* Re: [PATCH] riscv/kprobe: Fix instruction simulation of JALR
2023-01-16 6:43 [PATCH] riscv/kprobe: Fix instruction simulation of JALR Liao Chang
@ 2023-01-21 2:59 ` Guo Ren
2023-01-25 5:48 ` Palmer Dabbelt
2023-01-25 5:50 ` patchwork-bot+linux-riscv
2 siblings, 0 replies; 4+ messages in thread
From: Guo Ren @ 2023-01-21 2:59 UTC (permalink / raw)
To: Liao Chang
Cc: paul.walmsley, palmer, aou, mhiramat, me, penberg, linux-riscv,
linux-kernel, bjorn, chenlifu
On Mon, Jan 16, 2023 at 2:46 PM Liao Chang <liaochang1@huawei.com> wrote:
>
> Set kprobe at 'jalr 1140(ra)' of vfs_write results in the following
> crash:
>
> [ 32.092235] Unable to handle kernel access to user memory without uaccess routines at virtual address 00aaaaaad77b1170
> [ 32.093115] Oops [#1]
> [ 32.093251] Modules linked in:
> [ 32.093626] CPU: 0 PID: 135 Comm: ftracetest Not tainted 6.2.0-rc2-00013-gb0aa5e5df0cb-dirty #16
> [ 32.093985] Hardware name: riscv-virtio,qemu (DT)
> [ 32.094280] epc : ksys_read+0x88/0xd6
> [ 32.094855] ra : ksys_read+0xc0/0xd6
> [ 32.095016] epc : ffffffff801cda80 ra : ffffffff801cdab8 sp : ff20000000d7bdc0
> [ 32.095227] gp : ffffffff80f14000 tp : ff60000080f9cb40 t0 : ffffffff80f13e80
> [ 32.095500] t1 : ffffffff8000c29c t2 : ffffffff800dbc54 s0 : ff20000000d7be60
> [ 32.095716] s1 : 0000000000000000 a0 : ffffffff805a64ae a1 : ffffffff80a83708
> [ 32.095921] a2 : ffffffff80f160a0 a3 : 0000000000000000 a4 : f229b0afdb165300
> [ 32.096171] a5 : f229b0afdb165300 a6 : ffffffff80eeebd0 a7 : 00000000000003ff
> [ 32.096411] s2 : ff6000007ff76800 s3 : fffffffffffffff7 s4 : 00aaaaaad77b1170
> [ 32.096638] s5 : ffffffff80f160a0 s6 : ff6000007ff76800 s7 : 0000000000000030
> [ 32.096865] s8 : 00ffffffc3d97be0 s9 : 0000000000000007 s10: 00aaaaaad77c9410
> [ 32.097092] s11: 0000000000000000 t3 : ffffffff80f13e48 t4 : ffffffff8000c29c
> [ 32.097317] t5 : ffffffff8000c29c t6 : ffffffff800dbc54
> [ 32.097505] status: 0000000200000120 badaddr: 00aaaaaad77b1170 cause: 000000000000000d
> [ 32.098011] [<ffffffff801cdb72>] ksys_write+0x6c/0xd6
> [ 32.098222] [<ffffffff801cdc06>] sys_write+0x2a/0x38
> [ 32.098405] [<ffffffff80003c76>] ret_from_syscall+0x0/0x2
>
> Since the rs1 and rd might be the same one, such as 'jalr 1140(ra)',
> hence it requires obtaining the target address from rs1 followed by
> updating rd.
>
> Fixes: c22b0bcb1dd0 ("riscv: Add kprobes supported")
> Signed-off-by: Liao Chang <liaochang1@huawei.com>
> ---
> arch/riscv/kernel/probes/simulate-insn.c | 6 +-----
> 1 file changed, 1 insertion(+), 5 deletions(-)
>
> diff --git a/arch/riscv/kernel/probes/simulate-insn.c b/arch/riscv/kernel/probes/simulate-insn.c
> index d73e96f6ed7c..02aa262fb2ac 100644
> --- a/arch/riscv/kernel/probes/simulate-insn.c
> +++ b/arch/riscv/kernel/probes/simulate-insn.c
> @@ -71,17 +71,13 @@ bool __kprobes simulate_jalr(u32 opcode, unsigned long addr, struct pt_regs *reg
> u32 rd_index = (opcode >> 7) & 0x1f;
> u32 rs1_index = (opcode >> 15) & 0x1f;
>
> - ret = rv_insn_reg_set_val(regs, rd_index, addr + 4);
> - if (!ret)
> - return ret;
> -
> ret = rv_insn_reg_get_val(regs, rs1_index, &base_addr);
> if (!ret)
> return ret;
Ah, thank you, If rd == rs1, the regs-><rs1> got a overwritten value,
my mistake. We should read rs1 firstly.
