diff options
| author | Chen Huang <chenhuang5@huawei.com> | 2021-01-11 20:40:14 +0800 |
|---|---|---|
| committer | Palmer Dabbelt <palmerdabbelt@google.com> | 2021-01-14 15:09:13 -0800 |
| commit | f766f77a74f5784d8d4d3c36b1900731f97d08d0 (patch) | |
| tree | ea44eca33a9599d700a7a9802fbf4a2a76ad6fbc /arch/riscv | |
| parent | da401e89453266c11277b42e007159a2b6ef82d3 (diff) | |
| download | linux-f766f77a74f5784d8d4d3c36b1900731f97d08d0.tar.bz2 | |
riscv/stacktrace: Fix stack output without ra on the stack top
When a function doesn't have a callee, then it will not
push ra into the stack, such as lkdtm_BUG() function,
addi sp,sp,-16
sd s0,8(sp)
addi s0,sp,16
ebreak
The struct stackframe use {fp,ra} to get information from
stack, if walk_stackframe() with pr_regs, we will obtain
wrong value and bad stacktrace,
[<ffffffe00066c56c>] lkdtm_BUG+0x6/0x8
---[ end trace 18da3fbdf08e25d5 ]---
Correct the next fp and pc, after that, full stacktrace
shown as expects,
[<ffffffe00066c56c>] lkdtm_BUG+0x6/0x8
[<ffffffe0008b24a4>] lkdtm_do_action+0x14/0x1c
[<ffffffe00066c372>] direct_entry+0xc0/0x10a
[<ffffffe000439f86>] full_proxy_write+0x42/0x6a
[<ffffffe000309626>] vfs_write+0x7e/0x214
[<ffffffe00030992a>] ksys_write+0x98/0xc0
[<ffffffe000309960>] sys_write+0xe/0x16
[<ffffffe0002014bc>] ret_from_syscall+0x0/0x2
---[ end trace 61917f3d9a9fadcd ]---
Signed-off-by: Chen Huang <chenhuang5@huawei.com>
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Diffstat (limited to 'arch/riscv')
| -rw-r--r-- | arch/riscv/kernel/stacktrace.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c index 76dadf6d396b..51ce3620ac1f 100644 --- a/arch/riscv/kernel/stacktrace.c +++ b/arch/riscv/kernel/stacktrace.c @@ -54,9 +54,15 @@ void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs, /* Unwind stack frame */ frame = (struct stackframe *)fp - 1; sp = fp; - fp = frame->fp; - pc = ftrace_graph_ret_addr(current, NULL, frame->ra, - (unsigned long *)(fp - 8)); + if (regs && (regs->epc == pc) && (frame->fp & 0x7)) { + fp = frame->ra; + pc = regs->ra; + } else { + fp = frame->fp; + pc = ftrace_graph_ret_addr(current, NULL, frame->ra, + (unsigned long *)(fp - 8)); + } + } } |