* [PATCH v2 1/2] riscv: fgraph: Select HAVE_FUNCTION_GRAPH_TRACER depends on HAVE_DYNAMIC_FTRACE_WITH_ARGS
@ 2025-03-17 3:12 Pu Lehui
2025-03-17 3:12 ` [PATCH v2 2/2] riscv: fgraph: Fix stack layout to match __arch_ftrace_regs argument of ftrace_return_to_handler Pu Lehui
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: Pu Lehui @ 2025-03-17 3:12 UTC (permalink / raw)
To: linux-riscv, linux-kernel
Cc: Palmer Dabbelt, Alexandre Ghiti, Björn Töpel,
Masami Hiramatsu (Google), Steven Rostedt (Google),
Naresh Kamboju, Pu Lehui
From: Pu Lehui <pulehui@huawei.com>
Currently, fgraph on riscv relies on the infrastructure of
DYNAMIC_FTRACE_WITH_ARGS. However, DYNAMIC_FTRACE_WITH_ARGS may be
turned off on riscv, which will cause the enabled fgraph to be abnormal.
Therefore, let's select HAVE_FUNCTION_GRAPH_TRACER depends on
HAVE_DYNAMIC_FTRACE_WITH_ARGS.
Fixes: a3ed4157b7d8 ("fgraph: Replace fgraph_ret_regs with ftrace_regs")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202503160820.dvqMpH0g-lkp@intel.com/
Signed-off-by: Pu Lehui <pulehui@huawei.com>
---
arch/riscv/Kconfig | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 7612c52e9b1e..5d63abc499ce 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -149,7 +149,7 @@ config RISCV
select HAVE_DYNAMIC_FTRACE_WITH_ARGS if HAVE_DYNAMIC_FTRACE
select HAVE_FTRACE_GRAPH_FUNC
select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL
- select HAVE_FUNCTION_GRAPH_TRACER
+ select HAVE_FUNCTION_GRAPH_TRACER if HAVE_DYNAMIC_FTRACE_WITH_ARGS
select HAVE_FUNCTION_GRAPH_FREGS
select HAVE_FUNCTION_TRACER if !XIP_KERNEL && !PREEMPTION
select HAVE_EBPF_JIT if MMU
--
2.34.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH v2 2/2] riscv: fgraph: Fix stack layout to match __arch_ftrace_regs argument of ftrace_return_to_handler
2025-03-17 3:12 [PATCH v2 1/2] riscv: fgraph: Select HAVE_FUNCTION_GRAPH_TRACER depends on HAVE_DYNAMIC_FTRACE_WITH_ARGS Pu Lehui
@ 2025-03-17 3:12 ` Pu Lehui
2025-03-19 11:58 ` Masami Hiramatsu
2025-03-18 13:49 ` [PATCH v2 1/2] riscv: fgraph: Select HAVE_FUNCTION_GRAPH_TRACER depends on HAVE_DYNAMIC_FTRACE_WITH_ARGS Björn Töpel
2025-03-27 3:24 ` patchwork-bot+linux-riscv
2 siblings, 1 reply; 5+ messages in thread
From: Pu Lehui @ 2025-03-17 3:12 UTC (permalink / raw)
To: linux-riscv, linux-kernel
Cc: Palmer Dabbelt, Alexandre Ghiti, Björn Töpel,
Masami Hiramatsu (Google), Steven Rostedt (Google),
Naresh Kamboju, Pu Lehui
From: Pu Lehui <pulehui@huawei.com>
Naresh Kamboju reported a "Bad frame pointer" kernel warning while
running LTP trace ftrace_stress_test.sh in riscv. We can reproduce the
same issue with the following command:
```
$ cd /sys/kernel/debug/tracing
$ echo 'f:myprobe do_nanosleep%return args1=$retval' > dynamic_events
$ echo 1 > events/fprobes/enable
$ echo 1 > tracing_on
$ sleep 1
```
And we can get the following kernel warning:
[ 127.692888] ------------[ cut here ]------------
[ 127.693755] Bad frame pointer: expected ff2000000065be50, received ba34c141e9594000
