[PATCH] rmap bugfix, try_to_unmap

From: Rik van Riel (riel@conectiva.com.br)
Date: Mon Aug 12 2002 - 09:58:47 EST


Hi,

the following patch corrects a bug where rmap would continue
trying to swap out a page even after it failed on one pte,
which could result in leaked pte chains and a bug when exiting
applications which use mlock().

The bug was tracked down by Christian Ehrhardt, the reason
it wasn't found earlier was a subtlety in the code, so I've
taken the liberty of changing Christian's patch into something
more explicit, we shouldn't let this one happen again ;)

please apply,

Rik

-- 
Bravely reimplemented by the knights who say "NIH".

http://www.surriel.com/ http://distro.conectiva.com/

===== mm/rmap.c 1.7 vs edited ===== --- 1.7/mm/rmap.c Wed Jul 31 06:58:53 2002 +++ edited/mm/rmap.c Mon Aug 12 11:22:05 2002 @@ -328,7 +328,7 @@ case SWAP_SUCCESS: /* Free the pte_chain struct. */ pte_chain_free(pc, prev_pc, page); - break; + continue; case SWAP_AGAIN: /* Skip this pte, remembering status. */ prev_pc = pc; @@ -336,12 +336,13 @@ continue; case SWAP_FAIL: ret = SWAP_FAIL; - break; + goto give_up; case SWAP_ERROR: ret = SWAP_ERROR; - break; + goto give_up; } } +give_up: /* Check whether we can convert to direct pte pointer */ pc = page->pte.chain; if (pc && !pc->next) {

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