kernel.git/kernel/workqueue.c, branch linux-6.8.y

workqueue: Fix selection of wake_cpu in kick_pool()

2024-05-17T10:15:02Z

commit 57a01eafdcf78f6da34fad9ff075ed5dfdd9f420 upstream. With cpu_possible_mask=0-63 and cpu_online_mask=0-7 the following kernel oops was observed: smp: Bringing up secondary CPUs ... smp: Brought up 1 node, 8 CPUs Unable to handle kernel pointer dereference in virtual kernel address space Failing address: 0000000000000000 TEID: 0000000000000803 [..] Call Trace: arch_vcpu_is_preempted+0x12/0x80 select_idle_sibling+0x42/0x560 select_task_rq_fair+0x29a/0x3b0 try_to_wake_up+0x38e/0x6e0 kick_pool+0xa4/0x198 __queue_work.part.0+0x2bc/0x3a8 call_timer_fn+0x36/0x160 __run_timers+0x1e2/0x328 __run_timer_base+0x5a/0x88 run_timer_softirq+0x40/0x78 __do_softirq+0x118/0x388 irq_exit_rcu+0xc0/0xd8 do_ext_irq+0xae/0x168 ext_int_handler+0xbe/0xf0 psw_idle_exit+0x0/0xc default_idle_call+0x3c/0x110 do_idle+0xd4/0x158 cpu_startup_entry+0x40/0x48 rest_init+0xc6/0xc8 start_kernel+0x3c4/0x5e0 startup_continue+0x3c/0x50 The crash is caused by calling arch_vcpu_is_preempted() for an offline CPU. To avoid this, select the cpu with cpumask_any_and_distribute() to mask __pod_cpumask with cpu_online_mask. In case no cpu is left in the pool, skip the assignment. tj: This doesn't fully fix the bug as CPUs can still go down between picking the target CPU and the wake call. Fixing that likely requires adding cpu_online() test to either the sched or s390 arch code. However, regardless of how that is fixed, workqueue shouldn't be picking a CPU which isn't online as that would result in unpredictable and worse behavior. Signed-off-by: Sven Schnelle Fixes: 8639ecebc9b1 ("workqueue: Implement non-strict affinity scope for unbound workqueues") Cc: stable@vger.kernel.org # v6.6+ Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman

Revert "workqueue.c: Increase workqueue name length"

2024-04-04T18:25:06Z

This reverts commit 43f0cec175f92c7a01e43d5d6f276262670a97ed which is commit 31c89007285d365aa36f71d8fb0701581c770a27 upstream. The workqueue patches backported to 6.8.y caused some reported regressions, so revert them for now. Reported-by: Thorsten Leemhuis Cc: Tejun Heo Cc: Marek Szyprowski Cc: Nathan Chancellor Cc: Sasha Levin Cc: Audra Mitchell Link: https://lore.kernel.org/all/ce4c2f67-c298-48a0-87a3-f933d646c73b@leemhuis.info/ Signed-off-by: Greg Kroah-Hartman

Revert "workqueue: Move pwq->max_active to wq->max_active"

2024-04-04T18:25:06Z

This reverts commit 0c4ce23e6323e52d0590e78825cd3c63323d7a52 which is commit a045a272d887575da17ad86d6573e82871b50c27 upstream. The workqueue patches backported to 6.8.y caused some reported regressions, so revert them for now. Reported-by: Thorsten Leemhuis Cc: Tejun Heo Cc: Marek Szyprowski Cc: Nathan Chancellor Cc: Sasha Levin Cc: Audra Mitchell Link: https://lore.kernel.org/all/ce4c2f67-c298-48a0-87a3-f933d646c73b@leemhuis.info/ Signed-off-by: Greg Kroah-Hartman

Revert "workqueue: Factor out pwq_is_empty()"

2024-04-04T18:25:06Z

This reverts commit 70abdc2f6c906ffea699f6e0e08fcbd9437e6bcc which is commit afa87ce85379e2d93863fce595afdb5771a84004 upstream. The workqueue patches backported to 6.8.y caused some reported regressions, so revert them for now. Reported-by: Thorsten Leemhuis Cc: Tejun Heo Cc: Marek Szyprowski Cc: Nathan Chancellor Cc: Sasha Levin Cc: Audra Mitchell Link: https://lore.kernel.org/all/ce4c2f67-c298-48a0-87a3-f933d646c73b@leemhuis.info/ Signed-off-by: Greg Kroah-Hartman

