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| author | Masami Hiramatsu <mhiramat@kernel.org> | 2021-09-14 23:42:12 +0900 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2021-09-30 21:24:07 -0400 |
| commit | df91c5bccb0c2cb868b54bd68a6ddf1fcbede6b1 (patch) | |
| tree | a59ebf2643820e0c4a7928e667f9b86fc77a7a7c /kernel/kprobes.c | |
| parent | 7391dd19027cec4e0edf81b7c27079ae0ecd2d6b (diff) | |
| download | linux-df91c5bccb0c2cb868b54bd68a6ddf1fcbede6b1.tar.bz2 | |
kprobes: Enable stacktrace from pt_regs in kretprobe handler
Since the ORC unwinder from pt_regs requires setting up regs->ip
correctly, set the correct return address to the regs->ip before
calling user kretprobe handler.
This allows the kretrprobe handler to trace stack from the
kretprobe's pt_regs by stack_trace_save_regs() (eBPF will do
this), instead of stack tracing from the handler context by
stack_trace_save() (ftrace will do this).
Link: https://lkml.kernel.org/r/163163053237.489837.4272653874525136832.stgit@devnote2
Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/kprobes.c')
| -rw-r--r-- | kernel/kprobes.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 833f07f33115..ebc587b9a346 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1937,6 +1937,13 @@ unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs, BUG_ON(1); } + /* + * Set the return address as the instruction pointer, because if the + * user handler calls stack_trace_save_regs() with this 'regs', + * the stack trace will start from the instruction pointer. + */ + instruction_pointer_set(regs, (unsigned long)correct_ret_addr); + /* Run the user handler of the nodes. */ first = current->kretprobe_instances.first; while (first) { |