mirror of
https://github.com/hardkernel/linux.git
synced 2026-03-25 03:50:24 +09:00
e2a2d6c9ac
commit175e476b8cupstream. When a new table value was assigned, it was followed by a write memory barrier. This ensured that all writes before this point would complete before any writes after this point. However, to determine whether the rules are unused, the sequence counter is read. To ensure that all writes have been done before these reads, a full memory barrier is needed, not just a write memory barrier. The same argument applies when incrementing the counter, before the rules are read. Changing to using smp_mb() instead of smp_wmb() fixes the kernel panic reported incc00bcaa58(which is still present), while still maintaining the same speed of replacing tables. The smb_mb() barriers potentially slow the packet path, however testing has shown no measurable change in performance on a 4-core MIPS64 platform. Fixes:7f5c6d4f66("netfilter: get rid of atomic ops in fast path") Signed-off-by: Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> [Ported to stable, affected barrier is added byd3d40f2374in mainline] Signed-off-by: Pavel Machek (CIP) <pavel@denx.de> Signed-off-by: Nobuhiro Iwamatsu (CIP) <nobuhiro1.iwamatsu@toshiba.co.jp> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>