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.
Clone this repository
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Pull Kbuild fixes from Masahiro Yamada:
- move -Wsign-compare warning from W=2 to W=3
- fix the keyword _restrict to __restrict in genksyms
- fix more bugs in qconf
* tag 'kbuild-fixes-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kconfig: qconf: replace deprecated QString::sprintf() with QTextStream
kconfig: qconf: remove redundant help in the info view
kconfig: qconf: remove qInfo() to get back Qt4 support
kconfig: qconf: remove unused colNr
kconfig: qconf: fix the popup menu in the ConfigInfoView window
kconfig: qconf: fix signal connection to invalid slots
genksyms: keywords: Use __restrict not _restrict
kbuild: remove redundant patterns in filter/filter-out
extract-cert: add static to local data
Makefile.extrawarn: Move sign-compare from W=2 to W=3
Pull arm64 fixes from Catalin Marinas:
- Allow booting of late secondary CPUs affected by erratum 1418040
(currently they are parked if none of the early CPUs are affected by
this erratum).
- Add the 32-bit vdso Makefile to the vdso_install rule so that 'make
vdso_install' installs the 32-bit compat vdso when it is compiled.
- Print a warning that untrusted guests without a CPU erratum
workaround (Cortex-A57 832075) may deadlock the affected system.
* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
ARM64: vdso32: Install vdso32 from vdso_install
KVM: arm64: Print warning when cpu erratum can cause guests to deadlock
arm64: Allow booting of late CPUs affected by erratum 1418040
arm64: Move handling of erratum 1418040 into C code
QString::sprintf() is deprecated in the latest Qt version, and spawns
a lot of warnings:
HOSTCXX scripts/kconfig/qconf.o
scripts/kconfig/qconf.cc: In member function ‘void ConfigInfoView::menuInfo()’:
scripts/kconfig/qconf.cc:1090:61: warning: ‘QString& QString::sprintf(const char*, ...)’ is deprecated: Use asprintf(), arg() or QTextStream instead [-Wdeprecated-declarations]
1090 | head += QString().sprintf("<a href=\"s%s\">", sym->name);
| ^
In file included from /usr/include/qt5/QtGui/qkeysequence.h:44,
from /usr/include/qt5/QtWidgets/qaction.h:44,
from /usr/include/qt5/QtWidgets/QAction:1,
from scripts/kconfig/qconf.cc:7:
/usr/include/qt5/QtCore/qstring.h:382:14: note: declared here
382 | QString &sprintf(const char *format, ...) Q_ATTRIBUTE_FORMAT_PRINTF(2, 3);
| ^~~~~~~
scripts/kconfig/qconf.cc:1099:60: warning: ‘QString& QString::sprintf(const char*, ...)’ is deprecated: Use asprintf(), arg() or QTextStream instead [-Wdeprecated-declarations]
1099 | head += QString().sprintf("<a href=\"s%s\">", sym->name);
| ^
In file included from /usr/include/qt5/QtGui/qkeysequence.h:44,
from /usr/include/qt5/QtWidgets/qaction.h:44,
from /usr/include/qt5/QtWidgets/QAction:1,
from scripts/kconfig/qconf.cc:7:
/usr/include/qt5/QtCore/qstring.h:382:14: note: declared here
382 | QString &sprintf(const char *format, ...) Q_ATTRIBUTE_FORMAT_PRINTF(2, 3);
| ^~~~~~~
scripts/kconfig/qconf.cc:1127:90: warning: ‘QString& QString::sprintf(const char*, ...)’ is deprecated: Use asprintf(), arg() or QTextStream instead [-Wdeprecated-declarations]
1127 | debug += QString().sprintf("defined at %s:%d<br><br>", _menu->file->name, _menu->lineno);
| ^
In file included from /usr/include/qt5/QtGui/qkeysequence.h:44,
from /usr/include/qt5/QtWidgets/qaction.h:44,
from /usr/include/qt5/QtWidgets/QAction:1,
from scripts/kconfig/qconf.cc:7:
/usr/include/qt5/QtCore/qstring.h:382:14: note: declared here
382 | QString &sprintf(const char *format, ...) Q_ATTRIBUTE_FORMAT_PRINTF(2, 3);
| ^~~~~~~
scripts/kconfig/qconf.cc: In member function ‘QString ConfigInfoView::debug_info(symbol*)’:
scripts/kconfig/qconf.cc:1150:68: warning: ‘QString& QString::sprintf(const char*, ...)’ is deprecated: Use asprintf(), arg() or QTextStream instead [-Wdeprecated-declarations]
1150 | debug += QString().sprintf("prompt: <a href=\"m%s\">", sym->name);
| ^
In file included from /usr/include/qt5/QtGui/qkeysequence.h:44,
from /usr/include/qt5/QtWidgets/qaction.h:44,
from /usr/include/qt5/QtWidgets/QAction:1,
from scripts/kconfig/qconf.cc:7:
/usr/include/qt5/QtCore/qstring.h:382:14: note: declared here
382 | QString &sprintf(const char *format, ...) Q_ATTRIBUTE_FORMAT_PRINTF(2, 3);
| ^~~~~~~
scripts/kconfig/qconf.cc: In static member function ‘static void ConfigInfoView::expr_print_help(void*, symbol*, const char*)’:
scripts/kconfig/qconf.cc:1225:59: warning: ‘QString& QString::sprintf(const char*, ...)’ is deprecated: Use asprintf(), arg() or QTextStream instead [-Wdeprecated-declarations]
1225 | *text += QString().sprintf("<a href=\"s%s\">", sym->name);
| ^
In file included from /usr/include/qt5/QtGui/qkeysequence.h:44,
from /usr/include/qt5/QtWidgets/qaction.h:44,
from /usr/include/qt5/QtWidgets/QAction:1,
from scripts/kconfig/qconf.cc:7:
/usr/include/qt5/QtCore/qstring.h:382:14: note: declared here
382 | QString &sprintf(const char *format, ...) Q_ATTRIBUTE_FORMAT_PRINTF(2, 3);
| ^~~~~~~
The documentation also says:
"Warning: We do not recommend using QString::asprintf() in new Qt code.
