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? > 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-kernel@xxxxxxxxxxxxxxxx) (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. -- Cheers, Luca.
