* [PATCH net/next] net: ipconfig: Avoid spurious blank lines in boot log
@ 2020-11-10 7:37 Thierry Reding
2020-11-12 22:55 ` Jakub Kicinski
0 siblings, 1 reply; 2+ messages in thread
From: Thierry Reding @ 2020-11-10 7:37 UTC (permalink / raw)
To: David S . Miller, Alexey Kuznetsov, Hideaki YOSHIFUJI
Cc: Jakub Kicinski, netdev, linux-kernel, Jon Hunter
From: Thierry Reding <treding@nvidia.com>
When dumping the name and NTP servers advertised by DHCP, a blank line
is emitted if either of the lists is empty. This can lead to confusing
issues such as the blank line getting flagged as warning. This happens
because the blank line is the result of pr_cont("\n") and that may see
its level corrupted by some other driver concurrently writing to the
console.
Fix this by making sure that the terminating newline is only emitted
if at least one entry in the lists was printed before.
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
---
net/ipv4/ipconfig.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/net/ipv4/ipconfig.c b/net/ipv4/ipconfig.c
index 561f15b5a944..3cd13e1bc6a7 100644
--- a/net/ipv4/ipconfig.c
+++ b/net/ipv4/ipconfig.c
@@ -1441,7 +1441,7 @@ static int __init ip_auto_config(void)
int retries = CONF_OPEN_RETRIES;
#endif
int err;
- unsigned int i;
+ unsigned int i, count;
/* Initialise all name servers and NTP servers to NONE (but only if the
* "ip=" or "nfsaddrs=" kernel command line parameters weren't decoded,
@@ -1575,7 +1575,7 @@ static int __init ip_auto_config(void)
if (ic_dev_mtu)
pr_cont(", mtu=%d", ic_dev_mtu);
/* Name servers (if any): */
- for (i = 0; i < CONF_NAMESERVERS_MAX; i++) {
+ for (i = 0, count = 0; i < CONF_NAMESERVERS_MAX; i++) {
if (ic_nameservers[i] != NONE) {
if (i == 0)
pr_info(" nameserver%u=%pI4",
@@ -1583,12 +1583,14 @@ static int __init ip_auto_config(void)
else
pr_cont(", nameserver%u=%pI4",
i, &ic_nameservers[i]);
+
+ count++;
}
- if (i + 1 == CONF_NAMESERVERS_MAX)
+ if ((i + 1 == CONF_NAMESERVERS_MAX) && count > 0)
pr_cont("\n");
}
/* NTP servers (if any): */
- for (i = 0; i < CONF_NTP_SERVERS_MAX; i++) {
+ for (i = 0, count = 0; i < CONF_NTP_SERVERS_MAX; i++) {
if (ic_ntp_servers[i] != NONE) {
if (i == 0)
pr_info(" ntpserver%u=%pI4",
@@ -1596,8 +1598,10 @@ static int __init ip_auto_config(void)
else
pr_cont(", ntpserver%u=%pI4",
i, &ic_ntp_servers[i]);
+
+ count++;
}
- if (i + 1 == CONF_NTP_SERVERS_MAX)
+ if ((i + 1 == CONF_NTP_SERVERS_MAX) && count > 0)
pr_cont("\n");
}
#endif /* !SILENT */
--
2.29.2
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH net/next] net: ipconfig: Avoid spurious blank lines in boot log
2020-11-10 7:37 [PATCH net/next] net: ipconfig: Avoid spurious blank lines in boot log Thierry Reding
@ 2020-11-12 22:55 ` Jakub Kicinski
0 siblings, 0 replies; 2+ messages in thread
From: Jakub Kicinski @ 2020-11-12 22:55 UTC (permalink / raw)
To: Thierry Reding
Cc: David S . Miller, Alexey Kuznetsov, Hideaki YOSHIFUJI, netdev,
linux-kernel, Jon Hunter
On Tue, 10 Nov 2020 08:37:57 +0100 Thierry Reding wrote:
> From: Thierry Reding <treding@nvidia.com>
>
> When dumping the name and NTP servers advertised by DHCP, a blank line
> is emitted if either of the lists is empty. This can lead to confusing
> issues such as the blank line getting flagged as warning. This happens
> because the blank line is the result of pr_cont("\n") and that may see
> its level corrupted by some other driver concurrently writing to the
> console.
>
> Fix this by making sure that the terminating newline is only emitted
> if at least one entry in the lists was printed before.
>
> Reported-by: Jon Hunter <jonathanh@nvidia.com>
> Signed-off-by: Thierry Reding <treding@nvidia.com>
Applied, thanks!
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