diff options
authorShenghui Wang <>2019-05-07 16:03:19 +0800
committerJens Axboe <>2019-05-07 08:41:26 -0600
commit7889f44dd9cee15aff1c3f7daf81ca4dfed48fc7 (patch)
parentefeb862bd5bc001636e690debf6f9fbba98e5bfd (diff)
io_uring: use cpu_online() to check p->sq_thread_cpu instead of cpu_possible()for-5.2/io_uring-20190507for-5.2/io_uring
This issue is found by running liburing/test/io_uring_setup test. When test run, the testcase "attempt to bind to invalid cpu" would not pass with messages like: io_uring_setup(1, 0xbfc2f7c8), \ flags: IORING_SETUP_SQPOLL|IORING_SETUP_SQ_AFF, \ resv: 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000, \ sq_thread_cpu: 2 expected -1, got 3 FAIL On my system, there is: CPU(s) possible : 0-3 CPU(s) online : 0-1 CPU(s) offline : 2-3 CPU(s) present : 0-1 The sq_thread_cpu 2 is offline on my system, so the bind should fail. But cpu_possible() will pass the check. We shouldn't be able to bind to an offline cpu. Use cpu_online() to do the check. After the change, the testcase run as expected: EINVAL will be returned for cpu offlined. Reviewed-by: Jeff Moyer <> Signed-off-by: Shenghui Wang <> Signed-off-by: Jens Axboe <>
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 1157a068c253..48ea3977012a 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2471,7 +2471,7 @@ static int io_sq_offload_start(struct io_ring_ctx *ctx,
ret = -EINVAL;
- if (!cpu_possible(cpu))
+ if (!cpu_online(cpu))
goto err;
ctx->sqo_thread = kthread_create_on_cpu(io_sq_thread,