Hello,
I have a stm32h7 board, based on the stm32h743zi2 nucleo.
I have activated the watchdog.
The method to do the kthread was copied from this :
https://github.com/apache/nuttx/blob/master/boards/arm/stm32/photon/src/stm32_wdt.c#LL146C7-L146C7
The watchdog works, the system is stable
But now, the nsh 'ps' command ends up with a crash when trying to list
the kthread that resets the watchdog.
The problem has appeared between current trunk and revision
13d823f30710e6fabd3d6429a03bc37e1086c9e7
Here is the GDB session, a bit after cmd_ps is entered:
(pid 4 is the watchog maintenance kthread created like in the file
above)
open (path=0x3800c770 "/proc/4/cmdline", oflags=1) at
vfs/fs_open.c:447
447 if (fd < 0)
(gdb) n
453 leave_cancellation_point();
(gdb)
454 return fd;
(gdb)
455 }
(gdb)
nsh_readfile (vtbl=0x38005688, cmd=0x807ab7c "ps", filepath=0x3800c770
"/proc/4/cmdline", buffer=0x380056b0 " 0.0%", buflen=512)
at nsh_fsutils.c:219
219 if (fd < 0)
(gdb) print fd
$1 = 4
(gdb) n
229 ntotal = 0; /* No bytes read yet */
(gdb)
230 *buffer = '\0'; /* NUL terminate the empty buffer */
(gdb)
231 bufptr = buffer; /* Working pointer */
(gdb)
232 remaining = buflen - 1; /* Reserve one byte for a NUL
terminator */
(gdb)
233 ret = ERROR; /* Assume failure */
(gdb)
237 nread = read(fd, bufptr, remaining);
(gdb) s
read (fd=4, buf=0x380056b0, nbytes=511) at vfs/fs_read.c:166
166 enter_cancellation_point();
(gdb) n
170 ret = nx_read(fd, buf, nbytes);
(gdb) s
nx_read (fd=4, buf=0x380056b0, nbytes=511) at vfs/fs_read.c:132
132 ret = (ssize_t)fs_getfilep(fd, &filep);
(gdb) n
133 if (ret < 0)
(gdb)
140 return file_read(filep, buf, nbytes);
(gdb) s
file_read (filep=0x38002e40, buf=0x380056b0, nbytes=511) at
vfs/fs_read.c:67
67 int ret = -EBADF;
(gdb) n
69 DEBUGASSERT(filep);
(gdb)
70 inode = filep->f_inode;
(gdb)
74 if ((filep->f_oflags & O_RDOK) == 0)
(gdb)
85 else if (inode != NULL && inode->u.i_ops &&
inode->u.i_ops->read)
(gdb)
92 ret = (int)inode->u.i_ops->read(filep,
(gdb) s
procfs_read (filep=0x38002e40, buffer=0x380056b0 "", buflen=511) at
procfs/fs_procfs.c:445
445 handler = (FAR struct procfs_file_s *)filep->f_priv;
(gdb) n
446 DEBUGASSERT(handler);
(gdb)
450 return handler->procfsentry->ops->read(filep, buffer,
buflen);
(gdb) s
proc_read (filep=0x38002e40, buffer=0x380056b0 "", buflen=511) at
procfs/fs_procfsproc.c:1552
1552 procfile = (FAR struct proc_file_s *)filep->f_priv;
(gdb) n
1553 DEBUGASSERT(procfile != NULL);
(gdb)
1557 tcb = nxsched_get_tcb(procfile->pid);
(gdb)
1558 if (tcb == NULL)
(gdb) print tcb
$2 = (struct tcb_s *) 0x38003f28
(gdb) print *tcb
$3 = {flink = 0x38008640, blink = 0x0, group = 0x38003fe0, pid = 4,
sched_priority = 100 'd', init_priority = 100 'd',
