ARM: 9066/1: ftrace: pause/unpause function graph tracer in cpu_suspend()

stable inclusion
from stable-5.10.39
commit ec324393a63cfd28e2182a3efd52c93766b6dcd0
bugzilla: 51881
CVE: NA

--------------------------------

[ Upstream commit 8252ca87 ]

Enabling function_graph tracer on ARM causes kernel panic, because the
function graph tracer updates the "return address" of a function in order
to insert a trace callback on function exit, it saves the function's
original return address in a return trace stack, but cpu_suspend() may not
return through the normal return path.

cpu_suspend() will resume directly via the cpu_resume path, but the return
trace stack has been set-up by the subfunctions of cpu_suspend(), which
makes the "return address" inconsistent with cpu_suspend().

This patch refers to Commit de818bd4
("arm64: kernel: pause/unpause function graph tracer in cpu_suspend()"),

fixes the issue by pausing/resuming the function graph tracer on the thread
executing cpu_suspend(), so that the function graph tracer state is kept
consistent across functions that enter power down states and never return
by effectively disabling graph tracer while they are executing.

Signed-off-by: louis.wang <liang26812@gmail.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Acked-by: Weilong Chen <chenweilong@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>