2021-05-15 21:06:00 UTC: We're in read-only mode for probably ~30 minutes for a database migration. Join #lobsters on freenode or follow the todo list.

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    I like how the solution was to bump the culprit from 32bit to 64bit and avoid checking for overflow in the first place since it’s currently unimaginable that it would happen.

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      In a kernel with CONFIG_DEBUG_VM_VMACACHE=y, the bug can be observed after “around 40 minutes” according to the report in project zero’s bug tracker.

      After the change you need to increment the sequence number 2^32 times more often than before. This should raise the time to complete that demonstration to 2^32 * 40 / (60 * 24 * 365.25) or ~326,638 years.

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        I came here to quote “thereby making an overflow infeasible” with the same thought in mind; that said, 640K ought to be enough for anybody.

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          @kivikakk @johnLate and the best thing is is that it doesn’t even grow the data structures since the the adjacent fields were 64bits already[1]