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    Subject[PATCH 5.12 110/161] gfs2: fix scheduling while atomic bug in glocks
    Date
    From: Bob Peterson <rpeterso@redhat.com>

    commit 20265d9a67e40eafd39a8884658ca2e36f05985d upstream.

    Before this patch, in the unlikely event that gfs2_glock_dq encountered
    a withdraw, it would do a wait_on_bit to wait for its journal to be
    recovered, but it never released the glock's spin_lock, which caused a
    scheduling-while-atomic error.

    This patch unlocks the lockref spin_lock before waiting for recovery.

    Fixes: 601ef0d52e96 ("gfs2: Force withdraw to replay journals and wait for it to finish")
    Cc: stable@vger.kernel.org # v5.7+
    Reported-by: Alexander Aring <aahringo@redhat.com>
    Signed-off-by: Bob Peterson <rpeterso@redhat.com>
    Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    fs/gfs2/glock.c | 2 ++
    1 file changed, 2 insertions(+)

    --- a/fs/gfs2/glock.c
    +++ b/fs/gfs2/glock.c
    @@ -1465,9 +1465,11 @@ void gfs2_glock_dq(struct gfs2_holder *g
    glock_blocked_by_withdraw(gl) &&
    gh->gh_gl != sdp->sd_jinode_gl) {
    sdp->sd_glock_dqs_held++;
    + spin_unlock(&gl->gl_lockref.lock);
    might_sleep();
    wait_on_bit(&sdp->sd_flags, SDF_WITHDRAW_RECOVERY,
    TASK_UNINTERRUPTIBLE);
    + spin_lock(&gl->gl_lockref.lock);
    }
    if (gh->gh_flags & GL_NOCACHE)
    handle_callback(gl, LM_ST_UNLOCKED, 0, false);

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