Hello Ike, Please, let me know if you want me to go after the needed SRUs for this fix or if you will.
I'll wait for the final feedback from tests with your PPA. Cheers! -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1805256 Title: qemu-img hangs on rcu_call_ready_event logic in Aarch64 when converting images Status in kunpeng920: Triaged Status in kunpeng920 ubuntu-18.04 series: New Status in kunpeng920 ubuntu-18.04-hwe series: New Status in kunpeng920 ubuntu-19.10 series: New Status in kunpeng920 ubuntu-20.04 series: New Status in kunpeng920 upstream-kernel series: Fix Committed Status in QEMU: In Progress Status in qemu package in Ubuntu: Incomplete Status in qemu source package in Bionic: Incomplete Status in qemu source package in Disco: Incomplete Status in qemu source package in Eoan: Incomplete Status in qemu source package in Focal: Incomplete Bug description: Command: qemu-img convert -f qcow2 -O qcow2 ./disk01.qcow2 ./output.qcow2 Hangs indefinitely approximately 30% of the runs. ---- Workaround: qemu-img convert -m 1 -f qcow2 -O qcow2 ./disk01.qcow2 ./output.qcow2 Run "qemu-img convert" with "a single coroutine" to avoid this issue. ---- (gdb) thread 1 ... (gdb) bt #0 0x0000ffffbf1ad81c in __GI_ppoll #1 0x0000aaaaaabcf73c in ppoll #2 qemu_poll_ns #3 0x0000aaaaaabd0764 in os_host_main_loop_wait #4 main_loop_wait ... (gdb) thread 2 ... (gdb) bt #0 syscall () #1 0x0000aaaaaabd41cc in qemu_futex_wait #2 qemu_event_wait (ev=ev@entry=0xaaaaaac86ce8 <rcu_call_ready_event>) #3 0x0000aaaaaabed05c in call_rcu_thread #4 0x0000aaaaaabd34c8 in qemu_thread_start #5 0x0000ffffbf25c880 in start_thread #6 0x0000ffffbf1b6b9c in thread_start () (gdb) thread 3 ... (gdb) bt #0 0x0000ffffbf11aa20 in __GI___sigtimedwait #1 0x0000ffffbf2671b4 in __sigwait #2 0x0000aaaaaabd1ddc in sigwait_compat #3 0x0000aaaaaabd34c8 in qemu_thread_start #4 0x0000ffffbf25c880 in start_thread #5 0x0000ffffbf1b6b9c in thread_start ---- (gdb) run Starting program: /usr/bin/qemu-img convert -f qcow2 -O qcow2 ./disk01.ext4.qcow2 ./output.qcow2 [New Thread 0xffffbec5ad90 (LWP 72839)] [New Thread 0xffffbe459d90 (LWP 72840)] [New Thread 0xffffbdb57d90 (LWP 72841)] [New Thread 0xffffacac9d90 (LWP 72859)] [New Thread 0xffffa7ffed90 (LWP 72860)] [New Thread 0xffffa77fdd90 (LWP 72861)] [New Thread 0xffffa6ffcd90 (LWP 72862)] [New Thread 0xffffa67fbd90 (LWP 72863)] [New Thread 0xffffa5ffad90 (LWP 72864)] [Thread 0xffffa5ffad90 (LWP 72864) exited] [Thread 0xffffa6ffcd90 (LWP 72862) exited] [Thread 0xffffa77fdd90 (LWP 72861) exited] [Thread 0xffffbdb57d90 (LWP 72841) exited] [Thread 0xffffa67fbd90 (LWP 72863) exited] [Thread 0xffffacac9d90 (LWP 72859) exited] [Thread 0xffffa7ffed90 (LWP 72860) exited] <HUNG w/ 3 threads in the stack trace showed before> """ All the tasks left are blocked in a system call, so no task left to call qemu_futex_wake() to unblock thread #2 (in futex()), which would unblock thread #1 (doing poll() in a pipe with thread #2). Those 7 threads exit before disk conversion is complete (sometimes in the beginning, sometimes at the end). ---- [ Original Description ] On the HiSilicon D06 system - a 96 core NUMA arm64 box - qemu-img frequently hangs (~50% of the time) with this command: qemu-img convert -f qcow2 -O qcow2 /tmp/cloudimg /tmp/cloudimg2 Where "cloudimg" is a standard qcow2 Ubuntu cloud image. This qcow2->qcow2 conversion happens to be something uvtool does every time it fetches images. Once hung, attaching gdb gives the following backtrace: (gdb) bt #0 0x0000ffffae4f8154 in __GI_ppoll (fds=0xaaaae8a67dc0, nfds=187650274213760, timeout=<optimized out>, timeout@entry=0x0, sigmask=0xffffc123b950) at ../sysdeps/unix/sysv/linux/ppoll.c:39 #1 0x0000aaaabbefaf00 in ppoll (__ss=0x0, __timeout=0x0, __nfds=<optimized out>, __fds=<optimized out>) at /usr/include/aarch64-linux-gnu/bits/poll2.h:77 #2 qemu_poll_ns (fds=<optimized out>, nfds=<optimized out>, timeout=timeout@entry=-1) at util/qemu-timer.c:322 #3 0x0000aaaabbefbf80 in os_host_main_loop_wait (timeout=-1) at util/main-loop.c:233 #4 main_loop_wait (nonblocking=<optimized out>) at util/main-loop.c:497 #5 0x0000aaaabbe2aa30 in convert_do_copy (s=0xffffc123bb58) at qemu-img.c:1980 #6 img_convert (argc=<optimized out>, argv=<optimized out>) at qemu-img.c:2456 #7 0x0000aaaabbe2333c in main (argc=7, argv=<optimized out>) at qemu-img.c:4975 Reproduced w/ latest QEMU git (@ 53744e0a182) To manage notifications about this bug go to: https://bugs.launchpad.net/kunpeng920/+bug/1805256/+subscriptions
