[PATCH] x86/mm: fix regression with huge pages on PAE
From: Kirill A. Shutemov
Date: Mon Nov 09 2015 - 18:18:36 EST
Recent PAT patchset has caused issue on 32-bit PAE machines:
[ 8.905943] page:eea45000 count:0 mapcount:-128 mapping: (null) index:0x0
[ 8.913041] flags: 0x40000000()
[ 8.916293] page dumped because: VM_BUG_ON_PAGE(page_mapcount(page) < 0)
[ 8.923204] ------------[ cut here ]------------
[ 8.927958] kernel BUG at /home/build/linux-boris/mm/huge_memory.c:1485!
[ 8.934860] invalid opcode: 0000 [#1] SMP
[ 8.939094] Modules linked in: ahci libahci ata_generic skge r8169 firewire_ohci mii libata qla2xxx(+) scsi_transport_fc scsi_mod radeon tpm_infineon ttm backlight wmi acpi_cpufreq tpm_tis
[ 8.956548] CPU: 2 PID: 1758 Comm: modprobe Not tainted 4.3.0upstream-09269-gce5c2d2 #1
[ 8.964792] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./To be filled by O.E.M., BIOS 080014 07/18/2008
[ 8.975991] task: ed84e600 ti: f6458000 task.ti: f6458000
[ 8.981552] EIP: 0060:[<c11bde80>] EFLAGS: 00010246 CPU: 2
[ 8.987203] EIP is at zap_huge_pmd+0x240/0x260
[ 8.991778] EAX: 00000000 EBX: f6459eb0 ECX: 00000292 EDX: 00000292
[ 8.998234] ESI: f6634d98 EDI: eea45000 EBP: f6459dc8 ESP: f6459d98
[ 8.998355] ata1: SATA link down (SStatus 0 SControl 300)
[ 9.000330] ata2: SATA link down (SStatus 0 SControl 300)
[ 9.015804] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
[ 9.021364] CR0: 8005003b CR2: b75b21a0 CR3: 3655b880 CR4: 000006f0
[ 9.027818] Stack:
[ 9.029885] 00000080 00000000 80000002 ee795000 80000002 ffe00000 00000000 ffffff7f
[ 9.037930] eee6169c f70c5e40 b6600000 f6634d98 f6459e78 c119a7c8 b6600000 80000002
[ 9.045972] 00000003 c18992f4 c18992f0 00000003 00000286 f6459e0c c10db5f0 00000000
[ 9.054018] Call Trace:
[ 9.056537] [<c119a7c8>] unmap_single_vma+0x6e8/0x7c0
[ 9.061829] [<c10db5f0>] ? __wake_up+0x40/0x50
[ 9.063587] firewire_core 0000:08:05.0: created device fw0: GUID 000000001a1a2f03, S800
[ 9.074736] [<c119a8e7>] unmap_vmas+0x47/0x80
[ 9.079312] [<c11a0c44>] unmap_region+0x74/0xc0
[ 9.084067] [<c11a2d50>] do_munmap+0x1b0/0x280
[ 9.088732] [<c11a2e58>] vm_munmap+0x38/0x50
[ 9.093218] [<c11a2e88>] SyS_munmap+0x18/0x20
[ 9.097795] [<c1003861>] do_fast_syscall_32+0xa1/0x270
[ 9.103176] [<c1095400>] ? __do_page_fault+0x430/0x430
[ 9.108559] [<c169de51>] sysenter_past_esp+0x36/0x55
[ 9.113761] Code: 00 e9 05 fe ff ff 90 8d 74 26 00 0f 0b eb fe ba 4c e1 7a c1 89 f8 e8 f0 91 fd ff 0f 0b eb fe ba 6c e1 7a c1 89 f8 e8 e0 91 fd ff <0f> 0b eb fe ba c4 e1 7a c1 89 f8 e8 d0 91 fd ff 0f 0b eb fe 8d
[ 9.133727] EIP: [<c11bde80>] zap_huge_pmd+0x240/0x260 SS:ESP 0068:f6459d98
[ 9.140929] ---[ end trace cba8fb1fc2e2e78a ]---
The problem is in pmd_pfn_mask() and pmd_flags_mask(). These helpers use
PMD_PAGE_MASK to calculate resulting mask. PMD_PAGE_MASK is 'unsigned
long', not 'unsigned long long' as physaddr_t. As result upper bits of
resulting mask is truncated.
The patch reworks code to use PMD_SHIFT as base of mask calculation
instead of PMD_PAGE_MASK.
pud_pfn_mask() and pud_flags_mask() aren't problematic since we don't
have PUD page table level on 32-bit systems, but they reworked too to be
consistent with PMD counterpart.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Reported-and-Tested-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Fixes: f70abb0fc3da ("x86/asm: Fix pud/pmd interfaces to handle large PAT bit")
Cc: Toshi Kani <toshi.kani@xxxxxxx>
---
arch/x86/include/asm/pgtable_types.h | 14 ++++----------
1 file changed, 4 insertions(+), 10 deletions(-)
diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index dd5b0aa9dd2f..c1e797266ce9 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -279,17 +279,14 @@ static inline pmdval_t native_pmd_val(pmd_t pmd)
static inline pudval_t pud_pfn_mask(pud_t pud)
{
if (native_pud_val(pud) & _PAGE_PSE)
- return PUD_PAGE_MASK & PHYSICAL_PAGE_MASK;
+ return ~((1ULL << PUD_SHIFT) - 1) & PHYSICAL_PAGE_MASK;
else
return PTE_PFN_MASK;
}
static inline pudval_t pud_flags_mask(pud_t pud)
{
- if (native_pud_val(pud) & _PAGE_PSE)
- return ~(PUD_PAGE_MASK & (pudval_t)PHYSICAL_PAGE_MASK);
- else
- return ~PTE_PFN_MASK;
+ return ~pud_pfn_mask(pud);
}
static inline pudval_t pud_flags(pud_t pud)
@@ -300,17 +297,14 @@ static inline pudval_t pud_flags(pud_t pud)
static inline pmdval_t pmd_pfn_mask(pmd_t pmd)
{
if (native_pmd_val(pmd) & _PAGE_PSE)
- return PMD_PAGE_MASK & PHYSICAL_PAGE_MASK;
+ return ~((1ULL << PMD_SHIFT) - 1) & PHYSICAL_PAGE_MASK;
else
return PTE_PFN_MASK;
}
static inline pmdval_t pmd_flags_mask(pmd_t pmd)
{
- if (native_pmd_val(pmd) & _PAGE_PSE)
- return ~(PMD_PAGE_MASK & (pmdval_t)PHYSICAL_PAGE_MASK);
- else
- return ~PTE_PFN_MASK;
+ return ~pmd_pfn_mask(pmd);
}
static inline pmdval_t pmd_flags(pmd_t pmd)
--
2.6.2
--
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