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Arun Easi authored
munmap done by iscsiuio during a stop of the service triggers a "bad pte" warning sometimes. munmap kernel path goes through the mmapped pages and has a validation check for mapcount (in struct page) to be zero or above. kzalloc, which we had used to allocate udev->ctrl, uses slab allocations, which re-uses mapcount (union) for other purposes that can make the mapcount look negative. Avoid all these trouble by invoking one of the __get_free_pages wrappers to be used instead of kzalloc for udev->ctrl. BUG: Bad page map in process iscsiuio pte:80000000aa624067 pmd:3e6777067 page:ffffea0002a98900 count:2 mapcount:-2143289280 mapping: (null) index:0xffff8800aa624e00 page flags: 0x10075d00000090(dirty|slab) page dumped because: bad pte addr:00007fcba70a3000 vm_flags:0c0400fb anon_vma: (null) mapping:ffff8803edf66e90 index:0 Call Trace: dump_stack+0x19/0x1b print_bad_pte+0x1af/0x250 unmap_page_range+0x7a7/0x8a0 unmap_single_vma+0x81/0xf0 unmap_vmas+0x49/0x90 unmap_region+0xbe/0x140 ? vma_rb_erase+0x121/0x220 do_munmap+0x245/0x420 vm_munmap+0x41/0x60 SyS_munmap+0x22/0x30 tracesys+0xdd/0xe2 Signed-off-by:
Arun Easi <arun.easi@cavium.com> Signed-off-by:
Manish Rangankar <manish.rangankar@cavium.com> Signed-off-by:
Martin K. Petersen <martin.petersen@oracle.com>
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