License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.
By default all files without license information are under the default
license of the kernel, which is GPL version 2.
Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.
This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.
How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,
Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.
The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.
The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.
Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).
All documentation files were explicitly excluded.
The following heuristics were used to determine which SPDX license
identifiers to apply.
- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.
For non */uapi/* files that summary was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139
and resulted in the first patch in this series.
If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930
and resulted in the second patch in this series.
- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:
SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1
and that resulted in the third patch in this series.
- when the two scanners agreed on the detected license(s), that became
the concluded license(s).
- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.
- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).
- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.
- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.
In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.
Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.
Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.
In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.
Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct
This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.
These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-01 15:07:57 +01:00
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2005-04-16 15:20:36 -07:00
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2018-03-09 16:36:33 -06:00
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2005-04-16 15:20:36 -07:00
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2018-03-09 16:36:33 -06:00
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2005-04-16 15:20:36 -07:00
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include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 17:04:11 +09:00
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2005-04-16 15:20:36 -07:00
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2007-07-15 23:40:39 -07:00
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2016-12-24 11:46:01 -08:00
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2019-08-19 17:17:47 -07:00
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2026-07-29 07:54:13 +00:00
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2005-04-16 15:20:36 -07:00
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2005-04-08 14:53:31 +09:00
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2005-04-16 15:20:36 -07:00
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PCI/proc: Fix race between pci_proc_init() and pci_bus_add_device()
pci_proc_attach_device() creates procfs entries for PCI devices and is
called from pci_bus_add_device(). It lazily creates the per-bus procfs
directory (bus->procdir) via proc_mkdir() on first use, and returns early
if proc_initialized is not yet set.
On x86 with ACPI, PCI enumeration occurs at subsys_initcall, before
pci_proc_init() sets proc_initialized at device_initcall. The
for_each_pci_dev() loop in pci_proc_init() then creates procfs entries for
these already-enumerated devices, but runs without holding
pci_rescan_remove_lock.
On ARM64 with devicetree, PCI host bridges probe at device_initcall. With
async probing enabled, pci_bus_add_device() can run concurrently with
pci_proc_init(), and both may call pci_proc_attach_device() for the same
device or for different devices on the same bus. As pci_host_probe() holds
pci_rescan_remove_lock while pci_proc_init() does not, there is no
serialisation between the two paths.
When two threads concurrently call pci_proc_attach_device() for devices on
the same bus, both observe bus->procdir as NULL and both call proc_mkdir().
The proc filesystem serialises directory creation internally, so only one
caller succeeds. The other results in a warning like:
proc_dir_entry '000c:00/00.0' already registered
The caller receives NULL (duplicate entry) and unconditionally stores it to
bus->procdir, corrupting the valid pointer set by the first caller.
Serialise access to proc_initialized, proc_bus_pci_dir, bus->procdir and
dev->procent with a new mutex local to drivers/pci/proc.c, and store the
created entries to bus->procdir and dev->procent only on success, so a
failed creation can never overwrite a valid pointer.
Additionally, wrap the for_each_pci_dev() loop in pci_proc_init() with
pci_lock_rescan_remove() to serialise against concurrent PCI bus
operations, add an early return in pci_proc_attach_device() when
dev->procent is already set to make the function idempotent, and clear
bus->procdir in pci_proc_detach_bus() to prevent use of a dangling pointer
after proc_remove().
Reported-by: Shuan He <heshuan@bytedance.com>
Closes: https://lore.kernel.org/linux-pci/20250702155112.40124-2-heshuan@bytedance.com/
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20260611150543.511422-1-kwilczynski@kernel.org
2026-06-11 15:05:43 +00:00
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2005-04-16 15:20:36 -07:00
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2014-04-18 20:13:49 -04:00
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2005-04-16 15:20:36 -07:00
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2022-01-21 22:14:23 -08:00
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2013-06-23 12:29:00 +04:00
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2005-04-16 15:20:36 -07:00
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2014-04-18 20:13:49 -04:00
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2005-04-16 15:20:36 -07:00
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2022-01-21 22:14:23 -08:00
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2005-04-16 15:20:36 -07:00
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PCI/proc: Use file_ns_capable() when checking config space read access
proc_bus_pci_read() decides how much of the config space is readable based
on capable(CAP_SYS_ADMIN), which checks the credentials of the task calling
read(), not the credentials of the process that opened the file.
The sysfs equivalent, pci_read_config(), has checked the credentials of the
opening process since commit de139a339395 ("pci: check caps from sysfs file
open to read device dependent config space"), so a privileged process can
open the config space file and pass the file descriptor to an unprivileged
process (for example, a process running a KVM guest with an assigned
device), which can then read the entire config space. The check was
subsequently routed through the LSM framework in commit 47970b1b2aa6 ("pci:
use security_capable() when checking capablities during config space read")
and converted to the dedicated helper in commit ab0fa82b2df9 ("pci-sysfs:
use proper file capability helper function").
Thus, the two interfaces check the same capability against different
credentials. Checking the credentials of the task calling read() makes the
outcome depend on who reads rather than who opened, so the restriction is
bypassed whenever a more privileged process reads through the descriptor.
Checking the credentials recorded in file->f_cred settles the decision at
open() time and ties it to the file, where it cannot change with the
caller.
