Re: Some iotests are failing with -luks

[Kevin Wolf <kwolf@redhat.com>]

Am 11.09.2025 um 13:21 hat Thomas Huth geschrieben:
> On 10/09/2025 18.08, Kevin Wolf wrote:
> > Am 10.09.2025 um 17:16 hat Thomas Huth geschrieben:
> > > 
> > >   Hi,
> > > 
> > > when running "./check -luks" in the qemu-iotests directory,
> > > some tests are failing for me:
> > > 
> > > 295 296 inactive-node-nbd luks-detached-header
> > > 
> > > Is that a known problem already?
> > 
> > Not to me anyway.
> > 
> > > FWIW, 295 is failing with the following output:
> > > 
> > > 295   fail       [17:03:01] [17:03:17]   15.7s                failed, exit status 1
> > > [...]
> > > +EWARNING:qemu.machine.machine:qemu received signal 6; command: "/home/thuth/tmp/qemu-build/qemu-system-x86_64 -display none -vga none -chardev socket,id=mon,fd=5 -mon chardev=mon,mode=control -chardev socket,id=qtest,fd=3 -qtest chardev:qtest -accel qtest -nodefaults -display none -accel qtest"
> > > +EEWARNING:qemu.machine.machine:qemu received signal 6; command: "/home/thuth/tmp/qemu-build/qemu-system-x86_64 -display none -vga none -chardev socket,id=mon,fd=6 -mon chardev=mon,mode=control -chardev socket,id=qtest,fd=3 -qtest chardev:qtest -accel qtest -nodefaults -display none -accel qtest"
> > > +EEWARNING:qemu.machine.machine:qemu received signal 6; command: "/home/thuth/tmp/qemu-build/qemu-system-x86_64 -display none -vga none -chardev socket,id=mon,fd=10 -mon chardev=mon,mode=control -chardev socket,id=qtest,fd=3 -qtest chardev:qtest -accel qtest -nodefaults -display none -accel qtest"
> > > +E
> > > [...]
> > > 
> > > etc.
> > > 
> > > 296 looks very similar (also a "qemu received signal 6" error),
> > > but the others look like this:
> > 
> > When it gets signal 6 (i.e. SIGABRT), that usually means that you should
> > have a look at the coredump.
> 
> With "-p" I additionally get this error message in the log:
> 
> qemu-system-x86_64: ../../devel/qemu/block/graph-lock.c:294:
>  bdrv_graph_rdlock_main_loop: Assertion `!qemu_in_coroutine()' failed.
> 
> With -gdb I can get a back trace that looks like this:
> 
> Thread 1 "qemu-system-x86" received signal SIGABRT, Aborted.
> 0x00007ffff4ba7e9c in __pthread_kill_implementation () from target:/lib64/libc.so.6
> --Type <RET> for more, q to quit, c to continue without paging--
> #0  0x00007ffff4ba7e9c in __pthread_kill_implementation () from target:/lib64/libc.so.6
> #1  0x00007ffff4b4df3e in raise () from target:/lib64/libc.so.6
> #2  0x00007ffff4b356d0 in abort () from target:/lib64/libc.so.6
> #3  0x00007ffff4b35639 in __assert_fail_base.cold () from target:/lib64/libc.so.6
> #4  0x0000555555574eae in bdrv_graph_rdlock_main_loop () at ../../devel/qemu/block/graph-lock.c:294
> #5  0x0000555555aa2f43 in graph_lockable_auto_lock_mainloop (x=<optimized out>) at /home/thuth/devel/qemu/include/block/graph-lock.h:275
> #6  block_crypto_read_func (block=<optimized out>, offset=4096, buf=0x555558324100 "", buflen=256000, opaque=0x555558a259d0, errp=0x555558a8c370)
>     at ../../devel/qemu/block/crypto.c:71
> #7  0x0000555555a5a308 in qcrypto_block_luks_load_key (block=block@entry=0x555558686ec0, slot_idx=slot_idx@entry=0,
>     password=password@entry=0x555558626050 "hunter0", masterkey=masterkey@entry=0x55555886b2a0 "",
