LocalFileSystem & wait() triggers MbedOS Fault Handler #6624
Description
Description of defect
I'm observing an MbedOS hard fault when using the LocalFileSystem and wait(). I added a wait() command inside a loop that was writing multiple values to a CSV file. The hard fault seemed to occur when the wait() function was called.
Target(s) affected by this defect ?
LPC1768
Toolchain(s) (name and version) displaying this defect ?
GCC_ARM & Online Compiler
What version of Mbed-os are you using (tag or sha) ?
n/a
What version(s) of tools are you using. List all that apply (E.g. mbed-cli)
gcc-arm-none-eabi-7-2017-q4-major
mbed-cli version: 1.5.0
How is this defect reproduced ?
I wrote up a simple LocalFileSystem example for the Mbed Application board that writes 100 integer values to a .csv file:
#include "mbed.h"
LocalFileSystem local("local");
int main() {
FILE *fp = fopen("/local/test.csv","w");
for (int i = 0; i < 100; i++) {
fprintf(fp, "%d\n", i);
}
fclose(fp);
}
The above code works and a TEST.CSV file is created in the local filesystem with integer values 0-99. However, when I add a wait function to the for loop, the MbedOS Fault Handler is triggered:
#include "mbed.h"
LocalFileSystem local("local");
int main() {
FILE *fp = fopen("/local/test.csv","w");
for (int i = 0; i < 100; i++) {
fprintf(fp, "%d\n", i);
wait(0.05); // triggers ++ MbedOS Fault Handler ++
}
fclose(fp);
}
No values are stored into the csv file as the application doesn't get to fclose(fp);
Expected behavior
That the fault handler is not triggered and the for loop waits for 0.05 seconds, then saves a test.csv file with the 100 integer values.
Actual behavior
Output to the serial terminal of the Fault Handler error message:
++ MbedOS Fault Handler ++
FaultType: HardFault
Context:
R0 : 00000005
R1 : 100025AC
R2 : 00000122
R3 : 00000000
R4 : 00000005
R5 : 100025AC
R6 : 10002920
R7 : 10000288
R8 : 10000288
R9 : 00000000
R10 : 00000000
R11 : 00000000
R12 : 00002CD9
SP : 100025A8
LR : 00000CF1
PC : 00001794
xPSR : 01000000
PSP : 10002588
MSP : 10007FB8
CPUID: 412FC230
HFSR : 80000000
MMFSR: 00000000
BFSR : 00000000
UFSR : 00000000
DFSR : 00000002
AFSR : 00000000
SHCSR: 00000000
Mode : Thread
Priv : Privileged
Stack: PSP
Thread Info:
Current:
State: 00000002 EntryFn: 00001CF1 Stack Size: 00001000 Mem: 10001648 SP: 100025D0
Next:
State: 00000002 EntryFn: 00001CF1 Stack Size: 00001000 Mem: 10001648 SP: 100025D0
Wait Threads:
State: 00000083 EntryFn: 00003A8D Stack Size: 00000300 Mem: 10000F78 SP: 10001210
Delay Threads:
Idle Thread:
State: 00000001 EntryFn: 00001E79 Stack Size: 00000200 Mem: 10001278 SP: 10001420
-- MbedOS Fault Handler --