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Posted to commits@nuttx.apache.org by GitBox <gi...@apache.org> on 2021/02/01 07:57:57 UTC
[GitHub] [incubator-nuttx] btashton edited a comment on issue #2663: kthread_create hangs waiting on semaphore while trying to copy file descriptors
btashton edited a comment on issue #2663:
URL: https://github.com/apache/incubator-nuttx/issues/2663#issuecomment-770651598
@xiaoxiang781216 I just noticed something similar when trying to create a kernel thread off of a call in `sim_bringup()` (I'm add usbhost support via libusb). I get a segfault because in `sched_dupfiles` `rtcb->group` is 0 which means parent and child are both invalid
```c
Thread 1 "nuttx" received signal SIGSEGV, Segmentation fault.
sched_dupfiles (tcb=0x7ffff3e295d0) at group/group_setuptaskfiles.c:103
103 if (parent[i].f_inode &&
Missing separate debuginfos, use: dnf debuginfo-install libgcc-10.2.1-9.fc33.x86_64 libusbx-1.0.23-2.fc33.x86_64 systemd-libs-246.7-2.fc33.x86_64 zlib-1.2.11-23.fc33.x86_64
(gdb) p parent
$1 = (struct file *) 0x78
(gdb) list
98 /* Check if this file is opened by the parent. We can tell if
99 * if the file is open because it contain a reference to a non-NULL
100 * i-node structure.
101 */
102
103 if (parent[i].f_inode &&
104 (parent[i].f_oflags & O_CLOEXEC) == 0)
105 {
106 /* Yes... duplicate it for the child */
107
(gdb) p rtcb
$2 = (struct tcb_s *) 0x7ffff3e27c90
(gdb) p rtcb->group
$3 = (struct task_group_s *) 0x0
(gdb) p rtcb*
A syntax error in expression, near `'.
(gdb) p *rtcb
$4 = {flink = 0x43f8a0 <g_idletcb>, blink = 0x7ffff7f38020 <_IO_strn_jumps>, group = 0x0, pid = 1, start = 0x402184 <nxtask_start>, entry = {pthread = 0x408e78 <nsh_main>, main = 0x408e78 <nsh_main>}, sched_priority = 100 'd',
init_priority = 100 'd', task_state = 3 '\003', flags = 0, lockcount = 0, errcode = 0, waitdog = {next = 0x0, func = 0x85b82ce26aee8900, lag = 0, flags = 0 '\000', arg = 9635500753727424768}, adj_stack_size = 140737285094944,
stack_alloc_ptr = 0x85b82ce26aee8900, adj_stack_ptr = 0x4412a0, waitsem = 0x0, sigprocmask = 4091706928, sigwaitmask = 32767, sigpendactionq = {head = 0x4412a0, tail = 0xffffffff}, sigpostedq = {head = 0x3, tail = 0x4441d0}, sigunbinfo = {
si_signo = 5 '\005', si_code = 23 '\027', si_errno = 232 '\350', si_value = {sival_int = 48, sival_ptr = 0x3000000030}, si_pid = 32304, si_status = 32767}, msgwaitq = 0x7ffff3e27d60, mhead = 0x85b82ce26aee8900, xcp = {
sigdeliver = 0x7ffff3e27e1c, regs = {4539616, 0, 0, 0, 140737353413158, 4473296, 140737351999557, 140737351996080}}, name = "x\030\371\367\377\177\000\000\000\000\000\000\000\000\000\000 \203\363\367\t\000\000\000\340DE\000\000\000\000"}
(gdb) p rtcb->group
$5 = (struct task_group_s *) 0x0
(gdb) bt
#0 sched_dupfiles (tcb=0x7ffff3e295d0) at group/group_setuptaskfiles.c:103
#1 0x00000000004028c8 in group_setuptaskfiles (tcb=0x7ffff3e295d0) at group/group_setuptaskfiles.c:219
#2 0x0000000000401ae8 in nxtask_init (tcb=0x7ffff3e295d0, name=0x4335bf "usbhost", priority=50, stack=0x0, stack_size=65536, entry=0x42e28a <usbhost_waiter>, argv=0x0) at task/task_init.c:105
#3 0x000000000040196f in nxthread_create (name=0x4335bf "usbhost", ttype=2 '\002', priority=50, stack_size=65536, entry=0x42e28a <usbhost_waiter>, argv=0x0) at task/task_create.c:94
#4 0x0000000000401a83 in kthread_create (name=0x4335bf "usbhost", priority=50, stack_size=65536, entry=0x42e28a <usbhost_waiter>, argv=0x0) at task/task_create.c:235
#5 0x000000000042e3a8 in up_init_usbhost (bus=0) at sim_bringup.c:129
#6 0x000000000042e4e8 in sim_bringup () at sim_bringup.c:491
#7 0x000000000042e283 in board_app_initialize (arg=0) at sim_appinit.c:82
#8 0x000000000042a78f in boardctl (cmd=65281, arg=0) at boardctl.c:326
#9 0x0000000000408f33 in nsh_initialize () at nsh_init.c:103
#10 0x0000000000408ec4 in nsh_main (argc=1, argv=0x7ffff3e29340) at nsh_main.c:143
#11 0x000000000040591d in nxtask_startup (entrypt=0x408e78 <nsh_main>, argc=1, argv=0x7ffff3e29340) at sched/task_startup.c:165
#12 0x0000000000402232 in nxtask_start () at task/task_start.c:144
#13 0x0000000000000000 in ?? ()
```
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