lkml.org 
[lkml]   [2018]   [Sep]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v5 05/12] RISC-V: Disable preemption before enabling interrupts
Date
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 <palmer@sifive.com>
[Atish: Commit text and code comment formatting update]
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Christoph Hellwig <hch@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
\
 
 \ /
  Last update: 2018-09-13 20:38    [W:0.073 / U:0.896 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site