path: root/src
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authorJan Vorlicek <>2018-06-28 21:39:51 (GMT)
committerGitHub <>2018-06-28 21:39:51 (GMT)
commit73b3ec31925c11456924a95200a478af54d4b2e6 (patch)
tree869ec55326cafad84643699651ab9131726db0fe /src
parentaa00dad99dff3af496b245e6b10500a5e631a8ba (diff)
Port to 2.1: Fix alternate stack cleanup on MUSL (#18687)
The MUSL implementation of sigaltstack checks that the ss.ss_size is larger or equal than the MINSIGSTKSZ even when the ss_flags is set to SS_DISABLE even though Linux man page for sigaltstack states that when this flag is set, all other ss fields are ignored. We were not setting the ss_size in this case and it was causing a memory leak for each thread that has terminated on MUSL based Linux distros like Alpine. Glibc implementation doesn't check the ss_size when the SS_DISABLE is set so the problem was really MUSL specific.
Diffstat (limited to 'src')
1 files changed, 4 insertions, 0 deletions
diff --git a/src/pal/src/exception/signal.cpp b/src/pal/src/exception/signal.cpp
index 458e331..7f2e5c5 100644
--- a/src/pal/src/exception/signal.cpp
+++ b/src/pal/src/exception/signal.cpp
@@ -199,6 +199,10 @@ Return :
void FreeSignalAlternateStack()
stack_t ss, oss;
+ // The man page for sigaltstack says that when the ss.ss_flags is set to SS_DISABLE,
+ // all other ss fields are ignored. However, MUSL implementation checks that the
+ // ss_size is >= MINSIGSTKSZ even in this case.
+ ss.ss_size = MINSIGSTKSZ;
ss.ss_flags = SS_DISABLE;
int st = sigaltstack(&ss, &oss);
if ((st == 0) && (oss.ss_flags != SS_DISABLE))