Use file_ns_capable() to check CAP_SYS_ADMIN against the credentials in
effect when the file was opened, bringing the procfs interface in line with
the sysfs behaviour.
As a result, a file descriptor opened by a privileged process and passed to
an unprivileged one now allows the entire config space to be read through
procfs, matching sysfs.
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260720204145.1500105-1-kwilczynski@kernel.org
2026-07-20 20:41:45 +00:00
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2013-03-31 18:16:14 -04:00
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2005-04-16 15:20:36 -07:00
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2026-07-29 07:59:09 +00:00
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2005-04-16 15:20:36 -07:00
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Remove 'type' argument from access_ok() function
Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.
It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access. But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.
A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model. And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.
This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.
There were a couple of notable cases:
- csky still had the old "verify_area()" name as an alias.
- the iter_iov code had magical hardcoded knowledge of the actual
values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
really used it)
- microblaze used the type argument for a debug printout
but other than those oddities this should be a total no-op patch.
I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something. Any missed conversion should be trivially fixable, though.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-01-03 18:57:57 -08:00
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2005-04-16 15:20:36 -07:00
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2012-10-25 09:36:03 +08:00
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2005-04-16 15:20:36 -07:00
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2005-09-27 01:21:55 -07:00
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2005-04-16 15:20:36 -07:00
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2005-09-27 01:21:55 -07:00
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2008-07-22 14:40:47 -07:00
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2005-04-16 15:20:36 -07:00
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2005-09-27 01:21:55 -07:00
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2008-07-22 14:40:47 -07:00
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2005-04-16 15:20:36 -07:00
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2021-08-15 15:08:24 +00:00
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2005-04-16 15:20:36 -07:00
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2005-09-27 01:21:55 -07:00
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2008-07-22 14:40:47 -07:00
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2005-04-16 15:20:36 -07:00
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2005-09-27 01:21:55 -07:00
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2005-04-16 15:20:36 -07:00
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2012-10-25 09:36:03 +08:00
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2005-04-16 15:20:36 -07:00
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2014-04-18 20:13:49 -04:00
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2005-04-16 15:20:36 -07:00
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2013-01-23 17:07:38 -05:00
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2022-01-21 22:14:23 -08:00
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2005-04-16 15:20:36 -07:00
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2013-03-31 18:16:14 -04:00
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2019-08-19 17:17:47 -07:00
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2005-04-16 15:20:36 -07:00
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2026-07-29 07:59:09 +00:00
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2026-07-29 07:54:13 +00:00
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2005-04-16 15:20:36 -07:00
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Remove 'type' argument from access_ok() function
Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.
It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access. But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.
A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model. And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.
This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.
There were a couple of notable cases:
- csky still had the old "verify_area()" name as an alias.
- the iter_iov code had magical hardcoded knowledge of the actual
values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
really used it)
- microblaze used the type argument for a debug printout
but other than those oddities this should be a total no-op patch.
I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something. Any missed conversion should be trivially fixable, though.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-01-03 18:57:57 -08:00
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2005-04-16 15:20:36 -07:00
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2012-10-25 09:36:03 +08:00
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2005-04-16 15:20:36 -07:00
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2005-09-27 01:21:55 -07:00
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2005-04-16 15:20:36 -07:00
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2008-07-22 14:40:47 -07:00
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2005-09-27 01:21:55 -07:00
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2005-04-16 15:20:36 -07:00
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2008-07-22 14:40:47 -07:00
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2005-09-27 01:21:55 -07:00
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2005-04-16 15:20:36 -07:00
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2008-07-22 14:40:47 -07:00
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2005-09-27 01:21:55 -07:00
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2005-04-16 15:20:36 -07:00
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2005-09-27 01:21:55 -07:00
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2005-04-16 15:20:36 -07:00
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2012-10-25 09:36:03 +08:00
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2005-04-16 15:20:36 -07:00
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2013-03-31 18:16:14 -04:00
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2005-04-16 15:20:36 -07:00
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2021-07-06 00:31:45 +00:00
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2005-04-16 15:20:36 -07:00
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2021-07-06 00:31:45 +00:00
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2005-04-16 15:20:36 -07:00
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2008-01-10 14:27:12 +01:00
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2005-04-16 15:20:36 -07:00
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2022-01-21 22:14:23 -08:00
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2005-04-16 15:20:36 -07:00
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2019-08-19 17:17:47 -07:00
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2005-04-16 15:20:36 -07:00
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2017-04-12 13:25:56 +01:00
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2005-04-16 15:20:36 -07:00
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2017-04-12 13:25:54 +01:00
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2020-08-23 17:36:59 -05:00
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2021-07-13 13:21:22 -05:00
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2005-04-16 15:20:36 -07:00
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2013-11-14 11:28:18 -07:00
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2005-04-16 15:20:36 -07:00
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2022-01-21 22:14:23 -08:00
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2005-04-16 15:20:36 -07:00
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2022-07-15 17:36:16 +02:00
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2017-04-12 13:25:56 +01:00
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2005-04-16 15:20:36 -07:00
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2019-08-19 17:17:47 -07:00
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2005-04-16 15:20:36 -07:00
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2025-02-26 13:07:46 +01:00
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2017-04-12 13:25:56 +01:00
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2017-04-12 13:25:51 +01:00
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2017-04-12 13:25:56 +01:00
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2017-04-12 13:25:51 +01:00
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2008-10-24 10:32:33 -07:00
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2019-09-28 02:43:08 +03:00
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2017-04-12 13:25:51 +01:00
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2008-10-24 10:32:33 -07:00
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2019-09-28 02:43:08 +03:00
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2008-10-24 10:32:33 -07:00
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2017-04-12 13:25:52 +01:00
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2020-11-27 17:41:22 +01:00
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2022-07-15 17:36:16 +02:00
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PCI: Ignore write combining when mapping I/O port space
PCI exposes files like /proc/bus/pci/00/00.0 in procfs. These files
support operations like this:
ioctl(fd, PCIIOC_MMAP_IS_IO); # request I/O port space
ioctl(fd, PCIIOC_WRITE_COMBINE, 1); # request write-combining
mmap(fd, ...)
