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authorHelge Deller <deller@kernel.org>2024-01-26 09:32:20 +0100
committerPaolo Abeni <pabeni@redhat.com>2024-01-30 12:43:18 +0100
commit60365049ccbacd101654a66ddcb299abfabd4fc5 (patch)
tree188301b262de1c2f1de58202bae8511012b3fcc9 /net
parent59c93583491ab15db109f9902524d241c4fa4c0b (diff)
ipv6: Ensure natural alignment of const ipv6 loopback and router addresses
On a parisc64 kernel I sometimes notice this kernel warning: Kernel unaligned access to 0x40ff8814 at ndisc_send_skb+0xc0/0x4d8 The address 0x40ff8814 points to the in6addr_linklocal_allrouters variable and the warning simply means that some ipv6 function tries to read a 64-bit word directly from the not-64-bit aligned in6addr_linklocal_allrouters variable. Unaligned accesses are non-critical as the architecture or exception handlers usually will fix it up at runtime. Nevertheless it may trigger a performance penality for some architectures. For details read the "unaligned-memory-access" kernel documentation. The patch below ensures that the ipv6 loopback and router addresses will always be naturally aligned. This prevents the unaligned accesses for all architectures. Signed-off-by: Helge Deller <deller@gmx.de> Fixes: 034dfc5df99eb ("ipv6: export in6addr_loopback to modules") Acked-by: Paolo Abeni <pabeni@redhat.com> Link: https://lore.kernel.org/r/ZbNuFM1bFqoH-UoY@p100 Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'net')
-rw-r--r--net/ipv6/addrconf_core.c21
1 files changed, 14 insertions, 7 deletions
diff --git a/net/ipv6/addrconf_core.c b/net/ipv6/addrconf_core.c
index 507a8353a6bd..c008d21925d7 100644
--- a/net/ipv6/addrconf_core.c
+++ b/net/ipv6/addrconf_core.c
@@ -220,19 +220,26 @@ const struct ipv6_stub *ipv6_stub __read_mostly = &(struct ipv6_stub) {
EXPORT_SYMBOL_GPL(ipv6_stub);
/* IPv6 Wildcard Address and Loopback Address defined by RFC2553 */
-const struct in6_addr in6addr_loopback = IN6ADDR_LOOPBACK_INIT;
+const struct in6_addr in6addr_loopback __aligned(BITS_PER_LONG/8)
+ = IN6ADDR_LOOPBACK_INIT;
EXPORT_SYMBOL(in6addr_loopback);
-const struct in6_addr in6addr_any = IN6ADDR_ANY_INIT;
+const struct in6_addr in6addr_any __aligned(BITS_PER_LONG/8)
+ = IN6ADDR_ANY_INIT;
EXPORT_SYMBOL(in6addr_any);
-const struct in6_addr in6addr_linklocal_allnodes = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
+const struct in6_addr in6addr_linklocal_allnodes __aligned(BITS_PER_LONG/8)
+ = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
EXPORT_SYMBOL(in6addr_linklocal_allnodes);
-const struct in6_addr in6addr_linklocal_allrouters = IN6ADDR_LINKLOCAL_ALLROUTERS_INIT;
+const struct in6_addr in6addr_linklocal_allrouters __aligned(BITS_PER_LONG/8)
+ = IN6ADDR_LINKLOCAL_ALLROUTERS_INIT;
EXPORT_SYMBOL(in6addr_linklocal_allrouters);
-const struct in6_addr in6addr_interfacelocal_allnodes = IN6ADDR_INTERFACELOCAL_ALLNODES_INIT;
+const struct in6_addr in6addr_interfacelocal_allnodes __aligned(BITS_PER_LONG/8)
+ = IN6ADDR_INTERFACELOCAL_ALLNODES_INIT;
EXPORT_SYMBOL(in6addr_interfacelocal_allnodes);
-const struct in6_addr in6addr_interfacelocal_allrouters = IN6ADDR_INTERFACELOCAL_ALLROUTERS_INIT;
+const struct in6_addr in6addr_interfacelocal_allrouters __aligned(BITS_PER_LONG/8)
+ = IN6ADDR_INTERFACELOCAL_ALLROUTERS_INIT;
EXPORT_SYMBOL(in6addr_interfacelocal_allrouters);
-const struct in6_addr in6addr_sitelocal_allrouters = IN6ADDR_SITELOCAL_ALLROUTERS_INIT;
+const struct in6_addr in6addr_sitelocal_allrouters __aligned(BITS_PER_LONG/8)
+ = IN6ADDR_SITELOCAL_ALLROUTERS_INIT;
EXPORT_SYMBOL(in6addr_sitelocal_allrouters);
static void snmp6_free_dev(struct inet6_dev *idev)