From: Masami Hiramatsu <mhiramat@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>, Ingo Molnar <mingo@kernel.org>
Cc: X86 ML <x86@kernel.org>, Masami Hiramatsu <mhiramat@kernel.org>,
Daniel Xu <dxu@dxuuu.xyz>,
linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
kuba@kernel.org, mingo@redhat.com, ast@kernel.org,
tglx@linutronix.de, kernel-team@fb.com, yhs@fb.com,
Josh Poimboeuf <jpoimboe@redhat.com>
Subject: [PATCH -tip v2 09/10] x86/unwind/orc: Fixup kretprobe trampoline entry
Date: Fri, 12 Mar 2021 15:43:23 +0900 [thread overview]
Message-ID: <161553140351.1038734.4282308401106671492.stgit@devnote2> (raw)
In-Reply-To: <161553130371.1038734.7661319550287837734.stgit@devnote2>
Since the kretprobe replaces the function return address with
the kretprobe_trampoline on the stack, the ORC unwinder can not
continue the stack unwinding at that point.
To fix this issue, correct state->ip as like as function-graph
tracer in the unwind_next_frame().
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
Changes in v2:
- Remove kretprobe wrapper functions from unwind_orc.c
- Do not fixup state->ip when unwinding with regs because
kretprobe fixup instruction pointer before calling handler.
---
arch/x86/include/asm/unwind.h | 4 ++++
arch/x86/kernel/unwind_orc.c | 16 ++++++++++++++++
2 files changed, 20 insertions(+)
diff --git a/arch/x86/include/asm/unwind.h b/arch/x86/include/asm/unwind.h
index 70fc159ebe69..ab5e45b848d5 100644
--- a/arch/x86/include/asm/unwind.h
+++ b/arch/x86/include/asm/unwind.h
@@ -4,6 +4,7 @@
#include <linux/sched.h>
#include <linux/ftrace.h>
+#include <linux/llist.h>
#include <asm/ptrace.h>
#include <asm/stacktrace.h>
@@ -20,6 +21,9 @@ struct unwind_state {
bool signal, full_regs;
unsigned long sp, bp, ip;
struct pt_regs *regs, *prev_regs;
+#if defined(CONFIG_KRETPROBES)
+ struct llist_node *kr_iter;
+#endif
#elif defined(CONFIG_UNWINDER_FRAME_POINTER)
bool got_irq;
unsigned long *bp, *orig_sp, ip;
diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c
index 2a1d47f47eee..1d1b9388a1b1 100644
--- a/arch/x86/kernel/unwind_orc.c
+++ b/arch/x86/kernel/unwind_orc.c
@@ -2,6 +2,7 @@
#include <linux/objtool.h>
#include <linux/module.h>
#include <linux/sort.h>
+#include <linux/kprobes.h>
#include <asm/ptrace.h>
#include <asm/stacktrace.h>
#include <asm/unwind.h>
@@ -536,6 +537,21 @@ bool unwind_next_frame(struct unwind_state *state)
state->ip = ftrace_graph_ret_addr(state->task, &state->graph_idx,
state->ip, (void *)ip_p);
+ /*
+ * When the stack unwinder is called from the kretprobe handler
+ * or the interrupt handler which occurs in the kretprobe
+ * trampoline code, %sp is shown on the stack instead of the
+ * return address because kretprobe_trampoline() does
+ * "push %sp" at first.
+ * And also the unwinder may find the kretprobe_trampoline
+ * instead of the real return address on stack.
+ * In those cases, find the correct return address from
+ * task->kretprobe_instances list.
+ */
+ if (state->ip == sp ||
+ is_kretprobe_trampoline(state->ip))
+ state->ip = kretprobe_find_ret_addr(state->task,
+ &state->kr_iter);
state->sp = sp;
state->regs = NULL;
next prev parent reply other threads:[~2021-03-12 6:44 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-12 6:41 [PATCH -tip v2 00/10] kprobes: Fix stacktrace with kretprobes Masami Hiramatsu
2021-03-12 6:41 ` [PATCH -tip v2 01/10] ia64: kprobes: Fix to pass correct trampoline address to the handler Masami Hiramatsu
2021-03-12 6:42 ` [PATCH -tip v2 02/10] kprobes: treewide: Replace arch_deref_entry_point() with dereference_function_descriptor() Masami Hiramatsu
2021-05-24 9:26 ` Naveen N. Rao
2021-05-24 23:41 ` Masami Hiramatsu
2021-03-12 6:42 ` [PATCH -tip v2 03/10] kprobes: treewide: Remove trampoline_address from kretprobe_trampoline_handler() Masami Hiramatsu
2021-03-12 6:42 ` [PATCH -tip v2 04/10] kprobes: stacktrace: Recover the address changed by kretprobe Masami Hiramatsu
2021-03-17 0:27 ` Masami Hiramatsu
2021-03-12 6:42 ` [PATCH -tip v2 05/10] x86/kprobes: Add UNWIND_HINT_FUNC on kretprobe_trampoline code Masami Hiramatsu
2021-03-12 6:42 ` [PATCH -tip v2 06/10] ARC: Add instruction_pointer_set() API Masami Hiramatsu
2021-03-12 6:43 ` [PATCH -tip v2 07/10] ia64: " Masami Hiramatsu
2021-03-12 6:43 ` [PATCH -tip v2 08/10] kprobes: Setup instruction pointer in __kretprobe_trampoline_handler Masami Hiramatsu
2021-03-12 6:43 ` Masami Hiramatsu [this message]
2021-03-12 6:43 ` [PATCH -tip v2 10/10] tracing: Remove kretprobe unknown indicator from stacktrace Masami Hiramatsu
2021-03-12 18:56 ` [PATCH -tip v2 00/10] kprobes: Fix stacktrace with kretprobes Daniel Xu
2021-03-16 2:30 ` Josh Poimboeuf
2021-03-16 6:30 ` Masami Hiramatsu
2021-05-17 21:06 ` Andrii Nakryiko
2021-05-23 14:22 ` Masami Hiramatsu
2021-05-24 17:49 ` Andrii Nakryiko
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