On Fri, 2010-04-09 at 19:21 +0200, Thomas Bächler wrote: > Since I upgraded from 2.6.33.1 to .2, I get the following warning > sometimes, related to wireless: > > ------------[ cut here ]------------ > WARNING: at kernel/softirq.c:143 local_bh_enable_ip+0x82/0xb0() > Hardware name: TECRA A11 ... > [<ffffffff8135d42f>] _raw_spin_unlock_bh+0x1f/0x30 > [<ffffffffa04018ed>] ath_tx_node_cleanup+0x19d/0x1c0 [ath9k] > [<ffffffffa03fc607>] ath9k_sta_notify+0x57/0xb0 [ath9k] Indeed, the patch between 2.6.32.1 and 2.6.32.2 replaces spin_lock with spin_lock_bh and spin_unlock with spin_unlock_bh. The exact commit is 0524bcfa80f1fffb4e1fe18a0a28900869a58a7c by Ming Lei. It's the unlock that gives the warning. Line 143 in kernel/softirq.c is: WARN_ON_ONCE(in_irq() || irqs_disabled()); As I understand, the warning would be emitted when softirqs are enabled while hardirqs are disabled. Hardirqs have a higher priority, so it would create a priority inversion. > [<ffffffffa039bbc4>] __sta_info_unlink+0x174/0x220 [mac80211] > [<ffffffffa039bca8>] sta_info_unlink+0x38/0x60 [mac80211] > [<ffffffffa03a2639>] ieee80211_set_disassoc+0x1e9/0x290 [mac80211] > [<ffffffffa03a2e89>] ieee80211_mgd_deauth+0x159/0x160 [mac80211] > [<ffffffff8104d700>] ? default_wake_function+0x0/0x10 > [<ffffffffa03a9b69>] ieee80211_deauth+0x19/0x20 [mac80211] > [<ffffffffa02426de>] __cfg80211_mlme_deauth+0xee/0x130 [cfg80211] > [<ffffffff8135baad>] ? __mutex_lock_slowpath+0x26d/0x370 > [<ffffffffa0246839>] __cfg80211_disconnect+0x159/0x1d0 [cfg80211] > [<ffffffffa0248f9c>] cfg80211_wext_siwmlme+0x8c/0xa0 [cfg80211] > [<ffffffff8133e6b7>] ioctl_standard_iw_point+0x207/0x3a0 > [<ffffffffa0248f10>] ? cfg80211_wext_siwmlme+0x0/0xa0 [cfg80211] > [<ffffffff8133e850>] ? ioctl_standard_call+0x0/0xd0 > [<ffffffff8133e8e9>] ioctl_standard_call+0x99/0xd0 > [<ffffffff812b2660>] ? __dev_get_by_name+0xa0/0xc0 > [<ffffffff8133dce7>] wext_ioctl_dispatch+0x1f7/0x210 > [<ffffffff8133f330>] ? ioctl_private_call+0x0/0xa0 > [<ffffffff8133de91>] wext_handle_ioctl+0x41/0x90 > [<ffffffff812b8299>] dev_ioctl+0x679/0x850 > [<ffffffff812a0522>] sock_ioctl+0xe2/0x290 > [<ffffffff812a369d>] ? sys_recvfrom+0x13d/0x160 > [<ffffffff811324c8>] vfs_ioctl+0x38/0xd0 > [<ffffffff81132670>] do_vfs_ioctl+0x80/0x560 > [<ffffffff81132bd1>] sys_ioctl+0x81/0xa0 > [<ffffffff8100b1f9>] ? do_device_not_available+0x9/0x10 > [<ffffffff81009fc2>] system_call_fastpath+0x16/0x1b > ---[ end trace 8dbf12cb72787a6d ]--- This looks like a call initiated by userspace through wireless extensions. I don't see where hardirqs are disabled. A simple fix would be to use spin_lock_irqsave/spin_unlock_irqrestore, but I would prefer to understand what is going on. It's a regression in stable series, so it should be taken very seriously. -- Regards, Pavel Roskin -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
