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Message-Id: <20230803062404.2373480-1-rppt@kernel.org>
Date: Thu, 3 Aug 2023 09:24:04 +0300
From: Mike Rapoport <rppt@...nel.org>
To: Helge Deller <deller@....de>
Cc: Christoph Biedl <linux-kernel.bfrz@...chmal.in-ulm.de>,
"James E.J. Bottomley" <James.Bottomley@...senPartnership.com>,
John David Anglin <dave.anglin@...l.net>,
Mike Rapoport <rppt@...nel.org>,
Vlastimil Babka <vbabka@...e.cz>, linux-parisc@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH] parisc/mm: preallocate fixmap page tables at init
From: "Mike Rapoport (IBM)" <rppt@...nel.org>
Christoph Biedl reported early OOM on recent kernels:
swapper: page allocation failure: order:0, mode:0x100(__GFP_ZERO),
nodemask=(null)
CPU: 0 PID: 0 Comm: swapper Not tainted 6.3.0-rc4+ #16
Hardware name: 9000/785/C3600
Backtrace:
[<10408594>] show_stack+0x48/0x5c
[<10e152d8>] dump_stack_lvl+0x48/0x64
[<10e15318>] dump_stack+0x24/0x34
[<105cf7f8>] warn_alloc+0x10c/0x1c8
[<105d068c>] __alloc_pages+0xbbc/0xcf8
[<105d0e4c>] __get_free_pages+0x28/0x78
[<105ad10c>] __pte_alloc_kernel+0x30/0x98
[<10406934>] set_fixmap+0xec/0xf4
[<10411ad4>] patch_map.constprop.0+0xa8/0xdc
[<10411bb0>] __patch_text_multiple+0xa8/0x208
[<10411d78>] patch_text+0x30/0x48
[<1041246c>] arch_jump_label_transform+0x90/0xcc
[<1056f734>] jump_label_update+0xd4/0x184
[<1056fc9c>] static_key_enable_cpuslocked+0xc0/0x110
[<1056fd08>] static_key_enable+0x1c/0x2c
[<1011362c>] init_mem_debugging_and_hardening+0xdc/0xf8
[<1010141c>] start_kernel+0x5f0/0xa98
[<10105da8>] start_parisc+0xb8/0xe4
Mem-Info:
active_anon:0 inactive_anon:0 isolated_anon:0
active_file:0 inactive_file:0 isolated_file:0
unevictable:0 dirty:0 writeback:0
slab_reclaimable:0 slab_unreclaimable:0
mapped:0 shmem:0 pagetables:0
sec_pagetables:0 bounce:0
kernel_misc_reclaimable:0
free:0 free_pcp:0 free_cma:0
Node 0 active_anon:0kB inactive_anon:0kB active_file:0kB
inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB
mapped:0kB dirty:0kB writeback:0kB shmem:0kB
+writeback_tmp:0kB kernel_stack:0kB pagetables:0kB sec_pagetables:0kB
all_unreclaimable? no
Normal free:0kB boost:0kB min:0kB low:0kB high:0kB
reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB active_file:0kB
inactive_file:0kB unevictable:0kB writepending:0kB
+present:1048576kB managed:1039360kB mlocked:0kB bounce:0kB free_pcp:0kB
local_pcp:0kB free_cma:0kB
lowmem_reserve[]: 0 0
Normal: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB
0*1024kB 0*2048kB 0*4096kB = 0kB
0 total pagecache pages
0 pages in swap cache
Free swap = 0kB
Total swap = 0kB
262144 pages RAM
0 pages HighMem/MovableOnly
2304 pages reserved
Backtrace:
[<10411d78>] patch_text+0x30/0x48
[<1041246c>] arch_jump_label_transform+0x90/0xcc
[<1056f734>] jump_label_update+0xd4/0x184
[<1056fc9c>] static_key_enable_cpuslocked+0xc0/0x110
[<1056fd08>] static_key_enable+0x1c/0x2c
[<1011362c>] init_mem_debugging_and_hardening+0xdc/0xf8
[<1010141c>] start_kernel+0x5f0/0xa98
[<10105da8>] start_parisc+0xb8/0xe4
Kernel Fault: Code=15 (Data TLB miss fault) at addr 0f7fe3c0
CPU: 0 PID: 0 Comm: swapper Not tainted 6.3.0-rc4+ #16
Hardware name: 9000/785/C3600
This happens because patching static key code temporarily maps it via
fixmap and if it happens before page allocator is initialized set_fixmap()
cannot allocate memory using pte_alloc_kernel().
Make sure that fixmap page tables are preallocated early so that
pte_offset_kernel() in set_fixmap() never resorts to pte allocation.
Signed-off-by: Mike Rapoport (IBM) <rppt@...nel.org>
---
I didn't add Fixes tag with the commit Christoph bisected because that
commit didn't change anything in the initialization of the static keys
and I really doubt it is the actual cause of the issue.
arch/parisc/mm/fixmap.c | 3 ---
arch/parisc/mm/init.c | 34 ++++++++++++++++++++++++++++++++++
2 files changed, 34 insertions(+), 3 deletions(-)
diff --git a/arch/parisc/mm/fixmap.c b/arch/parisc/mm/fixmap.c
index cc15d737fda6..ae3493dae9dc 100644
--- a/arch/parisc/mm/fixmap.c
+++ b/arch/parisc/mm/fixmap.c
@@ -19,9 +19,6 @@ void notrace set_fixmap(enum fixed_addresses idx, phys_addr_t phys)
pmd_t *pmd = pmd_offset(pud, vaddr);
pte_t *pte;
- if (pmd_none(*pmd))
- 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);
diff --git a/arch/parisc/mm/init.c b/arch/parisc/mm/init.c
index 406c52fe23d5..389941c7f209 100644
--- a/arch/parisc/mm/init.c
+++ b/arch/parisc/mm/init.c
@@ -669,6 +669,39 @@ static void __init gateway_init(void)
PAGE_SIZE, PAGE_GATEWAY, 1);
}
+static void __init fixmap_init(void)
+{
+ unsigned long addr = FIXMAP_START;
+ unsigned long end = FIXMAP_START + FIXMAP_SIZE;
+ pgd_t *pgd = pgd_offset_k(addr);
+ p4d_t *p4d = p4d_offset(pgd, addr);
+ pud_t *pud = pud_offset(p4d, addr);
+ pmd_t *pmd;
+
+ BUILD_BUG_ON(FIXMAP_SIZE > PMD_SIZE);
+
+#if CONFIG_PGTABLE_LEVELS == 3
+ if (pud_none(*pud)) {
+ pmd = memblock_alloc(PAGE_SIZE << PMD_TABLE_ORDER,
+ PAGE_SIZE << PMD_TABLE_ORDER);
+ if (!pmd)
+ panic("fixmap: pmd allocation failed.\n");
+ pud_populate(NULL, pud, pmd);
+ }
+#endif
+
+ pmd = pmd_offset(pud, addr);
+ do {
+ pte_t *pte = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
+ if (!pte)
+ panic("fixmap: pte allocation failed.\n");
+
+ pmd_populate_kernel(&init_mm, pmd, pte);
+
+ addr += PAGE_SIZE;
+ } while (addr < end);
+}
+
static void __init parisc_bootmem_free(void)
{
unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0, };
@@ -683,6 +716,7 @@ void __init paging_init(void)
setup_bootmem();
pagetable_init();
gateway_init();
+ fixmap_init();
flush_cache_all_local(); /* start with known state */
flush_tlb_all_local(NULL);
base-commit: 5d0c230f1de8c7515b6567d9afba1f196fb4e2f4
--
2.34.1
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