On Tue, 2017-09-05 at 09:51 -0700, Carl Myers wrote: > Hi Luca, > > On Mon, Sep 04, 2017 at 10:34:37AM +0300, Luca Coelho wrote: > > Date: Mon, 04 Sep 2017 10:34:37 +0300 > > From: Luca Coelho <l...@coelho.fi> > > To: Carl Myers <cmy...@cmyers.org>, linux-wireless@vger.kernel.org > > Cc: linuxw...@intel.com > > Subject: Re: Bug Report for iwlwifi kernel module > > > > Hi Carl, > > > > On Sun, 2017-09-03 at 12:15 -0700, Carl Myers wrote: > > > Greetings all, > > > > > > Apologies if any of this is wrong, this is my first attempt to report a > > > bug in > > > the linux kernel =) > > > > > > I got here by running the get_maintainer script on the iwlwifi directory > > > of a > > > linux kernel checkout. > > > > > > I am running debian stock kernel 4.8.15, and using the built in iwlwifi > > > driver > > > > > > $⮀ uname -a > > > Linux powerhouse 4.8.0-2-amd64 #1 SMP Debian 4.8.15-2 (2017-01-04) x86_64 > > > GNU/Linux > > > $⮀ dpkg -l | grep iwlwifi > > > ii firmware-iwlwifi 20160110-1~bpo8+1 > > > all Binary firmware for Intel Wireless cards > > > > > > I am on a slightly older firmware and kernel due to the > > > currently-outstanding bug: > > > https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=849330 > > > > > > This is the newest combination of kernel/firmware I've been able to make > > > work. > > > > > > Here is the lspci -v output for my wifi: > > > 03:00.0 Network controller: Intel Corporation Wireless 8260 (rev 3a) > > > Subsystem: Intel Corporation Wireless 8260 > > > Flags: bus master, fast devsel, latency 0, IRQ 136 > > > Memory at df200000 (64-bit, non-prefetchable) [size=8K] > > > Capabilities: <access denied> > > > Kernel driver in use: iwlwifi > > > Kernel modules: iwlwifi > > > > First of all, what makes you think this is a bug in the iwlwifi driver > > module? > > > > > > Ok, good question. It's been giving me problems and I was mucking with it. > Every so often, my wifi just quits working and I have a script that unloads > and > reloads the module, whih generally fixes it for a time. I thought it was > likely > the cause because I was messing with it at the time and it was first in the > list > of modules, but now that you mention it, I guess it was only listed first > because it was recently removed and re-added.
Okay, you should report those bugs to us so we can fix them. https://bu gzilla.kernel.org is your friend. :) > > > Recently, while testing a 2nd panda wifi card (trying to make a hotspot > > > and use > > > the iwl card as a gateway device), I got a kernel panic. Here is the > > > relevant > > > excerpt from kern.log: > > > > > > Sep 3 11:37:49 powerhouse kernel: [21394.510512] ------------[ cut here > > > ]------------ > > > Sep 3 11:37:49 powerhouse kernel: [21394.510514] kernel BUG at > > > /build/linux-zDY19G/linux-4.8.15/kernel/module.c:890! > > > Sep 3 11:37:49 powerhouse kernel: [21394.510515] invalid opcode: 0000 > > > [#1] SMP > > > Sep 3 11:37:49 powerhouse kernel: [21394.510516] Modules linked in: > > > iwlmvm iwlwifi ipt_REJECT nf_reject_ipv4 xt_tcpudp nf_nat_h323 > > > nf_conntrack_h323 nf_nat_pptp nf_nat_proto_gre nf_conntrack_pptp > > > nf_conntrack_proto_gre nf_nat_tftp nf_conntrack_tftp nf_nat_sip > > > nf_conntrack_sip nf_nat_irc nf_conntrack_irc nf_nat_ftp nf_conntrack_ftp > > > hid_generic