Write combining is useful on PCI memory space, but I don't think it makes
sense on PCI I/O port space.
We *could* change proc_bus_pci_ioctl() to make it impossible to set
mmap_state == pci_mmap_io and write_combine at the same time, but that
would break the following sequence, which is currently legal:
mmap(fd, ...) # default is I/O, non-combining
ioctl(fd, PCIIOC_WRITE_COMBINE, 1); # request write-combining
ioctl(fd, PCIIOC_MMAP_IS_MEM); # request memory space
mmap(fd, ...) # get write-combining mapping
Ignore the write-combining flag when mapping I/O port space.
This patch should have no functional effect, based on this analysis of all
implementations of pci_mmap_page_range():
- ia64 mips parisc sh unicore32 x86 do not support mapping of I/O port
space at all.
- arm cris microblaze mn10300 sparc xtensa support mapping of I/O port
space, but ignore the write_combine argument to pci_mmap_page_range().
- powerpc supports mapping of I/O port space and uses write_combine, and
it disables write combining for I/O port space in
__pci_mmap_set_pgprot().
This patch makes it possible to remove __pci_mmap_set_pgprot() from
powerpc, which simplifies that path.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2016-06-08 14:46:54 -05:00
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2005-04-16 15:20:36 -07:00
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2026-02-21 16:37:42 -08:00
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2005-04-16 15:20:36 -07:00
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PCI: Revoke mappings like devmem
Since 3234ac664a87 ("/dev/mem: Revoke mappings when a driver claims
the region") /dev/kmem zaps PTEs when the kernel requests exclusive
acccess to an iomem region. And with CONFIG_IO_STRICT_DEVMEM, this is
the default for all driver uses.
Except there are two more ways to access PCI BARs: sysfs and proc mmap
support. Let's plug that hole.
For revoke_devmem() to work we need to link our vma into the same
address_space, with consistent vma->vm_pgoff. ->pgoff is already
adjusted, because that's how (io_)remap_pfn_range works, but for the
mapping we need to adjust vma->vm_file->f_mapping. The cleanest way is
to adjust this at at ->open time:
- for sysfs this is easy, now that binary attributes support this. We
just set bin_attr->mapping when mmap is supported
- for procfs it's a bit more tricky, since procfs PCI access has only
one file per device, and access to a specific resource first needs
to be set up with some ioctl calls. But mmap is only supported for
the same resources as sysfs exposes with mmap support, and otherwise
rejected, so we can set the mapping unconditionally at open time
without harm.
A special consideration is for arch_can_pci_mmap_io() - we need to
make sure that the ->f_mapping doesn't alias between ioport and iomem
space. There are only 2 ways in-tree to support mmap of ioports: generic
PCI mmap (ARCH_GENERIC_PCI_MMAP_RESOURCE), and sparc as the single
architecture hand-rolling. Both approaches support ioport mmap through a
special PFN range and not through magic PTE attributes. Aliasing is
therefore not a problem.
The only difference in access checks left is that sysfs PCI mmap does
not check for CAP_RAWIO. I'm not really sure whether that should be
added or not.
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kees Cook <keescook@chromium.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-mm@kvack.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-samsung-soc@vger.kernel.org
Cc: linux-media@vger.kernel.org
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-pci@vger.kernel.org
Link: https://patchwork.freedesktop.org/patch/msgid/20210204165831.2703772-3-daniel.vetter@ffwll.ch
2021-02-04 17:58:31 +01:00
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2005-04-16 15:20:36 -07:00
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2020-02-03 17:37:17 -08:00
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2005-04-16 15:20:36 -07:00
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2020-02-03 17:37:17 -08:00
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2005-04-16 15:20:36 -07:00
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2020-02-03 17:37:17 -08:00
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2005-04-16 15:20:36 -07:00
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2008-11-22 02:39:32 +08:00
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2006-06-12 17:06:02 -07:00
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2005-05-13 17:44:10 +10:00
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2006-06-12 15:14:29 -07:00
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2005-05-13 17:44:10 +10:00
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2008-11-22 02:39:32 +08:00
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2006-06-12 17:06:02 -07:00
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2005-05-13 17:44:10 +10:00
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2006-06-12 15:14:29 -07:00
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2005-04-16 15:20:36 -07:00
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2006-06-12 15:14:29 -07:00
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2005-05-13 17:44:10 +10:00
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2005-04-16 15:20:36 -07:00
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2019-07-02 13:21:33 +02:00
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2005-04-16 15:20:36 -07:00
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2008-01-22 20:53:43 +01:00
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2005-04-16 15:20:36 -07:00
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PCI/proc: Fix race between pci_proc_init() and pci_bus_add_device()
pci_proc_attach_device() creates procfs entries for PCI devices and is
called from pci_bus_add_device(). It lazily creates the per-bus procfs
directory (bus->procdir) via proc_mkdir() on first use, and returns early
if proc_initialized is not yet set.
