3c463721a7
This lockdep splat says it better than I could:
================================
WARNING: inconsistent lock state
6.2.0-rc2-07010-ga9b9500ffaac-dirty #967 Not tainted
--------------------------------
inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage.
kworker/1:3/179 [HC0[0]:SC0[0]:HE1:SE1] takes:
ffff3ec4036ce098 (_xmit_ETHER#2){+.?.}-{3:3}, at: netif_freeze_queues+0x5c/0xc0
{IN-SOFTIRQ-W} state was registered at:
_raw_spin_lock+0x5c/0xc0
sch_direct_xmit+0x148/0x37c
__dev_queue_xmit+0x528/0x111c
ip6_finish_output2+0x5ec/0xb7c
ip6_finish_output+0x240/0x3f0
ip6_output+0x78/0x360
ndisc_send_skb+0x33c/0x85c
ndisc_send_rs+0x54/0x12c
addrconf_rs_timer+0x154/0x260
call_timer_fn+0xb8/0x3a0
__run_timers.part.0+0x214/0x26c
run_timer_softirq+0x3c/0x74
__do_softirq+0x14c/0x5d8
____do_softirq+0x10/0x20
call_on_irq_stack+0x2c/0x5c
do_softirq_own_stack+0x1c/0x30
__irq_exit_rcu+0x168/0x1a0
irq_exit_rcu+0x10/0x40
el1_interrupt+0x38/0x64
irq event stamp: 7825
hardirqs last enabled at (7825): [<ffffdf1f7200cae4>] exit_to_kernel_mode+0x34/0x130
hardirqs last disabled at (7823): [<ffffdf1f708105f0>] __do_softirq+0x550/0x5d8
softirqs last enabled at (7824): [<ffffdf1f7081050c>] __do_softirq+0x46c/0x5d8
softirqs last disabled at (7811): [<ffffdf1f708166e0>] ____do_softirq+0x10/0x20
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(_xmit_ETHER#2);
<Interrupt>
lock(_xmit_ETHER#2);
*** DEADLOCK ***
3 locks held by kworker/1:3/179:
#0: ffff3ec400004748 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x1f4/0x6c0
#1: ffff80000a0bbdc8 ((work_completion)(&priv->tx_onestep_tstamp)){+.+.}-{0:0}, at: process_one_work+0x1f4/0x6c0
#2: ffff3ec4036cd438 (&dev->tx_global_lock){+.+.}-{3:3}, at: netif_tx_lock+0x1c/0x34
Workqueue: events enetc_tx_onestep_tstamp
Call trace:
print_usage_bug.part.0+0x208/0x22c
mark_lock+0x7f0/0x8b0
__lock_acquire+0x7c4/0x1ce0
lock_acquire.part.0+0xe0/0x220
lock_acquire+0x68/0x84
_raw_spin_lock+0x5c/0xc0
netif_freeze_queues+0x5c/0xc0
netif_tx_lock+0x24/0x34
enetc_tx_onestep_tstamp+0x20/0x100
process_one_work+0x28c/0x6c0
worker_thread+0x74/0x450
kthread+0x118/0x11c
but I'll say it anyway: the enetc_tx_onestep_tstamp() work item runs in
process context, therefore with softirqs enabled (i.o.w., it can be
interrupted by a softirq). If we hold the netif_tx_lock() when there is
an interrupt, and the NET_TX softirq then gets scheduled, this will take
the netif_tx_lock() a second time and deadlock the kernel.
To solve this, use netif_tx_lock_bh(), which blocks softirqs from
running.
Fixes:
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|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.