On Fri, Sep 14, 2018 at 05:22:16PM +0800, Michel Dänzer wrote: > On 2018-09-14 10:22 a.m., Huang Rui wrote: > > On Thu, Sep 13, 2018 at 07:32:24PM +0800, Christian König wrote: > >> Am 13.09.2018 um 10:31 schrieb Huang Rui: > >>> On Wed, Sep 12, 2018 at 09:23:55PM +0200, Christian König wrote: > >>>> While cutting the lists we sometimes accidentally added a list_head from > >>>> the stack to the LRUs, effectively corrupting the list. > >>>> > >>>> Remove the list cutting and use explicit list manipulation instead. > >>> This patch actually fixes the corruption bug. Was it a defect of > >>> list_cut_position or list_splice handlers? > >> > >> We somehow did something illegal with list_cut_position. I haven't > >> narrowed it down till the end, but we ended up with list_heads from the > >> stack to the lru. > > > > I am confused, in theory, even we do any manipulation with list helper, it > > should not trigger the list corruption. The usage of those helpers should > > ensure the list operation safely... > > There's nothing the helpers can do about being passed in pointers to > stack memory. It's a bug in the code using the helpers. > Actually, I was checking carefully with list cut and splice in our case, and it didn't find any illegal use. However, I also agree with the explicit list manipulation is more clear and simple for now. Thanks, Ray
