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Hans Verkuil 8ffd573c25 media: vivid: media_device_cleanup was called too early
Running the contrib/test/test-media script in v4l-utils with the vivid argument
will cause this kernel warning:

[  104.748720] videodev: v4l2_release
[  104.748731] ------------[ cut here ]------------
[  104.748750] DEBUG_LOCKS_WARN_ON(lock->magic != lock)
[  104.748790] WARNING: CPU: 6 PID: 1823 at kernel/locking/mutex.c:938 __mutex_lock+0x919/0xc10
[  104.748800] Modules linked in: rc_cec vivid v4l2_tpg videobuf2_dma_contig cec rc_core v4l2_dv_timings videobuf2_vmalloc videobuf2_memops
videobuf2_v4l2 videobuf2_common videodev mc vmw_balloon vmw_vmci button vmwgfx
[  104.748845] CPU: 6 PID: 1823 Comm: sleep Not tainted 5.4.0-rc1-test-no #150
[  104.748853] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/29/2019
[  104.748867] RIP: 0010:__mutex_lock+0x919/0xc10
[  104.748878] Code: 59 83 e8 9a fc 16 ff 44 8b 05 23 61 38 01 45 85 c0 0f 85 ef f7 ff ff 48 c7 c6 a0 1f 87 82 48 c7 c7 a0 1e 87 82 e8 cd bb
f7 fe <0f> 0b e9 d5 f7 ff ff f6 c3 04 0f 84 3b fd ff ff 49 89 df 41 83 e7
[  104.748886] RSP: 0018:ffff88811a357b80 EFLAGS: 00010286
[  104.748895] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[  104.748902] RDX: 0000000000000003 RSI: 0000000000000004 RDI: ffffed102346af62
[  104.748910] RBP: ffff88811a357cf0 R08: ffffffff81217c91 R09: fffffbfff061c271
[  104.748917] R10: fffffbfff061c270 R11: ffffffff830e1383 R12: ffff8881a46103c0
[  104.748924] R13: 0000000000000000 R14: ffff8881a4614f90 R15: ffff8881a46153d0
[  104.748933] FS:  0000000000000000(0000) GS:ffff8881b6780000(0000) knlGS:0000000000000000
[  104.748940] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  104.748949] CR2: 00007f163fc9ca20 CR3: 0000000003013004 CR4: 00000000001606e0
[  104.749036] Call Trace:
[  104.749051]  ? _raw_spin_unlock+0x1f/0x30
[  104.749067]  ? llist_add_batch+0x33/0x50
[  104.749081]  ? tick_nohz_tick_stopped+0x19/0x30
[  104.749130]  ? v4l2_release.cold+0x6c/0xd6 [videodev]
[  104.749143]  ? mutex_lock_io_nested+0xb80/0xb80
[  104.749153]  ? vprintk_emit+0xf2/0x220
[  104.749191]  ? vivid_req_validate+0x40/0x40 [vivid]
[  104.749201]  ? printk+0xad/0xde
[  104.749211]  ? kmsg_dump_rewind_nolock+0x54/0x54
[  104.749226]  ? locks_remove_file+0x78/0x2b0
[  104.749248]  ? __fsnotify_update_child_dentry_flags.part.0+0x170/0x170
[  104.749281]  ? vivid_req_validate+0x40/0x40 [vivid]
[  104.749321]  ? v4l2_release.cold+0x6c/0xd6 [videodev]
[  104.749361]  v4l2_release.cold+0x6c/0xd6 [videodev]
[  104.749378]  __fput+0x15a/0x390
[  104.749393]  task_work_run+0xb2/0xe0
[  104.749407]  do_exit+0x4d0/0x1200
[  104.749422]  ? do_user_addr_fault+0x367/0x610
[  104.749431]  ? release_task+0x990/0x990
[  104.749449]  ? rwsem_spin_on_owner+0x170/0x170
[  104.749463]  ? vmacache_find+0xb2/0x100
[  104.749476]  do_group_exit+0x85/0x130
[  104.749487]  __x64_sys_exit_group+0x23/0x30
[  104.749500]  do_syscall_64+0x5e/0x1c0
[  104.749511]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[  104.749520] RIP: 0033:0x7f163fc5c9d6
[  104.749536] Code: Bad RIP value.
[  104.749543] RSP: 002b:00007ffe6f3bec58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
[  104.749553] RAX: ffffffffffffffda RBX: 00007f163fd4d760 RCX: 00007f163fc5c9d6
[  104.749560] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000
[  104.749567] RBP: 0000000000000000 R08: 00000000000000e7 R09: ffffffffffffff80
[  104.749574] R10: 00007ffe6f3beb24 R11: 0000000000000246 R12: 00007f163fd4d760
[  104.749581] R13: 0000000000000002 R14: 00007f163fd56428 R15: 0000000000000000
[  104.749597] ---[ end trace 66f20f73fc0daf79 ]---

This is caused by media_device_cleanup() which destroys
v4l2_dev->mdev->req_queue_mutex. But v4l2_release() tries to lock
that mutex after media_device_cleanup() is called.

By moving media_device_cleanup() to the v4l2_device's release function it is
guaranteed that the mutex is valid whenever v4l2_release is called.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
2019-11-05 10:32:57 -03:00
arch csky-for-linus-5.4-rc1: arch/csky patches for 5.4-rc1 2019-09-30 10:16:17 -07:00
block block: fix null pointer dereference in blk_mq_rq_timed_out() 2019-09-27 07:01:25 -06:00
certs PKCS#7: Refactor verify_pkcs7_signature() 2019-08-05 18:40:18 -04:00
crypto Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-09-28 08:14:15 -07:00
Documentation media: dt-bindings: rcar_vin: Document RZ/G1 per-board settings 2019-11-05 09:02:32 -03:00
drivers media: vivid: media_device_cleanup was called too early 2019-11-05 10:32:57 -03:00
fs for-5.4-rc1-tag 2019-09-30 10:25:24 -07:00
include media: smiapp: Support probing NVM size 2019-10-24 18:53:38 -03:00
init Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-09-28 08:14:15 -07:00
ipc ipc/sem.c: convert to use built-in RCU list checking 2019-09-25 17:51:41 -07:00
kernel A few more tracing fixes: 2019-09-30 09:29:53 -07:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-09-28 17:47:33 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm Merge branch 'hugepage-fallbacks' (hugepatch patches from David Rientjes) 2019-09-28 14:26:47 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-09-28 17:47:33 -07:00
samples rpmsg updates for v5.4 2019-09-22 10:58:15 -07:00
scripts Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity 2019-09-27 19:37:27 -07:00
security Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-09-28 08:14:15 -07:00
sound sound fixes for 5.4-rc1 2019-09-24 16:46:16 -07:00
tools A few more tracing fixes: 2019-09-30 09:29:53 -07:00
usr Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-09-28 17:47:33 -07:00
virt * s390: ioctl hardening, selftests 2019-09-18 09:49:13 -07:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Modules updates for v5.4 2019-09-22 10:34:46 -07:00
.mailmap Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2019-09-18 12:34:53 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS CREDITS: Update email address 2019-09-13 17:21:38 +03:00
Kbuild kbuild: do not descend to ./Kbuild when cleaning 2019-08-21 21:03:58 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS media: hi556: Add support for Hi-556 sensor 2019-11-05 09:12:49 -03:00
Makefile Linux 5.4-rc1 2019-09-30 10:35:40 -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.