[PATCH v4] riscv:uprobe fix SR_SPIE set/clear handling

[Palmer Dabbelt]

On Wed, 20 Jul 2022 23:58:20 PDT (-0700), zouyipeng at huawei.com wrote:
> 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>
> Reviewed-by: Guo Ren <guoren at kernel.org>
> ---
> v2: Add Fixes tag
> v3: Rename Subject
> v4: Add Reviewed-by tags
>
>  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,

Thanks, this is on for-next.