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Linux kernel
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Pull locking fixes from Thomas Gleixner:
"Two more places which invoke tracing from RCU disabled regions in the
idle path.
Similar to the entry path the low level idle functions have to be
non-instrumentable"
* tag 'locking-urgent-2020-11-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
intel_idle: Fix intel_idle() vs tracing
sched/idle: Fix arch_cpu_idle() vs tracing
Pull irq fixes from Thomas Gleixner:
"Two fixes for irqchip drivers:
- Save and restore the GICV3 ITS state unconditionally on
suspend/resume to handle firmware which fails to do so.
- Use the correct index into the fwspec parameters to read the irq
trigger type in the EXIU chip driver"
* tag 'irq-urgent-2020-11-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
irqchip/gic-v3-its: Unconditionally save/restore the ITS state on suspend
irqchip/exiu: Fix the index of fwspec for IRQ type
cpuidle->enter() callbacks should not call into tracing because RCU
has already been disabled. Instead of doing the broadcast thing
itself, simply advertise to the cpuidle core that those states stop
the timer.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lkml.kernel.org/r/20201123143510.GR3021@hirez.programming.kicks-ass.net
Pull EFI fixes from Borislav Petkov:
"More EFI fixes forwarded from Ard Biesheuvel:
- revert efivarfs kmemleak fix again - it was a false positive
- make CONFIG_EFI_EARLYCON depend on CONFIG_EFI explicitly so it does
not pull in other dependencies unnecessarily if CONFIG_EFI is not
set
- defer attempts to load SSDT overrides from EFI vars until after the
efivar layer is up"
* tag 'efi-urgent-for-v5.10-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
efi: EFI_EARLYCON should depend on EFI
efivarfs: revert "fix memory leak in efivarfs_create()"
efi/efivars: Set generic ops before loading SSDT
Pull irqchip fixes from Marc Zyngier:
- Fix Exiu driver trigger type when using ACPI
- Fix GICv3 ITS suspend/resume to use the in-kernel path
at all times, sidestepping braindead firmware support
Link: https://lore.kernel.org/r/20201122184752.553990-1-maz@kernel.org
We call arch_cpu_idle() with RCU disabled, but then use
local_irq_{en,dis}able(), which invokes tracing, which relies on RCU.
Switch all arch_cpu_idle() implementations to use
raw_local_irq_{en,dis}able() and carefully manage the
lockdep,rcu,tracing state like we do in entry.
(XXX: we really should change arch_cpu_idle() to not return with
interrupts enabled)
Reported-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lkml.kernel.org/r/20201120114925.594122626@infradead.org
Pull x86 fixes from Borislav Petkov:
"A couple of urgent fixes which accumulated this last week:
- Two resctrl fixes to prevent refcount leaks when manipulating the
resctrl fs (Xiaochen Shen)
- Correct prctl(PR_GET_SPECULATION_CTRL) reporting (Anand K Mistry)
- A fix to not lose already seen MCE severity which determines
whether the machine can recover (Gabriele Paoloni)"
* tag 'x86_urgent_for_v5.10-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mce: Do not overwrite no_way_out if mce_end() fails
x86/speculation: Fix prctl() when spectre_v2_user={seccomp,prctl},ibpb
x86/resctrl: Add necessary kernfs_put() calls to prevent refcount leak
x86/resctrl: Remove superfluous kernfs_get() calls to prevent refcount leak
CONFIG_EFI_EARLYCON defaults to yes, and thus is enabled on systems that
do not support EFI, or do not have EFI support enabled, but do satisfy
the symbol's other dependencies.
While drivers/firmware/efi/ won't be entered during the build phase if
CONFIG_EFI=n, and drivers/firmware/efi/earlycon.c itself thus won't be
built, enabling EFI_EARLYCON does force-enable CONFIG_FONT_SUPPORT and
CONFIG_ARCH_USE_MEMREMAP_PROT, and CONFIG_FONT_8x16, which is
undesirable.
Fix this by making CONFIG_EFI_EARLYCON depend on CONFIG_EFI.
This reduces kernel size on headless systems by more than 4 KiB.
