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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
iomap_copy.c 
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright 2006 PathScale, Inc.  All Rights Reserved.
 */

#include <linux/export.h>
#include <linux/io.h>

/**
 * __iowrite32_copy - copy data to MMIO space, in 32-bit units
 * @to: destination, in MMIO space (must be 32-bit aligned)
 * @from: source (must be 32-bit aligned)
 * @count: number of 32-bit quantities to copy
 *
 * Copy data from kernel space to MMIO space, in units of 32 bits at a
 * time.  Order of access is not guaranteed, nor is a memory barrier
 * performed afterwards.
 */
void __attribute__((weak)) __iowrite32_copy(void __iomem *to,
					    const void *from,
					    size_t count)
{
	u32 __iomem *dst = to;
	const u32 *src = from;
	const u32 *end = src + count;

	while (src < end)
		__raw_writel(*src++, dst++);
}
EXPORT_SYMBOL_GPL(__iowrite32_copy);

/**
 * __ioread32_copy - copy data from MMIO space, in 32-bit units
 * @to: destination (must be 32-bit aligned)
 * @from: source, in MMIO space (must be 32-bit aligned)
 * @count: number of 32-bit quantities to copy
 *
 * Copy data from MMIO space to kernel space, in units of 32 bits at a
 * time.  Order of access is not guaranteed, nor is a memory barrier
 * performed afterwards.
 */
void __ioread32_copy(void *to, const void __iomem *from, size_t count)
{
	u32 *dst = to;
	const u32 __iomem *src = from;
	const u32 __iomem *end = src + count;

	while (src < end)
		*dst++ = __raw_readl(src++);
}
EXPORT_SYMBOL_GPL(__ioread32_copy);

/**
 * __iowrite64_copy - copy data to MMIO space, in 64-bit or 32-bit units
 * @to: destination, in MMIO space (must be 64-bit aligned)
 * @from: source (must be 64-bit aligned)
 * @count: number of 64-bit quantities to copy
 *
 * Copy data from kernel space to MMIO space, in units of 32 or 64 bits at a
 * time.  Order of access is not guaranteed, nor is a memory barrier
 * performed afterwards.
 */
void __attribute__((weak)) __iowrite64_copy(void __iomem *to,
					    const void *from,
					    size_t count)
{
#ifdef CONFIG_64BIT
	u64 __iomem *dst = to;
	const u64 *src = from;
	const u64 *end = src + count;

	while (src < end)
		__raw_writeq(*src++, dst++);
#else
	__iowrite32_copy(to, from, count * 2);
#endif
}

EXPORT_SYMBOL_GPL(__iowrite64_copy);
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