Re: [PATCH] padata: do not leak refcount in reorder_work

[Aishwarya <aishwarya.tcv@arm.com>]

Hi Dominik,

I wanted to report a regression observed while running the
`kselftest-mm` suite, specifically the
`mm_run_vmtests_sh_migration_migration_shared_anon` test, on an
Arm64 Marvell Thunder X2 (TX2) system.

The kernel was built using defconfig with the additional config
fragment from:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/testing/selftests/mm/config

This works fine on v6.15-rc7.

A bisect identified this patch as introducing the failure. Bisected
it on the tag "v6.15-rc7-7-g4a95bc121ccd" at repo:
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

Failure log:
11193 03:29:14.806502  # # running ./migration
11194 03:29:14.806876  # # -------------------
11195 03:29:14.820939  # # TAP version 13
11196 03:29:14.821236  # # 1..6
11197 03:29:14.821519  # # # Starting 6 tests from 1 test cases.
11198 03:29:14.821773  # # #  RUN           migration.private_anon ...
11199 03:29:34.602964  # # #            OK  migration.private_anon
11200 03:29:34.603418  # # ok 1 migration.private_anon
11201 03:29:34.603687  # # #  RUN           migration.shared_anon ...
11202 03:29:34.973479  # # Didn't migrate 1 pages
11203 03:29:34.973855  # # # migration.c:175:shared_anon:Expected migrate(ptr,
self->n1, self->n2) (-2) == 0 (0)
11204 03:29:34.984787  # # # shared_anon: Test terminated by assertion
11205 03:29:34.985105  # # #          FAIL  migration.shared_anon
11206 03:29:34.985365  # # not ok 2 migration.shared_anon
11207 03:29:34.988568  # # #  RUN           migration.private_anon_thp ...
11208 03:29:54.597572  # # #            OK  migration.private_anon_thp
11209 03:29:54.597951  # # ok 3 migration.private_anon_thp
11210 03:29:54.598487  # # #  RUN           migration.shared_anon_thp ...
11211 03:29:55.011183  # # Didn't migrate 1 pages
11212 03:29:55.011524  # # # migration.c:241:shared_anon_thp:Expected migrate(ptr,
self->n1, self->n2) (-2) == 0 (0)
11213 03:29:55.022519  # # # shared_anon_thp: Test terminated by assertion
11214 03:29:55.022834  # # #          FAIL  migration.shared_anon_thp
11215 03:29:55.027864  # # not ok 4 migration.shared_anon_thp
11216 03:29:55.028156  # # #  RUN           migration.private_anon_htlb ...
11217 03:30:14.595327  # # #            OK  migration.private_anon_htlb
11218 03:30:14.595777  # # ok 5 migration.private_anon_htlb
11219 03:30:14.596398  # # #  RUN           migration.shared_anon_htlb ...
11220 03:30:34.595239  # # #            OK  migration.shared_anon_htlb
11221 03:30:34.595623  # # ok 6 migration.shared_anon_htlb
11222 03:30:34.595859  # # # FAILED: 4 / 6 tests passed.
11223 03:30:34.603816  # # # Totals: pass:4 fail:2 xfail:0 xpass:0 skip:0 error:0
11224 03:30:34.604110  # # [FAIL]
11225 03:30:34.604342  # not ok 55 migration # exit=1

Thanks,
Aishwarya