Hi all! This is my first post on this list. Please pardon me if I overlooked or misunderstood some things. I had some imap crashes (sig11) starting at the end of 2019 after an upgrade of dovecot. I found out, that I didn't have any problems using version v2.3.8, but any version v2.3.9 and higher would trigger the crashes. After investigating more deeply and creating a core dump, I saw that the crash happened in an external plugin fetchmail_wakeup[1]. After recompiling that plugin with up to date dovecot headers, I didn't get crashes anymore. So I suspect there were ABI incompatible changes and it was forgotten to bump the minimum Plugin-ABI version supported. I could try to follow up some more details, but it would be quite a burden because of rebuilding the plugin with debug symbols against version 2.3.8 of dovecot and triggering the crash etc. Despite that I think it should be possible to detect changes that are ABI incompatible, as otherwise plugin users would always have to find out first hand with unknown consequences. That said there could be a possibility of the plugin using the API/ABI in an invalid way. If that was the cause, then the plugin should be changed. Hope this report turns out to help improve the situation. I don't have problems currently and will in future be sensitive to this specific possible cause of problems, but not having such crashes in the first place, would be worth it and maybe could still help others. Best regards, Alexander 1: slightly reduced version of: https://github.com/marschap/fetchmail_wakeup
On 2020-06-15, Alexander Strasser <eclipse7 at gmx.net> wrote:> I had some imap crashes (sig11) starting at the end of 2019 after > an upgrade of dovecot. > > I found out, that I didn't have any problems using version v2.3.8, > but any version v2.3.9 and higher would trigger the crashes. > > After investigating more deeply and creating a core dump, I saw > that the crash happened in an external plugin fetchmail_wakeup[1]. > > After recompiling that plugin with up to date dovecot headers, > I didn't get crashes anymore. > > So I suspect there were ABI incompatible changes and it was > forgotten to bump the minimum Plugin-ABI version supported.dovecot-2.3.8/configure #define DOVECOT_ABI_VERSION "2.3.ABIv8($PACKAGE_VERSION)" dovecot-2.3.9/configure #define DOVECOT_ABI_VERSION "2.3.ABIv9($PACKAGE_VERSION)" Did you disable version checking? (version_ignore = yes)
Hi! On 2020-06-16 12:37 -0000, Stuart Henderson wrote:> On 2020-06-15, Alexander Strasser <eclipse7 at gmx.net> wrote: > > I had some imap crashes (sig11) starting at the end of 2019 after > > an upgrade of dovecot. > > > > I found out, that I didn't have any problems using version v2.3.8, > > but any version v2.3.9 and higher would trigger the crashes. > > > > After investigating more deeply and creating a core dump, I saw > > that the crash happened in an external plugin fetchmail_wakeup[1]. > > > > After recompiling that plugin with up to date dovecot headers, > > I didn't get crashes anymore. > > > > So I suspect there were ABI incompatible changes and it was > > forgotten to bump the minimum Plugin-ABI version supported. > > dovecot-2.3.8/configure > #define DOVECOT_ABI_VERSION "2.3.ABIv8($PACKAGE_VERSION)" > > dovecot-2.3.9/configure > #define DOVECOT_ABI_VERSION "2.3.ABIv9($PACKAGE_VERSION)" > > Did you disable version checking? (version_ignore = yes)Thanks for the hint. I couldn't find version_ignore anywhere in the configs. I also don't remember having changed it. It's interesting that the ABI check didn't snap. Alexander