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From: Ruan Jinjie <ruanjinjie@huawei.com>
To: <paul.walmsley@sifive.com>, <palmer@dabbelt.com>,
	<aou@eecs.berkeley.edu>, <linux-riscv@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>
Cc: <ruanjinjie@huawei.com>
Subject: [PATCH v3] riscv: fix kprobe __user string arg print fault issue
Date: Thu, 4 May 2023 15:29:10 +0800	[thread overview]
Message-ID: <20230504072910.3742842-1-ruanjinjie@huawei.com> (raw)

On riscv qemu platform, when add kprobe event on do_sys_open() to show
filename string arg, it just print fault as follow:

echo 'p:myprobe do_sys_open dfd=$arg1 filename=+0($arg2):string flags=$arg3
mode=$arg4' > kprobe_events

bash-166     [000] ...1.   360.195367: myprobe: (do_sys_open+0x0/0x84)
dfd=0xffffffffffffff9c filename=(fault) flags=0x8241 mode=0x1b6

bash-166     [000] ...1.   360.219369: myprobe: (do_sys_open+0x0/0x84)
dfd=0xffffffffffffff9c filename=(fault) flags=0x8241 mode=0x1b6

bash-191     [000] ...1.   360.378827: myprobe: (do_sys_open+0x0/0x84)
dfd=0xffffffffffffff9c filename=(fault) flags=0x98800 mode=0x0

As riscv do not select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE,
the +0($arg2) addr is processed as a kernel address though it is a
userspace address, cause the above filename=(fault) print. So select
ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE to avoid the issue, after that the
kprobe trace is ok as below:

bash-166     [000] ...1.    96.767641: myprobe: (do_sys_open+0x0/0x84)
dfd=0xffffffffffffff9c filename="/dev/null" flags=0x8241 mode=0x1b6

bash-166     [000] ...1.    96.793751: myprobe: (do_sys_open+0x0/0x84)
dfd=0xffffffffffffff9c filename="/dev/null" flags=0x8241 mode=0x1b6

bash-177     [000] ...1.    96.962354: myprobe: (do_sys_open+0x0/0x84)
dfd=0xffffffffffffff9c filename="/sys/kernel/debug/tracing/events/kprobes/"
flags=0x98800 mode=0x0

Signed-off-by: Ruan Jinjie <ruanjinjie@huawei.com>
Acked-by: Björn Töpel <bjorn@rivosinc.com>
---
v2:
- add the config in alphabetical order
---
v3:
- change signed-off-by to use full name
---
 arch/riscv/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index d2967fefa1d7..b08ed929e220 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -26,6 +26,7 @@ config RISCV
 	select ARCH_HAS_GIGANTIC_PAGE
 	select ARCH_HAS_KCOV
 	select ARCH_HAS_MMIOWB
+	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
 	select ARCH_HAS_PMEM_API
 	select ARCH_HAS_PTE_SPECIAL
 	select ARCH_HAS_SET_DIRECT_MAP if MMU
-- 
2.25.1


WARNING: multiple messages have this Message-ID (diff)
From: Ruan Jinjie <ruanjinjie@huawei.com>
To: <paul.walmsley@sifive.com>, <palmer@dabbelt.com>,
	<aou@eecs.berkeley.edu>, <linux-riscv@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>
Cc: <ruanjinjie@huawei.com>
Subject: [PATCH v3] riscv: fix kprobe __user string arg print fault issue
Date: Thu, 4 May 2023 15:29:10 +0800	[thread overview]
Message-ID: <20230504072910.3742842-1-ruanjinjie@huawei.com> (raw)

On riscv qemu platform, when add kprobe event on do_sys_open() to show
filename string arg, it just print fault as follow:

echo 'p:myprobe do_sys_open dfd=$arg1 filename=+0($arg2):string flags=$arg3
mode=$arg4' > kprobe_events

bash-166     [000] ...1.   360.195367: myprobe: (do_sys_open+0x0/0x84)
dfd=0xffffffffffffff9c filename=(fault) flags=0x8241 mode=0x1b6

bash-166     [000] ...1.   360.219369: myprobe: (do_sys_open+0x0/0x84)
dfd=0xffffffffffffff9c filename=(fault) flags=0x8241 mode=0x1b6

bash-191     [000] ...1.   360.378827: myprobe: (do_sys_open+0x0/0x84)
dfd=0xffffffffffffff9c filename=(fault) flags=0x98800 mode=0x0

As riscv do not select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE,
the +0($arg2) addr is processed as a kernel address though it is a
userspace address, cause the above filename=(fault) print. So select
ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE to avoid the issue, after that the
kprobe trace is ok as below:

bash-166     [000] ...1.    96.767641: myprobe: (do_sys_open+0x0/0x84)
dfd=0xffffffffffffff9c filename="/dev/null" flags=0x8241 mode=0x1b6

bash-166     [000] ...1.    96.793751: myprobe: (do_sys_open+0x0/0x84)
dfd=0xffffffffffffff9c filename="/dev/null" flags=0x8241 mode=0x1b6

bash-177     [000] ...1.    96.962354: myprobe: (do_sys_open+0x0/0x84)
dfd=0xffffffffffffff9c filename="/sys/kernel/debug/tracing/events/kprobes/"
flags=0x98800 mode=0x0

Signed-off-by: Ruan Jinjie <ruanjinjie@huawei.com>
Acked-by: Björn Töpel <bjorn@rivosinc.com>
---
v2:
- add the config in alphabetical order
---
v3:
- change signed-off-by to use full name
---
 arch/riscv/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index d2967fefa1d7..b08ed929e220 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -26,6 +26,7 @@ config RISCV
 	select ARCH_HAS_GIGANTIC_PAGE
 	select ARCH_HAS_KCOV
 	select ARCH_HAS_MMIOWB
+	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
 	select ARCH_HAS_PMEM_API
 	select ARCH_HAS_PTE_SPECIAL
 	select ARCH_HAS_SET_DIRECT_MAP if MMU
-- 
2.25.1


_______________________________________________
linux-riscv mailing list
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http://lists.infradead.org/mailman/listinfo/linux-riscv

             reply	other threads:[~2023-05-04  7:30 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-04  7:29 Ruan Jinjie [this message]
2023-05-04  7:29 ` [PATCH v3] riscv: fix kprobe __user string arg print fault issue Ruan Jinjie
2023-05-15 11:55 ` Ruan Jinjie
2023-05-15 11:55   ` Ruan Jinjie
2023-06-02  9:41   ` Björn Töpel
2023-06-02  9:41     ` Björn Töpel
2023-06-08 18:53 ` Palmer Dabbelt
2023-06-08 18:53   ` Palmer Dabbelt
2023-06-08 19:00 ` patchwork-bot+linux-riscv
2023-06-08 19:00   ` patchwork-bot+linux-riscv

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