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charset="utf-8" Content-Transfer-Encoding: quoted-printable Date: Wed, 11 Sep 2019 11:19:48 -0000 From: Rafael David Tinoco To: qemu-devel@nongnu.org X-Launchpad-Notification-Type: bug X-Launchpad-Bug: product=qemu; status=In Progress; importance=Undecided; assignee=rafaeldtinoco@kernelpath.com; X-Launchpad-Bug: distribution=ubuntu; sourcepackage=qemu; component=main; status=In Progress; importance=Medium; assignee=rafaeldtinoco@kernelpath.com; X-Launchpad-Bug-Tags: qemu-img X-Launchpad-Bug-Information-Type: Public X-Launchpad-Bug-Private: no X-Launchpad-Bug-Security-Vulnerability: no X-Launchpad-Bug-Commenters: dannf jnsnow lizhengui rafaeldtinoco X-Launchpad-Bug-Reporter: dann frazier (dannf) X-Launchpad-Bug-Modifier: Rafael David Tinoco (rafaeldtinoco) References: <154327283728.15443.11625169757714443608.malonedeb@soybean.canonical.com> Message-Id: <156820078886.17538.11974988129261129073.launchpad@gac.canonical.com> X-Launchpad-Message-Rationale: Subscriber (QEMU) @qemu-devel-ml X-Launchpad-Message-For: qemu-devel-ml Precedence: bulk X-Generated-By: Launchpad (canonical.com); Revision="19044"; Instance="production-secrets-lazr.conf" X-Launchpad-Hash: 87b3a4c4e5c0a078d9c4656f18f04d0ce4b9fa6a X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 91.189.90.7 Subject: [Qemu-devel] [Bug 1805256] Re: qemu-img hangs on rcu_call_ready_event logic in Aarch64 when converting images X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Bug 1805256 <1805256@bugs.launchpad.net> Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" ** Description changed: + Command: + = + qemu-img convert -m 1 -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=3Dev@entry=3D0xaaaaaac86ce8 ) + #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] + = + + """ + = + 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=3D0xaaaae8a67dc0, nfds=3D187650= 274213760, = - timeout=3D, timeout@entry=3D0x0, sigmask=3D0xffffc123b= 950) - at ../sysdeps/unix/sysv/linux/ppoll.c:39 - #1 0x0000aaaabbefaf00 in ppoll (__ss=3D0x0, __timeout=3D0x0, __nfds=3D, = - __fds=3D) at /usr/include/aarch64-linux-gnu/bits/poll2= .h:77 - #2 qemu_poll_ns (fds=3D, nfds=3D, = - timeout=3Dtimeout@entry=3D-1) at util/qemu-timer.c:322 + #0 0x0000ffffae4f8154 in __GI_ppoll (fds=3D0xaaaae8a67dc0, nfds=3D187650= 274213760, + =C2=A0=C2=A0=C2=A0=C2=A0timeout=3D, timeout@entry=3D0x0, s= igmask=3D0xffffc123b950) + =C2=A0=C2=A0=C2=A0=C2=A0at ../sysdeps/unix/sysv/linux/ppoll.c:39 + #1 0x0000aaaabbefaf00 in ppoll (__ss=3D0x0, __timeout=3D0x0, __nfds=3D, + =C2=A0=C2=A0=C2=A0=C2=A0__fds=3D) at /usr/include/aarch64-= linux-gnu/bits/poll2.h:77 + #2 qemu_poll_ns (fds=3D, nfds=3D, + =C2=A0=C2=A0=C2=A0=C2=A0timeout=3Dtimeout@entry=3D-1) at util/qemu-timer.