On 10/27/22 14:07, Steven Rostedt wrote:
On Thu, 27 Oct 2022 16:34:53 -0400
Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
What about del_timer_try_shutdown(), that if it removes the timer, it sets
the function to NULL (making it equivalent to a successful shutdown),
otherwise it does nothing. Allowing the the timer to be rearmed.
I think this would work in this case.
Guenter,
Can you apply this patch on top of the series, and see if it makes the
warning go away?
That patch not only helps, it also fixes the crash seen with openrisc.
For that crash, I was able to collect some useful data; see the log below.
Thanks,
Guenter
---
WARNING: CPU: 0 PID: 7 at lib/debugobjects.c:502 debug_print_object+0xc0/0xe8
ODEBUG: free active (active state 0) object type: timer_list hint: rcu_lock_map+0x0/0x14
Modules linked in:
CPU: 0 PID: 7 Comm: ksoftirqd/0 Not tainted 6.1.0-rc2-00145-g2c4e85e9ac93 #1
Call trace:
[<048ecc8e>] dump_stack_lvl+0x44/0x80
[<c6a7029c>] dump_stack+0x1c/0x2c
[<b225e4eb>] __warn+0xdc/0x118
[<1070b766>] ? debug_print_object+0xc0/0xe8
[<57923a76>] warn_slowpath_fmt+0x78/0x90
[<1070b766>] debug_print_object+0xc0/0xe8
[<b3abbcb0>] __debug_check_no_obj_freed+0x230/0x2b8
[<508d9b5a>] ? delayed_put_task_struct+0x0/0x84
[<30f5a2a0>] ? _s_kernel_ro+0x0/0x200
[<403ab082>] debug_check_no_obj_freed+0x30/0x40
[<82702c56>] free_pcp_prepare+0xc4/0x2b0
[<508d9b5a>] ? delayed_put_task_struct+0x0/0x84
[<7798b190>] free_unref_page+0x44/0x210
[<d73717e5>] __free_pages+0x108/0x124
[<a32de4eb>] slob_free_pages+0x9c/0xac
[<bd51c171>] slob_free+0x40c/0x62c
[<a2d26e0e>] ? thread_stack_free_rcu+0x0/0x44
[<24b2df6c>] ? rcu_process_callbacks+0x114/0x224
[<24b2df6c>] ? rcu_process_callbacks+0x114/0x224
[<7794ec75>] ? rcu_process_callbacks+0xdc/0x224
[<7794ec75>] ? rcu_process_callbacks+0xdc/0x224
[<d76fe88f>] kmem_cache_free+0x64/0xa0
[<46d25dac>] free_task+0x7c/0xe0
[<2df25813>] __put_task_struct+0xe8/0x194
[<64f9675b>] delayed_put_task_struct+0x58/0x84
[<8755437e>] rcu_process_callbacks+0xf0/0x224
[<24b2df6c>] ? rcu_process_callbacks+0x114/0x224
[<020db442>] ? rcu_process_callbacks+0x178/0x224
[<87626af4>] __do_softirq+0x11c/0x2f8
[<c3f89a50>] ? smpboot_thread_fn+0x4c/0x304
[<c3f89a50>] ? smpboot_thread_fn+0x4c/0x304
[<021b0175>] ? smpboot_thread_fn+0x188/0x304
[<f2e79ebd>] ? smpboot_thread_fn+0x158/0x304
[<966be0e6>] run_ksoftirqd+0x4c/0x80
[<4bf65f60>] smpboot_thread_fn+0x180/0x304
[<3f914d93>] ? _raw_spin_unlock_irqrestore+0x50/0x84
[<bef37779>] ? __kthread_parkme+0x60/0xdc
[<b0798e10>] ? smpboot_thread_fn+0x0/0x304
[<c463cd92>] kthread+0x11c/0x144
[<3eaef0b7>] ? kthread+0x0/0x144
[<ef2f6228>] ret_from_fork+0x1c/0x84
