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| author | Eric Dumazet <edumazet@google.com> | 2012-07-29 23:20:37 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-07-30 14:53:22 -0700 |
| commit | 404e0a8b6a55d5e1cd138c6deb1bca9abdf75d8c (patch) | |
| tree | 38e9748d38c415cc97b973fecb9279cd43f76393 /block | |
| parent | cca32e4bf999a34ac08d959f351f2b30bcd02460 (diff) | |
| download | linux-404e0a8b6a55d5e1cd138c6deb1bca9abdf75d8c.tar.bz2 | |
net: ipv4: fix RCU races on dst refcounts
commit c6cffba4ffa2 (ipv4: Fix input route performance regression.)
added various fatal races with dst refcounts.
crashes happen on tcp workloads if routes are added/deleted at the same
time.
The dst_free() calls from free_fib_info_rcu() are clearly racy.
We need instead regular dst refcounting (dst_release()) and make
sure dst_release() is aware of RCU grace periods :
Add DST_RCU_FREE flag so that dst_release() respects an RCU grace period
before dst destruction for cached dst
Introduce a new inet_sk_rx_dst_set() helper, using atomic_inc_not_zero()
to make sure we dont increase a zero refcount (On a dst currently
waiting an rcu grace period before destruction)
rt_cache_route() must take a reference on the new cached route, and
release it if was not able to install it.
With this patch, my machines survive various benchmarks.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'block')
0 files changed, 0 insertions, 0 deletions