4.18-stable review patch. If anyone has any objections, please let me know.
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From: Jeff Barnhill 0xeffeff@gmail.com
[ Upstream commit 86f9bd1ff61c413a2a251fa736463295e4e24733 ]
The backend handling for /proc/net/if_inet6 in addrconf.c doesn't properly handle starting/stopping the iteration. The problem is that at some point during the iteration, an overflow is detected and the process is subsequently stopped. The item being shown via seq_printf() when the overflow occurs is not actually shown, though. When start() is subsequently called to resume iterating, it returns the next item, and thus the item that was being processed when the overflow occurred never gets printed.
Alter the meaning of the private data member "offset". Currently, when it is not 0 (which only happens at the very beginning), "offset" represents the next hlist item to be printed. After this change, "offset" always represents the current item.
This is also consistent with the private data member "bucket", which represents the current bucket, and also the use of "pos" as defined in seq_file.txt: The pos passed to start() will always be either zero, or the most recent pos used in the previous session.
Signed-off-by: Jeff Barnhill 0xeffeff@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv6/addrconf.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)
--- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -4203,7 +4203,6 @@ static struct inet6_ifaddr *if6_get_firs p++; continue; } - state->offset++; return ifa; }
@@ -4227,13 +4226,12 @@ static struct inet6_ifaddr *if6_get_next return ifa; }
+ state->offset = 0; while (++state->bucket < IN6_ADDR_HSIZE) { - state->offset = 0; hlist_for_each_entry_rcu(ifa, &inet6_addr_lst[state->bucket], addr_lst) { if (!net_eq(dev_net(ifa->idev->dev), net)) continue; - state->offset++; return ifa; } }