From: Chen Zhongjin <chenzhongjin@huawei.com>
To: <linux-kernel@vger.kernel.org>, <linux-riscv@lists.infradead.org>,
<linux-perf-users@vger.kernel.org>
Cc: <paul.walmsley@sifive.com>, <palmer@dabbelt.com>,
<aou@eecs.berkeley.edu>, <peterz@infradead.org>,
<mingo@redhat.com>, <acme@kernel.org>, <mark.rutland@arm.com>,
<alexander.shishkin@linux.intel.com>, <namhyung@kernel.org>,
<jolsa@kernel.org>, <guoren@kernel.org>, <nsaenzju@redhat.com>,
<frederic@kernel.org>, <changbin.du@intel.com>,
<vincent.chen@sifive.com>, <ardb@kernel.org>,
<mhiramat@kernel.org>, <rostedt@goodmis.org>,
<keescook@chromium.org>, <catalin.marinas@arm.com>,
<chenzhongjin@huawei.com>
Subject: [PATCH -next 6/7] riscv: stacktrace: Fix unwinding on ftrace_regs_call
Date: Tue, 20 Sep 2022 23:12:01 +0800 [thread overview]
Message-ID: <20220920151202.180057-7-chenzhongjin@huawei.com> (raw)
In-Reply-To: <20220920151202.180057-1-chenzhongjin@huawei.com>
When unwinding on ftrace_regs_call, the traced function will be skipped
because ftrace_regs_caller doesn't save the fp and ra.
Save the encoded fp so that we can get the pt_regs so that we can unwind
from ftrace_regs_call to the traced function.
Also the pt_regs->status should be set as kernel mode.
Stacktrace before this patch:
Call Trace:
...
[<ffffffff0161a0e0>] handler_pre+0x30/0x4a [kprobe_unwind]
[<ffffffff800bce92>] aggr_pre_handler+0x60/0x94
[<ffffffff80006df0>] kprobe_ftrace_handler+0x13e/0x188
[<ffffffff80008e7e>] ftrace_regs_call+0x8/0x10
[<ffffffff80002540>] do_one_initcall+0x4c/0x1f2
[<ffffffff8008a4e6>] do_init_module+0x56/0x210
...
Stacktrace after this patch:
Call Trace:
...
[<ffffffff016150e0>] handler_pre+0x30/0x4a [kprobe_unwind]
[<ffffffff800bce96>] aggr_pre_handler+0x60/0x94
[<ffffffff80006df0>] kprobe_ftrace_handler+0x13e/0x188
[<ffffffff80008e82>] ftrace_regs_call+0x8/0x10
+ [<ffffffff01615000>] empty_call+0x0/0x1e [kprobe_unwind]
[<ffffffff80002540>] do_one_initcall+0x4c/0x1f2
[<ffffffff8008a4ea>] do_init_module+0x56/0x210
...
Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
---
arch/riscv/kernel/mcount-dyn.S | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/arch/riscv/kernel/mcount-dyn.S b/arch/riscv/kernel/mcount-dyn.S
index d171eca623b6..56a4014c392f 100644
--- a/arch/riscv/kernel/mcount-dyn.S
+++ b/arch/riscv/kernel/mcount-dyn.S
@@ -10,6 +10,8 @@
#include <asm/asm-offsets.h>
#include <asm-generic/export.h>
#include <asm/ftrace.h>
+#include <asm/frame.h>
+#include <asm/csr.h>
.text
@@ -97,6 +99,11 @@
REG_S x29, PT_T4(sp)
REG_S x30, PT_T5(sp)
REG_S x31, PT_T6(sp)
+
+#ifdef CONFIG_FRAME_POINTER
+ li s0, SR_PP
+ REG_S s0, PT_STATUS(sp)
+#endif
.endm
.macro RESTORE_ALL
@@ -172,6 +179,7 @@ ENDPROC(ftrace_caller)
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
ENTRY(ftrace_regs_caller)
SAVE_ALL
+ ENCODE_FRAME_POINTER
addi a0, ra, -FENTRY_RA_OFFSET
la a1, function_trace_op
--
2.17.1
next prev parent reply other threads:[~2022-09-20 15:16 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-20 15:11 [PATCH -next 0/7] riscv: Improvments for stacktrace Chen Zhongjin
2022-09-20 15:11 ` [PATCH -next 1/7] riscv: stacktrace: Replace walk_stackframe with arch_stack_walk Chen Zhongjin
2022-09-20 15:11 ` [PATCH -next 2/7] riscv: stacktrace: Introduce unwind functions Chen Zhongjin
2022-09-20 15:11 ` [PATCH -next 3/7] riscv: stacktrace: Save pt_regs in encoded fp on irq entry Chen Zhongjin
2022-09-21 2:13 ` Guo Ren
2022-09-20 15:11 ` [PATCH -next 4/7] riscv: syscall: Don't clobber s0 when syscall Chen Zhongjin
2022-09-21 1:30 ` Guo Ren
2022-09-21 2:16 ` Guo Ren
2022-09-20 15:12 ` [PATCH -next 5/7] riscv: stacktrace: Implement stacktrace for irq Chen Zhongjin
2022-09-20 15:12 ` Chen Zhongjin [this message]
2022-09-21 1:43 ` [PATCH -next 6/7] riscv: stacktrace: Fix unwinding on ftrace_regs_call Guo Ren
2022-09-21 3:00 ` Chen Zhongjin
2022-09-20 15:12 ` [PATCH -next 7/7] riscv: stacktrace: Fix unwinding on __kretporbe_trampoline Chen Zhongjin
2022-09-21 2:30 ` [PATCH -next 0/7] riscv: Improvments for stacktrace Guo Ren
2022-09-21 12:33 ` Chen Zhongjin
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