Nicholas Piggin 5a9fe6b7f4 powerpc/64s: Fix local irq disable when PMIs are disabled
commit bc88ef6632 upstream.

When PMI interrupts are soft-masked, local_irq_save() will clear the PMI
mask bit, allowing PMIs in and causing a race condition. This causes a
deadlock in native_hpte_insert via hash_preload, which depends on PMIs
being disabled since commit 8b91cee5ea ("powerpc/64s/hash: Make hash
faults work in NMI context"). native_hpte_insert calls local_irq_save().
It's possible the lpar hash code is also affected when tracing is
enabled because __trace_hcall_entry() calls local_irq_save().

Fix this by making arch_local_irq_save() _or_ the IRQS_DISABLED bit into
the mask.

This was found with the stress_hpt option with a kbuild workload running
together with `perf record -g`.

Fixes: f442d00480 ("powerpc/64s: Add support to mask perf interrupts and replay them")
Fixes: 8b91cee5ea ("powerpc/64s/hash: Make hash faults work in NMI context")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Just take the fix without the new warning]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230121095352.2823517-1-npiggin@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-02-09 11:28:26 +01:00
2022-09-28 09:02:20 +02:00
2022-09-28 09:02:20 +02:00
2023-02-06 08:06:34 +01:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
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In order to build the documentation, use ``make htmldocs`` or
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    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.
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