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| author | Dmitry Vyukov <dvyukov@google.com> | 2021-03-23 07:49:23 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2021-03-23 17:22:50 -0700 |
| commit | 5aa3afe107d9099fc0dea2acf82c3e3c8f0f20e2 (patch) | |
| tree | 03a69b161a77f895e1c47c6c0f46eb617207181a /net | |
| parent | 4c94fe88cde4bb5c8e1baa01106c4e6db1c75738 (diff) | |
| download | linux-5aa3afe107d9099fc0dea2acf82c3e3c8f0f20e2.tar.bz2 | |
net: make unregister netdev warning timeout configurable
netdev_wait_allrefs() issues a warning if refcount does not drop to 0
after 10 seconds. While 10 second wait generally should not happen
under normal workload in normal environment, it seems to fire falsely
very often during fuzzing and/or in qemu emulation (~10x slower).
At least it's not possible to understand if it's really a false
positive or not. Automated testing generally bumps all timeouts
to very high values to avoid flake failures.
Add net.core.netdev_unregister_timeout_secs sysctl to make
the timeout configurable for automated testing systems.
Lowering the timeout may also be useful for e.g. manual bisection.
The default value matches the current behavior.
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=211877
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/dev.c | 6 | ||||
| -rw-r--r-- | net/core/sysctl_net_core.c | 10 |
2 files changed, 15 insertions, 1 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index c9a496f5e687..515309573cb8 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -10322,6 +10322,8 @@ int netdev_refcnt_read(const struct net_device *dev) } EXPORT_SYMBOL(netdev_refcnt_read); +int netdev_unregister_timeout_secs __read_mostly = 10; + #define WAIT_REFS_MIN_MSECS 1 #define WAIT_REFS_MAX_MSECS 250 /** @@ -10383,7 +10385,9 @@ static void netdev_wait_allrefs(struct net_device *dev) refcnt = netdev_refcnt_read(dev); - if (refcnt != 1 && time_after(jiffies, warning_time + 10 * HZ)) { + if (refcnt && + time_after(jiffies, warning_time + + netdev_unregister_timeout_secs * HZ)) { pr_emerg("unregister_netdevice: waiting for %s to become free. Usage count = %d\n", dev->name, refcnt); warning_time = jiffies; diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c index 4567de519603..d84c8a1b280e 100644 --- a/net/core/sysctl_net_core.c +++ b/net/core/sysctl_net_core.c @@ -24,6 +24,7 @@ static int two = 2; static int three = 3; +static int int_3600 = 3600; static int min_sndbuf = SOCK_MIN_SNDBUF; static int min_rcvbuf = SOCK_MIN_RCVBUF; static int max_skb_frags = MAX_SKB_FRAGS; @@ -570,6 +571,15 @@ static struct ctl_table net_core_table[] = { .proc_handler = proc_dointvec_minmax, .extra1 = SYSCTL_ONE, }, + { + .procname = "netdev_unregister_timeout_secs", + .data = &netdev_unregister_timeout_secs, + .maxlen = sizeof(unsigned int), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = SYSCTL_ZERO, + .extra2 = &int_3600, + }, { } }; |