On Fri, 01 May 2020 22:28:50 +0200 Peter Zijlstra <pet...@infradead.org> wrote:
> The current notifiers have the following error handling pattern all > over the place: > > int err, nr; > > err = __foo_notifier_call_chain(&chain, val_up, v, -1, &nr); > if (err & NOTIFIER_STOP_MASK) > __foo_notifier_call_chain(&chain, val_down, v, nr-1, NULL) > > And aside from the endless repetition thereof, it is broken. Consider > blocking notifiers; both calls take and drop the rwsem, this means > that the notifier list can change in between the two calls, making @nr > meaningless. > > Fix this by replacing all the __foo_notifier_call_chain() functions > with foo_notifier_call_chain_robust() that embeds the above pattern, > but ensures it is inside a single lock region. > > Note: I switched atomic_notifier_call_chain_robust() to use > the spinlock, since RCU cannot provide the guarantee > required for the recovery. > > Note: software_resume() error handling was broken afaict. > > Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> > Acked-by: Rafael J. Wysocki <rafael.j.wyso...@intel.com> > --- > include/linux/notifier.h | 15 +-- > kernel/cpu_pm.c | 48 ++++-------- > kernel/notifier.c | 144 > ++++++++++++++++++++++--------------- > kernel/power/hibernate.c | 26 +++--- > kernel/power/main.c | 8 +- > kernel/power/power.h | 3 > kernel/power/suspend.c | 14 +-- > kernel/power/user.c | 14 +-- > tools/power/pm-graph/sleepgraph.py | 2 > 9 files changed, 141 insertions(+), 133 deletions(-) > This looks like something that can go in outside this series. -- Steve