On x86 with ACPI, PCI enumeration occurs at subsys_initcall, before
pci_proc_init() sets proc_initialized at device_initcall. The
for_each_pci_dev() loop in pci_proc_init() then creates procfs entries for
these already-enumerated devices, but runs without holding
pci_rescan_remove_lock.
On ARM64 with devicetree, PCI host bridges probe at device_initcall. With
async probing enabled, pci_bus_add_device() can run concurrently with
pci_proc_init(), and both may call pci_proc_attach_device() for the same
device or for different devices on the same bus. As pci_host_probe() holds
pci_rescan_remove_lock while pci_proc_init() does not, there is no
serialisation between the two paths.
When two threads concurrently call pci_proc_attach_device() for devices on
the same bus, both observe bus->procdir as NULL and both call proc_mkdir().
The proc filesystem serialises directory creation internally, so only one
caller succeeds. The other results in a warning like:
proc_dir_entry '000c:00/00.0' already registered
The caller receives NULL (duplicate entry) and unconditionally stores it to
bus->procdir, corrupting the valid pointer set by the first caller.
Serialise access to proc_initialized, proc_bus_pci_dir, bus->procdir and
dev->procent with a new mutex local to drivers/pci/proc.c, and store the
created entries to bus->procdir and dev->procent only on success, so a
failed creation can never overwrite a valid pointer.
Additionally, wrap the for_each_pci_dev() loop in pci_proc_init() with
pci_lock_rescan_remove() to serialise against concurrent PCI bus
operations, add an early return in pci_proc_attach_device() when
dev->procent is already set to make the function idempotent, and clear
bus->procdir in pci_proc_detach_bus() to prevent use of a dangling pointer
after proc_remove().
Reported-by: Shuan He <heshuan@bytedance.com>
Closes: https://lore.kernel.org/linux-pci/20250702155112.40124-2-heshuan@bytedance.com/
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20260611150543.511422-1-kwilczynski@kernel.org
2026-06-11 15:05:43 +00:00
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2005-04-16 15:20:36 -07:00
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PCI/proc: Fix race between pci_proc_init() and pci_bus_add_device()
pci_proc_attach_device() creates procfs entries for PCI devices and is
called from pci_bus_add_device(). It lazily creates the per-bus procfs
directory (bus->procdir) via proc_mkdir() on first use, and returns early
if proc_initialized is not yet set.
On x86 with ACPI, PCI enumeration occurs at subsys_initcall, before
pci_proc_init() sets proc_initialized at device_initcall. The
for_each_pci_dev() loop in pci_proc_init() then creates procfs entries for
these already-enumerated devices, but runs without holding
pci_rescan_remove_lock.
On ARM64 with devicetree, PCI host bridges probe at device_initcall. With
async probing enabled, pci_bus_add_device() can run concurrently with
pci_proc_init(), and both may call pci_proc_attach_device() for the same
device or for different devices on the same bus. As pci_host_probe() holds
pci_rescan_remove_lock while pci_proc_init() does not, there is no
serialisation between the two paths.
When two threads concurrently call pci_proc_attach_device() for devices on
the same bus, both observe bus->procdir as NULL and both call proc_mkdir().
The proc filesystem serialises directory creation internally, so only one
caller succeeds. The other results in a warning like:
proc_dir_entry '000c:00/00.0' already registered
The caller receives NULL (duplicate entry) and unconditionally stores it to
bus->procdir, corrupting the valid pointer set by the first caller.
Serialise access to proc_initialized, proc_bus_pci_dir, bus->procdir and
dev->procent with a new mutex local to drivers/pci/proc.c, and store the
created entries to bus->procdir and dev->procent only on success, so a
failed creation can never overwrite a valid pointer.
Additionally, wrap the for_each_pci_dev() loop in pci_proc_init() with
pci_lock_rescan_remove() to serialise against concurrent PCI bus
operations, add an early return in pci_proc_attach_device() when
dev->procent is already set to make the function idempotent, and clear
bus->procdir in pci_proc_detach_bus() to prevent use of a dangling pointer
after proc_remove().
Reported-by: Shuan He <heshuan@bytedance.com>
Closes: https://lore.kernel.org/linux-pci/20250702155112.40124-2-heshuan@bytedance.com/
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20260611150543.511422-1-kwilczynski@kernel.org
2026-06-11 15:05:43 +00:00
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2005-04-16 15:20:36 -07:00
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PCI/proc: Fix race between pci_proc_init() and pci_bus_add_device()
pci_proc_attach_device() creates procfs entries for PCI devices and is
called from pci_bus_add_device(). It lazily creates the per-bus procfs
directory (bus->procdir) via proc_mkdir() on first use, and returns early
if proc_initialized is not yet set.
