From: Lennart Poettering <lennart@poettering.net>
Date: Thu, 10 Mar 2022 08:22:32 +0000 (+0100)
Subject: pid1: add comment to crash handler about memory allocations
X-Git-Tag: v251-rc1~177^2~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4fba096ba106a5629ae9a1ed895a744b974e56ca;p=thirdparty%2Fsystemd.git

pid1: add comment to crash handler about memory allocations
---

diff --git a/src/core/main.c b/src/core/main.c
index 7c9265f394e..fc524867ef6 100644
--- a/src/core/main.c
+++ b/src/core/main.c
@@ -232,6 +232,12 @@ _noreturn_ static void crash(int sig, siginfo_t *siginfo, void *context) {
         struct sigaction sa;
         pid_t pid;
 
+        /* NB: 💣 💣 💣 This is a signal handler, most likely executed in a situation where we have corrupted
+         * memory. Thus: please avoid any libc memory allocation here, or any functions that internally use
+         * memory allocation, as we cannot rely on memory allocation still working at this point! (Note that
+         * memory allocation is not async-signal-safe anyway — see signal-safety(7) for details —, and thus
+         * is not permissible in signal handlers.) */
+
         if (getpid_cached() != 1)
                 /* Pass this on immediately, if this is not PID 1 */
                 (void) raise(sig);