a8b7b2d0b3
In case the qdisc_match_from_root function() is called from non-rcu path with rtnl mutex held, a suspiciout rcu usage warning appears: [ 241.504354] ============================= [ 241.504358] WARNING: suspicious RCU usage [ 241.504366] 5.8.0-rc4-custom-01521-g72a7c7d549c3 #32 Not tainted [ 241.504370] ----------------------------- [ 241.504378] net/sched/sch_api.c:270 RCU-list traversed in non-reader section!! [ 241.504382] other info that might help us debug this: [ 241.504388] rcu_scheduler_active = 2, debug_locks = 1 [ 241.504394] 1 lock held by tc/1391: [ 241.504398] #0: ffffffff85a27850 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x49a/0xbd0 [ 241.504431] stack backtrace: [ 241.504440] CPU: 0 PID: 1391 Comm: tc Not tainted 5.8.0-rc4-custom-01521-g72a7c7d549c3 #32 [ 241.504446] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-2.fc32 04/01/2014 [ 241.504453] Call Trace: [ 241.504465] dump_stack+0x100/0x184 [ 241.504482] lockdep_rcu_suspicious+0x153/0x15d [ 241.504499] qdisc_match_from_root+0x293/0x350 Fix this by passing the rtnl held lockdep condition down to hlist_for_each_entry_rcu() Reported-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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.