On Mon, May 28, 2018 at 09:58:01AM +0200, Daniele Palmas wrote: > 2018-05-25 0:54 GMT+02:00 Daniele Palmas <dnl...@gmail.com>: > > Hi Greg, > > > > 2018-05-24 17:53 GMT+02:00 Greg KH <gre...@linuxfoundation.org>: > >> On Thu, May 24, 2018 at 05:04:49PM +0200, Daniele Palmas wrote: > >>> Hello, > >>> > >>> I have an issue with an USB mbim modem when trying to send with ping > >>> more than 14552 bytes: it looks like to me a kernel issue, but not at > >>> the cdc_mbim or cdc_ncm level, anyway not sure, so I'm reporting the > >>> issue. > >>> > >>> My kernel is 4.16. The device is the following: > >> > >> Does older kernels work, or is this something that has always been > >> there? > >> > > > > Not tested yet, I'm going to do. > > > > So, ping with more than 14552 was working properly until v4.5-rc7: > starting from v4.5 I'm not even able to make a data connection with > mbim since things fail badly with the following: > > [ 259.551836] ------------[ cut here ]------------ > [ 259.551848] WARNING: CPU: 2 PID: 0 at > /home/kernel/COD/linux/net/sched/sch_generic.c:303 > dev_watchdog+0x237/0x240() > [ 259.551860] NETDEV WATCHDOG: wwp0s20u7i2 (cdc_mbim): transmit queue > 0 timed out > [ 259.551861] Modules linked in: cdc_mbim cdc_wdm cdc_ncm usbnet mii > intel_rapl x86_pkg_temp_thermal intel_powerclamp coretemp kvm > snd_hda_codec_realtek snd_hda_codec_hdmi snd_hda_codec_generic > irqbypass crct10dif_pclmul snd_hda_intel snd_hda_codec snd_hda_core > crc32_pclmul snd_hwdep ghash_clmulni_intel aesni_intel aes_x86_64 > snd_pcm snd_seq_midi lrw snd_seq_midi_event gf128mul input_leds > snd_rawmidi snd_seq glue_helper snd_seq_device ablk_helper snd_timer > cryptd snd soundcore shpchp serio_raw mac_hid lpc_ich 8250_fintek > mei_me mei parport_pc ppdev lp parport autofs4 hid_generic usbhid hid > i915 i2c_algo_bit drm_kms_helper syscopyarea sysfillrect psmouse > sysimgblt ahci fb_sys_fops e1000e libahci drm ptp pps_core wmi fjes > video > [ 259.551889] CPU: 2 PID: 0 Comm: swapper/2 Not tainted > 4.5.0-040500-generic #201603140130 > [ 259.551890] Hardware name: LENOVO 10A6A0J5IX/SHARKBAY, BIOS > FBKT79AUS 04/17/2014 > [ 259.551891] 0000000000000286 108c91d75cf5b65f ffff88021eb03d98 > ffffffff813e0233 > [ 259.551893] ffff88021eb03de0 ffffffff81d816a0 ffff88021eb03dd0 > ffffffff81080e72 > [ 259.551894] 0000000000000000 ffff8800cee81880 0000000000000002 > ffff8800a19f8000 > [ 259.551895] Call Trace: > [ 259.551896] <IRQ> [<ffffffff813e0233>] dump_stack+0x63/0x90 > [ 259.551903] [<ffffffff81080e72>] warn_slowpath_common+0x82/0xc0 > [ 259.551904] [<ffffffff81080f0c>] warn_slowpath_fmt+0x5c/0x80 > [ 259.551907] [<ffffffff8173f557>] dev_watchdog+0x237/0x240 > [ 259.551909] [<ffffffff8173f320>] ? qdisc_rcu_free+0x40/0x40 > [ 259.551910] [<ffffffff810ecc75>] call_timer_fn+0x35/0x120 > [ 259.551911] [<ffffffff8173f320>] ? qdisc_rcu_free+0x40/0x40 > [ 259.551912] [<ffffffff810ed626>] run_timer_softirq+0x246/0x2f0 > [ 259.551914] [<ffffffff81085836>] __do_softirq+0xf6/0x280 > [ 259.551916] [<ffffffff81085b33>] irq_exit+0xa3/0xb0 > [ 259.551919] [<ffffffff81826092>] smp_apic_timer_interrupt+0x42/0x50 > [ 259.551920] [<ffffffff81824362>] apic_timer_interrupt+0x82/0x90 > [ 259.551922] <EOI> [<ffffffff816b669d>] ? cpuidle_enter_state+0x11d/0x2c0 > [ 259.551925] [<ffffffff816b6877>] cpuidle_enter+0x17/0x20 > [ 259.551928] [<ffffffff810c413a>] call_cpuidle+0x2a/0x40 > [ 259.551929] [<ffffffff810c4505>] cpu_startup_entry+0x295/0x350 > [ 259.551931] [<ffffffff81050d9e>] start_secondary+0x15e/0x190 > [ 259.551933] ---[ end trace 6f8d3c1a1b02644d ]--- > > but this is probably something different, cause with v4.16 data > connection works fine. > > If this is not helpful I guess I need to bisect.
Bisection would be best. It looks like you narrowed things down really well already, bisection should go very quickly. thanks, greg k-h
