Spurious check in the sssd nss memcache can cause the memory cache to be skipped

[sssd-bot]

Cloned from Pagure issue: https://pagure.io/SSSD/sssd/issue/3776

• Created at 2018-07-20 12:03:31 by jhrozek
• Closed at 2018-08-02 12:53:10 as Fixed
• Assigned to nobody
• Associated bugzillas
  • https://bugzilla.redhat.com/show_bug.cgi?id=1586127

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Ticket was cloned from Red Hat Bugzilla: Bug 1586127

Please note that this Bug is private and may not be accessible as it contains confidential Red Hat customer information.

Ticket was cloned from Red Hat Bugzilla: Bug 1586127

Please note that this Bug is private and may not be accessible as it contains confidential Red Hat customer information.

There is a check in the memory cache code that checks if a record pointer points to the mmapped region . But since some time ago, we return not a pointer to the mmapped region itself, but a copy to avoid issues with invalidating an entry while the same entry is being returned.

In most cases, the check is correct, simply because of how memory is laid out on Linux, but in some cases the check was failing and causing a high load of SSSD.

Comments

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Comment from jhrozek at 2018-07-20 12:03:33

Metadata Update from @jhrozek:

• Custom field rhbz adjusted to https://bugzilla.redhat.com/show_bug.cgi?id=1586127

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Comment from jhrozek at 2018-07-20 17:33:55

PR: #622

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Comment from jhrozek at 2018-07-20 17:33:56

Metadata Update from @jhrozek:

• Issue tagged with: PR, bug

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Comment from jhrozek at 2018-07-30 22:18:16

• master: f1c2d41

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Comment from jhrozek at 2018-08-02 12:53:13

Metadata Update from @jhrozek:

• Issue close_status updated to: Fixed
• Issue status updated to: Closed (was: Open)