Re: netpoll_send_skb_on_dev warning with bnx2

[Neil Horman]

On Thu, Oct 01, 2015 at 08:25:46PM -0700, Vinson Lee wrote:
> Hi.
> 
> I am seeing a netpoll_send_skb_on_dev warning with bnx2. It happens on
> Linux 4.1 and I am able to reproduce the warning with Linux 4.3-rc3.
> 
> ------------[ cut here ]------------
> WARNING: CPU: 11 PID: 3110 at net/core/netpoll.c:368
> netpoll_send_skb_on_dev+0x183/0x201()
> netpoll_send_skb_on_dev(): eth0 enabled interrupts in poll
> (bnx2_start_xmit+0x0/0x5d4 [bnx2])
> Modules linked in: netconsole(+) configfs ipv6 ppdev parport_pc lp
> parport tcp_diag inet_diag ipmi_devintf serio_raw iTCO_wdt
> iTCO_vendor_support ipmi_si ipmi_msghandler hpilo hpwdt bnx2 coretemp
> kvm_intel kvm crc32c_intel ghash_clmulni_intel microcode lpc_ich
> mfd_core i7core_edac edac_core pcc_cpufreq acpi_cpufreq shpchp
> sch_fq_codel hpsa radeon ttm drm_kms_helper drm fb_sys_fops sysimgblt
> sysfillrect syscopyarea i2c_algo_bit i2c_core
> CPU: 11 PID: 3110 Comm: modprobe Not tainted 4.3.0-rc3 #1
>  0000000000000170 ffff88060be17a18 ffffffff812bc84c ffffffff818b1a78
>  ffff88060be17a68 ffff88060be17a58 ffffffff81064712 000000000be17a68
>  ffffffff814ec12e ffff88060bc10900 0000000000000000 ffff8800d941c000
> Call Trace:
>  [<ffffffff812bc84c>] dump_stack+0x48/0x5c
>  [<ffffffff81064712>] warn_slowpath_common+0xa1/0xbb
>  [<ffffffff814ec12e>] ? netpoll_send_skb_on_dev+0x183/0x201
>  [<ffffffff810647cf>] warn_slowpath_fmt+0x46/0x48
>  [<ffffffffa039a6b9>] ? bnx2_run_loopback+0x391/0x391 [bnx2]
>  [<ffffffff814ec12e>] netpoll_send_skb_on_dev+0x183/0x201
>  [<ffffffff814ec58b>] netpoll_send_udp+0x3df/0x3f1
>  [<ffffffffa049324a>] write_msg+0xaf/0xe9 [netconsole]
>  [<ffffffff810a6daa>] call_console_drivers.clone.2+0xd1/0xe9
>  [<ffffffff810a70d0>] console_unlock+0x30e/0x3a5
>  [<ffffffff810a757d>] register_console+0x2af/0x322
>  [<ffffffffa04971b4>] init_netconsole+0x1b4/0x224 [netconsole]
>  [<ffffffffa0497000>] ? 0xffffffffa0497000
>  [<ffffffff810002bf>] do_one_initcall+0xf7/0x182
>  [<ffffffff811764fe>] ? kmem_cache_alloc_trace+0xb6/0xf0
>  [<ffffffff810cb8d8>] ? do_init_module+0x31/0x1e4
>  [<ffffffff810cb910>] do_init_module+0x69/0x1e4
>  [<ffffffff810ccedc>] load_module+0x1451/0x160b
>  [<ffffffff810ca1a3>] ? mod_kobject_put+0x4d/0x4d
>  [<ffffffff811606f3>] ? __vmalloc_node+0x3e/0x40
>  [<ffffffff810cd2aa>] SyS_init_module+0x14f/0x155
>  [<ffffffff815833d7>] entry_SYSCALL_64_fastpath+0x12/0x6a
> ---[ end trace 878215466e581776 ]---
> 
> Cheers,
> Vinson

Hmm, that would suggest that someone called local_irq_enable in either the xmit,
poll_controller or napi poll paths (or one of its always-disable, bretheren),
but I dont see where that might be happening.  Are you able to instrument the
kernel (either by cloning that WARN_ON_ONCE call or via stap script), so we can
further isolate which call path the problem is happening in?

Neil

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