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authorZong Li <zong.li@sifive.com>2020-10-21 10:38:39 +0300
committerThomas Gleixner <tglx@linutronix.de>2020-10-26 14:12:27 +0300
commit4230e2deaa484b385aa01d598b2aea8e7f2660a6 (patch)
treec542bc412a1c1769616b3f857ac8cc396d0674b0 /kernel/stop_machine.c
parent3650b228f83adda7e5ee532e2b90429c03f7b9ec (diff)
downloadlinux-4230e2deaa484b385aa01d598b2aea8e7f2660a6.tar.xz
stop_machine, rcu: Mark functions as notrace
Some architectures assume that the stopped CPUs don't make function calls to traceable functions when they are in the stopped state. See also commit cb9d7fd51d9f ("watchdog: Mark watchdog touch functions as notrace"). Violating this assumption causes kernel crashes when switching tracer on RISC-V. Mark rcu_momentary_dyntick_idle() and stop_machine_yield() notrace to prevent this. Fixes: 4ecf0a43e729 ("processor: get rid of cpu_relax_yield") Fixes: 366237e7b083 ("stop_machine: Provide RCU quiescent state in multi_cpu_stop()") Signed-off-by: Zong Li <zong.li@sifive.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Atish Patra <atish.patra@wdc.com> Tested-by: Colin Ian King <colin.king@canonical.com> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Acked-by: Paul E. McKenney <paulmck@kernel.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20201021073839.43935-1-zong.li@sifive.com
Diffstat (limited to 'kernel/stop_machine.c')
-rw-r--r--kernel/stop_machine.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
index 865bb0228ab6..890b79cf0e7c 100644
--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -178,7 +178,7 @@ static void ack_state(struct multi_stop_data *msdata)
set_state(msdata, msdata->state + 1);
}
-void __weak stop_machine_yield(const struct cpumask *cpumask)
+notrace void __weak stop_machine_yield(const struct cpumask *cpumask)
{
cpu_relax();
}