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| author | Thomas Gleixner <tglx@linutronix.de> | 2023-12-07 20:49:24 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-01-08 11:27:36 +0100 |
| commit | 8f6f8443a2dc19f4d8087ef64ccd8a818df997d2 (patch) | |
| tree | da57373db23bce836555207f06ae4150b6a7b2ea | |
| parent | f08531dd7c1108a9c9dca19df9b8bd65e8e20f29 (diff) | |
| download | linux-stable-8f6f8443a2dc19f4d8087ef64ccd8a818df997d2.tar.gz linux-stable-8f6f8443a2dc19f4d8087ef64ccd8a818df997d2.tar.bz2 linux-stable-8f6f8443a2dc19f4d8087ef64ccd8a818df997d2.zip | |
x86/alternatives: Sync core before enabling interrupts
commit 3ea1704a92967834bf0e64ca1205db4680d04048 upstream.
text_poke_early() does:
local_irq_save(flags);
memcpy(addr, opcode, len);
local_irq_restore(flags);
sync_core();
That's not really correct because the synchronization should happen before
interrupts are re-enabled to ensure that a pending interrupt observes the
complete update of the opcodes.
It's not entirely clear whether the interrupt entry provides enough
serialization already, but moving the sync_core() invocation into interrupt
disabled region does no harm and is obviously correct.
Fixes: 6fffacb30349 ("x86/alternatives, jumplabel: Use text_poke_early() before mm_init()")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/ZT6narvE%2BLxX%2B7Be@windriver.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/x86/kernel/alternative.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index dee94961a667..33882d5ab25d 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -690,8 +690,8 @@ void *__init_or_module text_poke_early(void *addr, const void *opcode, } else { local_irq_save(flags); memcpy(addr, opcode, len); - local_irq_restore(flags); sync_core(); + local_irq_restore(flags); /* * Could also do a CLFLUSH here to speed up CPU recovery; but |