Core dump in MythUIButtonList::GetItemCurrent

[faginbagin <mythtv@…>]

I think this line (~1564) in MythUIButtonList::GetItemCurrent?():

    if (m_itemList.isEmpty() || m_selPosition > m_itemList.size() ||

should be changed to:

    if (m_itemList.isEmpty() || m_selPosition >= m_itemList.size() ||

to prevent a core dump like the one I saw. See attached stack trace, in particular thread 1 where the Qt library throws an assertion when a couple of lines later, an attempt is made to fetch the item at position 2 (the third item). Examination of m_itemList shows it has a size of 2.

Looking back at the logs, it appears mythfrontend was coming out of playback mode and there had been a decoding error. I think another frontend had deleted another recording of the same series shortly before that time. Perhaps that's a clue to reproducing the crash?

[faginbagin <mythtv@…>]

full stack trace

[faginbagin <mythtv@…>]

log entries from the time up to the core dump

[faginbagin <mythtv@…>]

FYI, it happened again, this time on a different frontend, and again, a second frontend had recently deleted an episode of the same series the first frontend was playing, but not the episode being played on the first front end. I tried to reproduce it, but couldn't. Must require split second timing. I think this scenario might reproduce it. Given two front ends, FE1 and FE2:

• display the same series in both FE1 and FE2.
• On FE1, start playing the last episode. Advance to 1 minute from end.
• On FE2, start playing the first episode. Delete episode.
• On FE1, advance to end.

[Stuart Morgan <smorgan@…>]

In 4211abf7d62b9e15a61731bd1ae19400302c92ff/mythtv:

Fix segfault in MythUIButtonList::GetItemCurrent?(). Fixes #12040

[Stuart Morgan <smorgan@…>]

In 4ee21a4ca0c6f85e6c6b5f55cb3bbc5b623a5e14/mythtv:

Fix segfault in MythUIButtonList::GetItemCurrent?(). Fixes #12040
(cherry picked from commit 4211abf7d62b9e15a61731bd1ae19400302c92ff)

[Stuart Morgan <smorgan@…>]

In 6955690ffba711103bbd510de47ef6fe84f7c08c/mythtv:

Fix segfault in MythUIButtonList::GetItemCurrent?(). Fixes #12040
(cherry picked from commit 4211abf7d62b9e15a61731bd1ae19400302c92ff)