[ 127.693755] from func do_nanosleep return to ffffffff800ccb16
[ 127.698699] WARNING: CPU: 1 PID: 129 at kernel/trace/fgraph.c:755 ftrace_return_to_handler+0x1b2/0x1be
[ 127.699894] Modules linked in:
[ 127.700908] CPU: 1 UID: 0 PID: 129 Comm: sleep Not tainted 6.14.0-rc3-g0ab191c74642 #32
[ 127.701453] Hardware name: riscv-virtio,qemu (DT)
[ 127.701859] epc : ftrace_return_to_handler+0x1b2/0x1be
[ 127.702032] ra : ftrace_return_to_handler+0x1b2/0x1be
[ 127.702151] epc : ffffffff8013b5e0 ra : ffffffff8013b5e0 sp : ff2000000065bd10
[ 127.702221] gp : ffffffff819c12f8 tp : ff60000080853100 t0 : 6e00000000000000
[ 127.702284] t1 : 0000000000000020 t2 : 6e7566206d6f7266 s0 : ff2000000065bd80
[ 127.702346] s1 : ff60000081262000 a0 : 000000000000007b a1 : ffffffff81894f20
[ 127.702408] a2 : 0000000000000010 a3 : fffffffffffffffe a4 : 0000000000000000
[ 127.702470] a5 : 0000000000000000 a6 : 0000000000000008 a7 : 0000000000000038
[ 127.702530] s2 : ba34c141e9594000 s3 : 0000000000000000 s4 : ff2000000065bdd0
[ 127.702591] s5 : 00007fff8adcf400 s6 : 000055556dc1d8c0 s7 : 0000000000000068
[ 127.702651] s8 : 00007fff8adf5d10 s9 : 000000000000006d s10: 0000000000000001
[ 127.702710] s11: 00005555737377c8 t3 : ffffffff819d899e t4 : ffffffff819d899e
[ 127.702769] t5 : ffffffff819d89a0 t6 : ff2000000065bb18
[ 127.702826] status: 0000000200000120 badaddr: 0000000000000000 cause: 0000000000000003
[ 127.703292] [<ffffffff8013b5e0>] ftrace_return_to_handler+0x1b2/0x1be
[ 127.703760] [<ffffffff80017bce>] return_to_handler+0x16/0x26
[ 127.704009] [<ffffffff80017bb8>] return_to_handler+0x0/0x26
[ 127.704057] [<ffffffff800d3352>] common_nsleep+0x42/0x54
[ 127.704117] [<ffffffff800d44a2>] __riscv_sys_clock_nanosleep+0xba/0x10a
[ 127.704176] [<ffffffff80901c56>] do_trap_ecall_u+0x188/0x218
[ 127.704295] [<ffffffff8090cc3e>] handle_exception+0x14a/0x156
[ 127.705436] ---[ end trace 0000000000000000 ]---
The reason is that the stack layout for constructing argument for the
ftrace_return_to_handler in the return_to_handler does not match the
__arch_ftrace_regs structure of riscv, leading to unexpected results.
Fixes: a3ed4157b7d8 ("fgraph: Replace fgraph_ret_regs with ftrace_regs")
Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
Closes: https://lore.kernel.org/all/CA+G9fYvp_oAxeDFj88Tk2rfEZ7jtYKAKSwfYS66=57Db9TBdyA@mail.gmail.com
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Tested-by: Björn Töpel <bjorn@rivosinc.com>
---
arch/riscv/kernel/mcount.S | 24 +++++++++++-------------
1 file changed, 11 insertions(+), 13 deletions(-)
diff --git a/arch/riscv/kernel/mcount.S b/arch/riscv/kernel/mcount.S
index 068168046e0e..da4a4000e57e 100644
--- a/arch/riscv/kernel/mcount.S
+++ b/arch/riscv/kernel/mcount.S
@@ -12,8 +12,6 @@
#include <asm/asm-offsets.h>
#include <asm/ftrace.h>
-#define ABI_SIZE_ON_STACK 80
-
.text
.macro SAVE_ABI_STATE
@@ -28,12 +26,12 @@
* register if a0 was not saved.
