I run firefox - it does not open
I try to kill the process with kill -9 and it still persists with "sleep to
disk" status

when running strace firefox in console i can see it stops on some reading:

openat(AT_FDCWD, "/usr/lib64/firefox/libopus.so.0", O_RDONLY|O_CLOEXEC) = -1
ENOENT (Nie ma takiego pliku ani katalogu)
openat(AT_FDCWD, "/usr/lib64/libopus.so.0", O_RDONLY|O_CLOEXEC) = 33
read(33, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\3403\0\0\0\0\0\0"...,
832) = 832
newfstatat(33, "", {st_mode=S_IFREG|0755, st_size=363112, ...}, AT_EMPTY_PATH)
= 0
mmap(NULL, 365048, PROT_READ, MAP_PRIVATE|MAP_DENYWRITE, 33, 0) =
0x7fb0b652e000
mmap(0x7fb0b6531000, 278528, PROT_READ|PROT_EXEC,
MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 33, 0x3000) = 0x7fb0b6531000
mmap(0x7fb0b6575000, 69632, PROT_READ, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 33,
0x47000) = 0x7fb0b6575000
mmap(0x7fb0b6586000, 8192, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 33, 0x57000) = 0x7fb0b6586000
close(33)                               = 0
mprotect(0x7fb0b6586000, 4096, PROT_READ) = 0
mprotect(0x7fb0b65a4000, 4096, PROT_READ) = 0
mprotect(0x7fb0b65e1000, 4096, PROT_READ) = 0
mprotect(0x7fb0b6671000, 114688, PROT_READ) = 0
mprotect(0x7fb0b670c000, 12288, PROT_READ) = 0
mprotect(0x7fb0b6795000, 4096, PROT_READ) = 0
mprotect(0x7fb0b67ea000, 4096, PROT_READ) = 0
munmap(0x7fb0b67ec000, 134660)          = 0
futex(0x7fb0be208ab4, FUTEX_WAKE_PRIVATE, 1) = 1
futex(0x7fb0c9f020d8, FUTEX_WAKE_PRIVATE, 1) = 1
mprotect(0x196759205000, 8192, PROT_READ|PROT_WRITE) = 0
mprotect(0x196759205000, 8192, PROT_READ|PROT_EXEC) = 0
read(3,