reactor: Always retry waitpid #152
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A possible issue with how Docker Desktop v4.34+ (particulary on macOS) handles `pidfd` functionality causes an assertion failure in Seastar's `reactor::waitpid` method. The issue: - Seastar creates a `pidfd` using `pidfd_open` - It polls this file descriptor until it becomes readable - When readable, call `waitpid` with `WNOHANG`. According to [pidfd_open](https://man7.org/linux/man-pages/man2/pidfd_open.2.html), the file descriptor becomes readable when the process terminates - Seastar expects `waitpid` to either return a positive integer representing the child process that has ended or a negative value to indicate an error. However if `waitpid` returns `0`, then Seastar asserts, crashing the using application. This change introduces retry logic when using a `pidfd` and removes the assertion. Signed-off-by: Michael Boquard <[email protected]>
michael-redpanda
requested review from
pgellert,
BenPope,
oleiman,
IoannisRP and
StephanDollberg
and removed request for
a team
Which kernel version is this using under the hood? |
|
pgellert
approved these changes
Nov 11, 2024
4 tasks
|
Upstream merged: scylladb#2531 |
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A possible issue with how Docker Desktop v4.34+ (particulary on macOS) handles
pidfdfunctionality causes an assertion failure in Seastar'sreactor::waitpidmethod.The issue:
pidfdusingpidfd_openwaitpidwithWNOHANG. According to pidfd_open, the file descriptor becomes readable when the process terminateswaitpidto either return a positive integer representing the child process that has ended or a negative value to indicate an error. However ifwaitpidreturns0, then Seastar asserts, crashing the using application.This change introduces retry logic when using a
pidfdand removes the assertion.