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Gaosheng Cui cf2ea3c86a ALSA: mts64: fix possible null-ptr-defer in snd_mts64_interrupt
I got a null-ptr-defer error report when I do the following tests
on the qemu platform:

make defconfig and CONFIG_PARPORT=m, CONFIG_PARPORT_PC=m,
CONFIG_SND_MTS64=m

Then making test scripts:
cat>test_mod1.sh<<EOF
modprobe snd-mts64
modprobe snd-mts64
EOF

Executing the script, perhaps several times, we will get a null-ptr-defer
report, as follow:

syzkaller:~# ./test_mod.sh
snd_mts64: probe of snd_mts64.0 failed with error -5
modprobe: ERROR: could not insert 'snd_mts64': No such device
 BUG: kernel NULL pointer dereference, address: 0000000000000000
 #PF: supervisor write access in kernel mode
 #PF: error_code(0x0002) - not-present page
 PGD 0 P4D 0
 Oops: 0002 [#1] PREEMPT SMP PTI
 CPU: 0 PID: 205 Comm: modprobe Not tainted 6.1.0-rc8-00588-g76dcd734eca2 #6
 Call Trace:
  <IRQ>
  snd_mts64_interrupt+0x24/0xa0 [snd_mts64]
  parport_irq_handler+0x37/0x50 [parport]
  __handle_irq_event_percpu+0x39/0x190
  handle_irq_event_percpu+0xa/0x30
  handle_irq_event+0x2f/0x50
  handle_edge_irq+0x99/0x1b0
  __common_interrupt+0x5d/0x100
  common_interrupt+0xa0/0xc0
  </IRQ>
  <TASK>
  asm_common_interrupt+0x22/0x40
 RIP: 0010:_raw_write_unlock_irqrestore+0x11/0x30
  parport_claim+0xbd/0x230 [parport]
  snd_mts64_probe+0x14a/0x465 [snd_mts64]
  platform_probe+0x3f/0xa0
  really_probe+0x129/0x2c0
  __driver_probe_device+0x6d/0xc0
  driver_probe_device+0x1a/0xa0
  __device_attach_driver+0x7a/0xb0
  bus_for_each_drv+0x62/0xb0
  __device_attach+0xe4/0x180
  bus_probe_device+0x82/0xa0
  device_add+0x550/0x920
  platform_device_add+0x106/0x220
  snd_mts64_attach+0x2e/0x80 [snd_mts64]
  port_check+0x14/0x20 [parport]
  bus_for_each_dev+0x6e/0xc0
  __parport_register_driver+0x7c/0xb0 [parport]
  snd_mts64_module_init+0x31/0x1000 [snd_mts64]
  do_one_initcall+0x3c/0x1f0
  do_init_module+0x46/0x1c6
  load_module+0x1d8d/0x1e10
  __do_sys_finit_module+0xa2/0xf0
  do_syscall_64+0x37/0x90
  entry_SYSCALL_64_after_hwframe+0x63/0xcd
  </TASK>
 Kernel panic - not syncing: Fatal exception in interrupt
 Rebooting in 1 seconds..

The mts wa not initialized during interrupt,  we add check for
mts to fix this bug.

Fixes: 68ab801e32 ("[ALSA] Add snd-mts64 driver for ESI Miditerminal 4140")
Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Link: https://lore.kernel.org/r/20221206061004.1222966-1-cuigaosheng1@huawei.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2022-12-06 11:12:12 +01:00
arch Random number generator fixes for Linux 6.1-rc1. 2022-10-16 15:27:07 -07:00
block Random number generator fixes for Linux 6.1-rc1. 2022-10-16 15:27:07 -07:00
certs certs: make system keyring depend on built-in x509 parser 2022-09-24 04:31:18 +09:00
crypto treewide: use get_random_bytes() when possible 2022-10-11 17:42:58 -06:00
Documentation MAINTAINERS: update Tzung-Bi's email address 2022-10-26 14:17:37 +01:00
drivers Random number generator fixes for Linux 6.1-rc1. 2022-10-16 15:27:07 -07:00
fs Random number generator fixes for Linux 6.1-rc1. 2022-10-16 15:27:07 -07:00
include ALSA: seq: fix undefined behavior in bit shift for SNDRV_SEQ_FILTER_USE_EVENT 2022-11-23 07:57:35 +01:00
init - hfs and hfsplus kmap API modernization from Fabio Francesco 2022-10-12 11:00:22 -07:00
io_uring io_uring/rw: ensure kiocb_end_write() is always called 2022-10-12 16:30:56 -06:00
ipc - hfs and hfsplus kmap API modernization from Fabio Francesco 2022-10-12 11:00:22 -07:00
kernel Random number generator fixes for Linux 6.1-rc1. 2022-10-16 15:27:07 -07:00
lib Random number generator fixes for Linux 6.1-rc1. 2022-10-16 15:27:07 -07:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm Random number generator fixes for Linux 6.1-rc1. 2022-10-16 15:27:07 -07:00
net Random number generator fixes for Linux 6.1-rc1. 2022-10-16 15:27:07 -07:00
rust Kbuild: add Rust support 2022-09-28 09:02:20 +02:00
samples VFIO updates for v6.1-rc1 2022-10-12 14:46:48 -07:00
scripts Kbuild fixes for v6.1 2022-10-16 11:12:22 -07:00
security - Yu Zhao's Multi-Gen LRU patches are here. They've been under test in 2022-10-10 17:53:04 -07:00
sound ALSA: mts64: fix possible null-ptr-defer in snd_mts64_interrupt 2022-12-06 11:12:12 +01:00
tools kselftest/alsa: Add more coverage of sample rates and channel counts 2022-12-01 20:02:14 +01:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt VFIO updates for v6.1-rc1 2022-10-12 14:46:48 -07:00
.clang-format PCI/DOE: Add DOE mailbox support functions 2022-07-19 15:38:04 -07:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore Kbuild: add Rust support 2022-09-28 09:02:20 +02:00
.mailmap MAINTAINERS: update Tzung-Bi's email address 2022-10-26 14:17:37 +01:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS drm for 5.20/6.0 2022-08-03 19:52:08 -07:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: update Tzung-Bi's email address 2022-10-26 14:17:37 +01:00
Makefile Linux 6.1-rc1 2022-10-16 15:36:24 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.