mirror of https://gitee.com/openkylin/linux.git
a1f8dd34e6
When booting kernel with LOCKDEP option, below warning info was found:
WARNING: possible recursive locking detected
4.19.0-rc7+ #14 Not tainted
--------------------------------------------
swapper/0/1 is trying to acquire lock:
00000000dcfc0fc8 (&(&list->lock)->rlock#4){+...}, at: spin_lock_bh
include/linux/spinlock.h:334 [inline]
00000000dcfc0fc8 (&(&list->lock)->rlock#4){+...}, at:
tipc_link_reset+0x125/0xdf0 net/tipc/link.c:850
but task is already holding lock:
00000000cbb9b036 (&(&list->lock)->rlock#4){+...}, at: spin_lock_bh
include/linux/spinlock.h:334 [inline]
00000000cbb9b036 (&(&list->lock)->rlock#4){+...}, at:
tipc_link_reset+0xfa/0xdf0 net/tipc/link.c:849
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&(&list->lock)->rlock#4);
lock(&(&list->lock)->rlock#4);
*** DEADLOCK ***
May be due to missing lock nesting notation
2 locks held by swapper/0/1:
#0: 00000000f7539d34 (pernet_ops_rwsem){+.+.}, at:
register_pernet_subsys+0x19/0x40 net/core/net_namespace.c:1051
#1: 00000000cbb9b036 (&(&list->lock)->rlock#4){+...}, at:
spin_lock_bh include/linux/spinlock.h:334 [inline]
#1: 00000000cbb9b036 (&(&list->lock)->rlock#4){+...}, at:
tipc_link_reset+0xfa/0xdf0 net/tipc/link.c:849
stack backtrace:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.19.0-rc7+ #14
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1af/0x295 lib/dump_stack.c:113
print_deadlock_bug kernel/locking/lockdep.c:1759 [inline]
check_deadlock kernel/locking/lockdep.c:1803 [inline]
validate_chain kernel/locking/lockdep.c:2399 [inline]
__lock_acquire+0xf1e/0x3c60 kernel/locking/lockdep.c:3411
lock_acquire+0x1db/0x520 kernel/locking/lockdep.c:3900
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
_raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:168
spin_lock_bh include/linux/spinlock.h:334 [inline]
tipc_link_reset+0x125/0xdf0 net/tipc/link.c:850
tipc_link_bc_create+0xb5/0x1f0 net/tipc/link.c:526
tipc_bcast_init+0x59b/0xab0 net/tipc/bcast.c:521
tipc_init_net+0x472/0x610 net/tipc/core.c:82
ops_init+0xf7/0x520 net/core/net_namespace.c:129
__register_pernet_operations net/core/net_namespace.c:940 [inline]
register_pernet_operations+0x453/0xac0 net/core/net_namespace.c:1011
register_pernet_subsys+0x28/0x40 net/core/net_namespace.c:1052
tipc_init+0x83/0x104 net/tipc/core.c:140
do_one_initcall+0x109/0x70a init/main.c:885
do_initcall_level init/main.c:953 [inline]
do_initcalls init/main.c:961 [inline]
do_basic_setup init/main.c:979 [inline]
kernel_init_freeable+0x4bd/0x57f init/main.c:1144
kernel_init+0x13/0x180 init/main.c:1063
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413
The reason why the noise above was complained by LOCKDEP is because we
nested to hold l->wakeupq.lock and l->inputq->lock in tipc_link_reset
function. In fact it's unnecessary to move skb buffer from l->wakeupq
queue to l->inputq queue while holding the two locks at the same time.
Instead, we can move skb buffers in l->wakeupq queue to a temporary
list first and then move the buffers of the temporary list to l->inputq
queue, which is also safe for us.
Fixes:
|
||
|---|---|---|
| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| firmware | ||
| 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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.