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https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
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97ceddbc94
During unwinding, unwind_done() is used as an end condition. Normally it unwind to the user stack and then set the stack type to unknown, which is a normal exit. When something unexpected happens in unwind process and we cannot unwind anymore, we should set the error flag, and also set the stack type to unknown to indicate that the unwind process can not continue. The error flag emphasizes that the unwind process produce an unexpected error. There is no unexpected things when we unwind the PT_REGS in the top of IRQ stack and find out that is an user mode PT_REGS. Thus, we should not set error flag and just set stack type to unknown. Reported-by: Hengqi Chen <hengqi.chen@gmail.com> Acked-by: Hengqi Chen <hengqi.chen@gmail.com> Signed-off-by: Jinyang He <hejinyang@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
81 lines
1.8 KiB
C
81 lines
1.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Stack trace management functions
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*
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* Copyright (C) 2022 Loongson Technology Corporation Limited
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*/
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#include <linux/sched.h>
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#include <linux/stacktrace.h>
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#include <linux/uaccess.h>
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#include <asm/stacktrace.h>
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#include <asm/unwind.h>
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void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
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struct task_struct *task, struct pt_regs *regs)
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{
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unsigned long addr;
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struct pt_regs dummyregs;
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struct unwind_state state;
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if (!regs) {
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regs = &dummyregs;
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if (task == current) {
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regs->regs[3] = (unsigned long)__builtin_frame_address(0);
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regs->csr_era = (unsigned long)__builtin_return_address(0);
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} else {
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regs->regs[3] = thread_saved_fp(task);
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regs->csr_era = thread_saved_ra(task);
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}
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regs->regs[1] = 0;
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}
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for (unwind_start(&state, task, regs);
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!unwind_done(&state); unwind_next_frame(&state)) {
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addr = unwind_get_return_address(&state);
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if (!addr || !consume_entry(cookie, addr))
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break;
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}
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}
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static int
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copy_stack_frame(unsigned long fp, struct stack_frame *frame)
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{
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int ret = 1;
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unsigned long err;
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unsigned long __user *user_frame_tail;
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user_frame_tail = (unsigned long *)(fp - sizeof(struct stack_frame));
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if (!access_ok(user_frame_tail, sizeof(*frame)))
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return 0;
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pagefault_disable();
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err = (__copy_from_user_inatomic(frame, user_frame_tail, sizeof(*frame)));
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if (err || (unsigned long)user_frame_tail >= frame->fp)
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ret = 0;
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pagefault_enable();
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return ret;
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}
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void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie,
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const struct pt_regs *regs)
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{
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unsigned long fp = regs->regs[22];
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while (fp && !((unsigned long)fp & 0xf)) {
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struct stack_frame frame;
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frame.fp = 0;
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frame.ra = 0;
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if (!copy_stack_frame(fp, &frame))
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break;
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if (!frame.ra)
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break;
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if (!consume_entry(cookie, frame.ra))
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break;
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fp = frame.fp;
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}
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}
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