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Revision 580e4273d7a883ececfefa692c1f96bdbacb99b5 authored by Cong Wang on 02 October 2020, 19:13:34 UTC, committed by David S. Miller on 04 October 2020, 21:53:06 UTC 
net_sched: check error pointer in tcf_dump_walker()
 
Although we take RTNL on dump path, it is possible to
skip RTNL on insertion path. So the following race condition
is possible:

rtnl_lock()		// no rtnl lock
			mutex_lock(&idrinfo->lock);
			// insert ERR_PTR(-EBUSY)
			mutex_unlock(&idrinfo->lock);
tc_dump_action()
rtnl_unlock()

So we have to skip those temporary -EBUSY entries on dump path
too.

Reported-and-tested-by: syzbot+b47bc4f247856fb4d9e1@syzkaller.appspotmail.com
Fixes: 0fedc63fadf0 ("net_sched: commit action insertions together")
Cc: Vlad Buslov <vladbu@mellanox.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent 9a9e774
Raw File
debug_locks.c 
// SPDX-License-Identifier: GPL-2.0-only
/*
 * lib/debug_locks.c
 *
 * Generic place for common debugging facilities for various locks:
 * spinlocks, rwlocks, mutexes and rwsems.
 *
 * Started by Ingo Molnar:
 *
 *  Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
 */
#include <linux/rwsem.h>
#include <linux/mutex.h>
#include <linux/export.h>
#include <linux/spinlock.h>
#include <linux/debug_locks.h>

/*
 * We want to turn all lock-debugging facilities on/off at once,
 * via a global flag. The reason is that once a single bug has been
 * detected and reported, there might be cascade of followup bugs
 * that would just muddy the log. So we report the first one and
 * shut up after that.
 */
int debug_locks __read_mostly = 1;
EXPORT_SYMBOL_GPL(debug_locks);

/*
 * The locking-testsuite uses <debug_locks_silent> to get a
 * 'silent failure': nothing is printed to the console when
 * a locking bug is detected.
 */
int debug_locks_silent __read_mostly;
EXPORT_SYMBOL_GPL(debug_locks_silent);

/*
 * Generic 'turn off all lock debugging' function:
 */
noinstr int debug_locks_off(void)
{
	if (debug_locks && __debug_locks_off()) {
		if (!debug_locks_silent) {
			console_verbose();
			return 1;
		}
	}
	return 0;
}
EXPORT_SYMBOL_GPL(debug_locks_off);
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