rt2800usb rt2x00usb rt2800lib rt2x00lib crc_ccitt > > > ipt_MASQUERADE nf_nat_masquerade_ipv4 nf_conntrack_netlink nfnetlink > > > xfrm_user xfrm_algo iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 > > > nf_nat_ipv4 xt_addrtype xt_conntrack nf_nat nf_conntrack br_netfilter > > > bridge stp overlay iptable_filter appletalk ax25 ipx p8023 p8022 psnap > > > llc bnep snd_hda_codec_hdmi arc4 binfmt_misc nls_ascii nls_cp437 vfat fat > > > mac80211 snd_hda_codec_realtek intel_rapl x86_pkg_temp_thermal mxm_wmi > > > intel_powerclamp coretemp snd_hda_codec_generic kvm_intel kvm efi_pstore > > > irqbypass snd_hda_intel intel_cstate snd_hda_codec uvcvideo > > > videobuf2_vmalloc rtsx_pci_ms videobuf2_memops snd_hda_core > > > videobuf2_v4l2 iTCO_wdt videobuf2_core snd_hwdep intel_uncore videodev > > > joydev btusb intel_rapl_perf evdev media btrtl cfg80211 serio_raw pcspkr > > > efivars memstick iTCO_vendor_support snd_pcm snd_timer mei_me hci_uart > > > snd mei soundcore btbcm btqca btintel bluetooth rfkill wmi video > > > intel_lpss_acpi intel_lpss shpchp battery acpi_pad ac tpm_tis button > > > tpm_tis_core tpm nvidia_drm(POE) drm_kms_helper drm nvidia_modeset(POE) > > > nvidia(POE) parport_pc ppdev lp parport efivarfs ip_tables x_tables > > > autofs4 ext4 crc16 jbd2 crc32c_generic fscrypto ecb mbcache > > > algif_skcipher af_alg dm_crypt dm_mod hid_logitech_hidpp hid_logitech_dj > > > usbhid rtsx_pci_sdmmc mmc_core crct10dif_pclmul crc32_pclmul crc32c_intel > > > ghash_clmulni_intel aesni_intel ahci libahci aes_x86_64 lrw gf128mul > > > glue_helper xhci_pci ablk_helper cryptd libata xhci_hcd psmouse usbcore > > > nvme scsi_mod i2c_i801 nvme_core i2c_smbus rtsx_pci r8169 mii mfd_core > > > usb_common thermal i2c_hid hid fjes [last unloaded: iwlwifi] > > > Sep 3 11:37:49 powerhouse kernel: [21394.510561] CPU: 4 PID: 8122 Comm: > > > rmmod Tainted: P R OE 4.8.0-2-amd64 #1 Debian 4.8.15-2 > > > Sep 3 11:37:49 powerhouse kernel: [21394.510562] Hardware name: > > > System76, Inc. Oryx Pro/Oryx Pro, BIOS 1.05.09RSA1 11/16/2015 > > > Sep 3 11:37:49 powerhouse kernel: [21394.510563] task: ffff8dec4a3e0000 > > > task.stack: ffff8decf4cd4000 > > > Sep 3 11:37:49 powerhouse kernel: [21394.510564] RIP: > > > 0010:[<ffffffffbccf98b9>] [<ffffffffbccf98b9>] > > > SyS_delete_module+0x259/0x260 > > > Sep 3 11:37:49 powerhouse kernel: [21394.510568] RSP: > > > 0018:ffff8decf4cd7ef0 EFLAGS: 00010297 > > > Sep 3 11:37:49 powerhouse kernel: [21394.510569] RAX: 00000000ffffffff > > > RBX: ffffffffc1aa71c0 RCX: 0000000000000005 > > > Sep 3 11:37:49 powerhouse kernel: [21394.510570] RDX: ffffffffc1aa74a0 > > > RSI: ffffffffc1aa74c8 RDI: ffffffffc1aa71d8 > > > Sep 3 11:37:49 powerhouse kernel: [21394.510571] RBP: 000055fb472021f0 > > > R08: 0000000000000000 R09: 000000000000006d > > > Sep 3 11:37:49 powerhouse kernel: [21394.510572] R10: 000055fb472011c0 > > > R11: 8080808080808080 R12: 0000000000000a00 > > > Sep 3 11:37:49 powerhouse kernel: [21394.510572] R13: 0000000000000a00 > > > R14: 00007fff6cd8d4f8 R15: 0000000000000000 > > > Sep 3 11:37:49 powerhouse kernel: [21394.510573] FS: > > > 00007f498ef22700(0000) GS:ffff8ded76500000(0000) knlGS:0000000000000000 > > > Sep 3 11:37:49 powerhouse kernel: [21394.510574] CS: 0010 DS: 0000 ES: > > > 0000 CR0: 0000000080050033 > > > Sep 3 11:37:49 powerhouse kernel: [21394.510575] CR2: 00007f498eacf801 > > > CR3: 0000000fa99d0000 CR4: 00000000003406e0 > > > Sep 3 11:37:49 powerhouse kernel: [21394.510576] DR0: 0000000000000000 > > > DR1: 0000000000000000 DR2: 0000000000000000 > > > Sep 3 11:37:49 powerhouse kernel: [21394.510576] DR3: 0000000000000000 > > > DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > > Sep 3 11:37:49 powerhouse kernel: [21394.510577] Stack: > > > Sep 3 11:37:49 powerhouse kernel: [21394.510578] 00006d766d6c7769 > > > 0000000000000002 ffff8decf4cd4000 ffffffffbcc03290 > > > Sep 3 11:37:49 powerhouse kernel: [21394.510579] ffff8decf4cd7f58 > > > ffff8decf4cd4000 0000000000000050 00000000520cd409 > > > Sep 3 11:37:49 powerhouse kernel: [21394.510581] 00007fff6cd8d338 > > > 000055fb472021f0 00007fff6cd8d508 00007fff6cd8ebbb > > > Sep 3 11:37:49 powerhouse kernel: [21394.510582] Call Trace: > > > Sep 3 11:37:49 powerhouse kernel: [21394.510586] [<ffffffffbcc03290>] ? > > > exit_to_usermode_loop+0xa0/0xc0 > > > Sep 3 11:37:49 powerhouse kernel: [21394.510588] [<ffffffffbd1e8cb6>] ? > > > system_call_fast_compare_end+0xc/0x96 > > > Sep 3 11:37:49 powerhouse kernel: [21394.510588] Code: fe ff ff 41 f7 c4 > > > 00 02 00 00 48 c7 c5 f0 ff ff ff 0f 84 5c fe ff ff be 01 00 00 00 bf 03 > > > 00 00 00 e8 0c b3 f7 ff e9 b7 fe ff ff <0f> 0b e8 90 b4 f7 ff 0f 1f 44 00 > > > 00 31 c0 c3 0f 1f 84 00 00 00 > > > Sep 3 11:37:49 powerhouse kernel: [21394.510605] RIP > > > [<ffffffffbccf98b9>] SyS_delete_module+0x259/0x260 > > > Sep 3 11:37:49 powerhouse kernel: [21394.510607] RSP <ffff8decf4cd7ef0> > > > Sep 3 11:37:49 powerhouse kernel: [21394.510608] ---[ end trace > > > 5b24b93b49e857eb ]--- > > > Sep 3 11:37:49 powerhouse kernel: [21409.372738] ieee80211 phy3: > > > rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset > > > 0x0438 with error -110 > > > Sep 3 11:38:05 powerhouse kernel: [21425.406196] INFO: rcu_sched > > > detected stalls on CPUs/tasks: > > > Sep 3 11:38:20 powerhouse kernel: [21425.406201] 4-...: (0 ticks > > > this GP) idle=02d/140000000000000/0 softirq=277173/277173 fqs=8 > > > Sep 3 11:38:20 powerhouse kernel: [21425.406202] (detected by 7, > > > t=7721 jiffies, g=246559, c=246558, q=936) > > > Sep 3 11:38:20 powerhouse kernel: [21425.406204] Task dump for CPU 4: > > > Sep 3 11:38:20 powerhouse kernel: [21425.406206] rmmod R > > > running task 0 8122 8121 0x00000008 > > > Sep 3 11:38:20 powerhouse kernel: [21425.406209] 0000000000000002 > > > ffff8decf4cd7e48 ffffffffbd3df853 0000000000000000 > > > Sep 3 11:38:20 powerhouse kernel: [21425.406211] 0000000000000000 > > > ffffffffbcccc3d3 0000000000000246 000000000000000b > > > Sep 3 11:38:20 powerhouse kernel: [21425.406214] ffffffffbcc289f8 > > > 0000000000000006 ffff8decf4cd7e48 0000000000000004 > > > Sep 3 11:38:20 powerhouse kernel: [21425.406216] Call Trace: > > > Sep 3 11:38:20 powerhouse kernel: [21425.406222] [<ffffffffbcccc3d3>] ? > > > kmsg_dump+0x93/0xb0 > > > Sep 3 11:38:20 powerhouse kernel: [21425.406225] [<ffffffffbcc289f8>] ? > > > oops_end+0x78/0xd0 > > > Sep 3 11:38:20 powerhouse kernel: [21425.406228] [<ffffffffbcc26446>] ? > > > do_error_trap+0x86/0x100 > > > Sep 3 11:38:20 powerhouse kernel: [21425.406976] [<ffffffffbccf98b9>] ? > > > SyS_delete_module+0x259/0x260 > > > Sep 3 11:38:20 powerhouse kernel: [21425.406979] [<ffffffffbcdda242>] ? > > > kmem_cache_alloc+0x122/0x530 > > > Sep 3 11:38:20 powerhouse kernel: [21425.406982] [<ffffffffbd1e9a2e>] ? > > > invalid_op+0x1e/0x30 > > > Sep 3 11:38:20 powerhouse kernel: [21425.407276] [<ffffffffbccf98b9>] ? > > > SyS_delete_module+0x259/0x260 > > > Sep 3 11:38:20 powerhouse kernel: [21425.407277] perf: interrupt took > > > too long (8612 > 2500), lowering kernel.perf_event_max_sample_rate to > > > 23000 > > > Sep 3 11:3Sep 3 11:39:51 powerhouse kernel: [ 0.000000] Linux > > > version 4.8.0-2-amd64 (debian-ker...@lists.debian.org) (gcc version 5.4.1 > > > 20161202 (Debian 5.4.1-4) ) #1 SMP Debian 4.8.15-2 (2017-01-04) > > > Sep 3 11:39:51 powerhouse kernel: [ 0.000000] Command line: > > > BOOT_IMAGE=/vmlinuz-4.8.0-2-amd64 root=/dev/mapper/powerhouse--vg-root ro > > > quiet > > > > > > Obviously, I'm not certain the bug is in this kernel module or even has > > > anything to do with it, but I thought this was a good place to start. > > > Advice > > > welcome, happy to help however I can, I am a software engineer but not > > > very > > > experienced at kernel hacking. > > > > The bug you're seeing is happening in the module removal code[1]. > > Apparently the system is getting a bad value in refcnt and it's becoming > > negative, which should never happen. Have you been trying to force- > > remove modules or something like that? > > > > [1] > > https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/tree/kernel/module.c?h=linux-4.8.y#n890 > > > > > > In any case, this doesn't seem like a iwlwifi bug at all. > > > > HTH. > > Yeeeeahh, I don't normally force-remove it, but now that you mention it I did > have to force remove it earlier that day, I think, I think I hadn't rebooted > since that. So that very well could be the cause. I guess if you do things > like force-remove kernel modules, then the results aren't necessarily a bug, > huh? =) Right, force-removing a module is evil and you should never really do it, unless you *really* know what you are doing. And even then, don't do it. :) It's better to reboot completely rather than force-remove a module. If the shutdown itself gets stuck, then maybe you can force-remove the module that is holding it. > That was very helpful, thanks very much for your time! You're welcome! I'm glad I could help. > I'd love to figure out how to make this module more stable for me, but I'm not > sure where to even get started, and since I am on old firmware (due to the > previously mentioned bug), I'm not sure it's worth poking until I can get on > the > tip version first. v4.8 is old but not ancient and we will certainly still try to debug it if someone is seeing failures. The worst that can happen is that we will tell you to upgrade your kernel. You can't imagine what kind of ancient kernels people sometimes use. Some of them are the same version that Tutankhamun had installed in his hieroglyphs tablet. :D A good place to start is our wikipage[1]. You can find a lot of information on how to help us help you debug the iwlwifi driver. An even simpler start is to send us dmesg so we can have an initial idea of what is going on. [1] https://wireless.wiki.kernel.org/en/users/drivers/iwlwifi/debugging -- Cheers, Luca. >
