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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Max Filippov <jcmvbkbc@gmail.com>
Subject: [PATCH 4.9 75/76] xtensa: fix return_address
Date:   Mon, 15 Apr 2019 20:44:39 +0200
Message-Id: <20190415183729.593436709@linuxfoundation.org>
In-Reply-To: <20190415183707.712011689@linuxfoundation.org>
References: <20190415183707.712011689@linuxfoundation.org>
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From: Max Filippov <jcmvbkbc@gmail.com>

commit ada770b1e74a77fff2d5f539bf6c42c25f4784db upstream.

return_address returns the address that is one level higher in the call
stack than requested in its argument, because level 0 corresponds to its
caller's return address. Use requested level as the number of stack
frames to skip.

This fixes the address reported by might_sleep and friends.

Cc: stable@vger.kernel.org
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/xtensa/kernel/stacktrace.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/arch/xtensa/kernel/stacktrace.c
+++ b/arch/xtensa/kernel/stacktrace.c
@@ -272,10 +272,14 @@ static int return_address_cb(struct stac
 	return 1;
 }
 
+/*
+ * level == 0 is for the return address from the caller of this function,
+ * not from this function itself.
+ */
 unsigned long return_address(unsigned level)
 {
 	struct return_addr_data r = {
-		.skip = level + 1,
+		.skip = level,
 	};
 	walk_stackframe(stack_pointer(NULL), return_address_cb, &r);
 	return r.addr;