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From: Finn Thain <fthain@linux-m68k.org>
To: Michael Schmitz <schmitzmic@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
	 Guenter Roeck <linux@roeck-us.net>,
	linux-m68k@lists.linux-m68k.org
Subject: Re: spinlock recursion when running q800 emulation in qemu
Date: Fri, 15 Mar 2024 18:24:01 +1100 (AEDT)	[thread overview]
Message-ID: <614a23eb-6220-8fe2-a641-bd00baba6f9d@linux-m68k.org> (raw)
In-Reply-To: <45c98c27-6839-7e11-9cde-c9a1805234f5@gmail.com>


On Fri, 15 Mar 2024, Michael Schmitz wrote:

> 
> No luck with whatever I tried around signals, cache maintenance and mm.
> 
> The 'BUG: Bad rss-counter state' message suggests we're freeing the same 
> page ranges twice, sometimes in many cases. I cannot quite see how 
> preempting the kernel on interupt return would cause this. Signal 
> forcing process exit but process exiting before signal is received due 
> to preemption? But skipping preemption when a signal is pending did not 
> change anything in my tests...
> 
> Running out of ideas here, sorry.
> 

FWIW, I found that the failure mode (with CONFIG_PREEMPT) changed 
significantly after I disabled hard irqs in do_IRQ() using the patch I 
sent on the 8th. In three stress-ng test runs, I got a soft lockup, a WARN 
from set_fc() and some CONFIG_DEBUG_LIST failures...