= c:322 #3 0x0000aaaabbefbf80 in os_host_main_loop_wait (timeout=3D-1) - at util/main-loop.c:233 + =C2=A0=C2=A0=C2=A0=C2=A0at util/main-loop.c:233 #4 main_loop_wait (nonblocking=3D) at util/main-loop.c:497 #5 0x0000aaaabbe2aa30 in convert_do_copy (s=3D0xffffc123bb58) at qemu-im= g.c:1980 #6 img_convert (argc=3D, argv=3D) at qemu-= img.c:2456 #7 0x0000aaaabbe2333c in main (argc=3D7, argv=3D) at qemu= -img.c:4975 = Reproduced w/ latest QEMU git (@ 53744e0a182) ** Description changed: Command: = - qemu-img convert -m 1 -f qcow2 -O qcow2 ./disk01.qcow2 ./output.qcow2 + 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=3Dev@entry=3D0xaaaaaac86ce8 ) #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] = """ = 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=3D0xaaaae8a67dc0, nfds=3D187650= 274213760, =C2=A0=C2=A0=C2=A0=C2=A0timeout=3D, timeout@entry=3D0x0, s= igmask=3D0xffffc123b950) =C2=A0=C2=A0=C2=A0=C2=A0at ../sysdeps/unix/sysv/linux/ppoll.c:39 #1 0x0000aaaabbefaf00 in ppoll (__ss=3D0x0, __timeout=3D0x0, __nfds=3D, =C2=A0=C2=A0=C2=A0=C2=A0__fds=3D) at /usr/include/aarch64-= linux-gnu/bits/poll2.h:77 #2 qemu_poll_ns (fds=3D, nfds=3D, =C2=A0=C2=A0=C2=A0=C2=A0timeout=3Dtimeout@entry=3D-1) at util/qemu-timer.= c:322 #3 0x0000aaaabbefbf80 in os_host_main_loop_wait (timeout=3D-1) =C2=A0=C2=A0=C2=A0=C2=A0at util/main-loop.c:233 #4 main_loop_wait (nonblocking=3D) at util/main-loop.c:497 #5 0x0000aaaabbe2aa30 in convert_do_copy (s=3D0xffffc123bb58) at qemu-im= g.c:1980 #6 img_convert (argc=3D, argv=3D) at qemu-= img.c:2456 #7 0x0000aaaabbe2333c in main (argc=3D7, argv=3D) at qemu= -img.c:4975 = Reproduced w/ latest QEMU git (@ 53744e0a182) -- = 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 QEMU: In Progress Status in qemu package in Ubuntu: In Progress 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=3Dev@entry=3D0xaaaaaac86ce8 ) #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] """ 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=3D0xaaaae8a67dc0, nfds=3D187650= 274213760, =C2=A0=C2=A0=C2=A0=C2=A0timeout=3D, timeout@entry=3D0x0, s= igmask=3D0xffffc123b950) =C2=A0=C2=A0=C2=A0=C2=A0at ../sysdeps/unix/sysv/linux/ppoll.c:39 #1 0x0000aaaabbefaf00 in ppoll (__ss=3D0x0, __timeout=3D0x0, __nfds=3D, =C2=A0=C2=A0=C2=A0=C2=A0__fds=3D) at /usr/include/aarch64-= linux-gnu/bits/poll2.h:77 #2 qemu_poll_ns (fds=3D, nfds=3D, =C2=A0=C2=A0=C2=A0=C2=A0timeout=3Dtimeout@entry=3D-1) at util/qemu-timer.= c:322 #3 0x0000aaaabbefbf80 in os_host_main_loop_wait (timeout=3D-1) =C2=A0=C2=A0=C2=A0=C2=A0at util/main-loop.c:233 #4 main_loop_wait (nonblocking=3D) at util/main-loop.c:497 #5 0x0000aaaabbe2aa30 in convert_do_copy (s=3D0xffffc123bb58) at qemu-im= g.c:1980 #6 img_convert (argc=3D, argv=3D) at qemu-= img.c:2456 #7 0x0000aaaabbe2333c in main (argc=3D7, argv=3D) at qemu= -img.c:4975 Reproduced w/ latest QEMU git (@ 53744e0a182) To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1805256/+subscriptions