> 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? >> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> >> Signed-off-by: Anna-Maria Gleixner <anna-maria@xxxxxxxxxxxxx> >> Acked-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx> >> Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> >> Signed-off-by: Ziyang Xuan <william.xuanziyang@xxxxxxxxxx> >> --- >> net/can/bcm.c | 156 +++++++++++++++++--------------------------------- >> 1 file changed, 52 insertions(+), 104 deletions(-) > > What stable kernel tree(s) are you wanting this backported to? > > thanks, > > greg k-h > . > Thank you for your patient guidance.