On x86 with ACPI, PCI enumeration occurs at subsys_initcall, before
pci_proc_init() sets proc_initialized at device_initcall. The
for_each_pci_dev() loop in pci_proc_init() then creates procfs entries for
these already-enumerated devices, but runs without holding
pci_rescan_remove_lock.
On ARM64 with devicetree, PCI host bridges probe at device_initcall. With
async probing enabled, pci_bus_add_device() can run concurrently with
pci_proc_init(), and both may call pci_proc_attach_device() for the same
device or for different devices on the same bus. As pci_host_probe() holds
pci_rescan_remove_lock while pci_proc_init() does not, there is no
serialisation between the two paths.
When two threads concurrently call pci_proc_attach_device() for devices on
the same bus, both observe bus->procdir as NULL and both call proc_mkdir().
The proc filesystem serialises directory creation internally, so only one
caller succeeds. The other results in a warning like:
proc_dir_entry '000c:00/00.0' already registered
The caller receives NULL (duplicate entry) and unconditionally stores it to
bus->procdir, corrupting the valid pointer set by the first caller.
Serialise access to proc_initialized, proc_bus_pci_dir, bus->procdir and
dev->procent with a new mutex local to drivers/pci/proc.c, and store the
created entries to bus->procdir and dev->procent only on success, so a
failed creation can never overwrite a valid pointer.
Additionally, wrap the for_each_pci_dev() loop in pci_proc_init() with
pci_lock_rescan_remove() to serialise against concurrent PCI bus
operations, add an early return in pci_proc_attach_device() when
dev->procent is already set to make the function idempotent, and clear
bus->procdir in pci_proc_detach_bus() to prevent use of a dangling pointer
after proc_remove().
Reported-by: Shuan He <heshuan@bytedance.com>
Closes: https://lore.kernel.org/linux-pci/20250702155112.40124-2-heshuan@bytedance.com/
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20260611150543.511422-1-kwilczynski@kernel.org
2026-06-11 15:05:43 +00:00
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2005-04-16 15:20:36 -07:00
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PCI/proc: Fix race between pci_proc_init() and pci_bus_add_device()
pci_proc_attach_device() creates procfs entries for PCI devices and is
called from pci_bus_add_device(). It lazily creates the per-bus procfs
directory (bus->procdir) via proc_mkdir() on first use, and returns early
if proc_initialized is not yet set.
On x86 with ACPI, PCI enumeration occurs at subsys_initcall, before
pci_proc_init() sets proc_initialized at device_initcall. The
for_each_pci_dev() loop in pci_proc_init() then creates procfs entries for
these already-enumerated devices, but runs without holding
pci_rescan_remove_lock.
On ARM64 with devicetree, PCI host bridges probe at device_initcall. With
async probing enabled, pci_bus_add_device() can run concurrently with
pci_proc_init(), and both may call pci_proc_attach_device() for the same
device or for different devices on the same bus. As pci_host_probe() holds
pci_rescan_remove_lock while pci_proc_init() does not, there is no
serialisation between the two paths.
When two threads concurrently call pci_proc_attach_device() for devices on
the same bus, both observe bus->procdir as NULL and both call proc_mkdir().
The proc filesystem serialises directory creation internally, so only one
caller succeeds. The other results in a warning like:
proc_dir_entry '000c:00/00.0' already registered
The caller receives NULL (duplicate entry) and unconditionally stores it to
bus->procdir, corrupting the valid pointer set by the first caller.
Serialise access to proc_initialized, proc_bus_pci_dir, bus->procdir and
dev->procent with a new mutex local to drivers/pci/proc.c, and store the
created entries to bus->procdir and dev->procent only on success, so a
failed creation can never overwrite a valid pointer.
Additionally, wrap the for_each_pci_dev() loop in pci_proc_init() with
pci_lock_rescan_remove() to serialise against concurrent PCI bus
operations, add an early return in pci_proc_attach_device() when
dev->procent is already set to make the function idempotent, and clear
bus->procdir in pci_proc_detach_bus() to prevent use of a dangling pointer
after proc_remove().
Reported-by: Shuan He <heshuan@bytedance.com>
Closes: https://lore.kernel.org/linux-pci/20250702155112.40124-2-heshuan@bytedance.com/
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20260611150543.511422-1-kwilczynski@kernel.org
2026-06-11 15:05:43 +00:00
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2005-04-16 15:20:36 -07:00
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PCI/proc: Fix race between pci_proc_init() and pci_bus_add_device()
pci_proc_attach_device() creates procfs entries for PCI devices and is
called from pci_bus_add_device(). It lazily creates the per-bus procfs
directory (bus->procdir) via proc_mkdir() on first use, and returns early
if proc_initialized is not yet set.
On x86 with ACPI, PCI enumeration occurs at subsys_initcall, before
pci_proc_init() sets proc_initialized at device_initcall. The
for_each_pci_dev() loop in pci_proc_init() then creates procfs entries for
these already-enumerated devices, but runs without holding
pci_rescan_remove_lock.
On ARM64 with devicetree, PCI host bridges probe at device_initcall. With
async probing enabled, pci_bus_add_device() can run concurrently with
pci_proc_init(), and both may call pci_proc_attach_device() for the same
device or for different devices on the same bus. As pci_host_probe() holds
pci_rescan_remove_lock while pci_proc_init() does not, there is no
serialisation between the two paths.