start = 0x802fc91 <nxtask_start>, entry = {pthread = 0x806ecf1
<wdog_daemon>, main = 0x806ecf1 <wdog_daemon>}, task_state = 6 '\006',
flags = 4138, lockcount = 0, cpcount = 0, errcode = 0, timeslice =
200, waitdog = {next = 0x38005a40, arg = 939540264,
func = 0x802ecdd <nxsig_timeout>, lag = 316}, adj_stack_size
= 960,
stack_alloc_ptr = 0x38004328, stack_base_ptr = 0x38004368, waitobj
= 0x0,
sigprocmask = {_elem = {0, 0}}, sigwaitmask = {_elem = {0, 0}},
sigpendactionq = {head = 0x0, tail = 0x0}, sigpostedq = {head = 0x0,
tail = 0x0}, sigunbinfo = {si_signo = 255 '\377', si_code = 2
'\002', si_errno = 110 'n', si_value = {sival_int = 0, sival_ptr =
0x0},
si_user = 0x0}, mhead = 0x0, ticks = 0, xcp = {sigdeliver = 0x0,
saved_regs = 0x0, regs = 0x3800449c},
name = "watchdog\000\000\000\000\000\000\000\000"}
(gdb) n
1566 switch (procfile->node->node)
(gdb) n
1573 ret = proc_cmdline(procfile, tcb, buffer, buflen,
filep->f_pos);
(gdb) s
proc_cmdline (procfile=0x3800caa0, tcb=0x38003f28,
buffer=0x380056b0 "",
buflen=511, offset=0) at procfs/fs_procfsproc.c:664
664 remaining = buflen;
(gdb) n
665 totalsize = 0;
(gdb)
670 name = tcb->name;
(gdb)
674 linesize = strlen(name);
(gdb)
675 memcpy(procfile->line, name, linesize);
(gdb) print linesize
$4 = 8
(gdb) n
676 copysize = procfs_memcpy(procfile->line, linesize, buffer,
remaining,
(gdb) n
679 totalsize += copysize;
(gdb) print copysize
$5 = 8
(gdb) n
680 buffer += copysize;
(gdb) n
681 remaining -= copysize;
(gdb) n
683 if (totalsize >= buflen)
(gdb) print remaining
$6 = 503
(gdb) n
690 linesize = group_argvstr(tcb, procfile->line, remaining);
(gdb) s
group_argvstr (tcb=0x38003f28, args=0x3800caac "watchdog",
size=503) at
group/group_argvstr.c:61
61 size_t n = 0;
(gdb) n
68 if (!tcb || !tcb->group || !tcb->group->tg_info)
(gdb)
84 if ((tcb->flags & TCB_FLAG_TTYPE_MASK) ==
TCB_FLAG_TTYPE_PTHREAD)
(gdb)
93 FAR char **argv = tcb->group->tg_info->argv + 1;
(gdb)
95 while (*argv != NULL && n < size)
(gdb)
97 n += snprintf(args + n, size - n, " %s", *argv++);
(gdb) n
*CRASH*
When I just run, the stack dump shows a crash at
Fault: IRQ: 3 regs: 0x380037ec
arm_busfault: BASEPRI: 000000f0 PRIMASK: 00000000 IPSR: 00000003
CONTROL: 00000000
arm_busfault: CFSR: 00008200 HFSR: 40000000 DFSR: 00000000 BFAR:
00000003 AFSR: 00000000
arm_busfault: Bus Fault Reason:
arm_busfault: Precise data bus error
_assert: Current Version: NuttX bca 12.0.0-RC1 2eac660ff6-dirty May 11
2023 15:27:06 arm
_assert: Assertion failed panic: at file: armv7-m/arm_busfault.c:106
task: nsh_main 0x8039c41
up_dump_register: R0: 00000003 R1: ffffffff R2: 38003a1c R3: 00000003
up_dump_register: R4: 08039e89 R5: 3800571e R6: 38005734 FP: 380038c0
up_dump_register: R8: 00000000 SB: 00000000 SL: 00000000 R11: 00000000
