James, Can you please pick this up for the next update. > -----Original Message----- > From: Chandra Seetharaman [mailto:sekharan@xxxxxxxxxx] > Sent: Thursday, February 02, 2012 1:44 PM > To: Moger, Babu > Cc: linux-kernel@xxxxxxxxxxxxxxx; device-mapper development; Mike > Snitzer > Subject: Re: [PATCH] scsi_dh_rdac: Fix for unbalanced reference count > > Reviewed-by: Chandra Seetharaman <sekharan@xxxxxxxxxx> > > On Thu, 2012-02-02 at 15:21 +0000, Moger, Babu wrote: > > Resubmitting it again(Probably last one had some format issues). > > > > This patch fixes an unbalanced refcount issue. > > > > Elevating the lock for both kref_put and also for controller node > deletion. > > Previously, controller deletion was protected but the not the > kref_put. This was causing > > the other thread to pick up the controller structure which was > already kref'd zero. > > > > This was causing the following BUG_ON and also sometimes panic. > > > > WARNING: at lib/kref.c:43 kref_get+0x2d/0x30() (Not tainted) > > Hardware name: IBM System x3655 -[7985AC1]- > > Modules linked in: fuse scsi_dh_rdac autofs4 nfs lockd fscache > nfs_acl > > auth_rpcgss sunrpc 8021q garp stp llc ipv6 ib_srp(U) > scsi_transport_srp > > scsi_tgt ib_cm(U) ib_sa(U) ib_uverbs(U) ib_umad(U) mlx4_ib(U) > mlx4_core(U) > > ib_mthca(U) ib_mad(U) ib_core(U) dm_mirror dm_region_hash dm_log > dm_round_robin > > dm_multipath uinput bnx2 ses enclosure sg ibmpex ibmaem > ipmi_msghandler > > serio_raw k8temp hwmon amd64_edac_mod edac_core edac_mce_amd shpchp > i2c_piix4 > > ext4 mbcache jbd2 sr_mod cdrom sd_mod crc_t10dif sata_svw pata_acpi > ata_generic > > pata_serverworks aacraid radeon ttm drm_kms_helper drm i2c_algo_bit > i2c_core > > dm_mod [last unloaded: freq_table] > > Pid: 13735, comm: srp_daemon Not tainted 2.6.32-71.el6.x86_64 #1 > > Call Trace: > > [<ffffffff8106b857>] warn_slowpath_common+0x87/0xc0 > > [<ffffffff8106b8aa>] warn_slowpath_null+0x1a/0x20 > > [<ffffffff8125c39d>] kref_get+0x2d/0x30 > > [<ffffffffa01b4029>] rdac_bus_attach+0x459/0x580 [scsi_dh_rdac] > > [<ffffffff8135232a>] scsi_dh_handler_attach+0x2a/0x80 > > [<ffffffff81352c7b>] scsi_dh_notifier+0x9b/0xa0 > > [<ffffffff814cd7a5>] notifier_call_chain+0x55/0x80 > > [<ffffffff8109711a>] __blocking_notifier_call_chain+0x5a/0x80 > > [<ffffffff81097156>] blocking_notifier_call_chain+0x16/0x20 > > [<ffffffff8132bec5>] device_add+0x515/0x640 > > [<ffffffff813329e4>] ? attribute_container_device_trigger+0xc4/0xe0 > > [<ffffffff8134f659>] scsi_sysfs_add_sdev+0x89/0x2c0 > > [<ffffffff8134d096>] scsi_probe_and_add_lun+0xea6/0xed0 > > [<ffffffff8134beb2>] ? scsi_alloc_target+0x292/0x2d0 > > [<ffffffff8134d1e1>] __scsi_scan_target+0x121/0x750 > > [<ffffffff811df806>] ? sysfs_create_file+0x26/0x30 > > [<ffffffff8132b759>] ? device_create_file+0x19/0x20 > > [<ffffffff81332838>] ? attribute_container_add_attrs+0x78/0x90 > > [<ffffffff814b008c>] ? klist_next+0x4c/0xf0 > > [<ffffffff81332e30>] ? transport_configure+0x0/0x20 > > [<ffffffff813329e4>] ? attribute_container_device_trigger+0xc4/0xe0 > > [<ffffffff8134df40>] scsi_scan_target+0xd0/0xe0 > > [<ffffffffa02f053a>] srp_create_target+0x75a/0x890 [ib_srp] > > [<ffffffff8132a130>] dev_attr_store+0x20/0x30 > > [<ffffffff811df145>] sysfs_write_file+0xe5/0x170 > > [<ffffffff8116c818>] vfs_write+0xb8/0x1a0 > > [<ffffffff810d40a2>] ? audit_syscall_entry+0x272/0x2a0 > > [<ffffffff8116d251>] sys_write+0x51/0x90 > > [<ffffffff81013172>] system_call_fastpath+0x16/0x1b > > > > > > Signed-off-by: Babu Moger <babu.moger@xxxxxxxxxx> > > Acked-by: Mike Snitzer <snitzer@xxxxxxxxxx> > > --- > > --- linux-3.3-rc1-new/drivers/scsi/device_handler/scsi_dh_rdac.c.orig > 2012-01-19 17:04:48.000000000 -0600 > > +++ linux-3.3-rc1-new/drivers/scsi/device_handler/scsi_dh_rdac.c > 2012-02-01 10:50:31.000000000 -0600 > > @@ -364,10 +364,7 @@ static void release_controller(struct kr > > struct rdac_controller *ctlr; > > ctlr = container_of(kref, struct rdac_controller, kref); > > > > - flush_workqueue(kmpath_rdacd); > > - spin_lock(&list_lock); > > list_del(&ctlr->node); > > - spin_unlock(&list_lock); > > kfree(ctlr); > > } > > > > @@ -376,20 +373,17 @@ static struct rdac_controller *get_contr > > { > > struct rdac_controller *ctlr, *tmp; > > > > - spin_lock(&list_lock); > > - > > list_for_each_entry(tmp, &ctlr_list, node) { > > if ((memcmp(tmp->array_id, array_id, UNIQUE_ID_LEN) == 0) > && > > (tmp->index == index) && > > (tmp->host == sdev->host)) { > > kref_get(&tmp->kref); > > - spin_unlock(&list_lock); > > return tmp; > > } > > } > > ctlr = kmalloc(sizeof(*ctlr), GFP_ATOMIC); > > if (!ctlr) > > - goto done; > > + return NULL; > > > > /* initialize fields of controller */ > > memcpy(ctlr->array_id, array_id, UNIQUE_ID_LEN); > > @@ -405,8 +399,7 @@ static struct rdac_controller *get_contr > > INIT_WORK(&ctlr->ms_work, send_mode_select); > > INIT_LIST_HEAD(&ctlr->ms_head); > > list_add(&ctlr->node, &ctlr_list); > > -done: > > - spin_unlock(&list_lock); > > + > > return ctlr; > > } > > > > @@ -517,9 +510,12 @@ static int initialize_controller(struct > > index = 0; > > else > > index = 1; > > + > > + spin_lock(&list_lock); > > h->ctlr = get_controller(index, array_name, array_id, > sdev); > > if (!h->ctlr) > > err = SCSI_DH_RES_TEMP_UNAVAIL; > > + spin_unlock(&list_lock); > > } > > return err; > > } > > @@ -906,7 +902,9 @@ static int rdac_bus_attach(struct scsi_d > > return 0; > > > > clean_ctlr: > > + spin_lock(&list_lock); > > kref_put(&h->ctlr->kref, release_controller); > > + spin_unlock(&list_lock); > > > > failed: > > kfree(scsi_dh_data); > > @@ -921,14 +919,19 @@ static void rdac_bus_detach( struct scsi > > struct rdac_dh_data *h; > > unsigned long flags; > > > > - spin_lock_irqsave(sdev->request_queue->queue_lock, flags); > > scsi_dh_data = sdev->scsi_dh_data; > > + h = (struct rdac_dh_data *) scsi_dh_data->buf; > > + if (h->ctlr && h->ctlr->ms_queued) > > + flush_workqueue(kmpath_rdacd); > > + > > + spin_lock_irqsave(sdev->request_queue->queue_lock, flags); > > sdev->scsi_dh_data = NULL; > > spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags); > > > > - h = (struct rdac_dh_data *) scsi_dh_data->buf; > > + spin_lock(&list_lock); > > if (h->ctlr) > > kref_put(&h->ctlr->kref, release_controller); > > + spin_unlock(&list_lock); > > kfree(scsi_dh_data); > > module_put(THIS_MODULE); > > sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", RDAC_NAME); > > > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-scsi" > in > > the body of a message to majordomo@xxxxxxxxxxxxxxx > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > ��.n��������+%������w��{.n�����{������ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
