Bug#926946: tracker-miner-fs SIGSEGV in process_func_start()

[Iain Lane]

Package: src:tracker
Version: 2.1.8-1
Severity: serious
Tags: patch upstream fixed-upstream

Hi,

Just filing so I have a bug reference for the unblock.

In Ubuntu's error tracker we noticed reports of a crash in tracker-miner
that looks like this:

#0  0x00007f1a2c1db676 in process_func_start (crawler=0x0) at tracker-crawler.c:713
No locals.
#1  0x00007f1a2c1db9d0 in enumerate_next_cb (object=<optimized out>, result=<optimized out>, user_data=0x7f19ec0886f0) at tracker-crawler.c:930
        dpd = 0x7f19ec0886f0
        info = <optimized out>
        error = 0x0
#2  0x00007f1a2c030df6 in next_async_callback_wrapper (source_object=0x55d54803ccd0, res=0x55d547f2e1b0, user_data=0x7f19ec0886f0) at ../../../gio/gfileenumerator.c:305
        enumerator = 0x55d54803ccd0
#3  0x00007f1a2c070059 in g_task_return_now (task=0x55d547f2e1b0) at ../../../gio/gtask.c:1209
No locals.
#4  0x00007f1a2c070099 in complete_in_idle_cb (task=0x55d547f2e1b0) at ../../../gio/gtask.c:1223
No locals.
#5  0x00007f1a2be98958 in ?? ()
No symbol table info available.
#6  0x00007ffecede7820 in ?? ()
No symbol table info available.
#7  0x00007f1a00000000 in ?? ()
No symbol table info available.
#8  0x0000000000000000 in ?? ()
No symbol table info available.

Andrea Azzarone from the Canonical team fixed this upstream[0]. I'm
proposing to include the fix in buster, and I'm uploading to unstable
now to hopefully achieve this.

These are automated reports and I don't have steps to reproduce I'm
afraid. You can see from frame #0 that process_func_start() is passed
NULL. The fix avoids calling this if the operation has been cancelled,
in which case data_provider_end() will be called, which frees the data.
That's how we get NULL there.

Cheers,

-- 
Iain Lane                                  [ iain at orangesquash.org.uk ]
Debian Developer                                   [ laney at debian.org ]
Ubuntu Developer                                   [ laney at ubuntu.com ]

[0] https://gitlab.gnome.org/GNOME/tracker/merge_requests/86