up_dump_register: IP: a0000000 SP: 380038c0 LR: 08035537 PC: 080367a8
up_dump_register: xPSR: a1000000 PRIMASK: 00000000 CONTROL: 00000000
PC=nuttx/libs/libc/string/lib_strnlen.c:37 (discriminator 3)
LR=nuttx/libs/libc/stdio/lib_libvsprintf.c:940 (discriminator 4)
This is trying to measure the length of the command line
Running again with a breakpoint in proc_cmdline:
Breakpoint 1, proc_cmdline (procfile=0x3800caa0, tcb=0x38003f28,
buffer=0x380056b0 "", buflen=511, offset=0) at
procfs/fs_procfsproc.c:664
664 remaining = buflen;
(gdb) print *tcb
$4 = {flink = 0x38008640, blink = 0x0, group = 0x38003fe0, pid = 4,
sched_priority = 100 'd', init_priority = 100 'd',
start = 0x802fc91 <nxtask_start>, entry = {pthread = 0x806ecf1
<wdog_daemon>, main = 0x806ecf1 <wdog_daemon>}, task_state = 6 '\006',
flags = 4138, lockcount = 0, cpcount = 0, errcode = 0, timeslice =
200, waitdog = {next = 0x0, arg = 939540264,
func = 0x802ecdd <nxsig_timeout>, lag = 419}, adj_stack_size
= 960,
stack_alloc_ptr = 0x38004328, stack_base_ptr = 0x38004368, waitobj
= 0x0,
sigprocmask = {_elem = {0, 0}}, sigwaitmask = {_elem = {0, 0}},
sigpendactionq = {head = 0x0, tail = 0x0}, sigpostedq = {head = 0x0,
tail = 0x0}, sigunbinfo = {si_signo = 255 '\377', si_code = 2
'\002', si_errno = 110 'n', si_value = {sival_int = 0, sival_ptr =
0x0},
si_user = 0x0}, mhead = 0x0, ticks = 0, xcp = {sigdeliver = 0x0,
saved_regs = 0x0, regs = 0x3800449c},
name = "watchdog\000\000\000\000\000\000\000\000"}
(gdb) print *tcb->group
$5 = {flink = 0x38002b40, tg_pid = 4, tg_ppid = 0, tg_flags = 0
'\000',
tg_nmembers = 1 '\001', tg_mxmembers = 4 '\004', tg_members =
0x38004078,
tg_nwaiters = 0 '\000', tg_waitflags = 0 '\000', tg_exitsem =
{semcount = 0, flags = 0 '\000', waitlist = {head = 0x0, tail = 0x0}},
tg_statloc = 0x0, tg_joinlock = {sem = {semcount = 1, flags = 0
'\000', waitlist = {head = 0x0, tail = 0x0}}, holder = -1},
tg_joinhead
= 0x0,
tg_jointail = 0x0, tg_info = 0x38004090, tg_sigactionq = {head
= 0x0,
tail = 0x0}, tg_sigpendingq = {head = 0x0, tail = 0x0}, tg_envp = 0x0,
tg_envc = 0, itimer = 0x0, tg_filelist = {fl_lock = {sem =
{semcount
= 1, flags = 0 '\000', waitlist = {head = 0x0, tail = 0x0}}, holder
= -1},
fl_rows = 1 '\001', fl_files = 0x38004250}, tg_mm_map =
{mm_map_sq
= {head = 0x0, tail = 0x0}, mm_map_mutex = {mutex = {sem =
{semcount = 1,
flags = 0 '\000', waitlist = {head = 0x0, tail = 0x0}},
holder = -1}, count = 0}}}
(gdb) print *tcb->group->tg_info
$6 = {ta_lock = {sem = {semcount = 1, flags = 0 '\000', waitlist =
{head
= 0x0, tail = 0x0}}, holder = -1}, argv = 0x38004350,
ta_tlsset = 0 '\000', ta_tlsdtor = {0x0, 0x0, 0x0, 0x0},
ta_getopt =
{go_optarg = 0x0, go_opterr = 0, go_optind = 0, go_optopt = 0,