But for the patch, just exchanging the position is enough; keep the
original sequence for coding convention.
eg:
@@ -71,11 +71,11 @@ bool __kprobes simulate_jalr(u32 opcode, unsigned
long addr, struct pt_regs *reg
u32 rd_index = (opcode >> 7) & 0x1f;
u32 rs1_index = (opcode >> 15) & 0x1f;
- ret = rv_insn_reg_set_val(regs, rd_index, addr + 4);
+ ret = rv_insn_reg_get_val(regs, rs1_index, &base_addr);
if (!ret)
return ret;
- ret = rv_insn_reg_get_val(regs, rs1_index, &base_addr);
+ ret = rv_insn_reg_set_val(regs, rd_index, addr + 4);
if (!ret)
return ret;
Then:
Reviewed-by: Guo Ren <guoren@kernel.org>
>
> instruction_pointer_set(regs, (base_addr + sign_extend32((imm), 11))&~1);
>
> - return ret;
> + return rv_insn_reg_set_val(regs, rd_index, addr + 4);
> }
>
> #define auipc_rd_idx(opcode) \
> --
> 2.25.1
>
--
Best Regards
Guo Ren
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] riscv/kprobe: Fix instruction simulation of JALR
2023-01-16 6:43 [PATCH] riscv/kprobe: Fix instruction simulation of JALR Liao Chang
2023-01-21 2:59 ` Guo Ren
@ 2023-01-25 5:48 ` Palmer Dabbelt
2023-01-25 5:50 ` patchwork-bot+linux-riscv
2 siblings, 0 replies; 4+ messages in thread
From: Palmer Dabbelt @ 2023-01-25 5:48 UTC (permalink / raw)
To: Paul Walmsley, aou, penberg, mhiramat, Palmer Dabbelt, me, guoren,
Liao Chang
Cc: linux-riscv, linux-kernel, chenlifu, bjorn
On Mon, 16 Jan 2023 14:43:42 +0800, Liao Chang wrote:
> Set kprobe at 'jalr 1140(ra)' of vfs_write results in the following
> crash:
>
> [ 32.092235] Unable to handle kernel access to user memory without uaccess routines at virtual address 00aaaaaad77b1170
> [ 32.093115] Oops [#1]
> [ 32.093251] Modules linked in:
> [ 32.093626] CPU: 0 PID: 135 Comm: ftracetest Not tainted 6.2.0-rc2-00013-gb0aa5e5df0cb-dirty #16
> [ 32.093985] Hardware name: riscv-virtio,qemu (DT)
> [ 32.094280] epc : ksys_read+0x88/0xd6
> [ 32.094855] ra : ksys_read+0xc0/0xd6
> [ 32.095016] epc : ffffffff801cda80 ra : ffffffff801cdab8 sp : ff20000000d7bdc0
> [ 32.095227] gp : ffffffff80f14000 tp : ff60000080f9cb40 t0 : ffffffff80f13e80
> [ 32.095500] t1 : ffffffff8000c29c t2 : ffffffff800dbc54 s0 : ff20000000d7be60
> [ 32.095716] s1 : 0000000000000000 a0 : ffffffff805a64ae a1 : ffffffff80a83708
> [ 32.095921] a2 : ffffffff80f160a0 a3 : 0000000000000000 a4 : f229b0afdb165300
> [ 32.096171] a5 : f229b0afdb165300 a6 : ffffffff80eeebd0 a7 : 00000000000003ff
> [ 32.096411] s2 : ff6000007ff76800 s3 : fffffffffffffff7 s4 : 00aaaaaad77b1170
> [ 32.096638] s5 : ffffffff80f160a0 s6 : ff6000007ff76800 s7 : 0000000000000030
> [ 32.096865] s8 : 00ffffffc3d97be0 s9 : 0000000000000007 s10: 00aaaaaad77c9410
> [ 32.097092] s11: 0000000000000000 t3 : ffffffff80f13e48 t4 : ffffffff8000c29c
> [ 32.097317] t5 : ffffffff8000c29c t6 : ffffffff800dbc54
> [ 32.097505] status: 0000000200000120 badaddr: 00aaaaaad77b1170 cause: 000000000000000d
> [ 32.098011] [<ffffffff801cdb72>] ksys_write+0x6c/0xd6
> [ 32.098222] [<ffffffff801cdc06>] sys_write+0x2a/0x38
> [ 32.098405] [<ffffffff80003c76>] ret_from_syscall+0x0/0x2
>
> [...]
