mainlining shenanigans
0e8b8d6a2d
dev->unlink_list is reused unless dev is deleted.
So, list_del() should not be used.
Due to using list_del(), dev->unlink_list can't be reused so that
dev->nested_level update logic doesn't work.
In order to fix this bug, list_del_init() should be used instead
of list_del().
Test commands:
ip link add bond0 type bond
ip link add bond1 type bond
ip link set bond0 master bond1
ip link set bond0 nomaster
ip link set bond1 master bond0
ip link set bond1 nomaster
Splat looks like:
[ 255.750458][ T1030] ============================================
[ 255.751967][ T1030] WARNING: possible recursive locking detected
[ 255.753435][ T1030] 5.9.0-rc8+ #772 Not tainted
[ 255.754553][ T1030] --------------------------------------------
[ 255.756047][ T1030] ip/1030 is trying to acquire lock:
[ 255.757304][ T1030] ffff88811782a280 (&dev_addr_list_lock_key/1){+...}-{2:2}, at: dev_mc_sync_multiple+0xc2/0x150
[ 255.760056][ T1030]
[ 255.760056][ T1030] but task is already holding lock:
[ 255.761862][ T1030] ffff88811130a280 (&dev_addr_list_lock_key/1){+...}-{2:2}, at: bond_enslave+0x3d4d/0x43e0 [bonding]
[ 255.764581][ T1030]
[ 255.764581][ T1030] other info that might help us debug this:
[ 255.766645][ T1030] Possible unsafe locking scenario:
[ 255.766645][ T1030]
[ 255.768566][ T1030] CPU0
[ 255.769415][ T1030] ----
[ 255.770259][ T1030] lock(&dev_addr_list_lock_key/1);
[ 255.771629][ T1030] lock(&dev_addr_list_lock_key/1);
[ 255.772994][ T1030]
[ 255.772994][ T1030] *** DEADLOCK ***
[ 255.772994][ T1030]
[ 255.775091][ T1030] May be due to missing lock nesting notation
[ 255.775091][ T1030]
[ 255.777182][ T1030] 2 locks held by ip/1030:
[ 255.778299][ T1030] #0: ffffffffb1f63250 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x2e4/0x8b0
[ 255.780600][ T1030] #1: ffff88811130a280 (&dev_addr_list_lock_key/1){+...}-{2:2}, at: bond_enslave+0x3d4d/0x43e0 [bonding]
[ 255.783411][ T1030]
[ 255.783411][ T1030] stack backtrace:
[ 255.784874][ T1030] CPU: 7 PID: 1030 Comm: ip Not tainted 5.9.0-rc8+ #772
[ 255.786595][ T1030] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
[ 255.789030][ T1030] Call Trace:
[ 255.789850][ T1030] dump_stack+0x99/0xd0
[ 255.790882][ T1030] __lock_acquire.cold.71+0x166/0x3cc
[ 255.792285][ T1030] ? register_lock_class+0x1a30/0x1a30
[ 255.793619][ T1030] ? rcu_read_lock_sched_held+0x91/0xc0
[ 255.794963][ T1030] ? rcu_read_lock_bh_held+0xa0/0xa0
[ 255.796246][ T1030] lock_acquire+0x1b8/0x850
[ 255.797332][ T1030] ? dev_mc_sync_multiple+0xc2/0x150
[ 255.798624][ T1030] ? bond_enslave+0x3d4d/0x43e0 [bonding]
[ 255.800039][ T1030] ? check_flags+0x50/0x50
[ 255.801143][ T1030] ? lock_contended+0xd80/0xd80
[ 255.802341][ T1030] _raw_spin_lock_nested+0x2e/0x70
[ 255.803592][ T1030] ? dev_mc_sync_multiple+0xc2/0x150
[ 255.804897][ T1030] dev_mc_sync_multiple+0xc2/0x150
[ 255.806168][ T1030] bond_enslave+0x3d58/0x43e0 [bonding]
[ 255.807542][ T1030] ? __lock_acquire+0xe53/0x51b0
[ 255.808824][ T1030] ? bond_update_slave_arr+0xdc0/0xdc0 [bonding]
[ 255.810451][ T1030] ? check_chain_key+0x236/0x5e0
[ 255.811742][ T1030] ? mutex_is_locked+0x13/0x50
[ 255.812910][ T1030] ? rtnl_is_locked+0x11/0x20
[ 255.814061][ T1030] ? netdev_master_upper_dev_get+0xf/0x120
[ 255.815553][ T1030] do_setlink+0x94c/0x3040
[ ... ]
Reported-by: syzbot+4a0f7bc34e3997a6c7df@syzkaller.appspotmail.com
Fixes:
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| 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 | ||
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.