QProcess FailedToStart, not always

[Krzysztow]

Hi everyone,

I have this problem and can't overcome it. Maybe someone of You has an idea. I would really appreciate it. So goint to the problem...

In my application I need to start mplayer with radiostation url. And it works for few first times. After I play with some gui in the application and want to start the process again, I get FailedToStart error and nothing happens. The arguments are the same, and the program "mplayer" still exists.
In the documentation, they write:
"The process failed to start. Either the invoked program is missing, or you may have insufficient permissions to invoke the program."
However this is obvious, none of the cases apply to mine. But it still fails.
Additionally, this happens when the program is run on Embedded Linux. Running on Ubuntu, haven't gotten this kind of problem.

Thank You in advance, for any help.

[Krzysztow]

Hi, me once more...

So I run my application and on the second consloe observe the "top" output. And this QProcess::FailedToStart comes out, when the VSZ (Virtual Memory Size) approaches 270m. But from the console mplayer may be played, so this is not a physical limitation of the hardware, but probably some limitation to a process.

So this is the state (top process run) when mplayer is running correctly:



PID PPID USER STAT VSZ %MEM %CPU COMMAND
2289 2229 root R 16244 26% 12% mplayer -demuxer aac http://gr-relay-3.gaduradio.pl/45 -ss 0
2144 1919 root R 3044 5% 4% top -d1
2096 951 root R 3044 5% 3% top -d1
1918 899 root S 2348 4% 3% /usr/sbin/dropbear -r /etc/dropbear/dropbear_rsa_host_key -p 22
950 899 root S 2348 4% 2% /usr/sbin/dropbear -r /etc/dropbear/dropbear_rsa_host_key -p 22
2229 1138 root S 276m 461% 0% ./myapplication -qws
913 1 root S 16628 27% 0% /usr/bin/commserver
2292 2289 root S 15984 26% 0% mplayer -demuxer aac http://gr-relay-3.gaduradio.pl/45 -ss 0
951 950 root S 3044 5% 0% -sh
1919 1918 root S 3044 5% 0% -sh
1138 1137 root S 3044 5% 0% -sh
902 1 root S 2928 5% 0% /sbin/syslogd -n -C64 -m 20
860 1 root S 2868 5% 0% udhcpc -R -n -p /var/run/udhcpc.eth0.pid -i eth0
904 1 root S 2864 5% 0% /sbin/klogd -n
1137 899 root S 2348 4% 0% /usr/sbin/dropbear -r /etc/dropbear/dropbear_rsa_host_key -p 22
899 1 root S 2172 4% 0% /usr/sbin/dropbear -r /etc/dropbear/dropbear_rsa_host_key -p 22
909 1 root S 1904 3% 0% /usr/sbin/bftpd -d
929 1 root S 1828 3% 0% /sbin/getty 115200 ttySAC0
306 1 root S < 1808 3% 0% /sbin/udevd -d
1 0 root S 1572 3% 0% init [5]
280 2 root SWN 0 0% 0% [jffs2_gcd_mtd4]
135 2 root SW 0 0% 0% [pdflush]
136 2 root SW< 0 0% 0% [kswapd0]
5 2 root SW< 0 0% 0% [khelper]
4 2 root SW< 0 0% 0% [events/0]
2 0 root SW< 0 0% 0% [kthreadd]
3 2 root SW< 0 0% 0% [ksoftirqd/0]
102 2 root SW< 0 0% 0% [kblockd/0]
109 2 root SW< 0 0% 0% [kseriod]
112 2 root SW< 0 0% 0% [kmmcd]
134 2 root SW 0 0% 0% [pdflush]
137 2 root SW< 0 0% 0% [aio/0]
138 2 root SW< 0 0% 0% [nfsiod]
210 2 root SW< 0 0% 0% [mtdblockd]
272 2 root SW< 0 0% 0% [rpciod/0]



And now, when it does not start:


