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authorDavid Daney <david.daney@cavium.com>2016-06-16 15:50:31 -0700
committerRalf Baechle <ralf@linux-mips.org>2016-07-06 15:09:03 +0200
commit88d02a2ba6c52350f9a73ff1b01a5be839c3ca17 (patch)
tree0a326c810de156a42937b478d6c23a4631d1ebb3 /arch
parenta99cde438de0c4c0cecc1d1af1a55a75b10bfdef (diff)
downloadlinux-88d02a2ba6c52350f9a73ff1b01a5be839c3ca17.tar.gz
linux-88d02a2ba6c52350f9a73ff1b01a5be839c3ca17.tar.xz
MIPS: Fix page table corruption on THP permission changes.
When the core THP code is modifying the permissions of a huge page it calls pmd_modify(), which unfortunately was clearing the _PAGE_HUGE bit of the page table entry. The result can be kernel messages like: mm/memory.c:397: bad pmd 000000040080004d. mm/memory.c:397: bad pmd 00000003ff00004d. mm/memory.c:397: bad pmd 000000040100004d. or: ------------[ cut here ]------------ WARNING: at mm/mmap.c:3200 exit_mmap+0x150/0x158() Modules linked in: ipv6 at24 octeon3_ethernet octeon_srio_nexus m25p80 CPU: 12 PID: 1295 Comm: pmderr Not tainted 3.10.87-rt80-Cavium-Octeon #4 Stack : 0000000040808000 0000000014009ce1 0000000000400004 ffffffff81076ba0 0000000000000000 0000000000000000 ffffffff85110000 0000000000000119 0000000000000004 0000000000000000 0000000000000119 43617669756d2d4f 0000000000000000 ffffffff850fda40 ffffffff85110000 0000000000000000 0000000000000000 0000000000000009 ffffffff809207a0 0000000000000c80 ffffffff80f1bf20 0000000000000001 000000ffeca36828 0000000000000001 0000000000000000 0000000000000001 000000ffeca7e700 ffffffff80886924 80000003fd7a0000 80000003fd7a39b0 80000003fdea8000 ffffffff80885780 80000003fdea8000 ffffffff80f12218 000000000000000c 000000000000050f 0000000000000000 ffffffff80865c4c 0000000000000000 0000000000000000 ... Call Trace: [<ffffffff80865c4c>] show_stack+0x6c/0xf8 [<ffffffff80885780>] warn_slowpath_common+0x78/0xa8 [<ffffffff809207a0>] exit_mmap+0x150/0x158 [<ffffffff80882d44>] mmput+0x5c/0x110 [<ffffffff8088b450>] do_exit+0x230/0xa68 [<ffffffff8088be34>] do_group_exit+0x54/0x1d0 [<ffffffff8088bfc0>] __wake_up_parent+0x0/0x18 ---[ end trace c7b38293191c57dc ]--- BUG: Bad rss-counter state mm:80000003fa168000 idx:1 val:1536 Fix by not clearing _PAGE_HUGE bit. Signed-off-by: David Daney <david.daney@cavium.com> Tested-by: Aaro Koskinen <aaro.koskinen@nokia.com> Cc: stable@vger.kernel.org Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13687/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/mips/include/asm/pgtable.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
index f538167..7d44e88 100644
--- a/arch/mips/include/asm/pgtable.h
+++ b/arch/mips/include/asm/pgtable.h
@@ -633,7 +633,7 @@ static inline struct page *pmd_page(pmd_t pmd)
static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
{
- pmd_val(pmd) = (pmd_val(pmd) & _PAGE_CHG_MASK) |
+ pmd_val(pmd) = (pmd_val(pmd) & (_PAGE_CHG_MASK | _PAGE_HUGE)) |
(pgprot_val(newprot) & ~_PAGE_CHG_MASK);
return pmd;
}