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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Raw File
sch5627.rst
Kernel driver sch5627
=====================

Supported chips:

  * SMSC SCH5627

    Prefix: 'sch5627'

    Addresses scanned: none, address read from Super I/O config space

    Datasheet: Application Note available upon request

Author: Hans de Goede <hdegoede@redhat.com>


Description
-----------

SMSC SCH5627 Super I/O chips include complete hardware monitoring
capabilities. They can monitor up to 5 voltages, 4 fans and 8 temperatures.

The SMSC SCH5627 hardware monitoring part also contains an integrated
watchdog. In order for this watchdog to function some motherboard specific
initialization most be done by the BIOS, so if the watchdog is not enabled
by the BIOS the sch5627 driver will not register a watchdog device.

The hardware monitoring part of the SMSC SCH5627 is accessed by talking
through an embedded microcontroller. An application note describing the
protocol for communicating with the microcontroller is available upon
request. Please mail me if you want a copy.
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