On Thu, 2020-02-27 at 08:33 -0600, zanussi@xxxxxxxxxx wrote: > From: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> > > v4.14.170-rt75-rc2 stable review patch. > If anyone has any objections, please let me know. > > ----------- > > > [ Upstream commit 140d7f54a5fff02898d2ca9802b39548bf7455f1 ] > > If user task changes the CPU affinity mask of a running task it will > dispatch migration request if the current CPU is no longer allowed. This > might happen shortly before a task enters a migrate_disable() section. > Upon leaving the migrate_disable() section, the task will notice that > the current CPU is no longer allowed and will will dispatch its own > migration request to move it off the current CPU. > While invoking __schedule() the first migration request will be > processed and the task returns on the "new" CPU with "arg.done = 0". Its > own migration request will be processed shortly after and will result in > memory corruption if the stack memory, designed for request, was used > otherwise in the meantime. > > Spin until the migration request has been processed if it was accepted. > > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> > Signed-off-by: Tom Zanussi <zanussi@xxxxxxxxxx> > --- > kernel/sched/core.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) As I said in https://marc.info/?l=linux-rt-users&m=158258256415340&w=2 if you take thhis you should take the followup 2dcd94b443c5dcbc ("sched: migrate_enable: Use per-cpu cpu_stop_work") -Scott
