| From c15842b8d25ea4a866b164f2ab25b6ccc030b618 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Thu, 28 May 2020 22:29:25 +0200 |
| Subject: parisc: Fix kernel panic in mem_init() |
| |
| From: Helge Deller <deller@gmx.de> |
| |
| [ Upstream commit bf71bc16e02162388808949b179d59d0b571b965 ] |
| |
| The Debian kernel v5.6 triggers this kernel panic: |
| |
| Kernel panic - not syncing: Bad Address (null pointer deref?) |
| Bad Address (null pointer deref?): Code=26 (Data memory access rights trap) at addr 0000000000000000 |
| CPU: 0 PID: 0 Comm: swapper Not tainted 5.6.0-2-parisc64 #1 Debian 5.6.14-1 |
| IAOQ[0]: mem_init+0xb0/0x150 |
| IAOQ[1]: mem_init+0xb4/0x150 |
| RP(r2): start_kernel+0x6c8/0x1190 |
| Backtrace: |
| [<0000000040101ab4>] start_kernel+0x6c8/0x1190 |
| [<0000000040108574>] start_parisc+0x158/0x1b8 |
| |
| on a HP-PARISC rp3440 machine with this memory layout: |
| Memory Ranges: |
| 0) Start 0x0000000000000000 End 0x000000003fffffff Size 1024 MB |
| 1) Start 0x0000004040000000 End 0x00000040ffdfffff Size 3070 MB |
| |
| Fix the crash by avoiding virt_to_page() and similar functions in |
| mem_init() until the memory zones have been fully set up. |
| |
| Signed-off-by: Helge Deller <deller@gmx.de> |
| Cc: stable@vger.kernel.org # v5.0+ |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| arch/parisc/mm/init.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| diff --git a/arch/parisc/mm/init.c b/arch/parisc/mm/init.c |
| index ddca8287d43b..3e54484797f6 100644 |
| --- a/arch/parisc/mm/init.c |
| +++ b/arch/parisc/mm/init.c |
| @@ -588,7 +588,7 @@ void __init mem_init(void) |
| > BITS_PER_LONG); |
| |
| high_memory = __va((max_pfn << PAGE_SHIFT)); |
| - set_max_mapnr(page_to_pfn(virt_to_page(high_memory - 1)) + 1); |
| + set_max_mapnr(max_low_pfn); |
| memblock_free_all(); |
| |
| #ifdef CONFIG_PA11 |
| -- |
| 2.25.1 |
| |
