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authorClemens Ladisch <clemens@ladisch.de>2011-06-21 22:09:50 +0200
committerGreg Kroah-Hartman <gregkh@suse.de>2011-08-17 10:55:53 -0700
commit2366d7cc46e70064f33be79dc415b069d3122772 (patch)
treea6d2655cd014bb268cdcba7bf6032df8f2970d52 /Documentation
parenta4e0b4cc115c938f75ca7cf24b0a739da846a6c7 (diff)
mm: fix wrong vmap address calculations with odd NR_CPUS values
commit f982f91516fa4cfd9d20518833cd04ad714585be upstream. Commit db64fe02258f ("mm: rewrite vmap layer") introduced code that does address calculations under the assumption that VMAP_BLOCK_SIZE is a power of two. However, this might not be true if CONFIG_NR_CPUS is not set to a power of two. Wrong vmap_block index/offset values could lead to memory corruption. However, this has never been observed in practice (or never been diagnosed correctly); what caught this was the BUG_ON in vb_alloc() that checks for inconsistent vmap_block indices. To fix this, ensure that VMAP_BLOCK_SIZE always is a power of two. BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=31572 Reported-by: Pavel Kysilka <goldenfish@linuxsoft.cz> Reported-by: Matias A. Fonzo <selk@dragora.org> Signed-off-by: Clemens Ladisch <clemens@ladisch.de> Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> Cc: Nick Piggin <npiggin@suse.de> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Krzysztof Helt <krzysztof.h1@poczta.fm> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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