Revision 7ff57e98fb78ad94edafbdc7435f2d745e9e6bb5 authored by Fabio M. De Francesco on 23 February 2022, 10:02:52 UTC, committed by Jakub Kicinski on 24 February 2022, 17:09:33 UTC
smc_pnetid_by_table_ib() uses read_lock() and then it calls smc_pnet_apply_ib() which, in turn, calls mutex_lock(&smc_ib_devices.mutex). read_lock() disables preemption. Therefore, the code acquires a mutex while in atomic context and it leads to a SAC bug. Fix this bug by replacing the rwlock with a mutex. Reported-and-tested-by: syzbot+4f322a6d84e991c38775@syzkaller.appspotmail.com Fixes: 64e28b52c7a6 ("net/smc: add pnet table namespace support") Confirmed-by: Tony Lu <tonylu@linux.alibaba.com> Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com> Acked-by: Karsten Graul <kgraul@linux.ibm.com> Link: https://lore.kernel.org/r/20220223100252.22562-1-fmdefrancesco@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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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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