Segment fault php nginx?

Question

CodeIgniter

Good afternoon.
There is an old project on CodeIgniter.
PHP crashes completely randomly, nginx throws the following error in the logs:
**XXXX recv() failed: 104: Connection reset by peer.
And here is what the process trace gives:
munmap(0x7f403906e000, 9965568) = 0
setitimer(ITIMER_PROF, {it_interval={0, 0}, it_value={0, 0}}, NULL) = 0
clock_gettime(CLOCK_MONOTONIC, {239279, 362982551} ) = 0
accept(0, {sa_family=AF_INET, sin_port=htons(59161), sin_addr=inet_addr("127.0.0.1")}, [16]) = 5
clock_gettime(CLOCK_MONOTONIC, {239308, 282662413}) = 0
times ({tms_utime=53, tms_stime=22, tms_cutime=0, tms_cstime=0}) = 1741887746
poll([{fd=5, events=POLLIN}], 1, 5000) = 1 ([{fd=5, revents= POLLIN}])
read(5, "\1\1\0\1\0\10\0\0", 8) = 8
read(5, "\0\1\0\0\0\0\0\0", 8) = 8
read(5, "\1\4\0\1\7\206\2\0", 8) = 8
text/javascript, */*; q=0.01\v\34HTTP_ORIGINhttps://***\25\16HTTP_X_REQUESTED_WITHXMLHttpReque... (Linux; Android 4.4.2; SM-T231 Build/KOT49H) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2785.124 Safari/537.36\f$HTTP_REFERER https://***/profile\24,HTTP_ACCEPT_LANGUAGEru-RU,r... save_email=f7bdb7dda203d505de76652eeb20ad0a; autologin=a%3A2%3A%7Bs%3A7%3A%22user_id%22%3Bs%3A5%3A%2234881%22%3Bs%3A3%3A%22key%22%3Bs%3A16%3A%224f3204b9b6e1d131%22%3B% 7D; first_time_login=1; ***; language=az\25\vHTTP_CF_CONNECTING_IP5.197.53.95\0\0", 1928) = 1928
read(5, "\1\4\0\1\0\0\0\0", 8) = 8
clock_gettime( CLOCK_MONOTONIC, {239308, 283205847}) = 0
gettimeofday({1475321518, 776387}, NULL) = 0
gettimeofday({1475321518, 776479}, NULL) = 0
rt_sigaction
(SIGPROF, {0x6e27f0, [PROF], SA_RESTORER|SA_RESTART, 0x7f4044c4b0e0}, {0x6e27f0, [PROF] , SA_RESTORER|SA_RESTART, 0x7f4044c4b0e0}, 8) = 0
rt_sigprocmask(SIG_UNBLOCK, [PROF], NULL, 8) = 0
clock_gettime(CLOCK_MONOTONIC, {239308, 283678183}) = 0
getcwd("/", 4095) = 2
chdir( "/home/***/www") = 0
setitimer(ITIMER_PROF, {it_interval={0, 0}, it_value={30, 0}}, NULL) = 0
fcntl(4, F_SETLK, {type=F_RDLCK, whence=SEEK_SET, start=1, len=1}) = 0
stat("/home/***/www/index.php", {st_mode=S_IFREG|0644, st_size=6920, ...}) = 0
getcwd("/home/***/www", 4096) = 23
getcwd("/home/***/www",4096) = 23
stat("/home/***/www/system/", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
stat("application", {st_mode=S_IFDIR|0755, st_size=4096 , ...}) = 0
stat("/home/***/www/system/core/CodeIgniter.php", {st_mode=S_IFREG|0644, st_size=11880, ...}) = 0
chdir(" /") = 0
clock_gettime(CLOCK_MONOTONIC, {239308, 284499594}) = 0
times({tms_utime=53, tms_stime=22, tms_cutime=0, tms_cstime=0}) = 1741887747
setitimer(ITIMER_PROF, {it_interval={0, 0 }, it_value={0, 0}}, NULL) = 0
fcntl(4, F_SETLK, {type=F_UNLCK, whence=SEEK_SET, start=0, len=0}) = 0
--- SIGSEGV {si_signo=SIGSEGV, si_code=SI_KERNEL, si_addr=0} ---
+++ killed by SIGSEGV +++