* Arjan van de Ven <arjan@xxxxxxxxxxxxxxx> wrote:
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WARNING: at arch/x86/mm/pgtable_32.c:387 pmd_bad+0x44/0x53()
Modules linked in:
Pid: 1, comm: swapper Not tainted 2.6.25-rc3 #14
[<c0424ba5>] warn_on_slowpath+0x41/0x67
[<c0408c5c>] ? native_sched_clock+0x94/0xa6
[<c043f432>] ? lock_release_holdtime+0x1a/0x115
[<c04702d4>] ? handle_mm_fault+0x297/0x7e2
[<c063eee6>] ? _spin_unlock+0x1d/0x20
[<c04707f0>] ? handle_mm_fault+0x7b3/0x7e2
[<c04851c1>] ? do_sync_read+0xab/0xe9
[<c0417223>] pmd_bad+0x44/0x53
[<c046f37f>] follow_page+0x8b/0x1f2
[<c0470aa0>] get_user_pages+0x281/0x2ef
hm. I suspect some gcc related difference related to the handling of this masking:
pmd_val(x) & ~(PAGE_MASK | _PAGE_USER | _PAGE_PSE | _PAGE_NX)
versus:
pmd_val(x) & (~PAGE_MASK & ~_PAGE_USER)
perhaps it will work if you change it to:
pmd_val(x) & (~PAGE_MASK & ~_PAGE_USER & ~_PAGE_PSE & ~_PAGE_NX)
?
in any case, the commit has to be reverted as it clearly isnt a NOP on your box as it was intended to be. (it should only have made a difference in a rare hugetlbfs case)