On Sat, Jan 14, 2012 at 10:10 AM, Dan Williams <dan.j.williams@xxxxxxxxx> wrote: > We need to hold drain_mutex across the unregistration as port down events > queue device removal as chained events, so we need to make sure no other > drainers are active. > > [ 1118.673968] WARNING: at kernel/workqueue.c:996 __queue_work+0x11a/0x326() > [ 1118.681982] Hardware name: S2600CP > [ 1118.686193] Modules linked in: isci(-) libsas scsi_transport_sas nls_utf8 > ipv6 uinput sg iTCO_wdt iTCO_vendor_support i2c_i801 i2c_core ioatdma dca > sd_mod sr_mod cdrom ahci libahci libata [last unloaded: scsi_transport_sas] > [ 1118.709893] Pid: 6831, comm: rmmod Not tainted 3.2.0-isci+ #1 > [ 1118.716727] Call Trace: > [ 1118.719867] [<ffffffff8103e9f5>] warn_slowpath_common+0x85/0x9d > [ 1118.727000] [<ffffffff8103ea27>] warn_slowpath_null+0x1a/0x1c > [ 1118.733942] [<ffffffff81056d44>] __queue_work+0x11a/0x326 > [ 1118.740481] [<ffffffff81056f99>] queue_work_on+0x1b/0x22 > [ 1118.746925] [<ffffffff81057106>] queue_work+0x37/0x3e > [ 1118.753105] [<ffffffffa0120e05>] ? sas_discover_event+0x55/0x82 [libsas] > [ 1118.761094] [<ffffffff813217c3>] scsi_queue_work+0x42/0x44 > [ 1118.767717] [<ffffffffa0120e19>] sas_discover_event+0x69/0x82 [libsas] > [ 1118.775509] [<ffffffffa0120f5b>] sas_unregister_dev+0xc3/0xcc [libsas] > [ 1118.783319] [<ffffffffa0120fae>] sas_unregister_domain_devices+0x4a/0xc8 [libsas] > [ 1118.792731] [<ffffffffa0120071>] sas_deform_port+0x60/0x1a6 [libsas] > [ 1118.800339] [<ffffffffa01201ea>] sas_unregister_ports+0x33/0x44 [libsas] > [ 1118.808342] [<ffffffffa011f7e5>] sas_unregister_ha+0x41/0x6b [libsas] > [ 1118.816055] [<ffffffffa0134055>] isci_unregister+0x22/0x4d [isci] > [ 1118.823384] [<ffffffffa0143040>] isci_pci_remove+0x2e/0x60 [isci] > > Reported-by: Jacek Danecki <jacek.danecki@xxxxxxxxx> > Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx> > --- > drivers/scsi/libsas/sas_init.c | 8 ++++++-- > 1 files changed, 6 insertions(+), 2 deletions(-) > > diff --git a/drivers/scsi/libsas/sas_init.c b/drivers/scsi/libsas/sas_init.c > index dc93e118..1e13cf4 100644 > --- a/drivers/scsi/libsas/sas_init.c > +++ b/drivers/scsi/libsas/sas_init.c > @@ -163,14 +163,18 @@ int sas_unregister_ha(struct sas_ha_struct *sas_ha) > unsigned long flags; > > /* Set the state to unregistered to avoid further unchained > - * events to be queued > + * events to be queued, but since sas_unregister_ports() > + * generates unchained events relative to any in progress drains > + * we need to hold drain_mutex. > */ > + mutex_lock(&sas_ha->drain_mutex); > spin_lock_irqsave(&sas_ha->state_lock, flags); > clear_bit(SAS_HA_REGISTERED, &sas_ha->state); > spin_unlock_irqrestore(&sas_ha->state_lock, flags); > - sas_drain_work(sas_ha); > > sas_unregister_ports(sas_ha); > + mutex_unlock(&sas_ha->drain_mutex); lockdep correctly points out this won't work as we can't hold the mutex over transport actions since, transport actions also sometimes acquire the mutex. -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