When two threads concurrently call pci_proc_attach_device() for devices on
the same bus, both observe bus->procdir as NULL and both call proc_mkdir().
The proc filesystem serialises directory creation internally, so only one
caller succeeds. The other results in a warning like:
proc_dir_entry '000c:00/00.0' already registered
The caller receives NULL (duplicate entry) and unconditionally stores it to
bus->procdir, corrupting the valid pointer set by the first caller.
Serialise access to proc_initialized, proc_bus_pci_dir, bus->procdir and
dev->procent with a new mutex local to drivers/pci/proc.c, and store the
created entries to bus->procdir and dev->procent only on success, so a
failed creation can never overwrite a valid pointer.
Additionally, wrap the for_each_pci_dev() loop in pci_proc_init() with
pci_lock_rescan_remove() to serialise against concurrent PCI bus
operations, add an early return in pci_proc_attach_device() when
dev->procent is already set to make the function idempotent, and clear
bus->procdir in pci_proc_detach_bus() to prevent use of a dangling pointer
after proc_remove().
Reported-by: Shuan He <heshuan@bytedance.com>
Closes: https://lore.kernel.org/linux-pci/20250702155112.40124-2-heshuan@bytedance.com/
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20260611150543.511422-1-kwilczynski@kernel.org
2026-06-11 15:05:43 +00:00
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2005-04-16 15:20:36 -07:00
|
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|
PCI/proc: Fix race between pci_proc_init() and pci_bus_add_device()
pci_proc_attach_device() creates procfs entries for PCI devices and is
called from pci_bus_add_device(). It lazily creates the per-bus procfs
directory (bus->procdir) via proc_mkdir() on first use, and returns early
if proc_initialized is not yet set.
On x86 with ACPI, PCI enumeration occurs at subsys_initcall, before
pci_proc_init() sets proc_initialized at device_initcall. The
for_each_pci_dev() loop in pci_proc_init() then creates procfs entries for
these already-enumerated devices, but runs without holding
pci_rescan_remove_lock.
On ARM64 with devicetree, PCI host bridges probe at device_initcall. With
async probing enabled, pci_bus_add_device() can run concurrently with
pci_proc_init(), and both may call pci_proc_attach_device() for the same
device or for different devices on the same bus. As pci_host_probe() holds
pci_rescan_remove_lock while pci_proc_init() does not, there is no
serialisation between the two paths.
When two threads concurrently call pci_proc_attach_device() for devices on
the same bus, both observe bus->procdir as NULL and both call proc_mkdir().
The proc filesystem serialises directory creation internally, so only one
caller succeeds. The other results in a warning like:
proc_dir_entry '000c:00/00.0' already registered
The caller receives NULL (duplicate entry) and unconditionally stores it to
bus->procdir, corrupting the valid pointer set by the first caller.
Serialise access to proc_initialized, proc_bus_pci_dir, bus->procdir and
dev->procent with a new mutex local to drivers/pci/proc.c, and store the
created entries to bus->procdir and dev->procent only on success, so a
failed creation can never overwrite a valid pointer.
Additionally, wrap the for_each_pci_dev() loop in pci_proc_init() with
pci_lock_rescan_remove() to serialise against concurrent PCI bus
operations, add an early return in pci_proc_attach_device() when
dev->procent is already set to make the function idempotent, and clear
bus->procdir in pci_proc_detach_bus() to prevent use of a dangling pointer
after proc_remove().
Reported-by: Shuan He <heshuan@bytedance.com>
Closes: https://lore.kernel.org/linux-pci/20250702155112.40124-2-heshuan@bytedance.com/
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20260611150543.511422-1-kwilczynski@kernel.org
2026-06-11 15:05:43 +00:00
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2005-04-16 15:20:36 -07:00
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PCI/proc: Fix race between pci_proc_init() and pci_bus_add_device()
pci_proc_attach_device() creates procfs entries for PCI devices and is
called from pci_bus_add_device(). It lazily creates the per-bus procfs
directory (bus->procdir) via proc_mkdir() on first use, and returns early
if proc_initialized is not yet set.
On x86 with ACPI, PCI enumeration occurs at subsys_initcall, before
pci_proc_init() sets proc_initialized at device_initcall. The
for_each_pci_dev() loop in pci_proc_init() then creates procfs entries for
these already-enumerated devices, but runs without holding
pci_rescan_remove_lock.
On ARM64 with devicetree, PCI host bridges probe at device_initcall. With
async probing enabled, pci_bus_add_device() can run concurrently with
pci_proc_init(), and both may call pci_proc_attach_device() for the same
device or for different devices on the same bus. As pci_host_probe() holds
pci_rescan_remove_lock while pci_proc_init() does not, there is no
serialisation between the two paths.
When two threads concurrently call pci_proc_attach_device() for devices on
the same bus, both observe bus->procdir as NULL and both call proc_mkdir().
The proc filesystem serialises directory creation internally, so only one
caller succeeds. The other results in a warning like:
proc_dir_entry '000c:00/00.0' already registered
The caller receives NULL (duplicate entry) and unconditionally stores it to
bus->procdir, corrupting the valid pointer set by the first caller.
Serialise access to proc_initialized, proc_bus_pci_dir, bus->procdir and
dev->procent with a new mutex local to drivers/pci/proc.c, and store the
created entries to bus->procdir and dev->procent only on success, so a
failed creation can never overwrite a valid pointer.
