From: Peter Oskolkov <posk@google.com> stable inclusion from stable-v4.19.304 commit 47468fae2704151503214f4d4327c164118247fd category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I90HST Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit 22c2ad616b74f3de2256b242572ab449d031d941 upstream. In some testing scenarios, dst/route cache can fill up so quickly that even an explicit GC call occasionally fails to clean it up. This leads to sporadically failing calls to dst_alloc and "network unreachable" errors to the user, which is confusing. This patch adds a diagnostic message to make the cause of the failure easier to determine. Signed-off-by: Peter Oskolkov <posk@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Suraj Jitindar Singh <surajjs@amazon.com> Cc: <stable@vger.kernel.org> # 4.19.x Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Dong Chenchen <dongchenchen2@huawei.com> --- net/core/dst.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/net/core/dst.c b/net/core/dst.c index 81ccf20e2826..a263309df115 100644 --- a/net/core/dst.c +++ b/net/core/dst.c @@ -98,8 +98,12 @@ void *dst_alloc(struct dst_ops *ops, struct net_device *dev, struct dst_entry *dst; if (ops->gc && dst_entries_get_fast(ops) > ops->gc_thresh) { - if (ops->gc(ops)) + if (ops->gc(ops)) { + printk_ratelimited(KERN_NOTICE "Route cache is full: " + "consider increasing sysctl " + "net.ipv[4|6].route.max_size.\n"); return NULL; + } } dst = kmem_cache_alloc(ops->kmem_cachep, GFP_ATOMIC); -- 2.25.1