2 ms·

It think one of the reasons the kernel can't kill a process is because one of the process's threads is blocked inside a kernel call (not completely sure about t

by nonane 14y ago

It think one of the reasons the kernel can't kill a process is because one of the process's threads is blocked inside a kernel call (not completely sure about this). Hes using ps's 'wchan' option to get the address of the kernel function that the process is currently blocked or sleeping on. After he gets the wchan address, he uses gdb to map the address to function name. Taken from: http://unixhelp.ed.ac.uk/CGI/man-cgi?ps http://unixhelp.ed.ac.uk/CGI/man-cgi?ps nwchan WCHAN address of the kernel function where the process is sleeping (use wchan if you want the kernel function name). Running tasks will display a dash ('-') in this column.

mbell 14y ago
/proc/{pid}/wchan contains the function name, not its address. In this example he's just printing the syscall that his example process is running. The calls to strace and gdb are disjoint, he's cut out a lot of stuff here, probably why its confusing. In the commands he's used strace would dump all the syscall details to the console and GDB would just attach to the process and enter its normal console (presumably hes determined hes stuck in a loop so hes just using disassemble).