Skip to content

Instantly share code, notes, and snippets.

What would you like to do?
Find processes executing futex with FUTEX_WAIT (helps find deadlock-ed processes)
# Find all processes that are executing a futex(2) call with op=FUTEX_WAIT
# In some cases this can be helpful in finding deadlock-ed processes.
test ! $UID -eq 0 && echo -e "WARNING: Not running as root, only processes for this user are being scanned\n" >&2;
pids=$(ps -u $UID -opid --no-headers)
for pid in $pids; do
cat /proc/$pid/syscall |
awk "{if (\$1 == 202 && \$3 == \"0x0\") {
print $pid
# $1 is the syscall, we compare to 202 which is the futex call
# See: /usr/include/asm/unistd.h
# $2 is the 1st param, $3 is the 2nd param, etc
# We compare the second param to 0x0 which is FUTEX_WAIT
# See: /usr/include/linux/futex.h

This comment has been minimized.

Copy link

@liuyangc3 liuyangc3 commented Dec 4, 2015

nice work but I get an error when use this script:

[root@xxx ~]# /data0/script/
cat: /proc/2529/syscall: No such file or directory

and I fix it in my fork

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment