mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-10-31 08:28:13 +00:00
19138af1bd
Since the kretprobe replaces the function return address with
the kretprobe_trampoline on the stack, x86 unwinders can not
continue the stack unwinding at that point, or record
kretprobe_trampoline instead of correct return address.
To fix this issue, find the correct return address from task's
kretprobe_instances as like as function-graph tracer does.
With this fix, the unwinder can correctly unwind the stack
from kretprobe event on x86, as below.
<...>-135 [003] ...1 6.722338: r_full_proxy_read_0: (vfs_read+0xab/0x1a0 <- full_proxy_read)
<...>-135 [003] ...1 6.722377: <stack trace>
=> kretprobe_trace_func+0x209/0x2f0
=> kretprobe_dispatcher+0x4a/0x70
=> __kretprobe_trampoline_handler+0xca/0x150
=> trampoline_handler+0x44/0x70
=> kretprobe_trampoline+0x2a/0x50
=> vfs_read+0xab/0x1a0
=> ksys_read+0x5f/0xe0
=> do_syscall_64+0x33/0x40
=> entry_SYSCALL_64_after_hwframe+0x44/0xae
Link: https://lkml.kernel.org/r/163163055130.489837.5161749078833497255.stgit@devnote2
Reported-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com>
Tested-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
72 lines
1.8 KiB
C
72 lines
1.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
#include <linux/sched.h>
|
|
#include <linux/ftrace.h>
|
|
#include <asm/ptrace.h>
|
|
#include <asm/bitops.h>
|
|
#include <asm/stacktrace.h>
|
|
#include <asm/unwind.h>
|
|
|
|
unsigned long unwind_get_return_address(struct unwind_state *state)
|
|
{
|
|
unsigned long addr;
|
|
|
|
if (unwind_done(state))
|
|
return 0;
|
|
|
|
addr = READ_ONCE_NOCHECK(*state->sp);
|
|
|
|
return unwind_recover_ret_addr(state, addr, state->sp);
|
|
}
|
|
EXPORT_SYMBOL_GPL(unwind_get_return_address);
|
|
|
|
unsigned long *unwind_get_return_address_ptr(struct unwind_state *state)
|
|
{
|
|
return NULL;
|
|
}
|
|
|
|
bool unwind_next_frame(struct unwind_state *state)
|
|
{
|
|
struct stack_info *info = &state->stack_info;
|
|
|
|
if (unwind_done(state))
|
|
return false;
|
|
|
|
do {
|
|
for (state->sp++; state->sp < info->end; state->sp++) {
|
|
unsigned long addr = READ_ONCE_NOCHECK(*state->sp);
|
|
|
|
if (__kernel_text_address(addr))
|
|
return true;
|
|
}
|
|
|
|
state->sp = PTR_ALIGN(info->next_sp, sizeof(long));
|
|
|
|
} while (!get_stack_info(state->sp, state->task, info,
|
|
&state->stack_mask));
|
|
|
|
return false;
|
|
}
|
|
EXPORT_SYMBOL_GPL(unwind_next_frame);
|
|
|
|
void __unwind_start(struct unwind_state *state, struct task_struct *task,
|
|
struct pt_regs *regs, unsigned long *first_frame)
|
|
{
|
|
memset(state, 0, sizeof(*state));
|
|
|
|
state->task = task;
|
|
state->sp = PTR_ALIGN(first_frame, sizeof(long));
|
|
|
|
get_stack_info(first_frame, state->task, &state->stack_info,
|
|
&state->stack_mask);
|
|
|
|
/*
|
|
* The caller can provide the address of the first frame directly
|
|
* (first_frame) or indirectly (regs->sp) to indicate which stack frame
|
|
* to start unwinding at. Skip ahead until we reach it.
|
|
*/
|
|
if (!unwind_done(state) &&
|
|
(!on_stack(&state->stack_info, first_frame, sizeof(long)) ||
|
|
!__kernel_text_address(*first_frame)))
|
|
unwind_next_frame(state);
|
|
}
|
|
EXPORT_SYMBOL_GPL(__unwind_start);
|