Instead, consider using QTextStream or arg(), both of which support
Unicode strings seamlessly and are type-safe."
Use QTextStream as suggested.
Reported-by: Robert Crawford <flacycads@cox.net>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Pull s390 fixes from Vasily Gorbik:
- a couple of fixes for storage key handling relevant for debugging
- add cond_resched into potentially slow subchannels scanning loop
- fixes for PF/VF linking and to ignore stale PCI configuration request
events
* tag 's390-5.9-3' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390/pci: fix PF/VF linking on hot plug
s390/pci: re-introduce zpci_remove_device()
s390/pci: fix zpci_bus_link_virtfn()
s390/ptrace: fix storage key handling
s390/runtime_instrumentation: fix storage key handling
s390/pci: ignore stale configuration request event
s390/cio: add cond_resched() in the slow_eval_known_fn() loop
Add the 32-bit vdso Makefile to the vdso_install rule so that 'make
vdso_install' installs the 32-bit compat vdso when it is compiled.
Fixes: a7f71a2c8903 ("arm64: compat: Add vDSO")
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Acked-by: Will Deacon <will@kernel.org>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Link: https://lore.kernel.org/r/20200818014950.42492-1-swboyd@chromium.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The same information is repeated in the info view.
Remove the second one.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Pull kvm fixes from Paolo Bonzini:
- PAE and PKU bugfixes for x86
- selftests fix for new binutils
- MMU notifier fix for arm64
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: arm64: Only reschedule if MMU_NOTIFIER_RANGE_BLOCKABLE is not set
KVM: Pass MMU notifier range flags to kvm_unmap_hva_range()
kvm: x86: Toggling CR4.PKE does not load PDPTEs in PAE mode
kvm: x86: Toggling CR4.SMAP does not load PDPTEs in PAE mode
KVM: x86: fix access code passed to gva_to_gpa
selftests: kvm: Use a shorter encoding to clear RAX
Currently there are four places in which a PCI function is scanned
and made available to drivers:
1. In pci_scan_root_bus() as part of the initial zbus
creation.
2. In zpci_bus_add_devices() when registering
a device in configured state on a zbus that has already been
scanned.
3. When a function is already known to zPCI (in reserved/standby state)
and configuration is triggered through firmware by PEC 0x301.
4. When a device is already known to zPCI (in standby/reserved state)
and configuration is triggered from within Linux using
enable_slot().
The PF/VF linking step and setting of pdev->is_virtfn introduced with
commit e5794cf1a270 ("s390/pci: create links between PFs and VFs") was
only triggered for the second case, which is where VFs created through
sriov_numvfs usually land. However unlike some other platforms but like
POWER VFs can be individually enabled/disabled through
/sys/bus/pci/slots.
Fix this by doing VF setup as part of pcibios_bus_add_device() which is
called in all of the above cases.
Finally to remove the PF/VF links call the common code
pci_iov_remove_virtfn() function to remove linked VFs.
This takes care of the necessary sysfs cleanup.
Fixes: e5794cf1a270 ("s390/pci: create links between PFs and VFs")
Cc: <stable@vger.kernel.org> # 5.8: 2f0230b2f2d5: s390/pci: re-introduce zpci_remove_device()
Cc: <stable@vger.kernel.org> # 5.8
Acked-by: Pierre Morel <pmorel@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
If guests don't have certain CPU erratum workarounds implemented, then
there is a possibility a guest can deadlock the system. IOW, only trusted
guests should be used on systems with the erratum.
This is the case for Cortex-A57 erratum 832075.
Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: kvmarm@lists.cs.columbia.edu
Link: https://lore.kernel.org/r/20200803193127.3012242-2-robh@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
qconf is supposed to work with Qt4 and Qt5, but since commit
c4f7398bee9c ("kconfig: qconf: make debug links work again"),
building with Qt4 fails as follows:
HOSTCXX scripts/kconfig/qconf.o
scripts/kconfig/qconf.cc: In member function ‘void ConfigInfoView::clicked(const QUrl&)’:
scripts/kconfig/qconf.cc:1241:3: error: ‘qInfo’ was not declared in this scope; did you mean ‘setInfo’?
