(struct work_struct *work)
if (lu->tgt->workarounds & SBP2_WORKAROUND_DELAY_INQUIRY)
ssleep(SBP2_INQUIRY_DELAY);
memset(&eight_bytes_lun, 0, sizeof(eight_bytes_lun));
eight_bytes_lun.scsi_lun[0] = (lu->lun >> 8) & 0xff;
eight_bytes_lun.scsi_lun[1] = lu->lun & 0xff;
shost = container_of((void *)tgt, struct Scsi_Host, hostdata[0]);
sdev = __scsi_add_device(shost, 0, 0,
scsilun_to_int(&eight_bytes_lun), lu);
sdev = __scsi_add_device(shost, 0, 0, sbp2_lun2int(lu->lun), lu);
/*
* FIXME: We are unable to perform reconnects while in sbp2_login().
* Therefore __scsi_add_device() will get into trouble if a bus reset
@ -896,7 +903,8 @@ static void sbp2_login(struct work_struct *work)
}
/* No error during __scsi_add_device() */
lu->sdev = sdev;
lu->has_sdev = true;
scsi_device_put(sdev);
sbp2_allow_block(lu);
goto out;
@ -934,11 +942,11 @@ static int sbp2_add_logical_unit(struct sbp2_target *tgt, int lun_entry)
return -ENOMEM;
}
lu->tgt = tgt;
lu->sdev = NULL;
lu->lun = lun_entry & 0xffff;
lu->retries = 0;
lu->blocked = false;
lu->tgt = tgt;
lu->lun = lun_entry & 0xffff;
lu->retries = 0;
lu->has_sdev = false;
lu->blocked = false;
++tgt->dont_block;
INIT_LIST_HEAD(&lu->orb_list);
INIT_DELAYED_WORK(&lu->work, sbp2_login);