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.
code
Clone this repository
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Pull syscall tracing fix from Borislav Petkov:
"Fix the seccomp syscall rewriting so that trace and audit see the
rewritten syscall number, from Kees Cook"
* tag 'core_urgent_for_v5.9_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
core/entry: Report syscall correctly for trace and audit
Pull objtool fix from Borislav Petkov:
"Fix noreturn detection for ignored sibling functions (Josh Poimboeuf)"
* tag 'objtool_urgent_for_v5.9_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
objtool: Fix noreturn detection for ignored functions
On v5.8 when doing seccomp syscall rewrites (e.g. getpid into getppid
as seen in the seccomp selftests), trace (and audit) correctly see the
rewritten syscall on entry and exit:
seccomp_bpf-1307 [000] .... 22974.874393: sys_enter: NR 110 (...
seccomp_bpf-1307 [000] .N.. 22974.874401: sys_exit: NR 110 = 1304
With mainline we see a mismatched enter and exit (the original syscall
is incorrectly visible on entry):
seccomp_bpf-1030 [000] .... 21.806766: sys_enter: NR 39 (...
seccomp_bpf-1030 [000] .... 21.806767: sys_exit: NR 110 = 1027
When ptrace or seccomp change the syscall, this needs to be visible to
trace and audit at that time as well. Update the syscall earlier so they
see the correct value.
Fixes: d88d59b64ca3 ("core/entry: Respect syscall number rewrites")
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20200912005826.586171-1-keescook@chromium.org
Pull locking fixes from Borislav Petkov:
"Two fixes from the locking/urgent pile:
- Fix lockdep's detection of "USED" <- "IN-NMI" inversions (Peter
Zijlstra)
- Make percpu-rwsem operations on the semaphore's ->read_count
IRQ-safe because it can be used in an IRQ context (Hou Tao)"
* tag 'locking_urgent_for_v5.9_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/percpu-rwsem: Use this_cpu_{inc,dec}() for read_count
locking/lockdep: Fix "USED" <- "IN-NMI" inversions
When a function is annotated with STACK_FRAME_NON_STANDARD, objtool
doesn't validate its code paths. It also skips sibling call detection
within the function.
But sibling call detection is actually needed for the case where the
ignored function doesn't have any return instructions. Otherwise
objtool naively marks the function as implicit static noreturn, which
affects the reachability of its callers, resulting in "unreachable
instruction" warnings.
Fix it by just enabling sibling call detection for ignored functions.
The 'insn->ignore' check in add_jump_destinations() is no longer needed
after
e6da9567959e ("objtool: Don't use ignore flag for fake jumps").
Fixes the following warning:
arch/x86/kvm/vmx/vmx.o: warning: objtool: vmx_handle_exit_irqoff()+0x142: unreachable instruction
which triggers on an allmodconfig with CONFIG_GCOV_KERNEL unset.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lkml.kernel.org/r/5b1e2536cdbaa5246b60d7791b76130a74082c62.1599751464.git.jpoimboe@redhat.com
Pull EFI fix from Borislav Petkov:
"Ensure that the EFI bootloader control module only probes successfully
on systems that support the EFI SetVariable runtime service"
[ Tag and commit from Ard Biesheuvel, forwarded by Borislav ]
* tag 'efi-urgent-for-v5.9-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
efi: efibc: check for efivars write capability
The __this_cpu*() accessors are (in general) IRQ-unsafe which, given
that percpu-rwsem is a blocking primitive, should be just fine.
However, file_end_write() is used from IRQ context and will cause
load-store issues on architectures where the per-cpu accessors are not
natively irq-safe.
Fix it by using the IRQ-safe this_cpu_*() for operations on
read_count. This will generate more expensive code on a number of
platforms, which might cause a performance regression for some of the
other percpu-rwsem users.
If any such is reported, we can consider alternative solutions.
Fixes: 70fe2f48152e ("aio: fix freeze protection of aio writes")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lkml.kernel.org/r/20200915140750.137881-1-houtao1@huawei.com
Pull ARM SoC fixes from Olof Johansson:
"A collection of fixes I've been accruing over the last few weeks, none
of them have been severe enough to warrant flushing the queue but it's
been long enough now that it's a good idea to send them in.
