lkml.org 
[lkml]   [2019]   [Mar]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.19 137/149] gfs2: Fix missed wakeups in find_insert_glock
    Date
    4.19-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Andreas Gruenbacher <agruenba@redhat.com>

    commit 605b0487f0bc1ae9963bf52ece0f5c8055186f81 upstream.

    Mark Syms has reported seeing tasks that are stuck waiting in
    find_insert_glock. It turns out that struct lm_lockname contains four padding
    bytes on 64-bit architectures that function glock_waitqueue doesn't skip when
    hashing the glock name. As a result, we can end up waking up the wrong
    waitqueue, and the waiting tasks may be stuck forever.

    Fix that by using ht_parms.key_len instead of sizeof(struct lm_lockname) for
    the key length.

    Reported-by: Mark Syms <mark.syms@citrix.com>
    Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
    Signed-off-by: Bob Peterson <rpeterso@redhat.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    fs/gfs2/glock.c | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    --- a/fs/gfs2/glock.c
    +++ b/fs/gfs2/glock.c
    @@ -107,7 +107,7 @@ static int glock_wake_function(wait_queu

    static wait_queue_head_t *glock_waitqueue(struct lm_lockname *name)
    {
    - u32 hash = jhash2((u32 *)name, sizeof(*name) / 4, 0);
    + u32 hash = jhash2((u32 *)name, ht_parms.key_len / 4, 0);

    return glock_wait_table + hash_32(hash, GLOCK_WAIT_TABLE_BITS);
    }

    \
     
     \ /
      Last update: 2019-03-12 18:47    [W:4.634 / U:0.016 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site