[PATCH AUTOSEL 4.19 24/87] net: ipconfig: Avoid spurious blank lines in boot log
From: Sasha Levin <sashal@kernel.org>
Date: 2020-12-23 02:22:17
Also in:
lkml, stable
Subsystem:
networking [general], networking [ipv4/ipv6], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Ahern, Ido Schimmel, Linus Torvalds
From: Thierry Reding <redacted>
[ Upstream commit c9f64d1fc101c64ea2be1b2e562b4395127befc9 ]
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 <redacted>
Link: https://lore.kernel.org/r/20201110073757.1284594-1-thierry.reding@gmail.com (local)
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 88212615bf4ce..812c69fb8e773 100644
--- a/net/ipv4/ipconfig.c
+++ b/net/ipv4/ipconfig.c@@ -1445,7 +1445,7 @@ 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,
@@ -1573,7 +1573,7 @@ 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",
@@ -1581,12 +1581,14 @@ 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",
@@ -1594,8 +1596,10 @@ 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 */
--
2.27.0