linux uml segfault

[Anton Ivanov]

On 02/03/2021 14:23, Ritesh Raj Sarraf wrote:
> On Tue, 2021-03-02 at 11:34 +0000, Anton Ivanov wrote:
>> If gdb gives you the exact lines, that may be helpful.
> 
> It doesn't. But it does show drawbacks in my packaging. The debug
> symbols packaged are not read/honored by gdb at all.
> 
> ```
> Reading symbols from /usr/bin/linux.uml...
> Reading symbols from /usr/lib/debug/.build-
> id/6f/ea141539149074c72e80fb8004de124fda115b.debug...
> (No debugging symbols found in /usr/lib/debug/.build-
> id/6f/ea141539149074c72e80fb8004de124fda115b.debug)
> 
> warning: Can't open file /dev/shm/#20817 (deleted) during file-backed
> mapping note processing
> [New LWP 18788]
> [Thread debugging using libthread_db enabled]
> Using host libthread_db library "/lib/x86_64-linux-
> gnu/libthread_db.so.1".
> Core was generated by `linux ubd0=qemu-linux-image.img'.
> Program terminated with signal SIGABRT, Aborted.
> #0  0x00007f51842c0087 in kill () at ../sysdeps/unix/syscall-
> template.S:120
> 120     ../sysdeps/unix/syscall-template.S: No such file or directory.
> (gdb) bt
> #0  0x00007f51842c0087 in kill () at ../sysdeps/unix/syscall-
> template.S:120
> #1  0x000000006049dc20 in uml_abort ()
> #2  0x000000006049de7a in os_dump_core ()
> #3  0x0000000060486e47 in panic_exit ()
> #4  0x00000000604c0a03 in notifier_call_chain ()
> #5  0x00000000604c0a98 in atomic_notifier_call_chain ()
> #6  0x0000000060a26b85 in panic ()
> #7  0x00000000604869e1 in segv ()
> #8  0x0000000060486ba9 in segv_handler ()
> #9  0x000000006049ccc0 in sig_handler_common ()
> #10 0x000000006049d1ec in sig_handler ()
> #11 0x000000006049cdc6 in hard_handler ()
> #12 <signal handler called>
> #13 0x00000000604d45b4 in vprintk_store ()
> #14 0x00000000604d4aa8 in vprintk_emit ()
> #15 0x00000000604d4d86 in vprintk_deferred ()
> #16 0x0000000060a27a02 in printk_deferred ()
> #17 0x00000000609031b2 in get_random_u32 ()
> #18 0x000000006088ff65 in bucket_table_alloc.isra ()
> #19 0x0000000060890740 in rhashtable_init ()
> #20 0x00000000607efaa2 in ipc_init_ids ()
> #21 0x00000000600153c9 in sem_init ()
> ```
> 
> So the best I can extract for you is to compile the kernel with as much
> information as possible.

Can you try using one of the older kernels so we can verify if this is indeed a 5.10 thing.

I will do a dissect the moment I figure out how to reproduce it. I will try to do some more experiments on that tomorrow.

> 
> Thanks,
> Ritesh
> 

-- 
Anton R. Ivanov
https://www.kot-begemot.co.uk/