Shenghui Wang <[email protected]> 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 <[email protected]> > --- > fs/io_uring.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/fs/io_uring.c b/fs/io_uring.c > index 0e9fb2cb1984..aa3d39860a1c 100644 > --- a/fs/io_uring.c > +++ b/fs/io_uring.c > @@ -2241,7 +2241,7 @@ static int io_sq_offload_start(struct io_ring_ctx *ctx, > ctx->sqo_mm = current->mm; > > ret = -EINVAL; > - if (!cpu_possible(p->sq_thread_cpu)) > + if (!cpu_online(p->sq_thread_cpu)) > goto err; > > if (ctx->flags & IORING_SETUP_SQPOLL) { > @@ -2258,7 +2258,7 @@ static int io_sq_offload_start(struct io_ring_ctx *ctx, > > cpu = array_index_nospec(p->sq_thread_cpu, NR_CPUS); > ret = -EINVAL; > - if (!cpu_possible(p->sq_thread_cpu)) > + if (!cpu_online(p->sq_thread_cpu)) > goto err; > > ctx->sqo_thread = kthread_create_on_cpu(io_sq_thread,
Hmm. Why are we doing this check twice? Oh... Jens, I think you braino'd commit 917257daa0fea. Have a look. You probably wanted to get rid of the first check for cpu_possible. -Jeff
