* Two VM problems for the 2.4 TODO list
@ 2000-09-04 16:07 Stephen C. Tweedie
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From: Stephen C. Tweedie @ 2000-09-04 16:07 UTC (permalink / raw)
To: Theodore Ts'o; +Cc: Stephen Tweedie, linux-kernel
Hi Ted,
To be fixed for 2.4:
1) Non-atomic pte updates
The page aging code and mprotect both modify existing ptes
non-atomically. That can stomp on the VM hardware on other CPUs
setting the dirty bit on mmaped pages when using threads. 2.2 is
vulnerable too.
2) RSS locking
swapout holds the page_table_lock while swapping, and adjusts the
mm->rss while holding that lock. Other places in the mm are not
so careful about holding the lock, so rss (which is not an
atomic_t) can be corrupted.
--Stephen
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2000-09-04 16:07 Two VM problems for the 2.4 TODO list Stephen C. Tweedie
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