# /root/stress-ng -t 60 --zombie -1 
stress-ng: info:  [46] setting to a 60 second run per stressor
stress-ng: info:  [46] dispatching hogs: 1 zombie
[   29.670000] ------------[ cut here ]------------
[   29.670000] WARNING: CPU: 0 PID: 0 at arch/m68k/include/asm/processor.h:92 buserr_c+0x486/0x5ba
[   29.670000] Modules linked in:
[   29.670000] CPU: 0 PID: 0 Comm: swapper Not tainted 6.8.0-rc7-mac-00234-g138ba0024ff0 #9
[   29.670000] Stack from 00583c20:
[   29.670000]         00583c20 0054af2c 0054af2c 00000000 006e0100 00583c40 004980b6 0054af2c
[   29.670000]         00583c54 00492ff6 00000505 0059ff94 0b46005f 00583c84 0001c73e 0053a3bc
[   29.670000]         0000005c 000061b6 00000009 00000000 00000000 00000505 00583cc8 00696ef0
[   29.670000]         008dc490 00583cbc 000061b6 0053a3bc 0000005c 00000009 00000000 00000000
[   29.670000]         006eee78 00002ff5 00000008 00000001 005b0b4c 006eee74 02d61260 00583d34
[   29.670000]         000026b4 00583cc8 006eee78 00000000 006eee78 00002ff5 00000008 005b0b4c
[   29.670000] Call Trace: [<004980b6>] dump_stack+0x10/0x16
[   29.670000]  [<00492ff6>] __warn+0x90/0xb6
[   29.670000]  [<0001c73e>] warn_slowpath_fmt+0x10e/0x1a4
[   29.670000]  [<000061b6>] buserr_c+0x486/0x5ba
[   29.670000]  [<000061b6>] buserr_c+0x486/0x5ba
[   29.670000]  [<00002ff5>] __get_wchan+0x4d/0x58
[   29.670000]  [<000026b4>] buserr+0x20/0x28
[   29.670000]  [<00002ff5>] __get_wchan+0x4d/0x58
[   29.670000]  [<000ea558>] __free_one_page+0x2ec/0x532
[   29.670000]  [<000ea8bc>] free_pcppages_bulk+0x11e/0x18a
[   29.670000]  [<00002ff5>] __get_wchan+0x4d/0x58
[   29.670000]  [<00002700>] ret_from_kernel_thread+0xc/0x14
[   29.670000]  [<000eaa86>] free_unref_page_commit+0x15e/0x314
[   29.670000]  [<00002ce0>] show_regs+0x48/0xb8
[   29.670000]  [<00002004>] _start+0x4/0x8
[   29.670000]  [<000ed452>] free_unref_page+0x12a/0x190
[   29.670000]  [<00065be4>] rcu_cblist_dequeue+0x0/0x28
[   29.670000]  [<000ed648>] __free_pages+0xb4/0x10c
[   29.670000]  [<00018340>] thread_stack_free_rcu+0x3a/0x44
[   29.670000]  [<0006436c>] rcu_core+0x2c2/0x79e
[   29.670000]  [<00054fda>] handle_irq_event+0x7a/0x90
[   29.670000]  [<00064928>] rcu_core_si+0x8/0xc
[   29.670000]  [<0049952c>] __do_softirq+0xa4/0x1f8
[   29.670000]  [<00492600>] memmove+0x8c/0xe0
[   29.670000]  [<00038196>] parse_args+0x0/0x3a6
[   29.670000]  [<000485f8>] arch_cpu_idle_exit+0x0/0x8
[   29.670000]  [<000485f0>] arch_cpu_idle_enter+0x0/0x8
[   29.670000]  [<0001fee6>] irq_exit+0x44/0x4e
[   29.670000]  [<00002986>] do_IRQ+0x32/0x6c
[   29.670000]  [<00498cf8>] cpu_idle_poll.isra.0+0x0/0x6e
[   29.670000]  [<00498d66>] default_idle_call+0x0/0x46
[   29.670000]  [<00002874>] auto_irqhandler_fixup+0x4/0xc
[   29.670000]  [<00498cf8>] cpu_idle_poll.isra.0+0x0/0x6e
[   29.670000]  [<00498d66>] default_idle_call+0x0/0x46
[   29.670000]  [<00498d88>] default_idle_call+0x22/0x46
[   29.670000]  [<00048680>] do_idle+0x6a/0xf0
[   29.670000]  [<00048616>] do_idle+0x0/0xf0
[   29.670000]  [<00036742>] find_task_by_pid_ns+0x0/0x2a
[   29.670000]  [<0005cfd4>] __rcu_read_lock+0x0/0x12
[   29.670000]  [<000489cc>] cpu_startup_entry+0x1a/0x1c
[   29.670000]  [<00063976>] __rcu_read_unlock+0x0/0x26
[   29.670000]  [<00498e4a>] kernel_init+0x0/0xfa
[   29.670000]  [<004897c0>] strcpy+0x0/0x1e
[   29.670000]  [<0049379c>] _printk+0x0/0x16
[   29.670000]  [<00489942>] strlen+0x0/0x22
[   29.670000]  [<0062d2c6>] memblock_alloc_try_nid+0x0/0x82
[   29.670000]  [<0062139a>] arch_post_acpi_subsys_init+0x0/0x8
[   29.670000]  [<00621918>] console_on_rootfs+0x0/0x60
[   29.670000]  [<00620410>] _sinittext+0x410/0xadc
[   29.670000] 
[   29.670000] ---[ end trace 0000000000000000 ]---
[   29.670000] Unable to handle kernel access at virtual address 0b46005f
[   29.670000] Oops: 00000000
[   29.670000] Modules linked in:
[   29.670000] PC: [<002951de>] __list_add_valid_or_report+0x1a/0x102
[   29.670000] SR: 2700  SP: 00583cc8  a2: 00587590
[   29.670000] d0: 000007e0    d1: 006eee78    d2: 00000000    d3: 006eee78
[   29.670000] d4: 00002ff5    d5: 00000008    a0: 005b0b4c    a1: 0b46005b
[   29.670000] Process swapper (pid: 0, task=00587590)
[   29.670000] Frame format=7 eff addr=0b46005f ssw=0505 faddr=0b46005f
[   29.670000] wb 1 stat/addr/data: 0000 00000000 00000000
[   29.670000] wb 2 stat/addr/data: 0000 00000000 00000000
[   29.670000] wb 3 stat/addr/data: 0000 0b46005f 00000000
[   29.670000] push data: 00000000 00000000 00000000 00000000
[   29.670000] Stack from 00583d30:
[   29.670000]         00000000 00583d6c 000ea558 006eee78 005b0b4c 0b46005b 007a5380 00000000
[   29.670000]         0000000f 0000000c 00000005 00000001 006eee78 007a5358 005b2090 00583dc8
[   29.670000]         000ea8bc 006eee74 00002ff5 005b0314 00000000 000000fc 00000000 00000f07
[   29.670000]         00000003 000001ca 000000e0 00000001 006e307c 007a5358 005b0314 00000011
[   29.670000]         006eee74 00000039 00002700 005b04fc 00000000 000000aa 00583e08 000eaa86
[   29.670000]         005b0314 0000004e 007a5358 00000003 00000001 00002ce0 00000000 00000000
[   29.670000] Call Trace: [<000ea558>] __free_one_page+0x2ec/0x532
[   29.670000]  [<000ea8bc>] free_pcppages_bulk+0x11e/0x18a
[   29.670000]  [<00002ff5>] __get_wchan+0x4d/0x58
[   29.670000]  [<00002700>] ret_from_kernel_thread+0xc/0x14
[   29.670000]  [<000eaa86>] free_unref_page_commit+0x15e/0x314
[   29.670000]  [<00002ce0>] show_regs+0x48/0xb8
[   29.670000]  [<00002004>] _start+0x4/0x8
[   29.670000]  [<000ed452>] free_unref_page+0x12a/0x190
[   29.670000]  [<00065be4>] rcu_cblist_dequeue+0x0/0x28
[   29.670000]  [<000ed648>] __free_pages+0xb4/0x10c
[   29.670000]  [<00018340>] thread_stack_free_rcu+0x3a/0x44
[   29.670000]  [<0006436c>] rcu_core+0x2c2/0x79e
[   29.670000]  [<00054fda>] handle_irq_event+0x7a/0x90
[   29.670000]  [<00064928>] rcu_core_si+0x8/0xc
[   29.670000]  [<0049952c>] __do_softirq+0xa4/0x1f8
[   29.670000]  [<00492600>] memmove+0x8c/0xe0
[   29.670000]  [<00038196>] parse_args+0x0/0x3a6
[   29.670000]  [<000485f8>] arch_cpu_idle_exit+0x0/0x8
[   29.670000]  [<000485f0>] arch_cpu_idle_enter+0x0/0x8
[   29.670000]  [<0001fee6>] irq_exit+0x44/0x4e
[   29.670000]  [<00002986>] do_IRQ+0x32/0x6c
[   29.670000]  [<00498cf8>] cpu_idle_poll.isra.0+0x0/0x6e
[   29.670000]  [<00498d66>] default_idle_call+0x0/0x46
[   29.670000]  [<00002874>] auto_irqhandler_fixup+0x4/0xc
[   29.670000]  [<00498cf8>] cpu_idle_poll.isra.0+0x0/0x6e
[   29.670000]  [<00498d66>] default_idle_call+0x0/0x46
[   29.670000]  [<00498d88>] default_idle_call+0x22/0x46
[   29.670000]  [<00048680>] do_idle+0x6a/0xf0
[   29.670000]  [<00048616>] do_idle+0x0/0xf0
[   29.670000]  [<00036742>] find_task_by_pid_ns+0x0/0x2a
[   29.670000]  [<0005cfd4>] __rcu_read_lock+0x0/0x12
[   29.670000]  [<000489cc>] cpu_startup_entry+0x1a/0x1c
[   29.670000]  [<00063976>] __rcu_read_unlock+0x0/0x26
[   29.670000]  [<00498e4a>] kernel_init+0x0/0xfa
[   29.670000]  [<004897c0>] strcpy+0x0/0x1e
[   29.670000]  [<0049379c>] _printk+0x0/0x16
[   29.670000]  [<00489942>] strlen+0x0/0x22
[   29.670000]  [<0062d2c6>] memblock_alloc_try_nid+0x0/0x82
[   29.670000]  [<0062139a>] arch_post_acpi_subsys_init+0x0/0x8
[   29.670000]  [<00621918>] console_on_rootfs+0x0/0x60
[   29.670000]  [<00620410>] _sinittext+0x410/0xadc
[   29.670000] 
[   29.670000] Code: 206e 000c 226e 0010 4a88 6756 4a89 6774 <2029> 0004 b1c0 6600 008e 2410 b3c2 6600 00ae b288 670e 7001 b289 6708 242e fffc
[   29.670000] Disabling lock debugging due to kernel taint
[   29.670000] Kernel panic - not syncing: Aiee, killing interrupt handler!
[   29.670000] ---[ end Kernel panic - not syncing: Aiee, killing interrupt handler! ]---

