Re: NULL pointer dereference with MD write-back journal, where journal device is RAID-1

[Yu Kuai <yukuai1@huaweicloud.com>]

Hi,

在 2023/08/07 10:09, Corey Hickey 写道:
> On 2023-08-06 18:02, Yu Kuai wrote:
>>> Here are the errors reported by the kernel:
>>> --------------------------------------------------------------------
>>> [ 2566.222104] BUG: kernel NULL pointer dereference, address:
>>> 0000000000000157
>>> [ 2566.222111] #PF: supervisor read access in kernel mode
>>> [ 2566.222114] #PF: error_code(0x0000) - not-present page
>>> [ 2566.222117] PGD 0 P4D 0
>>> [ 2566.222121] Oops: 0000 [#1] PREEMPT SMP NOPTI
>>> [ 2566.222125] CPU: 1 PID: 5415 Comm: md10_raid5 Not tainted 6.4.8 #3
>>> [ 2566.222129] Hardware name: ASUS System Product Name/ROG CROSSHAIR VII
>>> HERO (WI-FI), BIOS 4603 09/13/2021
>>> [ 2566.222132] RIP: 0010:submit_bio_noacct+0x182/0x5c0
>>
>> Can you provide addr2line result? This will be helpful to locate the
>> problem.
> 
> I have not done this before; I struggled a bit until I found this:
> https://lwn.net/Articles/592724/
> 
> These are run within the kernel source tree, which I have not
> modified since the original compilation.
> 
> 
> $ scripts/decode_stacktrace.sh vmlinux < /tmp/trace1
> [ 2566.222171] ? __die (arch/x86/kernel/dumpstack.c:421 
> arch/x86/kernel/dumpstack.c:434)
> [ 2566.222176] ? page_fault_oops (arch/x86/mm/fault.c:707)
> [ 2566.222180] ? update_load_avg (kernel/sched/fair.c:3920 
> kernel/sched/fair.c:4255)
> [ 2566.222185] ? exc_page_fault (./arch/x86/include/asm/paravirt.h:695 
> arch/x86/mm/fault.c:1494 arch/x86/mm/fault.c:1542)
> [ 2566.222190] ? asm_exc_page_fault (./arch/x86/include/asm/idtentry.h:570)
> [ 2566.222196] ? submit_bio_noacct (block/blk-throttle.h:198 
> block/blk-throttle.h:210 block/blk-core.c:800)
> [ 2566.222201] handle_active_stripes.isra.0 (drivers/md/raid5.c:6709 
> (discriminator 1)) raid456
> [ 2566.222220] raid5d (drivers/md/raid5.c:6821) raid456
> [ 2566.222234] ? __schedule (kernel/sched/core.c:6677)
> [ 2566.222240] ? _raw_spin_lock_irqsave 
> (./arch/x86/include/asm/atomic.h:202 (discriminator 4) 
> ./include/linux/atomic/atomic-instrumented.h:543 (discriminator 4) 
> ./include/asm-generic/qspinlock.h:111 (discriminator 4) 
> ./include/linux/spinlock.h:186 (discriminator 4) 
> ./include/linux/spinlock_api_smp.h:111 (discriminator 4) 
> kernel/locking/spinlock.c:162 (discriminator 4))
> [ 2566.222245] ? preempt_count_add (./include/linux/ftrace.h:976 
> kernel/sched/core.c:5793 kernel/sched/core.c:5790 kernel/sched/core.c:5818)
> [ 2566.222248] ? _raw_spin_lock_irqsave 
> (./arch/x86/include/asm/atomic.h:202 (discriminator 4) 
> ./include/linux/atomic/atomic-instrumented.h:543 (discriminator 4) 
> ./include/asm-generic/qspinlock.h:111 (discriminator 4) 
> ./include/linux/spinlock.h:186 (discriminator 4) 
> ./include/linux/spinlock_api_smp.h:111 (discriminator 4) 
> kernel/locking/spinlock.c:162 (discriminator 4))
> [ 2566.222254] ? __pfx_md_thread (drivers/md/md.c:7862) md_mod
> [ 2566.222273] md_thread (drivers/md/md.c:7898) md_mod
> [ 2566.222293] ? __pfx_autoremove_wake_function (kernel/sched/wait.c:418)
> [ 2566.222299] kthread (kernel/kthread.c:379)
> [ 2566.222304] ? __pfx_kthread (kernel/kthread.c:332)
> [ 2566.222309] ret_from_fork (arch/x86/entry/entry_64.S:314)
> 
> 
> 
> $ scripts/decode_stacktrace.sh vmlinux < /tmp/trace2
> [ 2566.436288] ? do_exit (kernel/exit.c:818 (discriminator 1))
> [ 2566.436292] ? __warn (kernel/panic.c:673)
> [ 2566.436298] ? do_exit (kernel/exit.c:818 (discriminator 1))
> [ 2566.436301] ? report_bug (lib/bug.c:180 lib/bug.c:219)
> [ 2566.436308] ? handle_bug (arch/x86/kernel/traps.c:303)
> [ 2566.436312] ? exc_invalid_op (arch/x86/kernel/traps.c:345 
> (discriminator 1))
> [ 2566.436316] ? asm_exc_invalid_op (./arch/x86/include/asm/idtentry.h:568)
> [ 2566.436321] ? do_exit (kernel/exit.c:818 (discriminator 1))
> [ 2566.436325] ? do_exit (kernel/exit.c:818 (discriminator 1))
> [ 2566.436329] make_task_dead (kernel/exit.c:972)
> [ 2566.436333] rewind_stack_and_make_dead (??:?)
> 
> 
> 
> Is that what you are looking for?

Yes, and can you provide witch commit are you testing?

Thanks,
Kuai
> 
> Thanks,
> Corey
> .
>