linux-kernel - [PATCH 4.19 080/118] arm64: hibernate: Avoid sending cross-calling with interrupts disabled

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Date:   Tue, 11 Dec 2018 16:41:39 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Kunihiko Hayashi <hayashi.kunihiko@...ionext.com>,
        James Morse <james.morse@....com>,
        Will Deacon <will.deacon@....com>,
        Catalin Marinas <catalin.marinas@....com>
Subject: [PATCH 4.19 080/118] arm64: hibernate: Avoid sending cross-calling with interrupts disabled

4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Will Deacon <will.deacon@....com>

commit b4aecf78083d8c6424657c1746c7c3de6e61669f upstream.

Since commit 3b8c9f1cdfc50 ("arm64: IPI each CPU after invalidating the
I-cache for kernel mappings"), a call to flush_icache_range() will use
an IPI to cross-call other online CPUs so that any stale instructions
are flushed from their pipelines. This triggers a WARN during the
hibernation resume path, where flush_icache_range() is called with
interrupts disabled and is therefore prone to deadlock:

  | Disabling non-boot CPUs ...
  | CPU1: shutdown
  | psci: CPU1 killed.
  | CPU2: shutdown
  | psci: CPU2 killed.
  | CPU3: shutdown
  | psci: CPU3 killed.
  | WARNING: CPU: 0 PID: 1 at ../kernel/smp.c:416 smp_call_function_many+0xd4/0x350
  | Modules linked in:
  | CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.20.0-rc4 #1

Since all secondary CPUs have been taken offline prior to invalidating
the I-cache, there's actually no need for an IPI and we can simply call
__flush_icache_range() instead.

Cc: <stable@...r.kernel.org>
Fixes: 3b8c9f1cdfc50 ("arm64: IPI each CPU after invalidating the I-cache for kernel mappings")
Reported-by: Kunihiko Hayashi <hayashi.kunihiko@...ionext.com>
Tested-by: Kunihiko Hayashi <hayashi.kunihiko@...ionext.com>
Tested-by: James Morse <james.morse@....com>
Signed-off-by: Will Deacon <will.deacon@....com>
Signed-off-by: Catalin Marinas <catalin.marinas@....com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/arm64/kernel/hibernate.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/arm64/kernel/hibernate.c
+++ b/arch/arm64/kernel/hibernate.c
@@ -214,7 +214,7 @@ static int create_safe_exec_page(void *s
 	}
 
 	memcpy((void *)dst, src_start, length);
-	flush_icache_range(dst, dst + length);
+	__flush_icache_range(dst, dst + length);
 
 	pgdp = pgd_offset_raw(allocator(mask), dst_addr);
 	if (pgd_none(READ_ONCE(*pgdp))) {