On Wed, Dec 9, 2020 at 1:12 AM Daniel Borkmann <[email protected]> wrote: > > On 12/9/20 6:03 AM, Zhu Yanjun wrote: > > In the function xdp_umem_pin_pages, if npgs != umem->npgs and > > npgs >= 0, the function xdp_umem_unpin_pages is called. In this > > function, kfree is called to handle umem->pgs, and then in the > > function xdp_umem_pin_pages, kfree is called again to handle > > umem->pgs. Eventually, umem->pgs is freed twice. > > > > Acked-by: Björn Töpel <[email protected]> > > Signed-off-by: Zhu Yanjun <[email protected]> > > Please also fix up the commit log according to Bjorn's prior feedback [0]. > If it's just a cleanup, it should state so, the commit message right now > makes it sound like an actual double free bug.
The umem->pgs is actually freed twice. Since umem->pgs is set to NULL after the first kfree, the second kfree would not trigger call trace. IMO, the commit log is very clear about this. Zhu Yanjun > > [0] > https://lore.kernel.org/netdev/[email protected]/
