Oops, forgot to cc Lai. On Mon, Jan 29, 2024 at 11:11:47PM -1000, Tejun Heo wrote: > Hello, > > The only generic interface to execute asynchronously in the BH context is > tasklet; however, it's marked deprecated and has some design flaws such as > the execution code accessing the tasklet item after the execution is > complete which can lead to subtle use-after-free in certain usage scenarios > and less-developed flush and cancel mechanisms. > > Mikulas Patocka recently reported that dm-crypt and dm-crypt are affected by > the access-after-completion issue and suggested adding TASKLET_STATE_ONESHOT > flag which selectively removes post-completion access while significantly > limiting how the tasklet can be used in the following thread: > > http://lkml.kernel.org/r/82b964f0-c2c8-a2c6-5b1f-f3145dc2c8e5@xxxxxxxxxx > > Linus didn't like the approach and suggested extending workqueue to support > execution from atomic context: > > http://lkml.kernel.org/r/CAHk-=wjDW53w4-YcSmgKC5RruiRLHmJ1sXeYdp_ZgVoBw=5byA@xxxxxxxxxxxxxx > > As suggested, this patchset implements BH workqueues which are like regular > workqueues but executes work items in the BH (softirq) context and converts > several tasklet users. Lai, the patchset is at: http://lkml.kernel.org/r/20240130091300.2968534-1-tj@xxxxxxxxxx I'd really appreciate if you can take a look. Thanks. -- tejun