go_optptr = 0x0, go_binitialized = false}, ta_umask = 0,
ta_streamlist = {sl_lock = {sem = {semcount = 1, flags = 0 '\000',
waitlist = {
head = 0x0, tail = 0x0}}, holder = -1}, sl_std =
{{fs_next =
0x0, fs_lock = {mutex = {sem = {semcount = 1, flags = 0 '\000',
waitlist = {head = 0x0, tail = 0x0}}, holder = -1},
count
= 0}, fs_fd = 0, fs_bufstart = 0x38004110 "",
fs_bufend = 0x38004150 "\001", fs_bufpos = 0x38004110 "",
fs_bufread = 0x38004110 "", fs_buffer = '\000' <repeats 63 times>,
fs_oflags = 1, fs_flags = 12 '\f', fs_nungotten = 0 '\000',
fs_ungotten = "\000"}, {fs_next = 0x0, fs_lock = {mutex = {sem = {
semcount = 1, flags = 0 '\000', waitlist = {head =
0x0,
tail = 0x0}}, holder = -1}, count = 0}, fs_fd = 1,
fs_bufstart = 0x38004184 "", fs_bufend = 0x380041c4 "\006",
fs_bufpos = 0x38004184 "", fs_bufread = 0x38004184 "",
fs_buffer = '\000' <repeats 63 times>, fs_oflags = 6,
fs_flags
= 12 '\f', fs_nungotten = 0 '\000', fs_ungotten = "\000"}, {fs_next
= 0x0,
fs_lock = {mutex = {sem = {semcount = 1, flags = 0 '\000',
waitlist = {head = 0x0, tail = 0x0}}, holder = -1}, count = 0},
fs_fd = 2,
fs_bufstart = 0x380041f8 "", fs_bufend = 0x38004238 "\006",
fs_bufpos = 0x380041f8 "", fs_bufread = 0x380041f8 "",
fs_buffer = '\000' <repeats 63 times>, fs_oflags = 6,
fs_flags
= 12 '\f', fs_nungotten = 0 '\000', fs_ungotten = "\000"}}, sl_head
= 0x0,
sl_tail = 0x0}}
We see that argv = 0x38004350, which is in the stack:
stack_alloc_ptr =
0x38004328, stack_base_ptr = 0x38004368
(gdb) print (uint32_t[10])*tcb->group->tg_info->argv
$8 = {939541660, 3, 2, 939541660, 939541352, 134362499, 0, 0,
939541660, 3}
(gdb) print (char*[10])*tcb->group->tg_info->argv
$9 = {0x3800449c "pE", 0x3 "", 0x2 "", 0x3800449c "pE", 0x38004368 "",
0x8023583 <arm_hardfault+78> "F+\340{j\003\360\200C", 0x0, 0x0,
0x3800449c "pE", 0x3 ""}
This is not good! Too many non null values in that array, some of them
are not pointers! The value 3 is found in the BFAR of the crash dump.
kthread_create was called with argv = NULL
This calls kthread_create_with_stack with argv = NULL
This calls nxthread_create with argv = NULL
This calls nxtask_init with argv = NULL, envp=NULL
goto sched/task/task_init.c
This goes to nxtask_setup_arguments with argv=NULL
goto sched/task/task_setup.c
This calls nxtask_setup_stackargs
Looks like this function does the right thing.
I should get argc=0, allocation of two pointers, one for the task name
and one for the final null arg.
Then what is happening? Why do I see invalid values in the argv array?
Can someone help me? Can someone try to reproduce this?
I have built this image with a make distclean, apply config, make,
so I
dont expect dangling files.
Thanks,
Sebastien
