Currently, irq is enabled before preemption disabling happens.
If the scheduler fired right here and cpu is scheduled then it
may blow up.
Signed-off-by: Palmer Dabbelt <pal...@sifive.com>
[Atish: Commit text and code comment formatting update]
Signed-off-by: Atish Patra <atish.pa...@wdc.com>
Reviewed-by: Christoph Hellwig <h...@lst.de>
---
arch/riscv/kernel/smpboot.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index 712e9ca8..670749ec 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -111,7 +111,11 @@ asmlinkage void __init smp_callin(void)
* a local TLB flush right now just in case.
*/
local_flush_tlb_all();
- local_irq_enable();
+ /*
+ * Disable preemption before enabling interrupts, so we don't try to
+ * schedule a CPU that hasn't actually started yet.
+ */
preempt_disable();
+ local_irq_enable();
cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
}
--
2.7.4
