Re: [lkp] [sched/core] 3d26b7622f: BUG: unable to handle kernel NULL pointer dereference at 00000001

From: Ye Xiaolong
Date: Thu Sep 08 2016 - 22:30:17 EST

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In reply to: chengchao: "Re: [lkp] [sched/core] 3d26b7622f: BUG: unable to handle kernel NULL pointer dereference at 00000001"
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Hi, cheng hao,

On 09/09, chengchao wrote:
>Hi, xiaolong
>
> where can I find the commit 3d26b7622f3bab689696900ffd33c6dd7849d7c2?

This is the commit by 0Day bot for your original email patch sent on Sep 05 where
both CONFIG_PREEMPT_NONE and CONFIG_PREEMPT_VOLUNTARY will turn the
logic on.

+/**
+ * the caller keeps task_on_rq_queued, so it's more suitable for
+ * sched_exec on the case when needs migration
+ */
+void stop_one_cpu_sync(unsigned int cpu, cpu_stop_fn_t fn, void *arg)
+{
+ struct cpu_stop_work work = { .fn = fn, .arg = arg, .done = NULL };
+
+ if (!cpu_stop_queue_work(cpu, &work))
+ return;
+
+#if defined(CONFIG_PREEMPT_NONE) || defined(CONFIG_PREEMPT_VOLUNTARY)
+ /*
+ * CONFIG_PREEMPT doesn't need call schedule here, because
+ * preempt_enable already does the similar thing when call
+ * cpu_stop_queue_work
+ */
+ schedule();
+#endif
+}
+

> config-4.8.0-rc5-00001-g3d26b76:
># CONFIG_PREEMPT_NONE is not set
>CONFIG_PREEMPT_VOLUNTARY=y
># CONFIG_PREEMPT is not set
>
> the patch ("sched/core: simpler function for sched_exec migration") only is on if CONFIG_PREEMPT_NONE=y,
>so it doesn't cause the panic when CONFIG_PREEMPT_VOLUNTARY=y.
>
>
>the latest patch is here:
>https://lkml.org/lkml/2016/9/7/819

Will you send a formal updated patch to LKML? Then 0day will auto capture
and test it.

