On 5/14/19 11:40 AM, Johannes Berg wrote:
We know the WARN hits, we have the backtrace, and it is easy enough (in my setup
at least) to reproduce this. So, the WARN logic has done its job.
Having more of these spam the kernel doesn't add much benefit I think.
Well, this doesn't necessarily just catch a *single* issue, so it should
remain for the future, I'd think.
Anyone have any suggestions on how to fix the underlying issue?
I don't even have the backtrace and scenario that causes it.
johannes
Here is the info I have in my commit that changed this to WARN_ON_ONCE.
I never posted it because I had to hack ath10k to get to this state, so maybe
this is not a valid case to debug.
Maybe Yibo Zhao has a better example.
mac80211: don't spam kernel logs when chantx is null.
I set up ath10k to be chandef based again in order to test
WDS. My WDS stations are not very functional yet, and
when ethtool stats are queried, there is a WARN_ON splat
generated. Change this to WARN_ON_ONCE so that there is
less kernel spam.
[ 2401.445631] WARNING: CPU: 1 PID: 14070 at /home/greearb/git/linux-4.13.dev.y/net/mac80211/ieee80211_i.h:1452 sta_set_rate_info_tx+0x18c/0x1a0 [mac80211]
[ 2401.445727] Modules linked in: nf_conntrack_netlink nf_conntrack nfnetlink wanlink(O) ath10k_pci ath10k_core mac80211_hwsim ath5k ath9k ath9k_common
ath9k_hw ath mac80211 cfg80211 nf_defrag_ipv4 libcrc32c 8021q garp mrp stp llc fuse macvlan pktgen nfsv3 nfs fscache amd64_edac_mod edac_mce_amd kvm_amd kvm
irqbypass sp5100_tco fam15h_power k10temp i2c_piix4 ccp shpchp acpi_cpufreq nfsd auth_rpcgss nfs_acl lockd grace sch_fq_codel sunrpc sdhci_pci sdhci mmc_core
igb hwmon ptp pps_core i2c_algo_bit i2c_core dca ipv6 crc_ccitt [last unloaded: nfnetlink]
[ 2401.445911] CPU: 1 PID: 14070 Comm: btserver Tainted: G W O 4.13.11+ #18
[ 2401.445914] Hardware name: PC Engines apu2/apu2, BIOS 88a4f96 03/07/2016
[ 2401.445918] task: ffff880118c73b80 task.stack: ffffc90001400000
[ 2401.445973] RIP: 0010:sta_set_rate_info_tx+0x18c/0x1a0 [mac80211]
[ 2401.446003] RSP: 0018:ffffc90001403820 EFLAGS: 00010246
[ 2401.446007] RAX: 0000000000000000 RBX: ffff8800ca38e4a0 RCX: 000000000000000c
[ 2401.446010] RDX: 0000000000000000 RSI: ffff8800ca38e4a0 RDI: ffff8800ca38e000
[ 2401.446013] RBP: ffffc90001403850 R08: ffffffffa04437a0 R09: 0000000000002000
[ 2401.446016] R10: 000000001183be82 R11: 0000000000000000 R12: ffffc90001403970
[ 2401.446018] R13: 0000000000000000 R14: ffff8800c01d8900 R15: ffff8800ca180780
[ 2401.446023] FS: 00007f8123ed7740(0000) GS:ffff88011ec80000(0000) knlGS:0000000000000000
[ 2401.446026] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 2401.446029] CR2: 00000000036e8018 CR3: 00000000c0b29000 CR4: 00000000000406e0
[ 2401.446034] Call Trace:
[ 2401.446140] sta_set_sinfo+0x629/0x8b0 [mac80211]
[ 2401.446192] ieee80211_get_stats+0x3f2/0x8c0 [mac80211]
[ 2401.446207] ? __nla_put+0x20/0x30
[ 2401.446221] ? __kmalloc_reserve.isra.35+0x2c/0x80
[ 2401.446229] ? netlink_deliver_tap+0x2d/0x1e0
[ 2401.446235] ? sock_def_readable+0x6d/0x70
[ 2401.446239] ? __netlink_sendskb+0x36/0x40
[ 2401.446245] ? netlink_unicast+0x1b0/0x1f0
[ 2401.446252] ? rtnl_getlink+0x135/0x1c0
[ 2401.446261] ? get_page_from_freelist+0x913/0xac0
[ 2401.446270] ? vmap_page_range_noflush+0x27d/0x370
[ 2401.446277] ? map_vm_area+0x31/0x40
[ 2401.446284] ? __vmalloc_node_range+0x21f/0x270
[ 2401.446319] dev_ethtool+0x11d1/0x1ce0
[ 2401.446325] ? __rtnl_unlock+0x25/0x50
[ 2401.446330] ? netdev_run_todo+0x4d/0x2e0
[ 2401.446338] ? dev_get_by_name_rcu+0x6f/0xa0
[ 2401.446344] dev_ioctl+0x330/0x550
[ 2401.446349] ? reuse_swap_page+0x30/0x100
[ 2401.446355] sock_do_ioctl+0x3d/0x50
[ 2401.446359] ? sock_do_ioctl+0x3d/0x50
[ 2401.446363] sock_ioctl+0x1e5/0x2a0
[ 2401.446370] do_vfs_ioctl+0x8b/0x5b0
[ 2401.446376] ? getnstimeofday64+0x9/0x20
[ 2401.446383] ? __audit_syscall_entry+0xba/0x110
[ 2401.446391] ? syscall_trace_enter+0x1b0/0x2b0
[ 2401.446395] SyS_ioctl+0x74/0x80
[ 2401.446400] ? __audit_syscall_exit+0x215/0x2b0
[ 2401.446405] do_syscall_64+0x5c/0x190
[ 2401.446412] entry_SYSCALL64_slow_path+0x25/0x25
Thanks,
Ben
--
Ben Greear <greearb@xxxxxxxxxxxxxxx>
Candela Technologies Inc http://www.candelatech.com
