The class child_info_spawn has two constructors: one without arguments and one with two arguments. The former does not initialize any members. Commit 1f836c5f7394 used the latter to ensure that the local ch_spawn (i.e., ch_spawn_local) would be properly initialized. However, this was insufficient - it initialized only the base child_info members, not the fields specific to child_info_spawn. This led to the issue reported in https://cygwin.com/pipermail/cygwin/2025-August/258660.html.
This patch updates the former constructor to properly initialize member variable 'ev' which was referred without initialization, and switches ch_spawn_local to use it. Addresses: https://cygwin.com/pipermail/cygwin/2025-August/258660.html Fixes: 1f836c5f7394 ("Cygwin: spawn: Make system() thread-safe") Reported-by: Denis Excoffier <cyg...@denis-excoffier.org> Reviewed-by: Jeremy Drake <cyg...@jdrake.com> Signed-off-by: Takashi Yano <takashi.y...@nifty.ne.jp> --- winsup/cygwin/local_includes/child_info.h | 5 +++-- winsup/cygwin/spawn.cc | 2 +- winsup/cygwin/syscalls.cc | 2 +- 3 files changed, 5 insertions(+), 4 deletions(-) diff --git a/winsup/cygwin/local_includes/child_info.h b/winsup/cygwin/local_includes/child_info.h index 2da62ffaa..b8707b9ec 100644 --- a/winsup/cygwin/local_includes/child_info.h +++ b/winsup/cygwin/local_includes/child_info.h @@ -33,7 +33,7 @@ enum child_status #define EXEC_MAGIC_SIZE sizeof(child_info) /* Change this value if you get a message indicating that it is out-of-sync. */ -#define CURR_CHILD_INFO_MAGIC 0xacbf4682U +#define CURR_CHILD_INFO_MAGIC 0x39f766b5U #include "pinfo.h" struct cchildren @@ -148,7 +148,8 @@ public: char filler[4]; void cleanup (); - child_info_spawn () {}; + child_info_spawn () : + child_info (sizeof *this, _CH_NADA, false), ev (NULL) {}; child_info_spawn (child_info_types, bool); void record_children (); void reattach_children (); diff --git a/winsup/cygwin/spawn.cc b/winsup/cygwin/spawn.cc index 680f0fefd..6cd97ec17 100644 --- a/winsup/cygwin/spawn.cc +++ b/winsup/cygwin/spawn.cc @@ -950,7 +950,7 @@ spawnve (int mode, const char *path, const char *const *argv, if (!envp) envp = empty_env; - child_info_spawn ch_spawn_local (_CH_NADA, false); + child_info_spawn ch_spawn_local; switch (_P_MODE (mode)) { case _P_OVERLAY: diff --git a/winsup/cygwin/syscalls.cc b/winsup/cygwin/syscalls.cc index 863f8f23c..83a54ca05 100644 --- a/winsup/cygwin/syscalls.cc +++ b/winsup/cygwin/syscalls.cc @@ -4535,7 +4535,7 @@ popen (const char *command, const char *in_type) fcntl (stdchild, F_SETFD, stdchild_state | FD_CLOEXEC); /* Start a shell process to run the given command without forking. */ - child_info_spawn ch_spawn_local (_CH_NADA, false); + child_info_spawn ch_spawn_local; pid_t pid = ch_spawn_local.worker ("/bin/sh", argv, environ, _P_NOWAIT, __std[0], __std[1]); -- 2.45.1
