[PATCH -next v2] riscv:uprobe remove set/clear SR_SPIE in arch_uprobe_pre/post/abort_xol

[Yipeng Zou]

在 2022/7/20 17:51, Conor.Dooley at microchip.com 写道:
> On 20/07/2022 10:34, Yipeng Zou wrote:
>> [PATCH -next v2] riscv:uprobe remove set/clear SR_SPIE in arch_uprobe_pre/post/abort_xol
> Hey Yipeng,
> Just a suggestion on the commit message, how about just:
> "riscv: uprobe: fix SR_SPIE set/clear handling"
>
> Thanks,
> Conor.

oh, it's more reasonable, will rename in next version, thanks for advice.

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>> In riscv the process of uprobe going to clear spie before exec
>> the origin insn,and set spie after that.But When access the page
>> which origin insn has been placed a page fault may happen and
>> irq was disabled in arch_uprobe_pre_xol function,It cause a WARN
>> as follows.
>> There is no need to clear/set spie in arch_uprobe_pre/post/abort_xol.
>> We can just remove it.
>>
>> [   31.684157] BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:1488
>> [   31.684677] in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 76, name: work
>> [   31.684929] preempt_count: 0, expected: 0
>> [   31.685969] CPU: 2 PID: 76 Comm: work Tainted: G
>> [   31.686542] Hardware name: riscv-virtio,qemu (DT)
>> [   31.686797] Call Trace:
>> [   31.687053] [<ffffffff80006442>] dump_backtrace+0x30/0x38
>> [   31.687699] [<ffffffff80812118>] show_stack+0x40/0x4c
>> [   31.688141] [<ffffffff8081817a>] dump_stack_lvl+0x44/0x5c
>> [   31.688396] [<ffffffff808181aa>] dump_stack+0x18/0x20
>> [   31.688653] [<ffffffff8003e454>] __might_resched+0x114/0x122
>> [   31.688948] [<ffffffff8003e4b2>] __might_sleep+0x50/0x7a
>> [   31.689435] [<ffffffff80822676>] down_read+0x30/0x130
>> [   31.689728] [<ffffffff8000b650>] do_page_fault+0x166/x446
>> [   31.689997] [<ffffffff80003c0c>] ret_from_exception+0x0/0xc
>>
>> Fixes: 74784081aac8 ("riscv: Add uprobes supported")
>> Signed-off-by: Yipeng Zou <zouyipeng at huawei.com>
>> ---
>> v2: Add Fixes tag
>>
>>    arch/riscv/kernel/probes/uprobes.c | 6 ------
>>    1 file changed, 6 deletions(-)
>>
>> diff --git a/arch/riscv/kernel/probes/uprobes.c b/arch/riscv/kernel/probes/uprobes.c
>> index 7a057b5f0adc..c976a21cd4bd 100644
>> --- a/arch/riscv/kernel/probes/uprobes.c
>> +++ b/arch/riscv/kernel/probes/uprobes.c
>> @@ -59,8 +59,6 @@ int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
>>
>>           instruction_pointer_set(regs, utask->xol_vaddr);
>>
>> -       regs->status &= ~SR_SPIE;
>> -
>>           return 0;
>>    }
>>
>> @@ -72,8 +70,6 @@ int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
>>
>>           instruction_pointer_set(regs, utask->vaddr + auprobe->insn_size);
>>
>> -       regs->status |= SR_SPIE;
>> -
>>           return 0;
>>    }
>>
>> @@ -111,8 +107,6 @@ void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
>>            * address.
>>            */
>>           instruction_pointer_set(regs, utask->vaddr);
>> -
>> -       regs->status &= ~SR_SPIE;
>>    }
>>
>>    bool arch_uretprobe_is_alive(struct return_instance *ret, enum rp_check ctx,
>> --
>> 2.17.1
>>
>>
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-- 
Regards,
Yipeng Zou