>     readfunc=readfunc@entry=0x555555aa2f10 <block_crypto_read_func>, opaque=opaque@entry=0x555558a259d0, errp=0x555558a8c370)
>     at ../../devel/qemu/crypto/block-luks.c:927
> #8  0x0000555555a5ba7e in qcrypto_block_luks_find_key (block=0x555558686ec0, password=0x555558626050 "hunter0", masterkey=0x55555886b2a0 "",
>     readfunc=0x555555aa2f10 <block_crypto_read_func>, opaque=0x555558a259d0, errp=0x555558a8c370) at ../../devel/qemu/crypto/block-luks.c:1045
> #9  qcrypto_block_luks_amend_add_keyslot (block=0x555558686ec0, readfunc=0x555555aa2f10 <block_crypto_read_func>,
>     writefunc=0x555555aa2e50 <block_crypto_write_func>, opaque=0x555558a259d0, opts_luks=0x7fffec5fff38, force=<optimized out>, errp=0x555558a8c370)
>     at ../../devel/qemu/crypto/block-luks.c:1673
> #10 qcrypto_block_luks_amend_options (block=0x555558686ec0, readfunc=0x555555aa2f10 <block_crypto_read_func>,
>     writefunc=0x555555aa2e50 <block_crypto_write_func>, opaque=0x555558a259d0, options=0x7fffec5fff30, force=<optimized out>, errp=0x555558a8c370)
>     at ../../devel/qemu/crypto/block-luks.c:1865
> #11 0x0000555555aa3852 in block_crypto_amend_options_generic_luks (bs=<optimized out>, amend_options=<optimized out>, force=<optimized out>,
>     errp=<optimized out>) at ../../devel/qemu/block/crypto.c:949
> #12 0x0000555555aa38e9 in block_crypto_co_amend_luks (bs=<optimized out>, opts=<optimized out>, force=<optimized out>, errp=<optimized out>)
>     at ../../devel/qemu/block/crypto.c:1008
> #13 0x0000555555a96030 in blockdev_amend_run (job=0x555558a8c2b0, errp=0x555558a8c370) at ../../devel/qemu/block/amend.c:52
> #14 0x0000555555a874ad in job_co_entry (opaque=0x555558a8c2b0) at ../../devel/qemu/job.c:1112
> #15 0x0000555555bdc41b in coroutine_trampoline (i0=<optimized out>, i1=<optimized out>) at ../../devel/qemu/util/coroutine-ucontext.c:175
> #16 0x00007ffff4b68f70 in ?? () from target:/lib64/libc.so.6
> #17 0x00007fffffffc310 in ?? ()
> #18 0x0000000000000000 in ?? ()

Hm, so block_crypto_read_func() isn't prepared to be called in coroutine
context, but block_crypto_co_amend_luks() still calls it from a
coroutine. The indirection of going through QCrypto won't make it easier
to fix this properly.

It seems to me that while block_crypto_read/write_func are effectively
no_coroutine_fn, qcrypto_block_amend_options() should really take
function pointers that can be called from coroutines. It is called from
both coroutine and non-coroutine code paths, so should the function
pointers be coroutine_mixed_fn or do we want to change the callers?

Either way, we should add the appropriate coroutine markers to the
QCrypto interfaces to show the intention at least.

> > > inactive-node-nbd   fail       [17:13:56] [17:14:04]   7.5s                 failed, exit status 1
> > > [...]
> 
> With "-p" I'm getting this additional error message:
> 
> qemu-system-x86_64: -blockdev luks,file=disk-file,node-name=disk-fmt,active=off: Parameter 'key-secret' is required for cipher

The test case just isn't made for luks. iotests.py has special code for
luks in VM.add_drive(), but not in VM.add_blockdev().

For now, the test should probably just mark luks as unsupported.

Kevin