Antoine Tenart b3aa4e54ad net-sysfs: try not to restart the syscall if it will fail eventually ... [ Upstream commit 146e5e7333 ] Due to deadlocks in the networking subsystem spotted 12 years ago[1], a workaround was put in place[2] to avoid taking the rtnl lock when it was not available and restarting the syscall (back to VFS, letting userspace spin). The following construction is found a lot in the net sysfs and sysctl code: if (!rtnl_trylock()) return restart_syscall(); This can be problematic when multiple userspace threads use such interfaces in a short period, making them to spin a lot. This happens for example when adding and moving virtual interfaces: userspace programs listening on events, such as systemd-udevd and NetworkManager, do trigger actions reading files in sysfs. It gets worse when a lot of virtual interfaces are created concurrently, say when creating containers at boot time. Returning early without hitting the above pattern when the syscall will fail eventually does make things better. While it is not a fix for the issue, it does ease things. [1] https://lore.kernel.org/netdev/49A4D5D5.5090602@trash.net/ https://lore.kernel.org/netdev/m14oyhis31.fsf@fess.ebiederm.org/ and https://lore.kernel.org/netdev/20090226084924.16cb3e08@nehalam/ [2] Rightfully, those deadlocks are *hard* to solve. Signed-off-by: Antoine Tenart <atenart@kernel.org> Reviewed-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>		2021-11-18 19:16:14 +01:00
..
6lowpan	6lowpan: iphc: Fix an off-by-one check of array index	2021-07-22 16:19:03 +02:00
9p	net/9p: increase default msize to 128k	2021-09-05 08:36:44 +09:00
802	net: 802: remove dead leftover after ipx driver removal	2021-08-13 16:30:35 -07:00
8021q	dev_ioctl: split out ndo_eth_ioctl	2021-07-27 20:11:45 +01:00
appletalk	net: socket: rework compat_ifreq_ioctl()	2021-07-23 14:20:25 +01:00
atm	atm: Use list_for_each_entry() to simplify code in resources.c	2021-06-10 14:08:09 -07:00
ax25	ax25: use skb_expand_head	2021-08-03 11:21:39 +01:00
batman-adv	net: batman-adv: fix error handling	2021-10-26 14:47:12 +01:00
bluetooth	Bluetooth: call sock_hold earlier in sco_conn_del	2021-11-18 19:16:09 +01:00
bpf	bpf, test, cgroup: Use sk_{alloc,free} for test cases	2021-09-28 09:29:28 +02:00
bpfilter	bpfilter: Specify the log level for the kmsg message	2021-06-25 13:13:50 +02:00
bridge	Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf	2021-10-21 12:32:41 +01:00
caif	net-caif: avoid user-triggerable WARN_ON(1)	2021-09-14 12:51:15 +01:00
can	can: j1939: j1939_tp_cmd_recv(): check the dst address of TP.CM_BAM	2021-11-18 19:16:03 +01:00
ceph	Networking changes for 5.14.	2021-06-30 15:51:09 -07:00
core	net-sysfs: try not to restart the syscall if it will fail eventually	2021-11-18 19:16:14 +01:00
dcb	net: dcb: Return the correct errno code	2021-06-01 17:01:33 -07:00
dccp	dccp: don't duplicate ccid when cloning dccp sock	2021-09-08 11:28:35 +01:00
decnet	net: Remove redundant if statements	2021-08-05 13:27:50 +01:00
dns_resolver	net: remove redundant 'depends on NET'	2021-01-27 17:04:12 -08:00
dsa	net: dsa: Fix an error handling path in 'dsa_switch_parse_ports_of()'	2021-10-19 15:41:16 -07:00
ethernet	move netdev_boot_setup into Space.c	2021-08-03 13:05:26 +01:00
ethtool	ethtool: extend coalesce setting uAPI with CQE mode	2021-08-24 07:38:29 -07:00
hsr	net: hsr: don't check sequence number if tag removal is offloaded	2021-06-16 12:13:01 -07:00
ieee802154	Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net	2021-08-13 06:41:22 -07:00
ife	net: remove redundant 'depends on NET'	2021-01-27 17:04:12 -08:00
ipv4	net: Implement ->sock_is_readable() for UDP and AF_UNIX	2021-10-26 12:29:33 -07:00
ipv6	Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf	2021-10-21 12:32:41 +01:00
iucv	net/iucv: Replace deprecated CPU-hotplug functions.	2021-08-09 10:13:32 +01:00