Fixes: 69c1f396f25b805a ("efi/x86: Convert x86 EFI earlyprintk into generic earlycon implementation")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/r/20201124191646.3559757-1-geert@linux-m68k.org
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
On systems without HW-based collections (i.e. anything except GIC-500),
we rely on firmware to perform the ITS save/restore. This doesn't
really work, as although FW can properly save everything, it cannot
fully restore the state of the command queue (the read-side is reset
to the head of the queue). This results in the ITS consuming previously
processed commands, potentially corrupting the state.
Instead, let's always save the ITS state on suspend, disabling it in the
process, and restore the full state on resume. This saves us from broken
FW as long as it doesn't enable the ITS by itself (for which we can't do
anything).
This amounts to simply dropping the ITS_FLAGS_SAVE_SUSPEND_STATE.
Signed-off-by: Xu Qiang <xuqiang36@huawei.com>
[maz: added warning on resume, rewrote commit message]
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201107104226.14282-1-xuqiang36@huawei.com
A warning was hit when running xfstests/generic/068 in a Hyper-V guest:
[...] ------------[ cut here ]------------
[...] DEBUG_LOCKS_WARN_ON(lockdep_hardirqs_enabled())
[...] WARNING: CPU: 2 PID: 1350 at kernel/locking/lockdep.c:5280 check_flags.part.0+0x165/0x170
[...] ...
[...] Workqueue: events pwq_unbound_release_workfn
[...] RIP: 0010:check_flags.part.0+0x165/0x170
[...] ...
[...] Call Trace:
[...] lock_is_held_type+0x72/0x150
[...] ? lock_acquire+0x16e/0x4a0
[...] rcu_read_lock_sched_held+0x3f/0x80
[...] __send_ipi_one+0x14d/0x1b0
[...] hv_send_ipi+0x12/0x30
[...] __pv_queued_spin_unlock_slowpath+0xd1/0x110
[...] __raw_callee_save___pv_queued_spin_unlock_slowpath+0x11/0x20
[...] .slowpath+0x9/0xe
[...] lockdep_unregister_key+0x128/0x180
[...] pwq_unbound_release_workfn+0xbb/0xf0
[...] process_one_work+0x227/0x5c0
[...] worker_thread+0x55/0x3c0
[...] ? process_one_work+0x5c0/0x5c0
[...] kthread+0x153/0x170
[...] ? __kthread_bind_mask+0x60/0x60
[...] ret_from_fork+0x1f/0x30
The cause of the problem is we have call chain lockdep_unregister_key()
-> <irq disabled by raw_local_irq_save()> lockdep_unlock() ->
arch_spin_unlock() -> __pv_queued_spin_unlock_slowpath() -> pv_kick() ->
__send_ipi_one() -> trace_hyperv_send_ipi_one().
Although this particular warning is triggered because Hyper-V has a
trace point in ipi sending, but in general arch_spin_unlock() may call
another function having a trace point in it, so put the arch_spin_lock()
and arch_spin_unlock() after lock_recursion protection to fix this
problem and avoid similiar problems.
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20201113110512.1056501-1-boqun.feng@gmail.com
Pull RISC-V fixes from Palmer Dabbelt:
"I've collected a handful of fixes over the past few weeks:
- A fix to un-break the build-id argument to the vDSO build, which is
necessary for the LLVM linker.
- A fix to initialize the jump label subsystem, without which it (and
all the stuff that uses it) doesn't actually function.
- A fix to include <asm/barrier.h> from <vdso/processor.h>, without
which some drivers won't compile"
* tag 'riscv-for-linus-5.10-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
RISC-V: fix barrier() use in <vdso/processor.h>
RISC-V: Add missing jump label initialization
riscv: Explicitly specify the build id style in vDSO Makefile again
Currently, if mce_end() fails, no_way_out - the variable denoting
whether the machine can recover from this MCE - is determined by whether
the worst severity that was found across the MCA banks associated with
the current CPU, is of panic severity.
However, at this point no_way_out could have been already set by
mca_start() after looking at all severities of all CPUs that entered the
MCE handler. If mce_end() fails, check first if no_way_out is already
set and, if so, stick to it, otherwise use the local worst value.
[ bp: Massage. ]
Signed-off-by: Gabriele Paoloni <gabriele.paoloni@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20201127161819.3106432-2-gabriele.paoloni@intel.com
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