Revert "workqueue: Replace pwq_activate_inactive_work() with [__]pwq_activate_work()"

2024-04-04T18:25:06Z

This reverts commit f4505c2033ad25839f6fd9be6fc474b8306c44eb which is commit 4c6380305d21e36581b451f7337a36c93b64e050 upstream. The workqueue patches backported to 6.8.y caused some reported regressions, so revert them for now. Reported-by: Thorsten Leemhuis Cc: Tejun Heo Cc: Marek Szyprowski Cc: Nathan Chancellor Cc: Sasha Levin Cc: Audra Mitchell Link: https://lore.kernel.org/all/ce4c2f67-c298-48a0-87a3-f933d646c73b@leemhuis.info/ Signed-off-by: Greg Kroah-Hartman

Revert "workqueue: Move nr_active handling into helpers"

2024-04-04T18:25:05Z

This reverts commit 6584970ff38fc8f875c683dbb47bb38d4132a528 which is commit 1c270b79ce0b8290f146255ea9057243f6dd3c17 upstream. The workqueue patches backported to 6.8.y caused some reported regressions, so revert them for now. Reported-by: Thorsten Leemhuis Cc: Tejun Heo Cc: Marek Szyprowski Cc: Nathan Chancellor Cc: Sasha Levin Cc: Audra Mitchell Link: https://lore.kernel.org/all/ce4c2f67-c298-48a0-87a3-f933d646c73b@leemhuis.info/ Signed-off-by: Greg Kroah-Hartman

Revert "workqueue: Make wq_adjust_max_active() round-robin pwqs while activating"

2024-04-04T18:25:05Z

This reverts commit ddb232dc0f1339f9ed506730fd6bee6f5e3dcb37 which is commit c5404d4e6df6faba1007544b5f4e62c7c14416dd upstream. The workqueue patches backported to 6.8.y caused some reported regressions, so revert them for now. Reported-by: Thorsten Leemhuis Cc: Tejun Heo Cc: Marek Szyprowski Cc: Nathan Chancellor Cc: Sasha Levin Cc: Audra Mitchell Link: https://lore.kernel.org/all/ce4c2f67-c298-48a0-87a3-f933d646c73b@leemhuis.info/ Signed-off-by: Greg Kroah-Hartman

Revert "workqueue: RCU protect wq->dfl_pwq and implement accessors for it"

2024-04-04T18:25:05Z

This reverts commit 3fb5dbc8bb3759ad0a82d6bf5ed32866c0410a79 which is commit 9f66cff212bb3c1cd25996aaa0dfd0c9e9d8baab upstream. The workqueue patches backported to 6.8.y caused some reported regressions, so revert them for now. Reported-by: Thorsten Leemhuis Cc: Tejun Heo Cc: Marek Szyprowski Cc: Nathan Chancellor Cc: Sasha Levin Cc: Audra Mitchell Link: https://lore.kernel.org/all/ce4c2f67-c298-48a0-87a3-f933d646c73b@leemhuis.info/ Signed-off-by: Greg Kroah-Hartman

Revert "workqueue: Introduce struct wq_node_nr_active"

2024-04-04T18:25:05Z

This reverts commit 7a5cd14a4900e0017142ad479ba8e34671822fc6 which is commit 91ccc6e7233bb10a9c176aa4cc70d6f432a441a5 upstream. The workqueue patches backported to 6.8.y caused some reported regressions, so revert them for now. Reported-by: Thorsten Leemhuis Cc: Tejun Heo Cc: Marek Szyprowski Cc: Nathan Chancellor Cc: Sasha Levin Cc: Audra Mitchell Link: https://lore.kernel.org/all/ce4c2f67-c298-48a0-87a3-f933d646c73b@leemhuis.info/ Signed-off-by: Greg Kroah-Hartman

Revert "workqueue: Implement system-wide nr_active enforcement for unbound workqueues"

2024-04-04T18:25:05Z

This reverts commit 843288afd3cc6f3342659c6cf81fc47684d25563 which is commit 5797b1c18919cd9c289ded7954383e499f729ce0 upstream. The workqueue patches backported to 6.8.y caused some reported regressions, so revert them for now. Reported-by: Thorsten Leemhuis Cc: Tejun Heo Cc: Marek Szyprowski Cc: Nathan Chancellor Cc: Sasha Levin Cc: Audra Mitchell Link: https://lore.kernel.org/all/ce4c2f67-c298-48a0-87a3-f933d646c73b@leemhuis.info/ Signed-off-by: Greg Kroah-Hartman