2023-02-04 06:35:51

by Guo Ren

[permalink] [raw]
Subject: [PATCH V2] riscv: kprobe: Fixup misaligned load text

From: Guo Ren <[email protected]>

The current kprobe would cause a misaligned load for the probe point.
This patch fixup it with two half-word loads instead.

Fixes: c22b0bcb1dd0 ("riscv: Add kprobes supported")
Signed-off-by: Guo Ren <[email protected]>
Signed-off-by: Guo Ren <[email protected]>
Link: https://lore.kernel.org/linux-riscv/[email protected]/
Reported-by: Bjorn Topel <[email protected]>
Cc: Jessica Clarke <[email protected]>
---
Changelog
V2:
- Optimize coding convention (Thx Bjorn & Jessica)
---
arch/riscv/kernel/probes/kprobes.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/kernel/probes/kprobes.c b/arch/riscv/kernel/probes/kprobes.c
index c41bd8509032..d3b18e868f30 100644
--- a/arch/riscv/kernel/probes/kprobes.c
+++ b/arch/riscv/kernel/probes/kprobes.c
@@ -71,16 +71,18 @@ static bool __kprobes arch_check_kprobe(struct kprobe *p)

int __kprobes arch_prepare_kprobe(struct kprobe *p)
{
- unsigned long probe_addr = (unsigned long)p->addr;
+ u16 *insn = (u16 *)p->addr;

- if (probe_addr & 0x1)
+ if ((unsigned long)insn & 0x1)
return -EILSEQ;

if (!arch_check_kprobe(p))
return -EILSEQ;

/* copy instruction */
- p->opcode = *p->addr;
+ p->opcode = (kprobe_opcode_t)(*insn++);
+ if (GET_INSN_LENGTH(p->opcode) == 4)
+ p->opcode |= (kprobe_opcode_t)(*insn) << 16;

/* decode instruction */
switch (riscv_probe_decode_insn(p->addr, &p->ainsn.api)) {
--
2.36.1



2023-02-06 08:15:40

by Björn Töpel

[permalink] [raw]
Subject: Re: [PATCH V2] riscv: kprobe: Fixup misaligned load text

[email protected] writes:

> From: Guo Ren <[email protected]>
>
> The current kprobe would cause a misaligned load for the probe point.
> This patch fixup it with two half-word loads instead.
>
> Fixes: c22b0bcb1dd0 ("riscv: Add kprobes supported")
> Signed-off-by: Guo Ren <[email protected]>
> Signed-off-by: Guo Ren <[email protected]>
> Link: https://lore.kernel.org/linux-riscv/[email protected]/
> Reported-by: Bjorn Topel <[email protected]>
> Cc: Jessica Clarke <[email protected]>
> ---
> Changelog
> V2:
> - Optimize coding convention (Thx Bjorn & Jessica)

Thank you for fixing this!

Reviewed-by: Björn Töpel <[email protected]>

2023-02-09 23:40:52

by Palmer Dabbelt

[permalink] [raw]
Subject: Re: [PATCH V2] riscv: kprobe: Fixup misaligned load text


On Sat, 04 Feb 2023 01:35:31 -0500, [email protected] wrote:
> The current kprobe would cause a misaligned load for the probe point.
> This patch fixup it with two half-word loads instead.
>
>

Applied, thanks!

[1/1] riscv: kprobe: Fixup misaligned load text
https://git.kernel.org/palmer/c/eb7423273cc9

Best regards,
--
Palmer Dabbelt <[email protected]>


Subject: Re: [PATCH V2] riscv: kprobe: Fixup misaligned load text

Hello:

This patch was applied to riscv/linux.git (fixes)
by Palmer Dabbelt <[email protected]>:

On Sat, 4 Feb 2023 01:35:31 -0500 you wrote:
> From: Guo Ren <[email protected]>
>
> The current kprobe would cause a misaligned load for the probe point.
> This patch fixup it with two half-word loads instead.
>
> Fixes: c22b0bcb1dd0 ("riscv: Add kprobes supported")
> Signed-off-by: Guo Ren <[email protected]>
> Signed-off-by: Guo Ren <[email protected]>
> Link: https://lore.kernel.org/linux-riscv/[email protected]/
> Reported-by: Bjorn Topel <[email protected]>
> Cc: Jessica Clarke <[email protected]>
>
> [...]

Here is the summary with links:
- [V2] riscv: kprobe: Fixup misaligned load text
https://git.kernel.org/riscv/c/eb7423273cc9

You are awesome, thank you!
--
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