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Filename Latest commit message Latest commit date
Ilya Maximets b5c73fc92f openvswitch: fix lockup on tx to unregistering netdev with carrier
commit 47e55e4b410f7d552e43011baa5be1aab4093990 upstream.

Commit in a fixes tag attempted to fix the issue in the following
sequence of calls:

    do_output
    -> ovs_vport_send
       -> dev_queue_xmit
          -> __dev_queue_xmit
             -> netdev_core_pick_tx
                -> skb_tx_hash

When device is unregistering, the 'dev->real_num_tx_queues' goes to
zero and the 'while (unlikely(hash >= qcount))' loop inside the
'skb_tx_hash' becomes infinite, locking up the core forever.

But unfortunately, checking just the carrier status is not enough to
fix the issue, because some devices may still be in unregistering
state while reporting carrier status OK.

One example of such device is a net/dummy.  It sets carrier ON
on start, but it doesn't implement .ndo_stop to set the carrier off.
And it makes sense, because dummy doesn't really have a carrier.
Therefore, while this device is unregistering, it's still easy to hit
the infinite loop in the skb_tx_hash() from the OVS datapath.  There
might be other drivers that do the same, but dummy by itself is
important for the OVS ecosystem, because it is frequently used as a
packet sink for tcpdump while debugging OVS deployments.  And when the
issue is hit, the only way to recover is to reboot.

Fix that by also checking if the device is running.  The running
state is handled by the net core during unregistering, so it covers
unregistering case better, and we don't really need to send packets
to devices that are not running anyway.

While only checking the running state might be enough, the carrier
check is preserved.  The running and the carrier states seem disjoined
throughout the code and different drivers.  And other core functions
like __dev_direct_xmit() check both before attempting to transmit
a packet.  So, it seems safer to check both flags in OVS as well.

Fixes: 066b86787fa3 ("net: openvswitch: fix race on port output")
Reported-by: Friedrich Weber <f.weber@proxmox.com>
Closes: https://mail.openvswitch.org/pipermail/ovs-discuss/2025-January/053423.html
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Tested-by: Friedrich Weber <f.weber@proxmox.com>
Reviewed-by: Aaron Conole <aconole@redhat.com>
Link: https://patch.msgid.link/20250109122225.4034688-1-i.maximets@ovn.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Carlos Soto <carlos.soto@broadcom.com>
Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-05-02 07:39:23 +02:00
arch powerpc/prom_init: Use -ffreestanding to avoid a reference to bcmp 2025-05-02 07:39:22 +02:00
block block: fix 'kmem_cache of name 'bio-108' already exists' 2025-04-10 14:29:37 +02:00
certs
crypto crypto: testmgr - some more fixes to RSA test vectors 2025-03-13 12:43:21 +01:00
Documentation sched/isolation: Prevent boot crash when the boot CPU is nohz_full 2025-04-10 14:29:35 +02:00
drivers mmc: cqhci: Fix checking of CQHCI_HALT state 2025-05-02 07:39:22 +02:00
fs virtiofs: add filesystem context source name check 2025-05-02 07:39:21 +02:00
include nfs: add missing selections of CONFIG_CRC32 2025-05-02 07:39:20 +02:00
init module: sign with sha512 instead of sha1 by default 2025-05-02 07:39:21 +02:00
ipc
kernel ftrace: Add cond_resched() to ftrace_graph_set_hash() 2025-05-02 07:39:17 +02:00
lib lib: scatterlist: fix sg_split_phys to preserve original scatterlist offsets 2025-05-02 07:39:15 +02:00
LICENSES
mm mm: add missing release barrier on PGDAT_RECLAIM_LOCKED unlock 2025-05-02 07:39:16 +02:00
net openvswitch: fix lockup on tx to unregistering netdev with carrier 2025-05-02 07:39:23 +02:00
samples samples/bpf: Fix a resource leak 2024-12-14 19:44:50 +01:00
scripts selinux: Chain up tool resolving errors in install_policy.sh 2025-04-10 14:29:39 +02:00
security ima: Fix use-after-free on a dentry's dname.name 2025-03-13 12:43:19 +01:00
sound ALSA: usb-audio: Fix CME quirk for UF series keyboards 2025-05-02 07:39:10 +02:00
tools pm: cpupower: bench: Prevent NULL dereference on malloc failure 2025-05-02 07:39:09 +02:00
usr
virt KVM: arm64: Ignore PMCNTENSET_EL0 while checking for overflow status 2024-12-19 18:05:04 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore Remove *.orig pattern from .gitignore 2024-11-08 16:20:33 +01:00
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile kbuild: Add '-fno-builtin-wcslen' 2025-05-02 07:39:22 +02:00
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