On Tue, Jan 11, 2022 at 10:02:09AM +0800, Ziyang Xuan (William) wrote: > > On Mon, Jan 10, 2022 at 09:23:22PM +0800, Ziyang Xuan wrote: > >> From: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > >> > >> [ commit bf74aa86e111aa3b2fbb25db37e3a3fab71b5b68 upstream ] > >> > >> Stop tx/rx cycle rely on the active state of tasklet and hrtimer > >> sequentially in bcm_remove_op(), the op object will be freed if they > >> are all unactive. Assume the hrtimer timeout is short, the hrtimer > >> cb has been excuted after tasklet conditional judgment which must be > >> false after last round tasklet_kill() and before condition > >> hrtimer_active(), it is false when execute to hrtimer_active(). Bug > >> is triggerd, because the stopping action is end and the op object > >> will be freed, but the tasklet is scheduled. The resources of the op > >> object will occur UAF bug. > > > > That is not the changelog text of this commit. Why modify it? > > Above statement is the reason why I want to backport the patch to > stable tree. Maybe I could give an extra cover-letter to explain > the details of the problem, but modify the original changelog. Is it? > > > > >> > >> ---------------------------------------------------------------------- > >> > >> This patch switches the timer to HRTIMER_MODE_SOFT, which executed the > >> timer callback in softirq context and removes the hrtimer_tasklet. > >> > >> Reported-by: syzbot+652023d5376450cc8516@xxxxxxxxxxxxxxxxxxxxxxxxx > > This is the public problem reporter. Do I need to move it to cover-letter > but here? > > >> Cc: stable@xxxxxxxxxxxxxxx # 4.19 > > I want to backport the patch to linux-4.19.y stable tree. How do I need to > modify? No need, I can take it like this, thanks. greg k-h