Thanks,
Xiaolong

>
>int stop_one_cpu(unsigned int cpu, cpu_stop_fn_t fn, void *arg)
>{
> struct cpu_stop_done done;
> struct cpu_stop_work work = { .fn = fn, .arg = arg, .done = &done };
>
> cpu_stop_init_done(&done, 1);
> if (!cpu_stop_queue_work(cpu, &work))
> return -ENOENT;
>
>+#if defined(CONFIG_PREEMPT_NONE)
>+ /*
>+ * let the stopper thread runs as soon as possible,
>+ * and keep current TASK_RUNNING.
>+ */
>+ scheudle();
>+#endif
> wait_for_completion(&done.completion);
> return done.ret;
>}
>
>Thanks,
>Cheng
>
>on 09/09/2016 09:39 AM, kernel test robot wrote:
>>
>> FYI, we noticed the following commit:
>>
>> https://github.com/0day-ci/linux cheng-chao/sched-core-simpler-function-for-sched_exec-migration/20160905-142452
>> commit 3d26b7622f3bab689696900ffd33c6dd7849d7c2 ("sched/core: simpler function for sched_exec migration")
>>
>> in testcase: trinity
>> with following parameters:
>>
>> runtime: 300s
>>
>>
>>
>>
>> on test machine: qemu-system-i386 -enable-kvm -smp 2 -m 320M
>>
>> caused below changes:
>>
>>
>> +------------------------------------------------------------------+----------+------------+
>> | | v4.8-rc5 | 3d26b7622f |
>> +------------------------------------------------------------------+----------+------------+
>> | boot_successes | 2271 | 473 |
>> | boot_failures | 248 | 654 |
>> | genirq:Flags_mismatch_irq##(serial)vs.#(goldfish_pdev_bus) | 248 | 654 |
>> | calltrace:SyS_open | 248 | 654 |
>> | invoked_oom-killer:gfp_mask=0x | 33 | 32 |
>> | Mem-Info | 33 | 32 |
>> | BUG:kernel_reboot-without-warning_in_test_stage | 210 | 8 |
>> | genirq:Flags_mismatch_irq | 1 | |
>> | genirq:Flags_mismatch_irq##(ser | 1 | |
>> | genirq:Flags_mismatch_irq##(serial)vs | 1 | |
>> | genirq:Flags_mismatch_irq##(serial)vs.#(goldfi | 1 | |
>> | genirq:Flags_mismatch_irq##(serial)vs.#(goldfish_pdev_bu | 1 | |
>> | warn_alloc_failed+0x | 1 | |
>> | Out_of_memory:Kill_process | 1 | 4 |
>> | BUG:unable_to_handle_kernel | 0 | 533 |
>> | Oops | 0 | 533 |
>> | calltrace:smpboot_thread_fn | 0 | 593 |
>> | kernel_BUG_at_mm/slub.c | 0 | 531 |
>> | invalid_opcode:#[##]SMP | 0 | 536 |
>> | EIP_is_at_kfree | 0 | 531 |
>> | calltrace:SyS_execve | 0 | 533 |
>> | Kernel_panic-not_syncing:Fatal_exception | 0 | 613 |
>> | WARNING:at_arch/x86/kernel/traps.c:#do_debug | 0 | 86 |
>> | general_protection_fault:#[##]SMP | 0 | 20 |
>> | EIP_is_at.brk.pagetables | 0 | 1 |
>> | EIP_is_at_do_execveat_common | 0 | 1 |
>> | EIP_is_at_copy_strings | 0 | 1 |
>> | bounds:#[##]SMP | 0 | 2 |
>> | PANIC:double_fault | 0 | 2 |
>> | EIP_is_at_elf_format | 0 | 1 |
>> | general_protection_fault:#d34[##]SMP | 0 | 1 |
>> | EIP_is_at__lock_acquire | 0 | 3 |
>> | Kernel_panic-not_syncing:Out_of_memory_and_no_killable_processes | 0 | 1 |
>> | WARNING:at_kernel/sched/core.c:#__might_sleep | 0 | 2 |
>> | EIP_is_at_unlink_anon_vmas | 0 | 2 |
>> | BUG:Bad_rss-counter_state_mm:#idx:#val | 0 | 1 |
>> | BUG:non-zero_nr_ptes_on_freeing_mm | 0 | 1 |
>> | EIP_is_at_cpu_stopper_thread | 0 | 2 |
>> | genirq:Flags_mismatch_irq##(serial)vs.#(goldfish_pdev | 0 | 1 |
>> +------------------------------------------------------------------+----------+------------+
>>
>> [ 22.622360] BUG: unable to handle kernel NULL pointer dereference at 00000001
>> [ 22.623553] IP: [<5128c004>] 0x5128c004
>> [ 22.624210] *pde = 00000000
>> [ 22.624698] Oops: 0000 [#1] SMP
>> [ 22.625223] Modules linked in:
>> [ 22.625638] CPU: 1 PID: 15 Comm: migration/1 Not tainted 4.8.0-rc5-00001-g3d26b76 #1
>> [ 22.625638] task: 530910c0 task.stack: 5309a000
>> [ 22.625638] EIP: 0060:[<5128c004>] EFLAGS: 00010246 CPU: 1
>> [ 22.625638] EIP is at 0x5128c004
>> [ 22.625638] EAX: 00000001 EBX: 53790280 ECX: 00000000 EDX: 00000001
>> [ 22.625638] ESI: 5128c000 EDI: 41765d34 EBP: 5309bf04 ESP: 5309bee4
