Hi, John
Thanks for you reply.
On 2023/11/16 18:13, John Garry wrote:
On 16/11/2023 03:52, Xingui Yang wrote:
I think that patch title can be improved, but I would need to know more
about the problem before suggesting an improvement.
How about "Fix port add phy failed" ?
Firstly, when ex_phy is added to the parent port, ex_phy->port is not
set.
That seems correct, but why mention this now?
As a result, sas_port_delete_phy() won't be called in
sas_unregister_devs_sas_addr(), and although ex_phy's sas_address is
zero,
it is not deleted from the parent port's phy_list.
I am not sure why you mention this now either. You seem to be describing
how the problem occurs without actually mentioning what the problem is.
Secondly, phy->attached_sas_addr will be set to a zero-address when
phy->linkrate < SAS_LINK_RATE_1_5_GBPS and device-type != NO_DEVICE
during
device registration, such as stp. It will create a new port and all other
ex_phys whose addresses are zero will be added to the new port in
sas_ex_get_linkrate(), and it may trigger BUG() as follows:
I think that it would be better to first mention this crash, i.e. the
problem, how you recreate it, and then describe how and why it happens,
and then tell us how you will fix it
How about follows:
The following processes trigger a BUG(). A new port port-7:7:0 that
created by a new zero-address sata device tries to add phy-7:7:19 had
the same zero-address, but phy-7:7:19 is already part of another port.
[562240.051046] sas: phy19 part of wide port with phy16
[562240.051197] sas: ex 500e004aaaaaaa1f phy19:U:0 attached:
0000000000000000 (no device)
[562240.051203] sas: done REVALIDATING DOMAIN on port 0, pid:435909, res 0x0
[562240.062536] sas: ex 500e004aaaaaaa1f phy0 new device attached
[562240.062616] sas: ex 500e004aaaaaaa1f phy00:U:5 attached:
0000000000000000 (stp)
[562240.062680] port-7:7:0: trying to add phy phy-7:7:19 fails: it's
already part of another port
[562240.085064] ------------[ cut here ]------------
[562240.096612] kernel BUG at drivers/scsi/scsi_transport_sas.c:1083!
[562240.109611] Internal error: Oops - BUG: 0 [#1] SMP
[562240.343518] Process kworker/u256:3 (pid: 435909, stack limit =
0x0000000003bcbebf)
[562240.421714] Workqueue: 0000:b4:02.0_disco_q sas_revalidate_domain
[libsas]
[562240.437173] pstate: 40c00009 (nZcv daif +PAN +UAO)
[562240.450478] pc : sas_port_add_phy+0x13c/0x168 [scsi_transport_sas]
[562240.465283] lr : sas_port_add_phy+0x13c/0x168 [scsi_transport_sas]
[562240.479751] sp : ffff0000300cfa70
[562240.674822] Call trace:
[562240.682709] sas_port_add_phy+0x13c/0x168 [scsi_transport_sas]
[562240.694013] sas_ex_get_linkrate.isra.5+0xcc/0x128 [libsas]
[562240.704957] sas_ex_discover_end_dev+0xfc/0x538 [libsas]
[562240.715508] sas_ex_discover_dev+0x3cc/0x4b8 [libsas]
[562240.725634] sas_ex_discover_devices+0x9c/0x1a8 [libsas]
[562240.735855] sas_ex_revalidate_domain+0x2f0/0x450 [libsas]
[562240.746123] sas_revalidate_domain+0x158/0x160 [libsas]
[562240.756014] process_one_work+0x1b4/0x448
[562240.764548] worker_thread+0x54/0x468
[562240.772562] kthread+0x134/0x138
[562240.779989] ret_from_fork+0x10/0x18
We found that phy-7:7:19's port is not set when added to the parent
port,then it hadn't be deleted from the parent port's phy_list when call
sas_unregister_devs_sas_addr(), and the link rate of the new attached
sata device is 5 which is less then 1.5G/s, then the sata device's
sas_address was set to a zero-address.
Fix the problem as follows:
Firstly, set ex_phy->port when ex_phy is added to the parent port. And
set ex_dev->parent_port to NULL when the number of PHYs of the parent
port becomes 0.
Secondly, don't set a zero-address for phy->attached_sas_addr when
phy->attached_dev_type != NO_DEVICE.
Thanks,
Xingui
[562240.051046] sas: phy19 part of wide port with phy16
[562240.051197] sas: ex 500e004aaaaaaa1f phy19:U:0 attached:
0000000000000000 (no device)
[562240.051203] sas: done REVALIDATING DOMAIN on port 0, pid:435909,
res 0x0
[562240.062536] sas: ex 500e004aaaaaaa1f phy0 new device attached
[562240.062616] sas: ex 500e004aaaaaaa1f phy00:U:5 attached:
0000000000000000 (stp)
[562240.062680] port-7:7:0: trying to add phy phy-7:7:19 fails: it's
already part of another port
[562240.085064] ------------[ cut here ]------------
[562240.096612] kernel BUG at drivers/scsi/scsi_transport_sas.c:1083!
[562240.109611] Internal error: Oops - BUG: 0 [#1] SMP
[562240.343518] Process kworker/u256:3 (pid: 435909, stack limit =
0x0000000003bcbebf)
[562240.421714] Workqueue: 0000:b4:02.0_disco_q sas_revalidate_domain
[libsas]
[562240.437173] pstate: 40c00009 (nZcv daif +PAN +UAO)
[562240.450478] pc : sas_port_add_phy+0x13c/0x168 [scsi_transport_sas]
[562240.465283] lr : sas_port_add_phy+0x13c/0x168 [scsi_transport_sas]
[562240.479751] sp : ffff0000300cfa70
[562240.674822] Call trace:
[562240.682709] sas_port_add_phy+0x13c/0x168 [scsi_transport_sas]
[562240.694013] sas_ex_get_linkrate.isra.5+0xcc/0x128 [libsas]
[562240.704957] sas_ex_discover_end_dev+0xfc/0x538 [libsas]
[562240.715508] sas_ex_discover_dev+0x3cc/0x4b8 [libsas]
[562240.725634] sas_ex_discover_devices+0x9c/0x1a8 [libsas]
[562240.735855] sas_ex_revalidate_domain+0x2f0/0x450 [libsas]
[562240.746123] sas_revalidate_domain+0x158/0x160 [libsas]
[562240.756014] process_one_work+0x1b4/0x448
[562240.764548] worker_thread+0x54/0x468
[562240.772562] kthread+0x134/0x138
[562240.779989] ret_from_fork+0x10/0x18
We've done the following to solve this problem:
I'd use "Fix the problem as follows:""
Firstly, set ex_phy->port when ex_phy is added to the parent port. And
set
ex_dev->parent_port to NULL when the number of PHYs of the parent port
becomes 0.
Thanks,
John
.