kcm	net: sock: introduce sk_error_report	2021-06-29 11:28:21 -07:00
key	net: Remove unnecessary variables	2021-05-26 07:03:39 +02:00
l2tp	net/l2tp: Fix reference count leak in l2tp_udp_recv_core	2021-09-09 11:00:20 +01:00
l3mdev	l3mdev: Correct function names in the kerneldoc comments	2021-03-28 17:56:55 -07:00
lapb	net: lapb: Use list_for_each_entry() to simplify code in lapb_iface.c	2021-06-08 16:31:25 -07:00
llc	net: Remove redundant if statements	2021-08-05 13:27:50 +01:00
mac80211	mac80211: mesh: fix HE operation element length check	2021-10-01 11:02:24 +02:00
mac802154	ieee802154: Remove redundant initialization of variable ret	2021-09-07 14:06:08 +01:00
mctp	mctp: handle the struct sockaddr_mctp padding fields	2021-11-18 19:16:02 +01:00
mpls	mpls: defer ttl decrement in mpls_forward()	2021-07-23 17:17:56 +01:00
mptcp	mptcp: fix corrupt receiver key in MPC + data + checksum	2021-10-28 08:19:06 -07:00
ncsi	net/ncsi: add get MAC address command to get Intel i210 MAC address	2021-09-01 17:18:56 -07:00
netfilter	netfilter: ipvs: make global sysctl readonly in non-init netns	2021-10-14 23:08:35 +02:00
netlabel	net: fix NULL pointer reference in cipso_v4_doi_free	2021-08-30 12:23:18 +01:00
netlink	netlink: annotate data races around nlk->bound	2021-10-05 13:11:09 +01:00
netrom	net: Remove redundant if statements	2021-08-05 13:27:50 +01:00
nfc	NFC: digital: fix possible memory leak in digital_in_send_sdd_req()	2021-10-13 17:44:29 -07:00
nsh	…
openvswitch	Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net	2021-08-19 18:09:18 -07:00
packet	net/packet: clarify source of pr_*() messages	2021-09-10 10:00:59 +01:00
phonet	net: Remove redundant if statements	2021-08-05 13:27:50 +01:00
psample	psample: Add additional metadata attributes	2021-03-14 15:00:43 -07:00
qrtr	net: qrtr: revert check in qrtr_endpoint_post()	2021-09-02 11:37:02 +01:00
rds	net/rds: dma_map_sg is entitled to merge entries	2021-08-18 15:35:50 -07:00
rfkill	Another set of updates, all over the map:	2021-04-20 16:44:04 -07:00
rose	net: rose: Fix fall-through warnings for Clang	2021-03-10 12:45:15 -08:00
rxrpc	net: RxRPC: make dependent Kconfig symbols be shown indented	2021-08-18 10:12:11 +01:00
sched	net: sched: update default qdisc visibility after Tx queue cnt changes	2021-11-18 19:16:10 +01:00
sctp	sctp: add vtag check in sctp_sf_ootb	2021-10-22 12:36:45 -07:00
smc	net/smc: Correct spelling mistake to TCPF_SYN_RECV	2021-10-28 13:04:28 +01:00
strparser	net: sock: introduce sk_error_report	2021-06-29 11:28:21 -07:00
sunrpc	Bug fixes for NFSD error handling paths	2021-10-07 14:11:40 -07:00
switchdev	net: make switchdev_bridge_port_{,unoffload} loosely coupled with the bridge	2021-08-04 12:35:07 +01:00
tipc	tipc: fix size validations for the MSG_CRYPTO type	2021-10-26 13:43:07 +01:00
tls	net/tls: Fix flipped sign in async_wait.err assignment	2021-10-28 14:41:20 +01:00
unix	net: Implement ->sock_is_readable() for UDP and AF_UNIX	2021-10-26 12:29:33 -07:00
vmw_vsock	af_vsock: rename variables in receive loop	2021-09-06 02:25:16 -04:00
wireless	cfg80211: correct bridge/4addr mode check	2021-10-25 15:23:20 +02:00
x25	net: x25: Use list_for_each_entry() to simplify code in x25_route.c	2021-06-10 14:08:09 -07:00
xdp	Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net	2021-06-29 15:45:27 -07:00
xfrm	xfrm: fix rcu lock in xfrm_notify_userpolicy()	2021-09-23 10:11:12 +02:00
Kconfig	mctp: Add MCTP base	2021-07-29 15:06:49 +01:00
Makefile	mctp: Add MCTP base	2021-07-29 15:06:49 +01:00
compat.c	net: Return the correct errno code	2021-06-03 15:13:56 -07:00
devres.c	net: devres: Correct a grammatical error	2021-06-11 12:55:28 -07:00
socket.c	Core:	2021-08-31 16:43:06 -07:00
sysctl_net.c	net: Ensure net namespace isolation of sysctls	2021-04-12 13:27:11 -07:00