A handful of them are fixups for QSPI DT/bindings/compatibles, some
smaller fixes for system DMA clock control and TMU interrupts on i.MX,
a handful of fixes for OMAP, including a fix for DSI (display) on
omap5"
* tag 'armsoc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (27 commits)
arm64: dts: ns2: Fixed QSPI compatible string
ARM: dts: BCM5301X: Fixed QSPI compatible string
ARM: dts: NSP: Fixed QSPI compatible string
ARM: dts: bcm: HR2: Fixed QSPI compatible string
dt-bindings: spi: Fix spi-bcm-qspi compatible ordering
ARM: dts: imx6sx: fix the pad QSPI1B_SCLK mux mode for uart3
arm64: dts: imx8mp: correct sdma1 clk setting
arm64: dts: imx8mq: Fix TMU interrupt property
ARM: dts: imx7d-zii-rmu2: fix rgmii phy-mode for ksz9031 phy
ARM: dts: vfxxx: Add syscon compatible with OCOTP
ARM: dts: imx6q-logicpd: Fix broken PWM
arm64: dts: imx: Add missing imx8mm-beacon-kit.dtb to build
ARM: dts: imx6q-prtwd2: Remove unneeded i2c unit name
ARM: dts: imx6qdl-gw51xx: Remove unneeded #address-cells/#size-cells
ARM: dts: imx7ulp: Correct gpio ranges
ARM: dts: ls1021a: fix QuadSPI-memory reg range
arm64: defconfig: Enable ptn5150 extcon driver
arm64: defconfig: Enable USB gadget with configfs
ARM: configs: Update Integrator defconfig
ARM: dts: omap5: Fix DSI base address and clocks
...
Pull x86 fixes from Borislav Petkov:
- A defconfig fix (Daniel Díaz)
- Disable relocation relaxation for the compressed kernel when not
built as -pie as in that case kernels built with clang and linked
with LLD fail to boot due to the linker optimizing some instructions
in non-PIE form; the gory details in the commit message (Arvind
Sankar)
- A fix for the "bad bp value" warning issued by the frame-pointer
unwinder (Josh Poimboeuf)
* tag 'x86_urgent_for_v5.9_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/unwind/fp: Fix FP unwinding in ret_from_fork
x86/boot/compressed: Disable relocation relaxation
x86/defconfigs: Explicitly unset CONFIG_64BIT in i386_defconfig
Branden reports that commit
f88814cc2578c1 ("efi/efivars: Expose RT service availability via efivars abstraction")
regresses UEFI platforms that implement GetVariable but not SetVariable
when booting kernels that have EFIBC (bootloader control) enabled.
The reason is that EFIBC is a user of the efivars abstraction, which was
updated to permit users that rely only on the read capability, but not on
the write capability. EFIBC is in the latter category, so it has to check
explicitly whether efivars supports writes.
Fixes: f88814cc2578c1 ("efi/efivars: Expose RT service availability via efivars abstraction")
Tested-by: Branden Sherrell <sherrellbc@gmail.com>
Link: https://lore.kernel.org/linux-efi/AE217103-C96F-4AFC-8417-83EC11962004@gmail.com/
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
During the LPC RCU BoF Paul asked how come the "USED" <- "IN-NMI"
detector doesn't trip over rcu_read_lock()'s lockdep annotation.
Looking into this I found a very embarrasing typo in
verify_lock_unused():
- if (!(class->usage_mask & LOCK_USED))
+ if (!(class->usage_mask & LOCKF_USED))
fixing that will indeed cause rcu_read_lock() to insta-splat :/
The above typo means that instead of testing for: 0x100 (1 <<
LOCK_USED), we test for 8 (LOCK_USED), which corresponds to (1 <<
LOCK_ENABLED_HARDIRQ).
So instead of testing for _any_ used lock, it will only match any lock
used with interrupts enabled.
The rcu_read_lock() annotation uses .check=0, which means it will not
set any of the interrupt bits and will thus never match.
In order to properly fix the situation and allow rcu_read_lock() to
correctly work, split LOCK_USED into LOCK_USED and LOCK_USED_READ and by
having .read users set USED_READ and test USED, pure read-recursive
locks are permitted.
Fixes: f6f48e180404 ("lockdep: Teach lockdep about "USED" <- "IN-NMI" inversions")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/r/20200902160323.GK1362448@hirez.programming.kicks-ass.net
Pull USB/Thunderbolt fixes from Greg KH:
"Here are some small USB and Thunderbolt driver fixes for 5.9-rc5.
Nothing huge, just a number of bugfixes and new device ids for
problems reported:
- new USB serial driver ids
- bug fixes for syzbot reported problems
- typec driver fixes
- thunderbolt driver fixes
- revert of reported broken commit
All of these have been in linux-next with no reported issues"
* tag 'usb-5.9-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
usb: typec: intel_pmc_mux: Do not configure SBU and HSL Orientation in Alternate modes
usb: typec: intel_pmc_mux: Do not configure Altmode HPD High
usb: core: fix slab-out-of-bounds Read in read_descriptors
Revert "usb: dwc3: meson-g12a: fix shared reset control use"
usb: typec: ucsi: acpi: Check the _DEP dependencies
usb: typec: intel_pmc_mux: Un-register the USB role switch
usb: Fix out of sync data toggle if a configured device is reconfigured
USB: serial: option: support dynamic Quectel USB compositions
USB: serial: option: add support for SIM7070/SIM7080/SIM7090 modules
thunderbolt: Use maximum USB3 link rate when reclaiming if link is not up
thunderbolt: Disable ports that are not implemented
USB: serial: ftdi_sio: add IDs for Xsens Mti USB converter