PID PPID USER STAT VSZ %MEM %CPU COMMAND
2096 951 root S 3044 5% 4% top -d1
2293 1919 root R 3044 5% 4% top -d1
950 899 root S 2348 4% 2% /usr/sbin/dropbear -r /etc/dropbear/dropbear_rsa_host_key -p 22
1918 899 root S 2348 4% 1% /usr/sbin/dropbear -r /etc/dropbear/dropbear_rsa_host_key -p 22
2229 1138 root S 277m 462% 0% ./myapplication -qws
913 1 root S 16628 27% 0% /usr/bin/commserver
951 950 root S 3044 5% 0% -sh
1919 1918 root S 3044 5% 0% -sh
1138 1137 root S 3044 5% 0% -sh
902 1 root S 2928 5% 0% /sbin/syslogd -n -C64 -m 20
860 1 root S 2868 5% 0% udhcpc -R -n -p /var/run/udhcpc.eth0.pid -i eth0
904 1 root S 2864 5% 0% /sbin/klogd -n
1137 899 root S 2348 4% 0% /usr/sbin/dropbear -r /etc/dropbear/dropbear_rsa_host_key -p 22
899 1 root S 2172 4% 0% /usr/sbin/dropbear -r /etc/dropbear/dropbear_rsa_host_key -p 22
909 1 root S 1904 3% 0% /usr/sbin/bftpd -d
929 1 root S 1828 3% 0% /sbin/getty 115200 ttySAC0
306 1 root S < 1808 3% 0% /sbin/udevd -d
1 0 root S 1572 3% 0% init [5]
280 2 root SWN 0 0% 0% [jffs2_gcd_mtd4]
135 2 root SW 0 0% 0% [pdflush]
136 2 root SW< 0 0% 0% [kswapd0]
5 2 root SW< 0 0% 0% [khelper]
4 2 root SW< 0 0% 0% [events/0]
2 0 root SW< 0 0% 0% [kthreadd]
3 2 root SW< 0 0% 0% [ksoftirqd/0]
102 2 root SW< 0 0% 0% [kblockd/0]
109 2 root SW< 0 0% 0% [kseriod]
112 2 root SW< 0 0% 0% [kmmcd]
134 2 root SW 0 0% 0% [pdflush]
137 2 root SW< 0 0% 0% [aio/0]
138 2 root SW< 0 0% 0% [nfsiod]
210 2 root SW< 0 0% 0% [mtdblockd]
272 2 root SW< 0 0% 0% [rpciod/0]


in ps myapplication, in current session, my application has id 2229, so find / -name limits | grep 2229 gives:



/proc/2229/task/2229/limits
/proc/2229/task/2232/limits
/proc/2229/task/2236/limits
/proc/2229/task/2237/limits
/proc/2229/task/2238/limits
/proc/2229/task/2239/limits
/proc/2229/task/2240/limits
/proc/2229/task/2241/limits
/proc/2229/task/2242/limits
/proc/2229/task/2243/limits
/proc/2229/task/2244/limits
/proc/2229/task/2245/limits
/proc/2229/task/2246/limits
/proc/2229/task/2247/limits
/proc/2229/task/2251/limits
/proc/2229/task/2252/limits
/proc/2229/task/2253/limits
/proc/2229/task/2254/limits
/proc/2229/task/2255/limits
/proc/2229/task/2256/limits
/proc/2229/task/2257/limits
/proc/2229/task/2258/limits
/proc/2229/task/2259/limits
/proc/2229/task/2260/limits
/proc/2229/task/2261/limits
/proc/2229/task/2262/limits
/proc/2229/task/2263/limits
/proc/2229/limits


The multitude (as well as more than 100% VSZ size) of tasks is due to few plug-ins loaded. All of these tasks have the same limits, which are (cat /proc/2229/task/<number>/limits and cat /proc/2229/limits):



Limit Soft Limit Hard Limit Units
Max cpu time unlimited unlimited ms
Max file size unlimited unlimited bytes
Max data size unlimited unlimited bytes
Max stack size 8388608 unlimited bytes
Max core file size 0 0 bytes
Max resident set unlimited unlimited bytes
Max processes 512 512 processes
Max open files 1024 1024 files
Max locked memory 65536 65536 bytes
Max address space unlimited unlimited bytes
Max file locks unlimited unlimited locks
Max pending signals 512 512 signals
Max msgqueue size 819200 819200 bytes
Max nice priority 0 0
Max realtime priority 0 0
Max realtime timeout unlimited unlimited us


Hope this information is important and useful for solution. Please, if anyone has some thoughts on that, write them here.

Thank You in advance.