*/
.macro SAVE_RET_ABI_STATE
- addi sp, sp, -ABI_SIZE_ON_STACK
- REG_S ra, 1*SZREG(sp)
- REG_S s0, 8*SZREG(sp)
- REG_S a0, 10*SZREG(sp)
- REG_S a1, 11*SZREG(sp)
- addi s0, sp, ABI_SIZE_ON_STACK
+ addi sp, sp, -FREGS_SIZE_ON_STACK
+ REG_S ra, FREGS_RA(sp)
+ REG_S s0, FREGS_S0(sp)
+ REG_S a0, FREGS_A0(sp)
+ REG_S a1, FREGS_A1(sp)
+ addi s0, sp, FREGS_SIZE_ON_STACK
.endm
.macro RESTORE_ABI_STATE
@@ -43,11 +41,11 @@
.endm
.macro RESTORE_RET_ABI_STATE
- REG_L ra, 1*SZREG(sp)
- REG_L s0, 8*SZREG(sp)
- REG_L a0, 10*SZREG(sp)
- REG_L a1, 11*SZREG(sp)
- addi sp, sp, ABI_SIZE_ON_STACK
+ REG_L ra, FREGS_RA(sp)
+ REG_L s0, FREGS_S0(sp)
+ REG_L a0, FREGS_A0(sp)
+ REG_L a1, FREGS_A1(sp)
+ addi sp, sp, FREGS_SIZE_ON_STACK
.endm
SYM_TYPED_FUNC_START(ftrace_stub)
--
2.34.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v2 1/2] riscv: fgraph: Select HAVE_FUNCTION_GRAPH_TRACER depends on HAVE_DYNAMIC_FTRACE_WITH_ARGS
2025-03-17 3:12 [PATCH v2 1/2] riscv: fgraph: Select HAVE_FUNCTION_GRAPH_TRACER depends on HAVE_DYNAMIC_FTRACE_WITH_ARGS Pu Lehui
2025-03-17 3:12 ` [PATCH v2 2/2] riscv: fgraph: Fix stack layout to match __arch_ftrace_regs argument of ftrace_return_to_handler Pu Lehui
@ 2025-03-18 13:49 ` Björn Töpel
2025-03-27 3:24 ` patchwork-bot+linux-riscv
2 siblings, 0 replies; 5+ messages in thread
From: Björn Töpel @ 2025-03-18 13:49 UTC (permalink / raw)
To: Pu Lehui, linux-riscv, linux-kernel
Cc: Palmer Dabbelt, Alexandre Ghiti, Masami Hiramatsu (Google),
Steven Rostedt (Google), Naresh Kamboju, Pu Lehui
Pu Lehui <pulehui@huaweicloud.com> writes:
> From: Pu Lehui <pulehui@huawei.com>
>
> Currently, fgraph on riscv relies on the infrastructure of
> DYNAMIC_FTRACE_WITH_ARGS. However, DYNAMIC_FTRACE_WITH_ARGS may be
> turned off on riscv, which will cause the enabled fgraph to be abnormal.
> Therefore, let's select HAVE_FUNCTION_GRAPH_TRACER depends on
> HAVE_DYNAMIC_FTRACE_WITH_ARGS.
>
> Fixes: a3ed4157b7d8 ("fgraph: Replace fgraph_ret_regs with ftrace_regs")
> Reported-by: kernel test robot <lkp@intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202503160820.dvqMpH0g-lkp@intel.com/
> Signed-off-by: Pu Lehui <pulehui@huawei.com>
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2 2/2] riscv: fgraph: Fix stack layout to match __arch_ftrace_regs argument of ftrace_return_to_handler
2025-03-17 3:12 ` [PATCH v2 2/2] riscv: fgraph: Fix stack layout to match __arch_ftrace_regs argument of ftrace_return_to_handler Pu Lehui
@ 2025-03-19 11:58 ` Masami Hiramatsu
0 siblings, 0 replies; 5+ messages in thread
From: Masami Hiramatsu @ 2025-03-19 11:58 UTC (permalink / raw)
To: Pu Lehui
Cc: linux-riscv, linux-kernel, Palmer Dabbelt, Alexandre Ghiti,
Björn Töpel, Masami Hiramatsu (Google),
Steven Rostedt (Google), Naresh Kamboju, Pu Lehui
On Mon, 17 Mar 2025 03:12:14 +0000
Pu Lehui <pulehui@huaweicloud.com> wrote:
> From: Pu Lehui <pulehui@huawei.com>
>
> Naresh Kamboju reported a "Bad frame pointer" kernel warning while
> running LTP trace ftrace_stress_test.sh in riscv. We can reproduce the
> same issue with the following command:
>
> ```
> $ cd /sys/kernel/debug/tracing
> $ echo 'f:myprobe do_nanosleep%return args1=$retval' > dynamic_events
> $ echo 1 > events/fprobes/enable
> $ echo 1 > tracing_on
> $ sleep 1
> ```
>
> And we can get the following kernel warning:
>