---[ end trace 0000000000000000 ]---
Unable to handle kernel access
at virtual address 0xbd6ed6a4
Oops#: 0000
CPU #: 0
PC: c0056c78 SR: 00008679 SP: c1027c24
GPR00: 00000000 GPR01: c1027c24 GPR02: c1027c78 GPR03: 00008279
GPR04: 00000000 GPR05: 00000000 GPR06: 00000000 GPR07: 00000001
GPR08: 00000000 GPR09: c0056c64 GPR10: c1026000 GPR11: 00000000
GPR12: 00000000 GPR13: 00000001 GPR14: c05c0000 GPR15: 00000000
GPR16: 00000001 GPR17: bd6ed6a4 GPR18: ff4517b0 GPR19: fd145f00
GPR20: 00000000 GPR21: 00000000 GPR22: 00000000 GPR23: c0760000
GPR24: c10232a0 GPR25: 00000003 GPR26: 00000000 GPR27: 00000000
GPR28: c1a00458 GPR29: 00000000 GPR30: c0790000 GPR31: 00000000
RES: 00000000 oGPR11: ffffffff
Process ksoftirqd/0 (pid: 7, stackpage=c10232a0)
Stack:
Call trace:
[<6ce5cfad>] __lock_acquire.constprop.0+0xa8/0x914
[<4bc14e12>] ? __del_timer_sync+0x0/0x128
[<da915c87>] lock_acquire.part.0.isra.0+0xd4/0x1ac
[<4bc14e12>] ? __del_timer_sync+0x0/0x128
[<9b341df3>] lock_acquire+0x2c/0x44
[<233b5cbc>] __del_timer_sync+0x64/0x128
[<4bc14e12>] ? __del_timer_sync+0x0/0x128
[<05cd2741>] timer_fixup_free+0x34/0x5c
[<3fa496ad>] __debug_check_no_obj_freed+0x250/0x2b8
[<508d9b5a>] ? delayed_put_task_struct+0x0/0x84
[<30f5a2a0>] ? _s_kernel_ro+0x0/0x200
[<403ab082>] debug_check_no_obj_freed+0x30/0x40
[<82702c56>] free_pcp_prepare+0xc4/0x2b0
[<508d9b5a>] ? delayed_put_task_struct+0x0/0x84
[<7798b190>] free_unref_page+0x44/0x210
[<d73717e5>] __free_pages+0x108/0x124
[<a32de4eb>] slob_free_pages+0x9c/0xac
[<bd51c171>] slob_free+0x40c/0x62c
[<a2d26e0e>] ? thread_stack_free_rcu+0x0/0x44
[<24b2df6c>] ? rcu_process_callbacks+0x114/0x224
[<24b2df6c>] ? rcu_process_callbacks+0x114/0x224
[<7794ec75>] ? rcu_process_callbacks+0xdc/0x224
[<7794ec75>] ? rcu_process_callbacks+0xdc/0x224
[<d76fe88f>] kmem_cache_free+0x64/0xa0
[<46d25dac>] free_task+0x7c/0xe0
[<2df25813>] __put_task_struct+0xe8/0x194
[<64f9675b>] delayed_put_task_struct+0x58/0x84
[<8755437e>] rcu_process_callbacks+0xf0/0x224
[<24b2df6c>] ? rcu_process_callbacks+0x114/0x224
[<020db442>] ? rcu_process_callbacks+0x178/0x224
[<87626af4>] __do_softirq+0x11c/0x2f8
[<c3f89a50>] ? smpboot_thread_fn+0x4c/0x304
[<c3f89a50>] ? smpboot_thread_fn+0x4c/0x304
[<021b0175>] ? smpboot_thread_fn+0x188/0x304
[<f2e79ebd>] ? smpboot_thread_fn+0x158/0x304
[<966be0e6>] run_ksoftirqd+0x4c/0x80
[<4bf65f60>] smpboot_thread_fn+0x180/0x304
[<3f914d93>] ? _raw_spin_unlock_irqrestore+0x50/0x84
[<bef37779>] ? __kthread_parkme+0x60/0xdc
[<b0798e10>] ? smpboot_thread_fn+0x0/0x304
[<c463cd92>] kthread+0x11c/0x144
[<3eaef0b7>] ? kthread+0x0/0x144
[<ef2f6228>] ret_from_fork+0x1c/0x84
