Mauro Carvalho Chehab ec21a38df7 Revert "media: dvb-core: Fix use-after-free on race condition at dvb_frontend"
As reported by Thomas Voegtle <tv@lio96.de>, sometimes a DVB card does
not initialize properly booting Linux 6.4-rc4. This is not always, maybe
in 3 out of 4 attempts.

After double-checking, the root cause seems to be related to the
UAF fix, which is causing a race issue:

[   26.332149] tda10071 7-0005: found a 'NXP TDA10071' in cold state, will try to load a firmware
[   26.340779] tda10071 7-0005: downloading firmware from file 'dvb-fe-tda10071.fw'
[  989.277402] INFO: task vdr:743 blocked for more than 491 seconds.
[  989.283504]       Not tainted 6.4.0-rc5-i5 #249
[  989.288036] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[  989.295860] task:vdr             state:D stack:0     pid:743   ppid:711    flags:0x00004002
[  989.295865] Call Trace:
[  989.295867]  <TASK>
[  989.295869]  __schedule+0x2ea/0x12d0
[  989.295877]  ? asm_sysvec_apic_timer_interrupt+0x16/0x20
[  989.295881]  schedule+0x57/0xc0
[  989.295884]  schedule_preempt_disabled+0xc/0x20
[  989.295887]  __mutex_lock.isra.16+0x237/0x480
[  989.295891]  ? dvb_get_property.isra.10+0x1bc/0xa50
[  989.295898]  ? dvb_frontend_stop+0x36/0x180
[  989.338777]  dvb_frontend_stop+0x36/0x180
[  989.338781]  dvb_frontend_open+0x2f1/0x470
[  989.338784]  dvb_device_open+0x81/0xf0
[  989.338804]  ? exact_lock+0x20/0x20
[  989.338808]  chrdev_open+0x7f/0x1c0
[  989.338811]  ? generic_permission+0x1a2/0x230
[  989.338813]  ? link_path_walk.part.63+0x340/0x380
[  989.338815]  ? exact_lock+0x20/0x20
[  989.338817]  do_dentry_open+0x18e/0x450
[  989.374030]  path_openat+0xca5/0xe00
[  989.374031]  ? terminate_walk+0xec/0x100
[  989.374034]  ? path_lookupat+0x93/0x140
[  989.374036]  do_filp_open+0xc0/0x140
[  989.374038]  ? __call_rcu_common.constprop.91+0x92/0x240
[  989.374041]  ? __check_object_size+0x147/0x260
[  989.374043]  ? __check_object_size+0x147/0x260
[  989.374045]  ? alloc_fd+0xbb/0x180
[  989.374048]  ? do_sys_openat2+0x243/0x310
[  989.374050]  do_sys_openat2+0x243/0x310
[  989.374052]  do_sys_open+0x52/0x80
[  989.374055]  do_syscall_64+0x5b/0x80
[  989.421335]  ? __task_pid_nr_ns+0x92/0xa0
[  989.421337]  ? syscall_exit_to_user_mode+0x20/0x40
[  989.421339]  ? do_syscall_64+0x67/0x80
[  989.421341]  ? syscall_exit_to_user_mode+0x20/0x40
[  989.421343]  ? do_syscall_64+0x67/0x80
[  989.421345]  entry_SYSCALL_64_after_hwframe+0x63/0xcd
[  989.421348] RIP: 0033:0x7fe895d067e3
[  989.421349] RSP: 002b:00007fff933c2ba0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
[  989.421351] RAX: ffffffffffffffda RBX: 00007fff933c2c10 RCX: 00007fe895d067e3
[  989.421352] RDX: 0000000000000802 RSI: 00005594acdce160 RDI: 00000000ffffff9c
[  989.421353] RBP: 0000000000000802 R08: 0000000000000000 R09: 0000000000000000
[  989.421353] R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001
[  989.421354] R13: 00007fff933c2ca0 R14: 00000000ffffffff R15: 00007fff933c2c90
[  989.421355]  </TASK>

This reverts commit 6769a0b7ee.

Fixes: 6769a0b7ee ("media: dvb-core: Fix use-after-free on race condition at dvb_frontend")
Link: https://lore.kernel.org/all/da5382ad-09d6-20ac-0d53-611594b30861@lio96.de/
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
2023-06-14 23:16:29 +01:00
2023-05-19 13:56:26 -04:00
2022-09-28 09:02:20 +02:00
2023-06-04 14:04:27 -04:00

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.
Description
No description provided
Readme 3.4 GiB
Languages
C 97%
Assembly 1%
Shell 0.6%
Rust 0.5%
Python 0.4%
Other 0.3%