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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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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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| .. | ||
| cache-page.c | ||
| dma-alloc.c | ||
| elf-fdpic.c | ||
| extable.c | ||
| fault.c | ||
| highmem.c | ||
| init.c | ||
| kmap.c | ||
| Makefile | ||
| mmu-context.c | ||
| pgalloc.c | ||
| tlb-flush.S | ||
| tlb-miss.S | ||