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>
1 parent e13ad14
check_signature.c
// SPDX-License-Identifier: GPL-2.0
#include <linux/io.h>
#include <linux/export.h>
/**
* check_signature - find BIOS signatures
* @io_addr: mmio address to check
* @signature: signature block
* @length: length of signature
*
* Perform a signature comparison with the mmio address io_addr. This
* address should have been obtained by ioremap.
* Returns 1 on a match.
*/
int check_signature(const volatile void __iomem *io_addr,
const unsigned char *signature, int length)
{
while (length--) {
if (readb(io_addr) != *signature)
return 0;
io_addr++;
signature++;
}
return 1;
}
EXPORT_SYMBOL(check_signature);
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