Hi,
On Thu, Jun 16, 2016 at 03:50:31PM -0700, David Daney wrote:
> From: David Daney <david.daney@xxxxxxxxxx>
>
> 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.
[...]
> 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@xxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> ---
> arch/mips/include/asm/pgtable.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
> index a6b611f..477b1b1 100644
> --- a/arch/mips/include/asm/pgtable.h
> +++ b/arch/mips/include/asm/pgtable.h
> @@ -632,7 +632,7 @@ 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) | pgprot_val(newprot);
> + pmd_val(pmd) = (pmd_val(pmd) & (_PAGE_CHG_MASK | _PAGE_HUGE)) | pgprot_val(newprot);
> return pmd;
> }
The fix looks correct, but unfortunately at least EBH5600 still keeps
crashing with THP enabled. :-(
[ 606.429974] Got mcheck at 000000ffebed8c2c
[ 606.442262] CPU: 6 PID: 6767 Comm: ld Not tainted 4.7.0-rc3-octeon-distro.git-v2.17-27-g5cc128c-12208-g7d9ecdf #1
[ 606.473026] task: 800000041f384880 ti: 80000000ed7b0000 task.ti: 80000000ed7b0000
[ 606.495454] $ 0 : 0000000000000000 3e000000038ac006 000000ffebba7028 000000ffebb9f020
[ 606.519588] $ 4 : 0000000001529d94 00000001204f4236 0000000000000000 0000000000000000
[ 606.543722] $ 8 : 0000000000000001 7efefefefefefeff ffa0a0998d9e9c8b 8101010101010100
[ 606.567856] $12 : 4040404040404040 ffffffff84080018 0000000000000000 6162002e74657874
[ 606.591991] $16 : 000000012032a7d0 00000001204f4229 00000001201483f0 0000000000000000
[ 606.616125] $20 : 0000000000000000 000000000000000c 00000000053cd125 00000001204edb70
[ 606.640259] $24 : 0000000000000034 000000ffebed8b50
[ 606.664393] $28 : 000000ffebfac000 000000ffff808160 00000001204b9ad0 000000ffebed9cc8
[ 606.688528] Hi : 0000000000001001
[ 606.699237] Lo : 00000000000014f4
[ 606.709951] epc : 000000ffebed8c2c 0xffebed8c2c
[ 606.724048] ra : 000000ffebed9cc8 0xffebed9cc8
[ 606.738144] Status: 00308cf3 KX SX UX USER EXL IE
[ 606.752704] Cause : 00800060 (ExcCode 18)
[ 606.764717] PrId : 000d0409 (Cavium Octeon+)
[ 606.777770] Index : 80000000
[ 606.787178] PageMask : 1fe000
[ 606.796064] EntryHi : 000000012032a095
[ 606.807555] EntryLo0 : 00000000038a8006
[ 606.819046] EntryLo1 : 00000000038ac006
[ 606.830535] Wired : 0
[ 606.838120] PageGrain: e0000000
[ 606.847525]
[ 606.851986] Index: 40 pgmask=4kb va=0ffebba6000 asid=95
[ri=0 xi=1 pa=0041d2b2000 c=0 d=1 v=1 g=0] [ri=0 xi=1 pa=0041d2b3000 c=0 d=1 v=1 g=0]
[ 606.890740] Index: 41 pgmask=4kb va=0ffebbb6000 asid=95
[ri=0 xi=1 pa=0041d26e000 c=0 d=1 v=1 g=0] [ri=0 xi=1 pa=0041d26f000 c=0 d=1 v=1 g=0]
[ 606.929492] Index: 42 pgmask=4kb va=00120148000 asid=95
[ri=0 xi=0 pa=0041d6b7000 c=0 d=1 v=1 g=0] [ri=0 xi=0 pa=0041dcd1000 c=0 d=1 v=1 g=0]
[ 606.968241] Index: 43 pgmask=4kb va=0012012c000 asid=95
[ri=0 xi=1 pa=000e30e9000 c=0 d=1 v=1 g=0] [ri=0 xi=0 pa=0041e5f8000 c=0 d=1 v=1 g=0]
[ 607.006990] Index: 44 pgmask=4kb va=001204ec000 asid=95
[ri=0 xi=0 pa=000e317e000 c=0 d=1 v=1 g=0] [ri=0 xi=0 pa=000e32cf000 c=0 d=1 v=1 g=0]
[ 607.045743] Index: 45 pgmask=4kb va=001204fe000 asid=95
[ri=0 xi=0 pa=000e4206000 c=0 d=1 v=1 g=0] [ri=0 xi=0 pa=000e308f000 c=0 d=1 v=1 g=0]
[ 607.084493] Index: 46 pgmask=4kb va=001204f4000 asid=95
[ri=0 xi=0 pa=000e31d0000 c=0 d=1 v=1 g=0] [ri=0 xi=0 pa=000e2874000 c=0 d=1 v=1 g=0]
[ 607.123243] Index: 47 pgmask=4kb va=0ffebd3c000 asid=95
[ri=0 xi=0 pa=000ef2fc000 c=0 d=0 v=1 g=0] [ri=0 xi=0 pa=000ef01f000 c=0 d=0 v=1 g=0]
[ 607.161992] Index: 48 pgmask=4kb va=0ffebf28000 asid=95
[ri=0 xi=0 pa=000e3adf000 c=0 d=0 v=1 g=0] [ri=0 xi=0 pa=000e3ade000 c=0 d=0 v=1 g=0]
[ 607.200741] Index: 49 pgmask=4kb va=0ffff808000 asid=95
[ri=0 xi=0 pa=000e34a8000 c=0 d=1 v=1 g=0] [ri=0 xi=0 pa=000e43bb000 c=0 d=1 v=1 g=0]
[ 607.239489] Index: 50 pgmask=4kb va=0ffebfa4000 asid=95
[ri=0 xi=1 pa=000e35c6000 c=0 d=1 v=1 g=0] [ri=0 xi=1 pa=000e31eb000 c=0 d=1 v=1 g=0]
[ 607.278238] Index: 51 pgmask=4kb va=0ffebed8000 asid=95
[ri=0 xi=0 pa=000e3dce000 c=0 d=0 v=1 g=0] [ri=0 xi=0 pa=000e49ed000 c=0 d=0 v=1 g=0]
[ 607.316985] Index: 52 pgmask=4kb va=00120274000 asid=95
[ri=0 xi=0 pa=00000000000 c=0 d=0 v=0 g=0] [ri=0 xi=1 pa=00000000000 c=2 d=1 v=1 g=0]
[ 607.355734]
[ 607.360192]
Code: de100000 12000014 00000000 <de020010> 1456fffb df9991d0 de040008 0320f809 0220282d
[ 607.389654] Kernel panic - not syncing: Caught Machine Check exception - caused by multiple matching entries in the TLB.
[ 607.422806] ---[ end Kernel panic - not syncing: Caught Machine Check exception - caused by multiple matching entries in the TLB.
*** NMI Watchdog interrupt on Core 0x0 ***
A.
