Hi all, I have a application code that reads from the lm75 temperature sensor which is connected via i2c.
the application opens the sys file "/sys/class/hwmon/hwmon0/temp1_input" and using fscanf reads the data and process it. My problem is if i have multiple calls to reading the file the system crashes with no logs even after enabling debugs and setting console log levels appropriately. I added spinlocks in lm75 driver where the register is read and that didn't change anything . Please help me out fellow penguins..

You have given almost 0 info.

What programming language? PHP, C C++ ? Show the bit of code that is reading it.

Hi, sorry I didn't attach any reference code. it just does fopen and fscanf on the /sys... file , the application code looks similar to this...

int getsensortemps()
{

FILE* tempfile = NULL;
int *tempvalue = 0;
tempfile = fopen("/sys/class/hwmon/hwmon0/temp1_input", "r");
if( tempfile == NULL )return -1;
if(fscanf(tempfile, "%d" ,tempvalue) > 0){
*tempvalue=*tempvalue / 100;
fclose(tempfile);
return *tempvalue;
}
fclose(tempfile);
return -1
}

my problem is multiple process access this function
1) A background process which updates temp periodically
2) A CLI command which gives temp output

both access this function, and sometimes this causes crash with no logs. I even tried cat /sys/class/hwmon/hwmon0/temp1_input this also produced crash. The crash is not certain to happen but occurs randomly , with probability increasing with how fast we access the /sys/.... file...

the lm75 sensor code is generic one..

thanks in advance

https://elixir.bootlin.com/linux/lat...s/hwmon/lm75.c