[1.0] fix logging race in nsexec (regression in rc94) #3130
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kolyshkin
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AkihiroSuda
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Aug 5, 2021
AkihiroSuda
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Aug 11, 2021
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Let me mark this as a draft until getting #3120 merged |
As reported in issue 3119, there is a race in nsexec logging that can lead to garbled json received by log forwarder, which complains about it with a "failed to decode" error. This happens because dprintf (used since the very beginning of nsexec logging introduced in commit ba3cabf) relies on multiple write(2) calls, and with additional logging added by 64bb59f a race is possible between runc init parent and its children. The fix is to prepare a string and write it using a single call to write(2). [v2: NULLify json on error from asprintf] Signed-off-by: Kir Kolyshkin <[email protected]> (cherry picked from commit 2bab4a5) Signed-off-by: Kir Kolyshkin <[email protected]>
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#3120 is merged; no longer a draft. |
AkihiroSuda
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mrunalp
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This is a backport of #3120 to release-1.0 branch,
fixing rare
but criticalissue #3119. Update: this is not critical -- the effect is we lost onedebug log entry, and get a weird error in runc logs.
As reported in issue #3119, there is a race in nsexec logging
that can lead to garbled json received by log forwarder, which
complains about it with a "failed to decode" error.
This happens because dprintf (used since the very beginning of nsexec
logging introduced in commit ba3cabf) relies on multiple write(2)
calls, and with additional logging added by 64bb59f (appeared in rc94)
a race is possible between runc init parent and its children.
The fix is to prepare a string and write it using a single call to
write(2).
Signed-off-by: Kir Kolyshkin [email protected]
(cherry picked from commit fb6ba04)
Signed-off-by: Kir Kolyshkin [email protected]