Shenghui Wang <shhuiw@xxxxxxxxxxx> writes: > 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. > > Signed-off-by: Shenghui Wang <shhuiw@xxxxxxxxxxx> > --- > fs/io_uring.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/io_uring.c b/fs/io_uring.c > index d91cbd53d3ca..718d7b873f4a 100644 > --- a/fs/io_uring.c > +++ b/fs/io_uring.c > @@ -2472,7 +2472,7 @@ static int io_sq_offload_start(struct io_ring_ctx *ctx, > nr_cpu_ids); > > ret = -EINVAL; > - if (!cpu_possible(cpu)) > + if (!cpu_online(cpu)) > goto err; > > ctx->sqo_thread = kthread_create_on_cpu(io_sq_thread, Reviewed-by: Jeff Moyer <jmoyer@xxxxxxxxxx>