  reply	other threads:[~2024-03-15  7:22 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-04 17:58 spinlock recursion when running q800 emulation in qemu Guenter Roeck
2024-03-05  0:33 ` Finn Thain
2024-03-05  0:48   ` Michael Schmitz
     [not found]   ` <fcb506f2-523d-4efc-ae3d-fe3c79c6f09e@gmail.com>
2024-03-05  0:58     ` Guenter Roeck
2024-03-05  1:06       ` Michael Schmitz
2024-03-06  7:14 ` Michael Schmitz
2024-03-06  8:30   ` Brad Boyer
2024-03-06 23:13     ` Finn Thain
2024-03-06 23:46       ` Guenter Roeck
2024-03-07 23:35         ` Finn Thain
2024-03-06 23:42     ` Michael Schmitz
2024-03-06 23:52   ` Finn Thain
2024-03-08  0:20     ` Michael Schmitz
2024-03-08  0:56       ` Finn Thain
2024-03-08  8:06         ` Michael Schmitz
2024-03-08  9:15           ` Finn Thain
2024-03-08  9:33             ` Finn Thain
2024-03-08 20:14               ` Michael Schmitz
2024-03-09  5:02                 ` Finn Thain
2024-03-09 20:56                   ` Michael Schmitz
2024-03-09 22:18                     ` Finn Thain
2024-03-11  7:06                       ` Michael Schmitz
2024-03-11  8:35                         ` Finn Thain
2024-03-12  0:51                           ` Michael Schmitz
2024-03-12  7:59                             ` Geert Uytterhoeven
2024-03-12 20:14                               ` Michael Schmitz
2024-03-13  0:16                               ` Michael Schmitz
2024-03-13  4:39                                 ` Preemption (was: Re: spinlock recursion when running q800 emulation in qemu) Michael Schmitz
2024-03-13  4:40                                 ` spinlock recursion when running q800 emulation in qemu Finn Thain
2024-03-13  5:34                                   ` Michael Schmitz
2024-03-14  0:59                                   ` Michael Schmitz
2024-03-15  4:32                                     ` Michael Schmitz
2024-03-15  7:24                                       ` Finn Thain [this message]
2024-03-18  6:24                                         ` Michael Schmitz
2024-03-18  9:31                                           ` Finn Thain
2024-03-20  1:00                                             ` Michael Schmitz

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