On Fri, Jun 19, 2015 at 10:36:20AM -0700, Luck, Tony wrote:
> 96d98bfd0366 ("x86/mce: Don't use percpu workqueues") dropped the
> per-CPU workqueues in the MCE code but left the initialization per-CPU.
> This lead to early boot time splats (below) in the workqueues code
> because we were overwriting the workqueue during INIT_WORK() on each new
> CPU which would appear.
>
> Move initialization to mcheck_init() so it happens only once.
>
> mce: [Hardware Error]: Machine check events logged
> BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
> IP: [<ffffffff810980a1>] process_one_work+0x31/0x420
> PGD 0
> Oops: 0000 [#1] SMP
> Modules linked in:
> CPU: 36 PID: 263 Comm: kworker/36:0 Not tainted 4.1.0-rc8 #1
> Hardware name: Intel Corporation BRICKLAND/BRICKLAND, BIOS
> BRHSXSD1.86B.0065.R01.1505011640
> +05/01/2015
> task: ffff88181c284470 ti: ffff88181bd94000 task.ti: ffff88181bd94000
> RIP: 0010:[<ffffffff810980a1>] process_one_work+0x31/0x420
> RSP: 0000:ffff88181bd97e08 EFLAGS: 00010046
> RAX: 0000000fffffffe0 RBX: ffffffff81d0fa20 RCX: 0000000000000000
> RDX: 0000000fffffff00 RSI: ffffffff81d0fa20 RDI: ffff88181c2660c0
> RBP: ffff88181bd97e48 R08: ffff88181f416ec0 R09: ffff88181c284470
> R10: 0000000000000002 R11: ffffffff8109e5ac R12: ffff88181c2660c0
> R13: ffff88181f416ec0 R14: 0000000000000000 R15: ffff88181c2660f0
> ^^^^^^^^^^^^^^^^^
>
> 27: 4c 0f 45 f2 cmovne %rdx,%r14
> 2b:* 49 8b 46 08 mov 0x8(%r14),%rax <-- trapping
> instruction
> 2f: 44 8b b8 00 01 00 00 mov 0x100(%rax),%r15d
>
> ...
>
> Call Trace:
> worker_thread
> ? rescuer_thread
> kthread
> ? kthread_create_on_node
> ret_from_fork
> ? kthread_create_on_node
> Code: 48 89 e5 41 57 41 56 45 31 f6 41 55 41 54 49 89 fc 53 48 89 f3 48 83
> ec 18 48 8b 06 4c
> +8b 6f 48 48 89 c2 30 d2 a8 04 4c 0f 45 f2 <49> 8b 46 08 44 8b b8 00 01 00 00
> 41 c1 ef 05 44
> +89 f8 83 e0 01
> RIP [<ffffffff810980a1>] process_one_work
> RSP <ffff88181bd97e08>
> CR2: 0000000000000008
> ---[ end trace 8229a011b97532a0 ]---
> Kernel panic - not syncing: Fatal exception
> ---[ end Kernel panic - not syncing: Fatal exception
>
> Reported-by: Rui Wang <rui.y.w...@intel.com>
> Debugged-by: Borislav Petkov <b...@suse.de>
> Signed-off-by: Tony Luck <tony.l...@intel.com>
> ---
> arch/x86/kernel/cpu/mcheck/mce.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/mcheck/mce.c
> b/arch/x86/kernel/cpu/mcheck/mce.c
> index 478f81a6d824..158d9e7db974 100644
> --- a/arch/x86/kernel/cpu/mcheck/mce.c
> +++ b/arch/x86/kernel/cpu/mcheck/mce.c
> @@ -1665,9 +1665,6 @@ void mcheck_cpu_init(struct cpuinfo_x86 *c)
> return;
> }
>
> - INIT_WORK(&mce_work, mce_process_work);
> - init_irq_work(&mce_irq_work, mce_irq_work_cb);
> -
> machine_check_vector = do_machine_check;
>
> __mcheck_cpu_init_generic();
> @@ -1994,6 +1991,9 @@ int __init mcheck_init(void)
> mce_register_decode_chain(&mce_srao_nb);
> mcheck_vendor_init_severity();
>
> + INIT_WORK(&mce_work, mce_process_work);
> + init_irq_work(&mce_irq_work, mce_irq_work_cb);
> +
> return 0;
Hmm, and I was under the impression that mcheck_init() runs much
later... Not really.
Anyway, your version is better, I've replaced mine with it.
Thanks.
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
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