From: Mikulas Patocka mpatocka@redhat.com
[ Upstream commit 7e7df71fd57ff2894d96abb0080922bf39460a79 ]
I've got this infinite stacktrace when debugging another problem: [ 908.795225] INFO: rcu_preempt detected stalls on CPUs/tasks: [ 908.796176] 1-...!: (1 GPs behind) idle=952/1/4611686018427387904 softirq=1462/1462 fqs=355 [ 908.797692] 2-...!: (1 GPs behind) idle=f42/1/4611686018427387904 softirq=1550/1551 fqs=355 [ 908.799189] (detected by 0, t=2109 jiffies, g=130, c=129, q=235) [ 908.800284] Task dump for CPU 1: [ 908.800871] kworker/1:1 R running task 0 32 2 0x00000022 [ 908.802127] Workqueue: writecache-writeabck writecache_writeback [dm_writecache] [ 908.820285] Call trace: [ 908.824785] __switch_to+0x68/0x90 [ 908.837661] 0xfffffe00603afd90 [ 908.844119] 0xfffffe00603afd90 [ 908.850091] 0xfffffe00603afd90 [ 908.854285] 0xfffffe00603afd90 [ 908.863538] 0xfffffe00603afd90 [ 908.865523] 0xfffffe00603afd90
The machine just locked up and kept on printing the same line over and over again. This patch fixes it.
Signed-off-by: Mikulas Patocka mpatocka@redhat.com Signed-off-by: Will Deacon will.deacon@arm.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com --- arch/arm64/kernel/stacktrace.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c index 0cc01e0d38eb..40b2680748f8 100644 --- a/arch/arm64/kernel/stacktrace.c +++ b/arch/arm64/kernel/stacktrace.c @@ -69,6 +69,9 @@ int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame) frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp)); frame->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp + 8));
+ if (frame->fp <= fp) + return -EINVAL; + #ifdef CONFIG_FUNCTION_GRAPH_TRACER if (tsk->ret_stack && (frame->pc == (unsigned long)return_to_handler)) {