089bca2cae
All bonding device has same lockdep key and subclass is initialized with
nest_level.
But actual nest_level value can be changed when a lower device is attached.
And at this moment, the subclass should be updated but it seems to be
unsafe.
So this patch makes bonding use dynamic lockdep key instead of the
subclass.
Test commands:
ip link add bond0 type bond
for i in {1..5}
do
let A=$i-1
ip link add bond$i type bond
ip link set bond$i master bond$A
done
ip link set bond5 master bond0
Splat looks like:
[ 307.992912] WARNING: possible recursive locking detected
[ 307.993656] 5.4.0-rc3+ #96 Tainted: G W
[ 307.994367] --------------------------------------------
[ 307.995092] ip/761 is trying to acquire lock:
[ 307.995710] ffff8880513aac60 (&(&bond->stats_lock)->rlock#2/2){+.+.}, at: bond_get_stats+0xb8/0x500 [bonding]
[ 307.997045]
but task is already holding lock:
[ 307.997923] ffff88805fcbac60 (&(&bond->stats_lock)->rlock#2/2){+.+.}, at: bond_get_stats+0xb8/0x500 [bonding]
[ 307.999215]
other info that might help us debug this:
[ 308.000251] Possible unsafe locking scenario:
[ 308.001137] CPU0
[ 308.001533] ----
[ 308.001915] lock(&(&bond->stats_lock)->rlock#2/2);
[ 308.002609] lock(&(&bond->stats_lock)->rlock#2/2);
[ 308.003302]
*** DEADLOCK ***
[ 308.004310] May be due to missing lock nesting notation
[ 308.005319] 3 locks held by ip/761:
[ 308.005830] #0: ffffffff9fcc42b0 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x466/0x8a0
[ 308.006894] #1: ffff88805fcbac60 (&(&bond->stats_lock)->rlock#2/2){+.+.}, at: bond_get_stats+0xb8/0x500 [bonding]
[ 308.008243] #2: ffffffff9f9219c0 (rcu_read_lock){....}, at: bond_get_stats+0x9f/0x500 [bonding]
[ 308.009422]
stack backtrace:
[ 308.010124] CPU: 0 PID: 761 Comm: ip Tainted: G W 5.4.0-rc3+ #96
[ 308.011097] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
[ 308.012179] Call Trace:
[ 308.012601] dump_stack+0x7c/0xbb
[ 308.013089] __lock_acquire+0x269d/0x3de0
[ 308.013669] ? register_lock_class+0x14d0/0x14d0
[ 308.014318] lock_acquire+0x164/0x3b0
[ 308.014858] ? bond_get_stats+0xb8/0x500 [bonding]
[ 308.015520] _raw_spin_lock_nested+0x2e/0x60
[ 308.016129] ? bond_get_stats+0xb8/0x500 [bonding]
[ 308.017215] bond_get_stats+0xb8/0x500 [bonding]
[ 308.018454] ? bond_arp_rcv+0xf10/0xf10 [bonding]
[ 308.019710] ? rcu_read_lock_held+0x90/0xa0
[ 308.020605] ? rcu_read_lock_sched_held+0xc0/0xc0
[ 308.021286] ? bond_get_stats+0x9f/0x500 [bonding]
[ 308.021953] dev_get_stats+0x1ec/0x270
[ 308.022508] bond_get_stats+0x1d1/0x500 [bonding]
Fixes:
|
||
|---|---|---|
| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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.