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aa44433ac4
Use the perf_callchain_user() code as blueprint to also add support for
USER_STACKTRACE. To describe how to use this cite the commit message of the
LoongArch implementation which came with commit 4d7bf939df ("LoongArch:
Add USER_STACKTRACE support"), but replace -fno-omit-frame-pointer option
with the s390 specific -mbackchain option:
====================================================================== To
get the best stacktrace output, you can compile your userspace programs
with frame pointers (at least glibc + the app you are tracing).
1, export "CC = gcc -mbackchain";
2, compile your programs with "CC";
3, use uprobe to get stacktrace output.
...
echo 'p:malloc /usr/lib64/libc.so.6:0x0a4704 size=%r2:u64' > uprobe_events
echo 'p:free /usr/lib64/libc.so.6:0x0a4d50 ptr=%r2:u64' >> uprobe_events
echo 'comm == "demo"' > ./events/uprobes/malloc/filter
echo 'comm == "demo"' > ./events/uprobes/free/filter
echo 1 > ./options/userstacktrace
echo 1 > ./options/sym-userobj
...
======================================================================
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
104 lines
2.3 KiB
C
104 lines
2.3 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 IBM Corp. 2006
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*/
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#include <linux/stacktrace.h>
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#include <linux/uaccess.h>
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#include <linux/compat.h>
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#include <asm/stacktrace.h>
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#include <asm/unwind.h>
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#include <asm/kprobes.h>
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#include <asm/ptrace.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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struct unwind_state state;
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unsigned long addr;
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unwind_for_each_frame(&state, task, regs, 0) {
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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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int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry,
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void *cookie, struct task_struct *task)
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{
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struct unwind_state state;
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unsigned long addr;
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unwind_for_each_frame(&state, task, NULL, 0) {
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if (state.stack_info.type != STACK_TYPE_TASK)
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return -EINVAL;
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if (state.regs)
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return -EINVAL;
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addr = unwind_get_return_address(&state);
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if (!addr)
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return -EINVAL;
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#ifdef CONFIG_RETHOOK
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/*
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* Mark stacktraces with krethook functions on them
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* as unreliable.
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*/
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if (state.ip == (unsigned long)arch_rethook_trampoline)
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return -EINVAL;
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#endif
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if (!consume_entry(cookie, addr))
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return -EINVAL;
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}
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/* Check for stack corruption */
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if (unwind_error(&state))
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return -EINVAL;
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return 0;
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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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struct stack_frame_user __user *sf;
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unsigned long ip, sp;
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bool first = true;
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if (is_compat_task())
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return;
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if (!consume_entry(cookie, instruction_pointer(regs)))
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return;
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sf = (void __user *)user_stack_pointer(regs);
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pagefault_disable();
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while (1) {
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if (__get_user(sp, &sf->back_chain))
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break;
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if (__get_user(ip, &sf->gprs[8]))
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break;
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if (ip & 0x1) {
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/*
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* If the instruction address is invalid, and this
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* is the first stack frame, assume r14 has not
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* been written to the stack yet. Otherwise exit.
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*/
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if (first && !(regs->gprs[14] & 0x1))
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ip = regs->gprs[14];
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else
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break;
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}
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if (!consume_entry(cookie, ip))
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break;
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/* Sanity check: ABI requires SP to be aligned 8 bytes. */
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if (!sp || sp & 0x7)
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break;
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sf = (void __user *)sp;
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first = false;
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}
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pagefault_enable();
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}
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