Re: request_irq() with local bh disabled

On Thu, Mar 6, 2025 at 1:24 PM Borislav Petkov [off-list ref] wrote:

Hi,

this is latest Linus/master + tip/master on a 32-bit x86:

tglx says one cannot request_irq() with local bh disabled.

[   17.354927] cfg80211: Loading compiled-in X.509 certificates for regulatory database
[   17.906996] Loaded X.509 cert 'sforshee: 00b28ddf47aef9cea7'
[   17.950874] Loaded X.509 cert 'wens: 61c038651aabdcf94bd0ac7ff06c7248db18c600'
[   18.034884] platform regulatory.0: Direct firmware load for regulatory.db failed with error -2
[   18.038920] cfg80211: failed to load regulatory.db

[   18.726638] =============================
[   18.726638] [ BUG: Invalid wait context ]
[   18.726638] 6.14.0-rc5+ #1 Not tainted
[   18.726638] -----------------------------
[   18.726638] ip/991 is trying to lock:
[   18.726638] c36a2d64 (&desc->request_mutex){+.+.}-{4:4}, at: __setup_irq+0x98/0x6cc
[   18.726638] other info that might help us debug this:
[   18.746793] context-{5:5}
[   18.746793] 2 locks held by ip/991:
[   18.746793]  #0: c261f920 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x336/0x9fc
[   18.746793]  #1: c1f56ea0 (local_bh){.+.+}-{1:3}, at: dev_set_rx_mode+0x5/0x80

Hmmm.. not sure why local_bh is considered held..

void dev_set_rx_mode(struct net_device *dev)
{
    netif_addr_lock_bh(dev);
    __dev_set_rx_mode(dev);  // does not call ndo_open() (rtl_open in
your trace)
    netif_addr_unlock_bh(dev);
}


Note that netif_addr_lock_bh() is using:

local_bh_disable();
spin_lock_nested(&dev->addr_list_lock, nest_level);

Would the following "debug" patch change anything for your tree ?
I know this looks strange, but I do not have anything more sensible to suggest.

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index ab550a89b9bfaa5682e65f1dcc7f5f99ce90eb94..52e10d738bf0e35296a876011828cd0b40580678

100644

--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h

@@ -4751,7 +4751,8 @@ static inline void netif_addr_unlock(struct

net_device *dev)

 static inline void netif_addr_unlock_bh(struct net_device *dev)
 {
-       spin_unlock_bh(&dev->addr_list_lock);
+       spin_unlock(&dev->addr_list_lock);
+       local_bh_enable();
 }

