From 9e4f3a348127bfd7a7cf633d6eb4b6109a4381f6 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Date: Mon, 4 Jul 2016 20:57:32 +0200 Subject: [PATCH 12/16] char: do not use atexit cleanup handler MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RH-Author: Marc-André Lureau Message-id: <20160704205732.27022-6-marcandre.lureau@redhat.com> Patchwork-id: 70942 O-Subject: [RHEV-7.3 qemu-kvm-rhev PATCH v2 5/5] char: do not use atexit cleanup handler Bugzilla: 1347077 RH-Acked-by: Xiao Wang RH-Acked-by: Laurent Vivier RH-Acked-by: Victor Kaplansky RH-Acked-by: Paolo Bonzini From: Marc-André Lureau It turns out qemu is calling exit() in various places from various threads without taking much care of resources state. The atexit() cleanup handlers cannot easily destroy resources that are in use (by the same thread or other). Since c1111a24a3, TCG arm guests run into the following abort() when running tests, the chardev mutex is locked during the write, so qemu_mutex_destroy() returns an error: #0 0x00007fffdbb806f5 in raise () at /lib64/libc.so.6 #1 0x00007fffdbb822fa in abort () at /lib64/libc.so.6 #2 0x00005555557616fe in error_exit (err=, msg=msg@entry=0x555555c38c30 <__func__.14622> "qemu_mutex_destroy") at /home/drjones/code/qemu/util/qemu-thread-posix.c:39 #3 0x0000555555b0be20 in qemu_mutex_destroy (mutex=mutex@entry=0x5555566aa0e0) at /home/drjones/code/qemu/util/qemu-thread-posix.c:57 #4 0x00005555558aab00 in qemu_chr_free_common (chr=0x5555566aa0e0) at /home/drjones/code/qemu/qemu-char.c:4029 #5 0x00005555558b05f9 in qemu_chr_delete (chr=) at /home/drjones/code/qemu/qemu-char.c:4038 #6 0x00005555558b05f9 in qemu_chr_delete (chr=) at /home/drjones/code/qemu/qemu-char.c:4044 #7 0x00005555558b062c in qemu_chr_cleanup () at /home/drjones/code/qemu/qemu-char.c:4557 #8 0x00007fffdbb851e8 in __run_exit_handlers () at /lib64/libc.so.6 #9 0x00007fffdbb85235 in () at /lib64/libc.so.6 #10 0x00005555558d1b39 in testdev_write (testdev=0x5555566aa0a0) at /home/drjones/code/qemu/backends/testdev.c:71 #11 0x00005555558d1b39 in testdev_write (chr=, buf=0x7fffc343fd9a "", len=0) at /home/drjones/code/qemu/backends/testdev.c:95 #12 0x00005555558adced in qemu_chr_fe_write (s=0x5555566aa0e0, buf=buf@entry=0x7fffc343fd98 "0q", len=len@entry=2) at /home/drjones/code/qemu/qemu-char.c:282 Instead of using a atexit() handler, only run the chardev cleanup as initially proposed at the end of main(), where there are less chances (hic) of conflicts or other races. Signed-off-by: Marc-André Lureau Reported-by: Andrew Jones Signed-off-by: Paolo Bonzini (cherry picked from commit dd9250d5d99a2671584f65b7d0745355bbbe353f) Signed-off-by: Marc-André Lureau Signed-off-by: Miroslav Rezanina --- include/sysemu/char.h | 7 +++++++ qemu-char.c | 4 +--- vl.c | 1 + 3 files changed, 9 insertions(+), 3 deletions(-) diff --git a/include/sysemu/char.h b/include/sysemu/char.h index 2c39987..c4692d5 100644 --- a/include/sysemu/char.h +++ b/include/sysemu/char.h @@ -152,6 +152,13 @@ CharDriverState *qemu_chr_new(const char *label, const char *filename, void qemu_chr_disconnect(CharDriverState *chr); /** + * @qemu_chr_cleanup: + * + * Delete all chardevs (when leaving qemu) + */ +void qemu_chr_cleanup(void); + +/** * @qemu_chr_new_noreplay: * * Create a new character backend from a URI. diff --git a/qemu-char.c b/qemu-char.c index 87212b8..0cbb6a1ea 100644 --- a/qemu-char.c +++ b/qemu-char.c @@ -4566,7 +4566,7 @@ void qmp_chardev_remove(const char *id, Error **errp) qemu_chr_delete(chr); } -static void qemu_chr_cleanup(void) +void qemu_chr_cleanup(void) { CharDriverState *chr, *tmp; @@ -4621,8 +4621,6 @@ static void register_types(void) * is specified */ qemu_add_machine_init_done_notifier(&muxes_realize_notify); - - atexit(qemu_chr_cleanup); } type_init(register_types); diff --git a/vl.c b/vl.c index 899dd55..2b4e22e 100644 --- a/vl.c +++ b/vl.c @@ -4673,6 +4673,7 @@ int main(int argc, char **argv, char **envp) #ifdef CONFIG_TPM tpm_cleanup(); #endif + qemu_chr_cleanup(); return 0; } -- 1.8.3.1