inet: frag: don't re-use chainlist for evictor

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commit 65ba1f1ec0 ("inet: frags: fix a race between inet_evict_bucket
and inet_frag_kill") describes the bug, but the fix doesn't work reliably.

Problem is that ->flags member can be set on other cpu without chainlock
being held by that task, i.e. the RMW-Cycle can clear INET_FRAG_EVICTED
bit after we put the element on the evictor private list.

We can crash when walking the 'private' evictor list since an element can
be deleted from list underneath the evictor.

Join work with Nikolay Alexandrov.

Fixes: b13d3cbfb8 ("inet: frag: move eviction of queues to work queue")
Reported-by: Johan Schuijt <johan@transip.nl>
Tested-by: Frank Schreuder <fschreuder@transip.nl>
Signed-off-by: Nikolay Alexandrov <nikolay@cumulusnetworks.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

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This commit is contained in:

Florian Westphal 2015-07-23 12:05:37 +02:00 • committed by David S. Miller

parent 81296fc673

commit d1fe19444d

2 changed files with 5 additions and 5 deletions

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2

include/net/inet_frag.h

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8

net/ipv4/inet_fragment.c

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