> [ 127.692888] ------------[ cut here ]------------
> [ 127.693755] Bad frame pointer: expected ff2000000065be50, received ba34c141e9594000
> [ 127.693755] from func do_nanosleep return to ffffffff800ccb16
> [ 127.698699] WARNING: CPU: 1 PID: 129 at kernel/trace/fgraph.c:755 ftrace_return_to_handler+0x1b2/0x1be
> [ 127.699894] Modules linked in:
> [ 127.700908] CPU: 1 UID: 0 PID: 129 Comm: sleep Not tainted 6.14.0-rc3-g0ab191c74642 #32
> [ 127.701453] Hardware name: riscv-virtio,qemu (DT)
> [ 127.701859] epc : ftrace_return_to_handler+0x1b2/0x1be
> [ 127.702032] ra : ftrace_return_to_handler+0x1b2/0x1be
> [ 127.702151] epc : ffffffff8013b5e0 ra : ffffffff8013b5e0 sp : ff2000000065bd10
> [ 127.702221] gp : ffffffff819c12f8 tp : ff60000080853100 t0 : 6e00000000000000
> [ 127.702284] t1 : 0000000000000020 t2 : 6e7566206d6f7266 s0 : ff2000000065bd80
> [ 127.702346] s1 : ff60000081262000 a0 : 000000000000007b a1 : ffffffff81894f20
> [ 127.702408] a2 : 0000000000000010 a3 : fffffffffffffffe a4 : 0000000000000000
> [ 127.702470] a5 : 0000000000000000 a6 : 0000000000000008 a7 : 0000000000000038
> [ 127.702530] s2 : ba34c141e9594000 s3 : 0000000000000000 s4 : ff2000000065bdd0
> [ 127.702591] s5 : 00007fff8adcf400 s6 : 000055556dc1d8c0 s7 : 0000000000000068
> [ 127.702651] s8 : 00007fff8adf5d10 s9 : 000000000000006d s10: 0000000000000001
> [ 127.702710] s11: 00005555737377c8 t3 : ffffffff819d899e t4 : ffffffff819d899e
> [ 127.702769] t5 : ffffffff819d89a0 t6 : ff2000000065bb18
> [ 127.702826] status: 0000000200000120 badaddr: 0000000000000000 cause: 0000000000000003
> [ 127.703292] [<ffffffff8013b5e0>] ftrace_return_to_handler+0x1b2/0x1be
> [ 127.703760] [<ffffffff80017bce>] return_to_handler+0x16/0x26
> [ 127.704009] [<ffffffff80017bb8>] return_to_handler+0x0/0x26
> [ 127.704057] [<ffffffff800d3352>] common_nsleep+0x42/0x54
> [ 127.704117] [<ffffffff800d44a2>] __riscv_sys_clock_nanosleep+0xba/0x10a
> [ 127.704176] [<ffffffff80901c56>] do_trap_ecall_u+0x188/0x218
> [ 127.704295] [<ffffffff8090cc3e>] handle_exception+0x14a/0x156
> [ 127.705436] ---[ end trace 0000000000000000 ]---
>
> The reason is that the stack layout for constructing argument for the
> ftrace_return_to_handler in the return_to_handler does not match the
> __arch_ftrace_regs structure of riscv, leading to unexpected results.
>
Thanks for fixing! This looks good to me.
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Thank you,
> Fixes: a3ed4157b7d8 ("fgraph: Replace fgraph_ret_regs with ftrace_regs")
> Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
> Closes: https://lore.kernel.org/all/CA+G9fYvp_oAxeDFj88Tk2rfEZ7jtYKAKSwfYS66=57Db9TBdyA@mail.gmail.com
> Signed-off-by: Pu Lehui <pulehui@huawei.com>
> Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
> Tested-by: Björn Töpel <bjorn@rivosinc.com>
> ---
> arch/riscv/kernel/mcount.S | 24 +++++++++++-------------
> 1 file changed, 11 insertions(+), 13 deletions(-)
>
> diff --git a/arch/riscv/kernel/mcount.S b/arch/riscv/kernel/mcount.S
> index 068168046e0e..da4a4000e57e 100644
> --- a/arch/riscv/kernel/mcount.S
> +++ b/arch/riscv/kernel/mcount.S
> @@ -12,8 +12,6 @@
> #include <asm/asm-offsets.h>
> #include <asm/ftrace.h>
>
> -#define ABI_SIZE_ON_STACK 80
> -
> .text
>
> .macro SAVE_ABI_STATE
> @@ -28,12 +26,12 @@
> * register if a0 was not saved.
