| Message ID | 20201128062242.825448-1-chenhuang5@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] riscv: stacktrace: fix stackframe without ra on the top | expand |
diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c index 595342910c3f..3842fac26e85 100644 --- a/arch/riscv/kernel/stacktrace.c +++ b/arch/riscv/kernel/stacktrace.c @@ -57,9 +57,14 @@ 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 && (pc == regs->epc) && (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)); + } } }
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> --- arch/riscv/kernel/stacktrace.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)