Messages in this thread | | | Subject | Re: [PATCH 2/2] scsi: libsas: delete sas port if expander discover failed | From | Jason Yan <> | Date | Tue, 14 May 2019 19:37:01 +0800 |
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On 2019/5/14 18:45, John Garry wrote: > On 14/05/2019 03:42, Jason Yan wrote: >> The sas_port(phy->port) allocated in sas_ex_discover_expander() will not >> be deleted when the expander failed to discover. This will cause >> resource leak and a further issue of kernel BUG like below: >> >> [159785.843156] port-2:17:29: trying to add phy phy-2:17:29 fails: it's >> already part of another port >> [159785.852144] ------------[ cut here ]------------ >> [159785.856833] kernel BUG at drivers/scsi/scsi_transport_sas.c:1086! >> [159785.863000] Internal error: Oops - BUG: 0 [#1] SMP >> [159785.867866] CPU: 39 PID: 16993 Comm: kworker/u96:2 Tainted: G >> W OE 4.19.25-vhulk1901.1.0.h111.aarch64 #1 >> [159785.878458] Hardware name: Huawei Technologies Co., Ltd. >> Hi1620EVBCS/Hi1620EVBCS, BIOS Hi1620 CS B070 1P TA 03/21/2019 >> [159785.889231] Workqueue: 0000:74:02.0_disco_q sas_discover_domain >> [159785.895224] pstate: 40c00009 (nZcv daif +PAN +UAO) >> [159785.900094] pc : sas_port_add_phy+0x188/0x1b8 >> [159785.904524] lr : sas_port_add_phy+0x188/0x1b8 >> [159785.908952] sp : ffff0001120e3b80 >> [159785.912341] x29: ffff0001120e3b80 x28: 0000000000000000 >> [159785.917727] x27: ffff802ade8f5400 x26: ffff0000681b7560 >> [159785.923111] x25: ffff802adf11a800 x24: ffff0000680e8000 >> [159785.928496] x23: ffff802ade8f5728 x22: ffff802ade8f5708 >> [159785.933880] x21: ffff802adea2db40 x20: ffff802ade8f5400 >> [159785.939264] x19: ffff802adea2d800 x18: 0000000000000010 >> [159785.944649] x17: 00000000821bf734 x16: ffff00006714faa0 >> [159785.950033] x15: ffff0000e8ab4ecf x14: 7261702079646165 >> [159785.955417] x13: 726c612073277469 x12: ffff00006887b830 >> [159785.960802] x11: ffff00006773eaa0 x10: 7968702079687020 >> [159785.966186] x9 : 0000000000002453 x8 : 726f702072656874 >> [159785.971570] x7 : 6f6e6120666f2074 x6 : ffff802bcfb21290 >> [159785.976955] x5 : ffff802bcfb21290 x4 : 0000000000000000 >> [159785.982339] x3 : ffff802bcfb298c8 x2 : 337752b234c2ab00 >> [159785.987723] x1 : 337752b234c2ab00 x0 : 0000000000000000 >> [159785.993108] Process kworker/u96:2 (pid: 16993, stack limit = >> 0x0000000072dae094) >> [159786.000576] Call trace: >> [159786.003097] sas_port_add_phy+0x188/0x1b8 >> [159786.007179] sas_ex_get_linkrate.isra.5+0x134/0x140 >> [159786.012130] sas_ex_discover_expander+0x128/0x408 >> [159786.016906] sas_ex_discover_dev+0x218/0x4c8 >> [159786.021249] sas_ex_discover_devices+0x9c/0x1a8 >> [159786.025852] sas_discover_root_expander+0x134/0x160 >> [159786.030802] sas_discover_domain+0x1b8/0x1e8 >> [159786.035148] process_one_work+0x1b4/0x3f8 >> [159786.039230] worker_thread+0x54/0x470 >> [159786.042967] kthread+0x134/0x138 >> [159786.046269] ret_from_fork+0x10/0x18 >> [159786.049918] Code: 91322300 f0004402 91178042 97fe4c9b (d4210000) >> [159786.056083] Modules linked in: hns3_enet_ut(OE) hclge(OE) hnae3(OE) >> hisi_sas_test_hw(OE) hisi_sas_test_main(OE) serdes(OE) >> [159786.067202] ---[ end trace 03622b9e2d99e196 ]--- >> [159786.071893] Kernel panic - not syncing: Fatal exception >> [159786.077190] SMP: stopping secondary CPUs >> [159786.081192] Kernel Offset: disabled >> [159786.084753] CPU features: 0x2,a2a00a38 >> >> Fixes: 2908d778ab3e ("[SCSI] aic94xx: new driver") >> Reported-by: Jian Luo <luojian5@huawei.com> >> Signed-off-by: Jason Yan <yanaijie@huawei.com> >> CC: John Garry <john.garry@huawei.com> >> --- >> drivers/scsi/libsas/sas_expander.c | 2 ++ >> 1 file changed, 2 insertions(+) >> >> diff --git a/drivers/scsi/libsas/sas_expander.c >> b/drivers/scsi/libsas/sas_expander.c >> index 83f2fd70ce76..9f7e2457360e 100644 >> --- a/drivers/scsi/libsas/sas_expander.c >> +++ b/drivers/scsi/libsas/sas_expander.c >> @@ -1019,6 +1019,8 @@ static struct domain_device >> *sas_ex_discover_expander( >> list_del(&child->dev_list_node); >> spin_unlock_irq(&parent->port->dev_list_lock); >> sas_put_device(child); >> + sas_port_delete(phy->port); >> + phy->port = NULL; > > This looks ok. > > However, I wonder if we miss something else, and I see this code earlier > in sas_ex_discover_expander(): > > kref_get(&parent->kref); > child->parent = parent; > child->port = port; > child->iproto = phy->attached_iproto; > child->tproto = phy->attached_tproto; > > I assume the kref get is for the child referencing the parent. Do we > need the kref put? I couldn't see it. > > If yes, maybe it should it go in sas_free_device(), along with kfree() > for expander device phys. >
Yes, the parent's kref will put in sas_free_device(). So the call chain will be:
sas_put_device ->sas_free_device ->sas_put_device(dev->parent); ->kref_put
Thanks, Jason
> Thanks, > John > >> return NULL; >> } >> list_add_tail(&child->siblings, &parent->ex_dev.children); >> > > > > > . >
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