scsi: libsas: delete sas port if expander discover failed [Linux 4.14.129]

scsi: libsas: delete sas port if expander discover failed [Linux 4.14.129]

This Linux kernel change "scsi: libsas: delete sas port if expander discover failed" is included in the Linux 4.14.129 release. This change is authored by Jason Yan <yanaijie [at] huawei.com> on Tue May 14 10:42:39 2019 +0800. The commit for this change in Linux stable tree is 5992a69 (patch) which is from upstream commit 3b05417. The same Linux upstream change may have been applied to various maintained Linux releases and you can find all Linux releases containing changes from upstream 3b05417.

scsi: libsas: delete sas port if expander discover failed

[ Upstream commit 3b0541791453fbe7f42867e310e0c9eb6295364d ]

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 <[email protected]>
Signed-off-by: Jason Yan <[email protected]>
CC: John Garry <[email protected]>
Signed-off-by: Martin K. Petersen <mart[email protected]>
Signed-off-by: Sasha Levin <[email protected]>

There are 2 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 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 ffea620..259ee0d 100644
--- a/drivers/scsi/libsas/sas_expander.c
+++ b/drivers/scsi/libsas/sas_expander.c
@@ -989,6 +989,8 @@ 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;
        return NULL;
    }
    list_add_tail(&child->siblings, &parent->ex_dev.children);

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