CVE-2024-50234: wifi: iwlegacy: Clear stale interrupts before resuming device

In the Linux kernel, the following vulnerability has been resolved:

wifi: iwlegacy: Clear stale interrupts before resuming device

iwl4965 fails upon resume from hibernation on my laptop. The reason seems to be a stale interrupt which isn't being cleared out before interrupts are enabled. We end up with a race beween the resume trying to bring things back up, and the restart work (queued form the interrupt handler) trying to bring things down. Eventually the whole thing blows up.

Fix the problem by clearing out any stale interrupts before interrupts get enabled during resume.

Here's a debug log of the indicent: [ 12.042589] ieee80211 phy0: ilisr ISR inta 0x00000080, enabled 0xaa00008b, fh 0x00000000 [ 12.042625] ieee80211 phy0: il4965irqtasklet inta 0x00000080, enabled 0x00000000, fh 0x00000000 [ 12.042651] iwl4965 0000:10:00.0: RFKILL bit toggled to enable radio. [ 12.042653] iwl4965 0000:10:00.0: On demand firmware reload [ 12.042690] ieee80211 phy0: il4965irqtasklet End inta 0x00000000, enabled 0xaa00008b, fh 0x00000000, flags 0x00000282 [ 12.052207] ieee80211 phy0: il4965macstart enter [ 12.052212] ieee80211 phy0: ilprepstation Add STA to driver ID 31: ff:ff:ff:ff:ff:ff [ 12.052244] ieee80211 phy0: il4965sethwready hardware ready [ 12.052324] ieee80211 phy0: ilapminit Init card's basic functions [ 12.052348] ieee80211 phy0: ilapminit L1 Enabled; Disabling L0S [ 12.055727] ieee80211 phy0: il4965loadbsm Begin load bsm [ 12.056140] ieee80211 phy0: il4965verifybsm Begin verify bsm [ 12.058642] ieee80211 phy0: il4965verifybsm BSM bootstrap uCode image OK [ 12.058721] ieee80211 phy0: il4965loadbsm BSM write complete, poll 1 iterations [ 12.058734] ieee80211 phy0: il4965up iwl4965 is coming up [ 12.058737] ieee80211 phy0: il4965macstart Start UP work done. [ 12.058757] ieee80211 phy0: il4965down iwl4965 is going down [ 12.058761] ieee80211 phy0: ilscancanceltimeout Scan cancel timeout [ 12.058762] ieee80211 phy0: ildoscanabort Not performing scan to abort [ 12.058765] ieee80211 phy0: ilclearucodestations Clearing ucode stations in driver [ 12.058767] ieee80211 phy0: ilclearucodestations No active stations found to be cleared [ 12.058819] ieee80211 phy0: ilapmstop Stop card, put in low power state [ 12.058827] ieee80211 phy0: ilapmstopmaster stop master [ 12.058864] ieee80211 phy0: il4965clearfreeframes 0 frames on pre-allocated heap on clear. [ 12.058869] ieee80211 phy0: Hardware restart was requested [ 16.132299] iwl4965 0000:10:00.0: STARTALIVE timeout after 4000ms. [ 16.132303] ------------[ cut here ]------------ [ 16.132304] Hardware became unavailable upon resume. This could be a software issue prior to suspend or a hardware issue. [ 16.132338] WARNING: CPU: 0 PID: 181 at net/mac80211/util.c:1826 ieee80211reconfig+0x8f/0x14b0 [mac80211] [ 16.132390] Modules linked in: ctr ccm schfqcodel xttcpudp xtmultiport xtstate iptablefilter iptablenat nfnat nfconntrack nfdefragipv4 iptables xtables binfmtmisc joydev mousedev btusb btrtl btintel btbcm bluetooth ecdhgeneric ecc iTCOwdt i2cdev iwl4965 iwlegacy coretemp sndhdacodecanalog pcspkr psmouse mac80211 sndhdacodecgeneric libarc4 sdhcipci cqhci sha256generic sdhci libsha256 firewireohci sndhdaintel sndinteldspcfg mmccore sndhdacodec sndhwdep firewirecore ledclass iosfmbi sndhdacore uhcihcd lpcich crcitut cfg80211 ehcipci ehcihcd sndpcm usbcore mfdcore rfkill sndtimer snd usbcommon soundcore video parportpc parport intelagp wmi intelgtt backlight e1000e agpgart evdev [ 16.132456] CPU: 0 UID: 0 PID: 181 Comm: kworker/u8:6 Not tainted 6.11.0-cl+ #143 [ 16.132460] Hardware name: Hewlett-Packard HP Compaq 6910p/30BE, BIOS 68MCU Ver. F.19 07/06/2010 [ 16.132463] Workqueue: async asyncrunentryfn [ 16.132469] RIP: 0010:ieee80211reconfig+0x8f/0x14b0 [mac80211] [ 16.132501] Code: da 02 00 0 ---truncated---