> */
> .macro SAVE_RET_ABI_STATE
> - addi sp, sp, -ABI_SIZE_ON_STACK
> - REG_S ra, 1*SZREG(sp)
> - REG_S s0, 8*SZREG(sp)
> - REG_S a0, 10*SZREG(sp)
> - REG_S a1, 11*SZREG(sp)
> - addi s0, sp, ABI_SIZE_ON_STACK
> + addi sp, sp, -FREGS_SIZE_ON_STACK
> + REG_S ra, FREGS_RA(sp)
> + REG_S s0, FREGS_S0(sp)
> + REG_S a0, FREGS_A0(sp)
> + REG_S a1, FREGS_A1(sp)
> + addi s0, sp, FREGS_SIZE_ON_STACK
> .endm
>
> .macro RESTORE_ABI_STATE
> @@ -43,11 +41,11 @@
> .endm
>
> .macro RESTORE_RET_ABI_STATE
> - REG_L ra, 1*SZREG(sp)
> - REG_L s0, 8*SZREG(sp)
> - REG_L a0, 10*SZREG(sp)
> - REG_L a1, 11*SZREG(sp)
> - addi sp, sp, ABI_SIZE_ON_STACK
> + REG_L ra, FREGS_RA(sp)
> + REG_L s0, FREGS_S0(sp)
> + REG_L a0, FREGS_A0(sp)
> + REG_L a1, FREGS_A1(sp)
> + addi sp, sp, FREGS_SIZE_ON_STACK
> .endm
>
> SYM_TYPED_FUNC_START(ftrace_stub)
> --
> 2.34.1
>
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2 1/2] riscv: fgraph: Select HAVE_FUNCTION_GRAPH_TRACER depends on HAVE_DYNAMIC_FTRACE_WITH_ARGS
2025-03-17 3:12 [PATCH v2 1/2] riscv: fgraph: Select HAVE_FUNCTION_GRAPH_TRACER depends on HAVE_DYNAMIC_FTRACE_WITH_ARGS Pu Lehui
2025-03-17 3:12 ` [PATCH v2 2/2] riscv: fgraph: Fix stack layout to match __arch_ftrace_regs argument of ftrace_return_to_handler Pu Lehui
2025-03-18 13:49 ` [PATCH v2 1/2] riscv: fgraph: Select HAVE_FUNCTION_GRAPH_TRACER depends on HAVE_DYNAMIC_FTRACE_WITH_ARGS Björn Töpel
@ 2025-03-27 3:24 ` patchwork-bot+linux-riscv
2 siblings, 0 replies; 5+ messages in thread
From: patchwork-bot+linux-riscv @ 2025-03-27 3:24 UTC (permalink / raw)
To: Pu Lehui
Cc: linux-riscv, linux-kernel, palmer, alex, bjorn, mhiramat, rostedt,
naresh.kamboju, pulehui
Hello:
This series was applied to riscv/linux.git (for-next)
by Alexandre Ghiti <alexghiti@rivosinc.com>:
On Mon, 17 Mar 2025 03:12:13 +0000 you wrote:
> From: Pu Lehui <pulehui@huawei.com>
>
> Currently, fgraph on riscv relies on the infrastructure of
> DYNAMIC_FTRACE_WITH_ARGS. However, DYNAMIC_FTRACE_WITH_ARGS may be
> turned off on riscv, which will cause the enabled fgraph to be abnormal.
> Therefore, let's select HAVE_FUNCTION_GRAPH_TRACER depends on
> HAVE_DYNAMIC_FTRACE_WITH_ARGS.
>
> [...]
Here is the summary with links:
- [v2,1/2] riscv: fgraph: Select HAVE_FUNCTION_GRAPH_TRACER depends on HAVE_DYNAMIC_FTRACE_WITH_ARGS
https://git.kernel.org/riscv/c/e8eb8e1bdae9
- [v2,2/2] riscv: fgraph: Fix stack layout to match __arch_ftrace_regs argument of ftrace_return_to_handler
https://git.kernel.org/riscv/c/67a5ba8f742f
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] 5+ messages in thread
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2025-03-17 3:12 [PATCH v2 1/2] riscv: fgraph: Select HAVE_FUNCTION_GRAPH_TRACER depends on HAVE_DYNAMIC_FTRACE_WITH_ARGS Pu Lehui
2025-03-17 3:12 ` [PATCH v2 2/2] riscv: fgraph: Fix stack layout to match __arch_ftrace_regs argument of ftrace_return_to_handler Pu Lehui
2025-03-19 11:58 ` Masami Hiramatsu
2025-03-18 13:49 ` [PATCH v2 1/2] riscv: fgraph: Select HAVE_FUNCTION_GRAPH_TRACER depends on HAVE_DYNAMIC_FTRACE_WITH_ARGS Björn Töpel
2025-03-27 3:24 ` patchwork-bot+linux-riscv
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