diff mbox series

[RFC,v2,6/8] arm64: Check the return PC of every stack frame

Message ID 20210315165800.5948-7-madvenka@linux.microsoft.com (mailing list archive)
State New, archived
Headers show
Series arm64: Implement reliable stack trace | expand

Commit Message

Madhavan T. Venkataraman March 15, 2021, 4:57 p.m. UTC 
From: "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com>

If a function encountered in a stack trace is not a valid kernel text
address, the stack trace is considered unreliable. Mark the stack trace
as not reliable.

Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
---
 arch/arm64/kernel/stacktrace.c | 10 ++++++++++
 1 file changed, 10 insertions(+)
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Patch

diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index 594806a0c225..358aae3906d7 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -101,6 +101,16 @@  static void check_if_reliable(unsigned long fp, struct stackframe *frame,
 		}
 	}
 #endif
+
+	/*
+	 * A NULL or invalid return address probably means there's some
+	 * generated code which __kernel_text_address() doesn't know about.
+	 * Mark the stack trace as not reliable.
+	 */
+	if (!__kernel_text_address(frame->pc)) {
+		frame->reliable = false;
+		return;
+	}
 }
 
 /*