Date: Sun, 9 Jul 2023 22:41:27 +0000 From: John F Carr <jfc@mit.edu> To: Current FreeBSD <freebsd-current@freebsd.org> Subject: shell hung in fork system call Message-ID: <909E2C96-3BFA-41AD-8EE7-0902231C2B95@mit.edu>
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Kernel and system at a146207d66f320ed239c1059de9df854b66b55b7 plus some irrelevant local changes, four 64 bit ARM processors, make.conf sets CPUTYPE?=cortex-a57. I typed ^C while /bin/sh was starting a pipeline and my shell got hung in the middle of fork(). >From the terminal: # git log --oneline --|more ^C^C^C load: 3.26 cmd: sh 95505 [fork] 5308.67r 0.00u 0.03s 0% 2860k mi_switch+0x198 sleepq_switch+0xfc sleepq_timedwait+0x40 _sleep+0x264 fork1+0x67c sys_fork+0x34 do_el0_sync+0x4c8 handle_el0_sync+0x44 load: 3.16 cmd: sh 95505 [fork] 5311.75r 0.00u 0.03s 0% 2860k mi_switch+0x198 sleepq_switch+0xfc sleepq_timedwait+0x40 _sleep+0x264 fork1+0x67c sys_fork+0x34 do_el0_sync+0x4c8 handle_el0_sync+0x44 According to ps -d on another terminal the shell has no children: PID TT STAT TIME COMMAND [...] 873 u0 IWs 0:00.00 `-- login [pam] (login) 874 u0 I 0:00.17 `-- -sh (sh) 95504 u0 I 0:00.01 `-- su - 95505 u0 D+ 0:00.05 `-- -su (sh) [...] Nothing on the (115200 bps serial) console. No change in system performance. The system is busy copying a large amount of data from the network to a ZFS pool on spinning disks. The git|more pipeline could have taken some time to get going while I/O requests worked their way through the queue. It would not have touched the busy pool, only the zroot pool on an SSD. Has anything changed recently that might cause this?help
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