lkml.org 
[lkml]   [2022]   [Aug]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.15 045/244] bpf: Acquire map uref in .init_seq_private for hash map iterator
    Date
    From: Hou Tao <houtao1@huawei.com>

    commit ef1e93d2eeb58a1f08c37b22a2314b94bc045f15 upstream.

    bpf_iter_attach_map() acquires a map uref, and the uref may be released
    before or in the middle of iterating map elements. For example, the uref
    could be released in bpf_iter_detach_map() as part of
    bpf_link_release(), or could be released in bpf_map_put_with_uref() as
    part of bpf_map_release().

    So acquiring an extra map uref in bpf_iter_init_hash_map() and
    releasing it in bpf_iter_fini_hash_map().

    Fixes: d6c4503cc296 ("bpf: Implement bpf iterator for hash maps")
    Signed-off-by: Hou Tao <houtao1@huawei.com>
    Acked-by: Yonghong Song <yhs@fb.com>
    Link: https://lore.kernel.org/r/20220810080538.1845898-3-houtao@huaweicloud.com
    Signed-off-by: Alexei Starovoitov <ast@kernel.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    kernel/bpf/hashtab.c | 2 ++
    1 file changed, 2 insertions(+)

    --- a/kernel/bpf/hashtab.c
    +++ b/kernel/bpf/hashtab.c
    @@ -2019,6 +2019,7 @@ static int bpf_iter_init_hash_map(void *
    seq_info->percpu_value_buf = value_buf;
    }

    + bpf_map_inc_with_uref(map);
    seq_info->map = map;
    seq_info->htab = container_of(map, struct bpf_htab, map);
    return 0;
    @@ -2028,6 +2029,7 @@ static void bpf_iter_fini_hash_map(void
    {
    struct bpf_iter_seq_hash_map_info *seq_info = priv_data;

    + bpf_map_put_with_uref(seq_info->map);
    kfree(seq_info->percpu_value_buf);
    }


    \
     
     \ /
      Last update: 2022-08-23 11:48    [W:4.031 / U:0.416 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site