>> [ 22.625638] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
>> [ 22.625638] CR0: 80050033 CR2: 00000001 CR3: 01950000 CR4: 00000690
>> [ 22.625638] Stack:
>> [ 22.625638] 53790280 410c5173 00000001 537902b0 53790284 530910c0 530023c0 41761ca0
>> [ 22.625638] 5309bf1c 410543d3 00000000 5301da60 530023c0 410542e0 5309bfa4 410513e0
>> [ 22.625638] 00000001 00000001 530023c0 00000000 00000000 dead4ead ffffffff ffffffff
>> [ 22.625638] Call Trace:
>> [ 22.625638] [<410c5173>] ? cpu_stopper_thread+0x73/0xf0
>> [ 22.625638] [<410543d3>] smpboot_thread_fn+0xf3/0x1e0
>> [ 22.625638] [<410542e0>] ? sort_range+0x20/0x20
>> [ 22.625638] [<410513e0>] kthread+0xa0/0xc0
>> [ 22.625638] [<41543e46>] ? wait_for_common+0xa6/0x150
>> [ 22.625638] [<415483e2>] ret_from_kernel_thread+0xe/0x24
>> [ 22.625638] [<41051340>] ? kthread_create_on_node+0x160/0x160
>> [ 22.625638] Code: 00 00 00 95 a1 7c 37 73 00 00 00 46 02 00 00 6c f5 bd 3f 7b 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 80 e4 1a 53 <02> 00 00 00 00 00 00 00 00 00 00 00 9d 6e ac 57 6c 6b 70 2f 6c
>> [ 22.625638] EIP: [<5128c004>] 0x5128c004 SS:ESP 0068:5309bee4
>> [ 22.625638] CR2: 0000000000000001
>> [ 22.625638] ---[ end trace d07782e5cdd90364 ]---
>> [ 22.623351] ------------[ cut here ]------------
>> [ 22.623351] kernel BUG at mm/slub.c:3851!
>> [ 22.623351] invalid opcode: 0000 [#2] SMP
>> [ 22.623351] Modules linked in:
>> [ 22.623351] CPU: 0 PID: 267 Comm: sh Tainted: G D 4.8.0-rc5-00001-g3d26b76 #1
>> [ 22.623351] task: 531ae480 task.stack: 5128c000
>> [ 22.623351] EIP: 0060:[<411268d3>] EFLAGS: 00010246 CPU: 0
>> [ 22.623351] EIP is at kfree+0x193/0x1a0
>> [ 22.623351] EAX: 00000000 EBX: 539cc1a0 ECX: 00000000 EDX: 00000000
>> [ 22.623351] ESI: 37740000 EDI: 5128df08 EBP: 5128dec4 ESP: 5128deb0
>> [ 22.623351] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
>> [ 22.623351] CR0: 80050033 CR2: 377d358c CR3: 125e6000 CR4: 00000690
>> [ 22.623351] Stack:
>> [ 22.623351] 377d4000 00002000 530aee00 37740000 525e0480 5128df24 41184169 530aee00
>> [ 22.623351] 00000000 00000005 00000000 00000000 00000000 000930a0 00000000 00000000
>> [ 22.623351] ffffffff 377d5608 00000001 377a61bf 5140f300 520ca8c0 5128df08 5128df08
>> [ 22.623351] Call Trace:
>> [ 22.623351] [<41184169>] load_elf_binary+0xb69/0xbc0
>> [ 22.623351] [<4113ddf2>] search_binary_handler+0x62/0x1a0
>> [ 22.623351] [<4113e4f3>] do_execveat_common+0x5c3/0x760
>> [ 22.623351] [<4113e8ff>] SyS_execve+0x1f/0x30
>> [ 22.623351] [<410012a5>] do_int80_syscall_32+0x45/0x110
>> [ 22.623351] [<415484d0>] entry_INT80_32+0x2c/0x2c
>> [ 22.623351] Code: ff 40 18 eb b6 8d 76 00 6a 01 57 89 da 89 f0 89 f9 e8 12 fb ff ff 58 5a eb a1 8d b6 00 00 00 00 8b 43 14 a8 01 0f 85 7c ff ff ff <0f> 0b 8d 74 26 00 8d bc 27 00 00 00 00 55 89 e5 57 56 53 89 d7
>> [ 22.623351] EIP: [<411268d3>] kfree+0x193/0x1a0 SS:ESP 0068:5128deb0
>> [ 22.651614] ---[ end trace d07782e5cdd90365 ]---
>> [ 22.651616] Kernel panic - not syncing: Fatal exception
>> [ 22.654918] Shutting down cpus with NMI
>> [ 22.654918] Kernel Offset: disabled
>>
>>
>>
>> To reproduce:
>>
>> git clone git://git.kernel.org/pub/scm/linux/kernel/git/wfg/lkp-tests.git
>> cd lkp-tests
>> bin/lkp install job.yaml # job file is attached in this email
>> bin/lkp run job.yaml
>>
>>
>>
>> Thanks,
>> Xiaolong
>>

Next message: Rob Herring: "Re: [PATCH] dt-binding: remoteproc: Document generic properties"
Previous message: Rob Herring: "Re: [PATCH] of: Overlay manager"
In reply to: chengchao: "Re: [lkp] [sched/core] 3d26b7622f: BUG: unable to handle kernel NULL pointer dereference at 00000001"
Next in thread: chengchao: "Re: [lkp] [sched/core] 3d26b7622f: BUG: unable to handle kernel NULL pointer dereference at 00000001"
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