1241 | qInfo() << "Clicked link is empty";
| ^~~~~
| setInfo
scripts/kconfig/qconf.cc:1254:3: error: ‘qInfo’ was not declared in this scope; did you mean ‘setInfo’?
1254 | qInfo() << "Clicked symbol is invalid:" << data;
| ^~~~~
| setInfo
make[1]: *** [scripts/Makefile.host:129: scripts/kconfig/qconf.o] Error 1
make: *** [Makefile:606: xconfig] Error 2
qInfo() does not exist in Qt4. In my understanding, these call-sites
should be unreachable. Perhaps, qWarning(), assertion, or something
is better, but qInfo() is not the right one to use here, I think.
Fixes: c4f7398bee9c ("kconfig: qconf: make debug links work again")
Reported-by: Ronald Warsow <rwarsow@gmx.de>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Pull SCSI fixes from James Bottomley:
"23 fixes in 5 drivers (qla2xxx, ufs, scsi_debug, fcoe, zfcp). The bulk
of the changes are in qla2xxx and ufs and all are mostly small and
definitely don't impact the core"
* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (23 commits)
Revert "scsi: qla2xxx: Disable T10-DIF feature with FC-NVMe during probe"
Revert "scsi: qla2xxx: Fix crash on qla2x00_mailbox_command"
scsi: qla2xxx: Fix null pointer access during disconnect from subsystem
scsi: qla2xxx: Check if FW supports MQ before enabling
scsi: qla2xxx: Fix WARN_ON in qla_nvme_register_hba
scsi: qla2xxx: Allow ql2xextended_error_logging special value 1 to be set anytime
scsi: qla2xxx: Reduce noisy debug message
scsi: qla2xxx: Fix login timeout
scsi: qla2xxx: Indicate correct supported speeds for Mezz card
scsi: qla2xxx: Flush I/O on zone disable
scsi: qla2xxx: Flush all sessions on zone disable
scsi: qla2xxx: Use MBX_TOV_SECONDS for mailbox command timeout values
scsi: scsi_debug: Fix scp is NULL errors
scsi: zfcp: Fix use-after-free in request timeout handlers
scsi: ufs: No need to send Abort Task if the task in DB was cleared
scsi: ufs: Clean up completed request without interrupt notification
scsi: ufs: Improve interrupt handling for shared interrupts
scsi: ufs: Fix interrupt error message for shared interrupts
scsi: ufs-pci: Add quirk for broken auto-hibernate for Intel EHL
scsi: ufs-mediatek: Fix incorrect time to wait link status
...
When an MMU notifier call results in unmapping a range that spans multiple
PGDs, we end up calling into cond_resched_lock() when crossing a PGD boundary,
since this avoids running into RCU stalls during VM teardown. Unfortunately,
if the VM is destroyed as a result of OOM, then blocking is not permitted
and the call to the scheduler triggers the following BUG():
| BUG: sleeping function called from invalid context at arch/arm64/kvm/mmu.c:394
| in_atomic(): 1, irqs_disabled(): 0, non_block: 1, pid: 36, name: oom_reaper
| INFO: lockdep is turned off.
| CPU: 3 PID: 36 Comm: oom_reaper Not tainted 5.8.0 #1
| Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015
| Call trace:
| dump_backtrace+0x0/0x284
| show_stack+0x1c/0x28
| dump_stack+0xf0/0x1a4
| ___might_sleep+0x2bc/0x2cc
| unmap_stage2_range+0x160/0x1ac
| kvm_unmap_hva_range+0x1a0/0x1c8
| kvm_mmu_notifier_invalidate_range_start+0x8c/0xf8
| __mmu_notifier_invalidate_range_start+0x218/0x31c
| mmu_notifier_invalidate_range_start_nonblock+0x78/0xb0
| __oom_reap_task_mm+0x128/0x268
| oom_reap_task+0xac/0x298
| oom_reaper+0x178/0x17c
| kthread+0x1e4/0x1fc
| ret_from_fork+0x10/0x30
Use the new 'flags' argument to kvm_unmap_hva_range() to ensure that we
only reschedule if MMU_NOTIFIER_RANGE_BLOCKABLE is set in the notifier
flags.
Cc: <stable@vger.kernel.org>
Fixes: 8b3405e345b5 ("kvm: arm/arm64: Fix locking for kvm_free_stage2_pgd")
Cc: Marc Zyngier <maz@kernel.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: James Morse <james.morse@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Message-Id: <20200811102725.7121-3-will@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
For fixing the PF to VF link removal we need to perform some action on
every removal of a zdev from the common PCI subsystem.
So in preparation re-introduce zpci_remove_device() and use that instead
of directly calling the common code functions. This was actually still
declared from earlier code but no longer implemented.
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>