The following commit has been merged into the sched/core branch of tip:
Commit-ID: ab31c7fd2d37bc3580d9d712d5f2dfb69901fca9
Gitweb: https://git.kernel.org/tip/ab31c7fd2d37bc3580d9d712d5f2dfb69901fca9
Author: Huang, Ying <ying.huang@xxxxxxxxx>
AuthorDate: Tue, 22 Mar 2022 08:39:22 +01:00
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Tue, 22 Mar 2022 08:49:22 +01:00
sched/numa: Fix boot crash on arm64 systems
Qian Cai reported a boot crash on arm64 systems, caused by:
0fb3978b0aac ("sched/numa: Fix NUMA topology for systems with CPU-less nodes")
The bug is that node_state() must be supplied a valid node_states[] array index,
but in task_numa_placement() the max_nid search can fail with NUMA_NO_NODE,
which is not a valid index.
Fix it by checking that max_nid is a valid index.
[ mingo: Added changelog. ]
Fixes: 0fb3978b0aac ("sched/numa: Fix NUMA topology for systems with CPU-less nodes")
Reported-by: Qian Cai <quic_qiancai@xxxxxxxxxxx>
Tested-by: Qian Cai <quic_qiancai@xxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/sched/fair.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 89d21fd..ee0664c 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -2437,7 +2437,7 @@ static void task_numa_placement(struct task_struct *p)
}
/* Cannot migrate task to CPU-less node */
- if (!node_state(max_nid, N_CPU)) {
+ if (max_nid != NUMA_NO_NODE && !node_state(max_nid, N_CPU)) {
int near_nid = max_nid;
int distance, near_distance = INT_MAX;
|