lkml.org 
[lkml]   [2019]   [May]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.1 050/405] io_uring: use cpu_online() to check p->sq_thread_cpu instead of cpu_possible()
    Date
    [ Upstream commit 7889f44dd9cee15aff1c3f7daf81ca4dfed48fc7 ]

    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 <jmoyer@redhat.com>
    Signed-off-by: Shenghui Wang <shhuiw@foxmail.com>
    Signed-off-by: Jens Axboe <axboe@kernel.dk>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    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 84efb8956734f..30a5687a17b65 100644
    --- a/fs/io_uring.c
    +++ b/fs/io_uring.c
    @@ -2334,7 +2334,7 @@ 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,
    --
    2.20.1


    \
     
     \ /
      Last update: 2019-05-30 05:11    [W:4.063 / U:0.664 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site