Additionally, wrap the for_each_pci_dev() loop in pci_proc_init() with
pci_lock_rescan_remove() to serialise against concurrent PCI bus
operations, add an early return in pci_proc_attach_device() when
dev->procent is already set to make the function idempotent, and clear
bus->procdir in pci_proc_detach_bus() to prevent use of a dangling pointer
after proc_remove().
Reported-by: Shuan He <heshuan@bytedance.com>
Closes: https://lore.kernel.org/linux-pci/20250702155112.40124-2-heshuan@bytedance.com/
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20260611150543.511422-1-kwilczynski@kernel.org
2026-06-11 15:05:43 +00:00
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|
2013-04-12 17:27:28 +01:00
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2005-04-16 15:20:36 -07:00
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2014-04-18 20:13:49 -04:00
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2005-04-16 15:20:36 -07:00
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PCI/proc: Fix race between pci_proc_init() and pci_bus_add_device()
pci_proc_attach_device() creates procfs entries for PCI devices and is
called from pci_bus_add_device(). It lazily creates the per-bus procfs
directory (bus->procdir) via proc_mkdir() on first use, and returns early
if proc_initialized is not yet set.
On x86 with ACPI, PCI enumeration occurs at subsys_initcall, before
pci_proc_init() sets proc_initialized at device_initcall. The
for_each_pci_dev() loop in pci_proc_init() then creates procfs entries for
these already-enumerated devices, but runs without holding
pci_rescan_remove_lock.
On ARM64 with devicetree, PCI host bridges probe at device_initcall. With
async probing enabled, pci_bus_add_device() can run concurrently with
pci_proc_init(), and both may call pci_proc_attach_device() for the same
device or for different devices on the same bus. As pci_host_probe() holds
pci_rescan_remove_lock while pci_proc_init() does not, there is no
serialisation between the two paths.
When two threads concurrently call pci_proc_attach_device() for devices on
the same bus, both observe bus->procdir as NULL and both call proc_mkdir().
The proc filesystem serialises directory creation internally, so only one
caller succeeds. The other results in a warning like:
proc_dir_entry '000c:00/00.0' already registered
The caller receives NULL (duplicate entry) and unconditionally stores it to
bus->procdir, corrupting the valid pointer set by the first caller.
Serialise access to proc_initialized, proc_bus_pci_dir, bus->procdir and
dev->procent with a new mutex local to drivers/pci/proc.c, and store the
created entries to bus->procdir and dev->procent only on success, so a
failed creation can never overwrite a valid pointer.
Additionally, wrap the for_each_pci_dev() loop in pci_proc_init() with
pci_lock_rescan_remove() to serialise against concurrent PCI bus
operations, add an early return in pci_proc_attach_device() when
dev->procent is already set to make the function idempotent, and clear
bus->procdir in pci_proc_detach_bus() to prevent use of a dangling pointer
after proc_remove().
Reported-by: Shuan He <heshuan@bytedance.com>
Closes: https://lore.kernel.org/linux-pci/20250702155112.40124-2-heshuan@bytedance.com/
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20260611150543.511422-1-kwilczynski@kernel.org
2026-06-11 15:05:43 +00:00
|
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|
2013-04-12 17:27:28 +01:00
|
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|
|
PCI/proc: Fix race between pci_proc_init() and pci_bus_add_device()
pci_proc_attach_device() creates procfs entries for PCI devices and is
called from pci_bus_add_device(). It lazily creates the per-bus procfs
directory (bus->procdir) via proc_mkdir() on first use, and returns early
if proc_initialized is not yet set.
On x86 with ACPI, PCI enumeration occurs at subsys_initcall, before
pci_proc_init() sets proc_initialized at device_initcall. The
for_each_pci_dev() loop in pci_proc_init() then creates procfs entries for
these already-enumerated devices, but runs without holding
pci_rescan_remove_lock.
On ARM64 with devicetree, PCI host bridges probe at device_initcall. With
async probing enabled, pci_bus_add_device() can run concurrently with
pci_proc_init(), and both may call pci_proc_attach_device() for the same
device or for different devices on the same bus. As pci_host_probe() holds
pci_rescan_remove_lock while pci_proc_init() does not, there is no
serialisation between the two paths.
When two threads concurrently call pci_proc_attach_device() for devices on
the same bus, both observe bus->procdir as NULL and both call proc_mkdir().
The proc filesystem serialises directory creation internally, so only one
caller succeeds. The other results in a warning like:
proc_dir_entry '000c:00/00.0' already registered
The caller receives NULL (duplicate entry) and unconditionally stores it to
bus->procdir, corrupting the valid pointer set by the first caller.
Serialise access to proc_initialized, proc_bus_pci_dir, bus->procdir and
dev->procent with a new mutex local to drivers/pci/proc.c, and store the
created entries to bus->procdir and dev->procent only on success, so a
failed creation can never overwrite a valid pointer.
Additionally, wrap the for_each_pci_dev() loop in pci_proc_init() with
pci_lock_rescan_remove() to serialise against concurrent PCI bus
operations, add an early return in pci_proc_attach_device() when
dev->procent is already set to make the function idempotent, and clear
bus->procdir in pci_proc_detach_bus() to prevent use of a dangling pointer
after proc_remove().
