20273941f2
Christoph reported a nice splat which illustrated a race in the new stack based kmap_atomic implementation. The problem is that we pop our stack slot before we're completely done resetting its state -- in particular clearing the PTE (sometimes that's CONFIG_DEBUG_HIGHMEM). If an interrupt happens before we actually clear the PTE used for the last slot, that interrupt can reuse the slot in a dirty state, which triggers a BUG in kmap_atomic(). Fix this by introducing kmap_atomic_idx() which reports the current slot index without actually releasing it and use that to find the PTE and delay the _pop() until after we're completely done. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Reported-by: Christoph Hellwig <hch@infradead.org> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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.. | ||
40x_mmu.c | ||
44x_mmu.c | ||
dma-noncoherent.c | ||
fault.c | ||
fsl_booke_mmu.c | ||
gup.c | ||
hash_low_32.S | ||
hash_low_64.S | ||
hash_native_64.c | ||
hash_utils_64.c | ||
highmem.c | ||
hugetlbpage-hash64.c | ||
hugetlbpage.c | ||
init_32.c | ||
init_64.c | ||
Makefile | ||
mem.c | ||
mmap_64.c | ||
mmu_context_hash32.c | ||
mmu_context_hash64.c | ||
mmu_context_nohash.c | ||
mmu_decl.h | ||
numa.c | ||
pgtable.c | ||
pgtable_32.c | ||
pgtable_64.c | ||
ppc_mmu_32.c | ||
slb.c | ||
slb_low.S | ||
slice.c | ||
stab.c | ||
subpage-prot.c | ||
tlb_hash32.c | ||
tlb_hash64.c | ||
tlb_low_64e.S | ||
tlb_nohash.c | ||
tlb_nohash_low.S |