Fix netlink buffer overflow for concurrent TCMU#399
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liulanzheng merged 1 commit intocontainerd:mainfrom Apr 15, 2026
Merged
Fix netlink buffer overflow for concurrent TCMU#399liulanzheng merged 1 commit intocontainerd:mainfrom
liulanzheng merged 1 commit intocontainerd:mainfrom
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With default libnl3 buffer size (32kb) and NETLINK_S_CONGESTED flag, creating >50 TCMU devices in parallel causes kernel hangs and devices to never be set up. This is because the genlmsg_multicast_allns() notifications are silently dropped from a full buffer. This fix increases the buffer size and also prevents a single buffer-full event from poisoning subsequent deliveries into the buffer. See: containerd#398 for details Signed-off-by: Robert Landlord <robertlandlord1@gmail.com>
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liulanzheng
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Apr 15, 2026
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What this PR does / why we need it:
With default libnl3 buffer size (32kb) and NETLINK_S_CONGESTED flag, creating >50 TCMU devices in parallel causes kernel hangs and devices to never be set up. This is because the genlmsg_multicast_allns() notifications are silently dropped from a full buffer. This fix increases the buffer size and also prevents a single buffer-full event from poisoning subsequent deliveries into the buffer.
Which issue(s) this PR fixes (optional, in
fixes #<issue number>(, fixes #<issue_number>, ...)format, will close the issue(s) when PR gets merged):Fixes #398
Please check the following list: