From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Helge Deller <deller@gmx.de>
Subject: [PATCH 5.4 336/355] parisc: Fix set_fixmap() on PA1.x CPUs
Date:   Mon, 15 Nov 2021 18:04:20 +0100
Message-Id: <20211115165324.608541703@linuxfoundation.org>
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From: Helge Deller <deller@gmx.de>

commit 6e866a462867b60841202e900f10936a0478608c upstream.

Fix a kernel crash which happens on PA1.x CPUs while initializing the
FTRACE/KPROBE breakpoints.  The PTE table entries for the fixmap area
were not created correctly.

Signed-off-by: Helge Deller <deller@gmx.de>
Fixes: ccfbc68d41c2 ("parisc: add set_fixmap()/clear_fixmap()")
Cc: stable@vger.kernel.org # v5.2+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/parisc/mm/fixmap.c |    5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

--- a/arch/parisc/mm/fixmap.c
+++ b/arch/parisc/mm/fixmap.c
@@ -18,12 +18,9 @@ void notrace set_fixmap(enum fixed_addre
 	pte_t *pte;
 
 	if (pmd_none(*pmd))
-		pmd = pmd_alloc(NULL, pgd, vaddr);
-
-	pte = pte_offset_kernel(pmd, vaddr);
-	if (pte_none(*pte))
 		pte = pte_alloc_kernel(pmd, vaddr);
 
+	pte = pte_offset_kernel(pmd, vaddr);
 	set_pte_at(&init_mm, vaddr, pte, __mk_pte(phys, PAGE_KERNEL_RWX));
 	flush_tlb_kernel_range(vaddr, vaddr + PAGE_SIZE);
 }