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Filename Latest commit message Latest commit date
Lang Dai 2502107a9c uio: free uio id after uio file node is freed
[ Upstream commit 8fd0e2a6df262539eaa28b0a2364cca10d1dc662 ]

uio_register_device() do two things.
1) get an uio id from a global pool, e.g. the id is <A>
2) create file nodes like /sys/class/uio/uio<A>

uio_unregister_device() do two things.
1) free the uio id <A> and return it to the global pool
2) free the file node /sys/class/uio/uio<A>

There is a situation is that one worker is calling uio_unregister_device(),
and another worker is calling uio_register_device().
If the two workers are X and Y, they go as below sequence,
1) X free the uio id <AAA>
2) Y get an uio id <AAA>
3) Y create file node /sys/class/uio/uio<AAA>
4) X free the file note /sys/class/uio/uio<AAA>
Then it will failed at the 3rd step and cause the phenomenon we saw as it
is creating a duplicated file node.

Failure reports as follows:
sysfs: cannot create duplicate filename '/class/uio/uio10'
Call Trace:
   sysfs_do_create_link_sd.isra.2+0x9e/0xb0
   sysfs_create_link+0x25/0x40
   device_add+0x2c4/0x640
   __uio_register_device+0x1c5/0x576 [uio]
   adf_uio_init_bundle_dev+0x231/0x280 [intel_qat]
   adf_uio_register+0x1c0/0x340 [intel_qat]
   adf_dev_start+0x202/0x370 [intel_qat]
   adf_dev_start_async+0x40/0xa0 [intel_qat]
   process_one_work+0x14d/0x410
   worker_thread+0x4b/0x460
   kthread+0x105/0x140
 ? process_one_work+0x410/0x410
 ? kthread_bind+0x40/0x40
 ret_from_fork+0x1f/0x40
 Code: 85 c0 48 89 c3 74 12 b9 00 10 00 00 48 89 c2 31 f6 4c 89 ef
 e8 ec c4 ff ff 4c 89 e2 48 89 de 48 c7 c7 e8 b4 ee b4 e8 6a d4 d7
 ff <0f> 0b 48 89 df e8 20 fa f3 ff 5b 41 5c 41 5d 5d c3 66 0f 1f 84
---[ end trace a7531c1ed5269e84 ]---
 c6xxvf b002:00:00.0: Failed to register UIO devices
 c6xxvf b002:00:00.0: Failed to register UIO devices

Signed-off-by: Lang Dai <lang.dai@intel.com>

Link: https://lore.kernel.org/r/1600054002-17722-1-git-send-email-lang.dai@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-11-05 11:43:18 +01:00
arch riscv: Define AT_VECTOR_SIZE_ARCH for ARCH_DLINFO 2020-11-05 11:43:17 +01:00
block block: ratelimit handle_bad_sector() message 2020-10-29 09:58:01 +01:00
certs
crypto crypto: algif_skcipher - EBUSY on aio should be an error 2020-10-29 09:57:30 +01:00
Documentation media: videodev2.h: RGB BT2020 and HSV are always full range 2020-11-05 11:43:15 +01:00
drivers uio: free uio id after uio file node is freed 2020-11-05 11:43:18 +01:00
fs xfs: fix realtime bitmap/summary file truncation when growing rt volume 2020-11-05 11:43:14 +01:00
include usb: typec: tcpm: During PR_SWAP, source caps should be sent only after tSwapSourceStart 2020-11-05 11:43:15 +01:00
init printk: reduce LOG_BUF_SHIFT range for H8300 2020-11-05 11:43:16 +01:00
ipc
kernel bpf: Permit map_ptr arithmetic with opcode add and offset 0 2020-11-05 11:43:17 +01:00
lib lib/crc32.c: fix trivial typo in preprocessor condition 2020-10-29 09:57:52 +01:00
LICENSES
mm mm/page_owner: change split_page_owner to take a count 2020-10-29 09:57:52 +01:00
net tipc: fix memory leak caused by tipc_buf_append() 2020-11-01 12:01:04 +01:00
samples samples/bpf: Fix possible deadlock in xdpsock 2020-11-05 11:43:17 +01:00
scripts scripts/setlocalversion: make git describe output more reliable 2020-11-01 12:01:01 +01:00
security evm: Check size of security.evm before using it 2020-11-01 12:01:05 +01:00
sound ALSA: hda/ca0132 - Add new quirk ID for SoundBlaster AE-7. 2020-10-29 09:58:09 +01:00
tools selftests/bpf: Define string const as global for test_sysctl_prog.c 2020-11-05 11:43:17 +01:00
usr
virt KVM: arm64: Assume write fault on S1PTW permission fault on instruction fetch 2020-10-01 13:18:25 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS Documentation/llvm: add documentation on building w/ Clang/LLVM 2020-08-26 10:40:46 +02:00
Makefile Linux 5.4.74 2020-11-01 12:01:07 +01:00
README

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.