Hello Bartosz, On Mon, Feb 06, 2023 at 07:01:11PM +0100, Bartosz Golaszewski wrote: > On Mon, Feb 6, 2023 at 4:51 PM Uwe Kleine-König > <u.kleine-koenig@xxxxxxxxxxxxxx> wrote: > > > > Hello, > > > > ah, this is the mail I missed before. > > > > On Wed, Jan 25, 2023 at 11:11:59PM +0100, Wolfram Sang wrote: > > > > > > > So, this code handled all my stress-testing well so far. I'll try to > > > > think of some more ideas until this evening, but likely I will apply it > > > > later. Nonetheless, more review eyes are still welcome! > > > > > > Ah yes, I now recalled why I had the gut feeling that this solution is > > > not complete. See this mail thread from 2015: > > > > > > https://lkml.iu.edu/hypermail/linux/kernel/1501.2/01700.html > > > > > > There are still drivers using i2c_del_adapter()+kfree(), so removing the > > > completion could cause use-after-free there, or? > > > > There is also a strange construct in spi that I understand at one point > > in time, but I failed to swap it in quickly. It's about commit > > 794aaf01444d4e765e2b067cba01cc69c1c68ed9. I think there should be a > > nicer solution than to track if the controller was allocated using devm, > > but I don't remember the details. But before addressing the i2c problem > > it might be worth to invest some time into that spi issue to not make > > the same mistake for i2c. > > Yeah, I've seen these constructs before elsewhere... Sadly, we have > workarounds upon workarounds within workarounds chased by other > workarounds due to this issue. Another pointer: Some time ago I did to the counter framework what would be needed here for i2c. See https://lore.kernel.org/all/20211230150300.72196-1-u.kleine-koenig@xxxxxxxxxxxxxx/. This was applied in commit f2ee4759fb700b32a1bd830960fe86bf6bdfd0ab and its parents. Maybe it can serve as a template for i2c. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | https://www.pengutronix.de/ |
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