Applied, thanks!
(with Guo's suggested cleanup)
[1/1] riscv/kprobe: Fix instruction simulation of JALR
https://git.kernel.org/palmer/c/ca0254998be4
Best regards,
--
Palmer Dabbelt <palmer@rivosinc.com>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] riscv/kprobe: Fix instruction simulation of JALR
2023-01-16 6:43 [PATCH] riscv/kprobe: Fix instruction simulation of JALR Liao Chang
2023-01-21 2:59 ` Guo Ren
2023-01-25 5:48 ` Palmer Dabbelt
@ 2023-01-25 5:50 ` patchwork-bot+linux-riscv
2 siblings, 0 replies; 4+ messages in thread
From: patchwork-bot+linux-riscv @ 2023-01-25 5:50 UTC (permalink / raw)
To: Liao Chang
Cc: linux-riscv, paul.walmsley, palmer, aou, mhiramat, guoren, me,
penberg, linux-kernel, bjorn, chenlifu
Hello:
This patch was applied to riscv/linux.git (fixes)
by Palmer Dabbelt <palmer@rivosinc.com>:
On Mon, 16 Jan 2023 14:43:42 +0800 you wrote:
> Set kprobe at 'jalr 1140(ra)' of vfs_write results in the following
> crash:
>
> [ 32.092235] Unable to handle kernel access to user memory without uaccess routines at virtual address 00aaaaaad77b1170
> [ 32.093115] Oops [#1]
> [ 32.093251] Modules linked in:
> [ 32.093626] CPU: 0 PID: 135 Comm: ftracetest Not tainted 6.2.0-rc2-00013-gb0aa5e5df0cb-dirty #16
> [ 32.093985] Hardware name: riscv-virtio,qemu (DT)
> [ 32.094280] epc : ksys_read+0x88/0xd6
> [ 32.094855] ra : ksys_read+0xc0/0xd6
> [ 32.095016] epc : ffffffff801cda80 ra : ffffffff801cdab8 sp : ff20000000d7bdc0
> [ 32.095227] gp : ffffffff80f14000 tp : ff60000080f9cb40 t0 : ffffffff80f13e80
> [ 32.095500] t1 : ffffffff8000c29c t2 : ffffffff800dbc54 s0 : ff20000000d7be60
> [ 32.095716] s1 : 0000000000000000 a0 : ffffffff805a64ae a1 : ffffffff80a83708
> [ 32.095921] a2 : ffffffff80f160a0 a3 : 0000000000000000 a4 : f229b0afdb165300
> [ 32.096171] a5 : f229b0afdb165300 a6 : ffffffff80eeebd0 a7 : 00000000000003ff
> [ 32.096411] s2 : ff6000007ff76800 s3 : fffffffffffffff7 s4 : 00aaaaaad77b1170
> [ 32.096638] s5 : ffffffff80f160a0 s6 : ff6000007ff76800 s7 : 0000000000000030
> [ 32.096865] s8 : 00ffffffc3d97be0 s9 : 0000000000000007 s10: 00aaaaaad77c9410
> [ 32.097092] s11: 0000000000000000 t3 : ffffffff80f13e48 t4 : ffffffff8000c29c
> [ 32.097317] t5 : ffffffff8000c29c t6 : ffffffff800dbc54
> [ 32.097505] status: 0000000200000120 badaddr: 00aaaaaad77b1170 cause: 000000000000000d
> [ 32.098011] [<ffffffff801cdb72>] ksys_write+0x6c/0xd6
> [ 32.098222] [<ffffffff801cdc06>] sys_write+0x2a/0x38
> [ 32.098405] [<ffffffff80003c76>] ret_from_syscall+0x0/0x2
>
> [...]
Here is the summary with links:
- riscv/kprobe: Fix instruction simulation of JALR
https://git.kernel.org/riscv/c/ca0254998be4
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 4+ messages in thread