My email application is developed using Mailcore2. The development process is good, but the released application has collected a lot of crashes, all of which are in the Mailcore2 library.
The crash log is as follows：
Exception Type: EXC_BAD_ACCESS (SIGSEGV)
Exception Subtype: KERN_INVALID_ADDRESS at 0x00009b1a732b3bb0
VM Region Info: 0x9b1a732b3bb0 is not in any region. Bytes after previous region: 170056867330993
REGION TYPE START - END [ VSIZE] PRT/MAX SHRMOD REGION DETAIL
commpage (reserved) 1000000000-7000000000 [384.0G] ---/--- SM=NUL ...(unallocated)
--->
UNUSED SPACE AT END
Termination Signal: Segmentation fault: 11
Termination Reason: Namespace SIGNAL, Code 0xb
Terminating Process: exc handler [1957]
Triggered by Thread: 0
Thread 0 name:
Thread 0 Crashed:
0 MailCore 0x0000000108339fe4 -[MCOIMAPSession folderStatusOperation:] + 64 (MCOIMAPSession.mm:216)
1 MailCore 0x0000000108339fdc -[MCOIMAPSession folderStatusOperation:] + 56 (MCOIMAPSession.mm:216)
After a long time of analysis and research, I found that the crash was caused by the early release of the IMAPAsyncSession * _session object in the MCOIMAPSession under concurrent conditions.
The problem should be because the MC_SAFE_RELEASE macro is not locked. The _session object was released early, and subsequent access to _session caused the EXC_BAD_ACCESS to crash.
If two threads run the release() function at the same time, like the following：
At this time, other pointers to the _session object become dangling pointers
My email application is developed using Mailcore2. The development process is good, but the released application has collected a lot of crashes, all of which are in the Mailcore2 library.
The crash log is as follows：
After a long time of analysis and research, I found that the crash was caused by the early release of the IMAPAsyncSession * _session object in the MCOIMAPSession under concurrent conditions.
The problem should be because the MC_SAFE_RELEASE macro is not locked. The _session object was released early, and subsequent access to _session caused the EXC_BAD_ACCESS to crash.
If two threads run the release() function at the same time, like the following：
At this time, other pointers to the _session object become dangling pointers