On 05.06.23 12:37, Mauro Carvalho Chehab wrote: > Em Mon, 5 Jun 2023 11:38:49 +0200 > "Linux regression tracking (Thorsten Leemhuis)" <regressions@xxxxxxxxxxxxx> escreveu: > >> Hi, Thorsten here, the Linux kernel's regression tracker. >> >> On 30.05.23 13:12, Thomas Voegtle wrote: >>> >>> I have the problem that sometimes my DVB card does not initialize >>> properly booting Linux 6.4-rc4. >>> This is not always, maybe in 3 out of 4 attempts. >>> When this happens somehow you don't see anything special in dmesg, but >>> the card just doesn't work. >>> >>> Reverting this helps: >>> commit 6769a0b7ee0c3b31e1b22c3fadff2bfb642de23f >>> Author: Hyunwoo Kim <imv4bel@xxxxxxxxx> >>> Date: Thu Nov 17 04:59:22 2022 +0000 >>> >>> media: dvb-core: Fix use-after-free on race condition at dvb_frontend >>> >>> >>> I have: >>> 03:00.0 Multimedia video controller [0400]: Conexant Systems, Inc. >>> CX23887/8 >>> PCIe Broadcast Audio and Video Decoder with 3D Comb [14f1:8880] (rev 04) >>> Subsystem: Hauppauge computer works Inc. Device [0070:c138] >>> Kernel driver in use: cx23885 >> >> Hmmm, that was posted last Tuesday and received not a single reply. :-/ >> >> Hyunwoo Kim: could you please look at it, as it's a regression caused by >> a commit of yours (one that would be good to solve before 6.4 is >> finalized!)? And in case you are unable to do so let us know? >> >> But FWIW: >> >> Mauro: I wonder if this is something you or someone else has to look >> into, as Hyunwoo Kim posted a few times per months to Linux lists, but >> according to a quick search on lore hasn't posted anything since ~two >> months now. :-/ > > Yeah, I was slow applying this one, as I was afraid of it to cause > troubles. The DVB frontend state machine is complex, and uses a > semaphore to update its state. There was some past attempts of > addressing some lifetime issues there that we ended needing to revert > or not being applied, as the fix caused more harm than good. > [...] Thx for the update. That's unfortunate, but how it is sometimes. Which leads to a follow-up question: is reverting the culprit temporarily an option? Or did those old use-after-free problems became known to be a problem we can't live with anymore for another few months? Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat) -- Everything you wanna know about Linux kernel regression tracking: https://linux-regtracking.leemhuis.info/about/#tldr If I did something stupid, please tell me, as explained on that page.
