2a61d8b883
A proc_remove() can sleep. so that it can't be inside of spin_lock. Hence proc_remove() is moved to outside of spin_lock. and it also adds mutex to sync create and remove of proc entry(config->pde). test commands: SHELL#1 %while :; do iptables -A INPUT -p udp -i enp2s0 -d 192.168.1.100 \ --dport 9000 -j CLUSTERIP --new --hashmode sourceip \ --clustermac 01:00:5e:00:00:21 --total-nodes 3 --local-node 3; \ iptables -F; done SHELL#2 %while :; do echo +1 > /proc/net/ipt_CLUSTERIP/192.168.1.100; \ echo -1 > /proc/net/ipt_CLUSTERIP/192.168.1.100; done [ 2949.569864] BUG: sleeping function called from invalid context at kernel/sched/completion.c:99 [ 2949.579944] in_atomic(): 1, irqs_disabled(): 0, pid: 5472, name: iptables [ 2949.587920] 1 lock held by iptables/5472: [ 2949.592711] #0: 000000008f0ebcf2 (&(&cn->lock)->rlock){+...}, at: refcount_dec_and_lock+0x24/0x50 [ 2949.603307] CPU: 1 PID: 5472 Comm: iptables Tainted: G W 4.19.0-rc5+ #16 [ 2949.604212] Hardware name: To be filled by O.E.M. To be filled by O.E.M./Aptio CRB, BIOS 5.6.5 07/08/2015 [ 2949.604212] Call Trace: [ 2949.604212] dump_stack+0xc9/0x16b [ 2949.604212] ? show_regs_print_info+0x5/0x5 [ 2949.604212] ___might_sleep+0x2eb/0x420 [ 2949.604212] ? set_rq_offline.part.87+0x140/0x140 [ 2949.604212] ? _rcu_barrier_trace+0x400/0x400 [ 2949.604212] wait_for_completion+0x94/0x710 [ 2949.604212] ? wait_for_completion_interruptible+0x780/0x780 [ 2949.604212] ? __kernel_text_address+0xe/0x30 [ 2949.604212] ? __lockdep_init_map+0x10e/0x5c0 [ 2949.604212] ? __lockdep_init_map+0x10e/0x5c0 [ 2949.604212] ? __init_waitqueue_head+0x86/0x130 [ 2949.604212] ? init_wait_entry+0x1a0/0x1a0 [ 2949.604212] proc_entry_rundown+0x208/0x270 [ 2949.604212] ? proc_reg_get_unmapped_area+0x370/0x370 [ 2949.604212] ? __lock_acquire+0x4500/0x4500 [ 2949.604212] ? complete+0x18/0x70 [ 2949.604212] remove_proc_subtree+0x143/0x2a0 [ 2949.708655] ? remove_proc_entry+0x390/0x390 [ 2949.708655] clusterip_tg_destroy+0x27a/0x630 [ipt_CLUSTERIP] [ ... ] Fixes: b3e456fce9f5 ("netfilter: ipt_CLUSTERIP: fix a race condition of proc file creation") Signed-off-by: Taehee Yoo <ap420073@gmail.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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.