When hmm_vma_walk_test() skips a VMA (e.g., unsupported VM_IO/PFNMAP range), it must update hmm_vma_walk->last to the end of the skipped VMA. Failing to do so causes hmm_range_fault() to restart from the same address during -EBUSY retries, reprocessing the skipped VMA indefinitely. This results in an infinite loop if the VMA remains non-processable. Update hmm_vma_walk->last to the VMA's end address in hmm_vma_walk_test() when skipping the range. This ensures subsequent iterations resume correctly after the skipped VMA, preventing infinite retry loops. Signed-off-by: sooraj <sooraj20636@xxxxxxxxx> --- mm/hmm.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/hmm.c b/mm/hmm.c index 7e0229ae4a5a..29e3678fede5 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -547,6 +547,8 @@ static int hmm_vma_walk_test(unsigned long start, unsigned long end, hmm_pfns_fill(start, end, range, HMM_PFN_ERROR); + /* Update last to the end of the skipped VMA to prevent reprocessing */ + hmm_vma_walk->last = end; /* Skip this vma and continue processing the next vma. */ return 1; } -- 2.45.2