 /*

[   18.746793] stack backtrace:
[   18.746793] CPU: 1 UID: 0 PID: 991 Comm: ip Not tainted 6.14.0-rc5+ #1
[   18.746793] Hardware name: Acer AOA150/, BIOS v0.3309 10/06/2008
[   18.746793] Call Trace:
[   18.746793]  dump_stack_lvl+0x94/0x10c
[   18.746793]  dump_stack+0x13/0x18
[   18.746793]  __lock_acquire+0xa1c/0x2500
[   18.746793]  lock_acquire+0xc3/0x2ac
[   18.746793]  ? __setup_irq+0x98/0x6cc
[   18.746793]  ? debug_smp_processor_id+0x12/0x14
[   18.746793]  ? __mutex_lock+0x54/0xcb8
[   18.746793]  ? __mutex_lock+0x54/0xcb8
[   18.746793]  ? trace_preempt_off+0x2e/0xb4
[   18.746793]  ? __might_sleep+0x35/0x6c
[   18.746793]  ? __mutex_lock+0x54/0xcb8
[   18.746793]  ? preempt_count_add+0x6c/0xd4
[   18.746793]  __mutex_lock+0x82/0xcb8
[   18.746793]  ? __setup_irq+0x98/0x6cc
[   18.746793]  mutex_lock_nested+0x27/0x2c
[   18.746793]  ? __setup_irq+0x98/0x6cc
[   18.746793]  __setup_irq+0x98/0x6cc
[   18.746793]  ? __kmalloc_cache_noprof+0x1b1/0x2d0
[   18.746793]  ? request_threaded_irq+0x84/0x188
[   18.746793]  request_threaded_irq+0xc2/0x188
[   18.746793]  rtl_open+0x33b/0x5e4 [r8169]
[   18.746793]  ? raw_notifier_call_chain+0x20/0x24
[   18.746793]  __dev_open+0xce/0x17c
[   18.746793]  ? dev_set_rx_mode+0x74/0x80
[   18.746793]  __dev_change_flags+0x176/0x1cc
[   18.746793]  dev_change_flags+0x29/0x6c
[   18.746793]  do_setlink.isra.0+0x28f/0x1180
[   18.746793]  ? __mutex_lock+0x107/0xcb8
[   18.746793]  ? __mutex_lock+0x107/0xcb8
[   18.746793]  ? trace_preempt_on+0x2e/0xac
[   18.746793]  ? __mutex_lock+0x107/0xcb8
[   18.746793]  ? preempt_count_sub+0xb1/0x100
[   18.746793]  ? debug_smp_processor_id+0x12/0x14
[   18.746793]  ? __mutex_lock+0x107/0xcb8
[   18.746793]  ? rtnl_newlink+0x336/0x9fc
[   18.746793]  ? __kmalloc_cache_noprof+0x1b1/0x2d0
[   18.746793]  ? do_alloc_pages+0x64/0xbc
[   18.746793]  rtnl_newlink+0x762/0x9fc
[   18.746793]  ? __this_cpu_preempt_check+0xf/0x20
[   18.746793]  ? do_alloc_pages+0x64/0xbc
[   18.746793]  ? do_setlink.isra.0+0x1180/0x1180
[   18.746793]  rtnetlink_rcv_msg+0x3fd/0x584
[   18.746793]  ? rtnetlink_rcv_msg+0x58/0x584
[   18.746793]  ? netlink_deliver_tap.constprop.0+0xe5/0x4ac
[   18.746793]  ? local_clock_noinstr+0x68/0x1c0
[   18.746793]  ? rtnl_fdb_dump+0x370/0x370
[   18.746793]  netlink_rcv_skb+0x42/0xdc
[   18.746793]  ? do_alloc_pages+0x64/0xbc
[   18.746793]  rtnetlink_rcv+0x12/0x14
[   18.746793]  netlink_unicast+0x198/0x2a8
[   18.746793]  netlink_sendmsg+0x1bb/0x3ec
[   18.746793]  ? netlink_unicast+0x2a8/0x2a8
[   18.746793]  ____sys_sendmsg+0x233/0x280
[   18.746793]  ? netlink_unicast+0x2a8/0x2a8
[   18.746793]  ? do_alloc_pages+0x64/0xbc
[   18.746793]  ___sys_sendmsg+0x66/0x9c
[   18.746793]  ? __might_fault+0x3b/0x84
[   18.746793]  ? __might_fault+0x3b/0x84
[   18.746793]  ? local_clock_noinstr+0x68/0x1c0
[   18.746793]  ? do_alloc_pages+0x64/0xbc
[   18.746793]  __sys_sendmsg+0x52/0x88
[   18.746793]  ? _copy_from_user+0x51/0x60
[   18.746793]  __ia32_sys_socketcall+0x30b/0x320
[   18.746793]  ? __might_fault+0x7d/0x84
[   18.746793]  ia32_sys_call+0x2695/0x284c
[   18.746793]  __do_fast_syscall_32+0x67/0xf0
[   18.746793]  do_fast_syscall_32+0x29/0x5c
[   18.746793]  do_SYSENTER_32+0x15/0x18
[   18.746793]  entry_SYSENTER_32+0x98/0xf9
[   18.746793] EIP: 0xb7edd579
[   18.746793] Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d 76 00 58 b8 77 00 00 00 cd 80 90 8d 76
[   18.746793] EAX: ffffffda EBX: 00000010 ECX: bff4ab70 EDX: 00000000
[   18.746793] ESI: b7e5f000 EDI: 005692a0 EBP: 00000010 ESP: bff4ab60
[   18.746793] DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b EFLAGS: 00000282
[   18.874284] hpet: Lost 9 RTC interrupts
[   18.874867] RTL8201CP Ethernet r8169-0-200:00: attached PHY driver (mii_bus:phy_addr=r8169-0-200:00, irq=MAC)
[   18.932445] r8169 0000:02:00.0 eth0: Link is Down
[   19.264574] ath5k 0000:03:00.0: can't disable ASPM; OS doesn't have ASPM control
[   19.269295] ath5k 0000:03:00.0: registered as 'phy0'
[   19.827560] ath: EEPROM regdomain: 0x65
[   19.829929] ath: EEPROM indicates we should expect a direct regpair map
[   19.832273] ath: Country alpha2 being used: 00
[   19.834396] ath: Regpair used: 0x65
[   19.837790] ieee80211 phy0: Selected rate control algorithm 'minstrel_ht'
[   19.854976] ath5k: phy0: Atheros AR2425 chip found (MAC: 0xe2, PHY: 0x70)
[   20.566012] r8169 0000:02:00.0 eth0: Link is Up - 100Mbps/Full - flow control rx/tx
[   20.966578] NET: Registered PF_INET6 protocol family

--
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette