[bug report] nvmet-tcp: Memory leak when connecting / disconnecting to the target

[bug report] nvmet-tcp: Memory leak when connecting / disconnecting to the target

[Victor Gladkov]

[Environment]
Branch: nvme-5.7
Commit: 9210c075cef29c1f764b4252f93105103bdfb292

[Steps]
At the target:
1.1 Check free memory before the test
	# grep MemFree /proc/meminfo
	MemFree:        64060460 kB
1.2 Create portal:
	#./target_create_portal.sh 1 69.69.69.1 4420 tcp
1.3 Create target:
	#./target_add.sh /dev/nvme1n1 target_t0 1

At the host:
2.1 Connect to the target (number of IO queues is 10)
2.2 Disconnect from the target.
2.3 Repeat steps 2.1 and 2.2 ~1000 times

At the target:
3.1 Check free memory after the test
	# grep MemFree /proc/meminfo
	MemFree:        63685072 kB 

[Result]:
Free memory of the target system was reduce to 375388 kB
Note: The size of leakage memory depends on the number of IO queues.

Best Regards,
Victor Gladkov


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Re: [bug report] nvmet-tcp: Memory leak when connecting / disconnecting to the target

[Sagi Grimberg]

> [Environment]
> Branch: nvme-5.7
> Commit: 9210c075cef29c1f764b4252f93105103bdfb292

Hi, can you please provide kmemleak output for this test case?

Is this specific to nvmet-tcp? what about nvmet-rdma?

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RE: [bug report] nvmet-tcp: Memory leak when connecting / disconnecting to the target

[Victor Gladkov]

> > [Environment]
> > Branch: nvme-5.7
> > Commit: 9210c075cef29c1f764b4252f93105103bdfb292
> 
> Hi, can you please provide kmemleak output for this test case?
> 
> Is this specific to nvmet-tcp? what about nvmet-rdma?

Kmemleak doesn't report any leaks :(

It's happening with nvmet-tcp only. The nvmet-rdma works without leaks.


Target terminal record
----
# lsmod|grep kmem
kmemleak_test          16384  0
#
# modinfo kmemleak_test
filename:       /lib/modules/5.7.0-rc1+KS+/kernel/mm/kmemleak-test.ko
license:        GPL
srcversion:     67EF7E2143EBE69D39BFA1A
depends:
retpoline:      Y
intree:         Y
name:           kmemleak_test
vermagic:       5.7.0-rc1+KS+ SMP mod_unload modversions
#
#
# ./target_load_drivers.sh
nvmet_tcp              28672  0
nvmet_rdma             36864  0
nvmet                 102400  2 nvmet_tcp,nvmet_rdma
rdma_cm               118784  7 rpcrdma,ib_srpt,ib_srp,nvmet_rdma,ib_iser,ib_isert,rdma_ucm
ib_core               409600  14 rdma_cm,ib_ipoib,rpcrdma,ib_srpt,ib_srp,nvmet_rdma,iw_cm,ib_iser,ib_umad,ib_isert,rdma_ucm,ib_uverbs,mlx5_ib,ib_cm
nvme                   49152  4
nvme_core             110592  6 nvme
t10_pi                 16384  2 sd_mod,nvme_core
#
# ./target_create_portal.sh 1 69.69.69.1 4420 tcp
transport type is tcp
/sys/kernel/config/nvmet/ports/1
#
# ./target_add.sh /dev/nvme1n1 target_t0 1
#
# dmesg -c
#
# date
Tue Jun  2 05:01:09 EDT 2020
#
# grep Free /proc/meminfo
MemFree:        61740020 kB
SwapFree:       32964604 kB
HugePages_Free:        0
#
# cat /sys/kernel/debug/kmemleak
#
# echo scan > /sys/kernel/debug/kmemleak
# cat /sys/kernel/debug/kmemleak
#
# date
Tue Jun  2 05:04:12 EDT 2020
#
# dmesg |grep -c "creating controller 1 for subsystem target_t0 for"
1001
#
# grep Free /proc/meminfo
MemFree:        61370724 kB
SwapFree:       32964604 kB
HugePages_Free:        0
#
# echo scan > /sys/kernel/debug/kmemleak
# cat /sys/kernel/debug/kmemleak
#
-------
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