Reported-by: Shuan He <heshuan@bytedance.com>
Closes: https://lore.kernel.org/linux-pci/20250702155112.40124-2-heshuan@bytedance.com/
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20260611150543.511422-1-kwilczynski@kernel.org
2026-06-11 15:05:43 +00:00
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|
2005-04-16 15:20:36 -07:00
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|
PCI/proc: Fix race between pci_proc_init() and pci_bus_add_device()
pci_proc_attach_device() creates procfs entries for PCI devices and is
called from pci_bus_add_device(). It lazily creates the per-bus procfs
directory (bus->procdir) via proc_mkdir() on first use, and returns early
if proc_initialized is not yet set.
On x86 with ACPI, PCI enumeration occurs at subsys_initcall, before
pci_proc_init() sets proc_initialized at device_initcall. The
for_each_pci_dev() loop in pci_proc_init() then creates procfs entries for
these already-enumerated devices, but runs without holding
pci_rescan_remove_lock.
On ARM64 with devicetree, PCI host bridges probe at device_initcall. With
async probing enabled, pci_bus_add_device() can run concurrently with
pci_proc_init(), and both may call pci_proc_attach_device() for the same
device or for different devices on the same bus. As pci_host_probe() holds
pci_rescan_remove_lock while pci_proc_init() does not, there is no
serialisation between the two paths.
When two threads concurrently call pci_proc_attach_device() for devices on
the same bus, both observe bus->procdir as NULL and both call proc_mkdir().
The proc filesystem serialises directory creation internally, so only one
caller succeeds. The other results in a warning like:
proc_dir_entry '000c:00/00.0' already registered
The caller receives NULL (duplicate entry) and unconditionally stores it to
bus->procdir, corrupting the valid pointer set by the first caller.
Serialise access to proc_initialized, proc_bus_pci_dir, bus->procdir and
dev->procent with a new mutex local to drivers/pci/proc.c, and store the
created entries to bus->procdir and dev->procent only on success, so a
failed creation can never overwrite a valid pointer.
Additionally, wrap the for_each_pci_dev() loop in pci_proc_init() with
pci_lock_rescan_remove() to serialise against concurrent PCI bus
operations, add an early return in pci_proc_attach_device() when
dev->procent is already set to make the function idempotent, and clear
bus->procdir in pci_proc_detach_bus() to prevent use of a dangling pointer
after proc_remove().
Reported-by: Shuan He <heshuan@bytedance.com>
Closes: https://lore.kernel.org/linux-pci/20250702155112.40124-2-heshuan@bytedance.com/
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20260611150543.511422-1-kwilczynski@kernel.org
2026-06-11 15:05:43 +00:00
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2010-07-03 20:04:39 +04:00
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2005-04-16 15:20:36 -07:00
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PCI/proc: Fix race between pci_proc_init() and pci_bus_add_device()
pci_proc_attach_device() creates procfs entries for PCI devices and is
called from pci_bus_add_device(). It lazily creates the per-bus procfs
directory (bus->procdir) via proc_mkdir() on first use, and returns early
if proc_initialized is not yet set.
On x86 with ACPI, PCI enumeration occurs at subsys_initcall, before
pci_proc_init() sets proc_initialized at device_initcall. The
for_each_pci_dev() loop in pci_proc_init() then creates procfs entries for
these already-enumerated devices, but runs without holding
pci_rescan_remove_lock.
On ARM64 with devicetree, PCI host bridges probe at device_initcall. With
async probing enabled, pci_bus_add_device() can run concurrently with
pci_proc_init(), and both may call pci_proc_attach_device() for the same
device or for different devices on the same bus. As pci_host_probe() holds
pci_rescan_remove_lock while pci_proc_init() does not, there is no
serialisation between the two paths.
When two threads concurrently call pci_proc_attach_device() for devices on
the same bus, both observe bus->procdir as NULL and both call proc_mkdir().
The proc filesystem serialises directory creation internally, so only one
caller succeeds. The other results in a warning like:
proc_dir_entry '000c:00/00.0' already registered
The caller receives NULL (duplicate entry) and unconditionally stores it to
bus->procdir, corrupting the valid pointer set by the first caller.
Serialise access to proc_initialized, proc_bus_pci_dir, bus->procdir and
dev->procent with a new mutex local to drivers/pci/proc.c, and store the
created entries to bus->procdir and dev->procent only on success, so a
failed creation can never overwrite a valid pointer.
Additionally, wrap the for_each_pci_dev() loop in pci_proc_init() with
pci_lock_rescan_remove() to serialise against concurrent PCI bus
operations, add an early return in pci_proc_attach_device() when
dev->procent is already set to make the function idempotent, and clear
bus->procdir in pci_proc_detach_bus() to prevent use of a dangling pointer
after proc_remove().
Reported-by: Shuan He <heshuan@bytedance.com>
Closes: https://lore.kernel.org/linux-pci/20250702155112.40124-2-heshuan@bytedance.com/
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20260611150543.511422-1-kwilczynski@kernel.org
2026-06-11 15:05:43 +00:00
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2010-07-03 20:04:39 +04:00
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2005-04-16 15:20:36 -07:00
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2008-05-11 16:58:53 -04:00
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