| Message ID | 20230319151017.531737-28-bugaevc@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | The rest of the x86_64-gnu port | expand |
Applied, thanks! Sergey Bugaev, le dim. 19 mars 2023 18:10:10 +0300, a ecrit: > Previously, once we set up TLS, we would implicitly switch from using > __hurd_reply_port0 to reply_port inside the TCB, leaving the former > unused. But we never deallocated it, so it got leaked. > > Instead, migrate the port into the new TCB's reply_port slot. This > avoids both the port leak and an extra syscall to create a new reply > port for the TCB. > > Signed-off-by: Sergey Bugaev <bugaevc@gmail.com> > --- > sysdeps/mach/hurd/i386/tls.h | 5 +++++ > sysdeps/mach/hurd/x86_64/tls.h | 9 ++++++++- > 2 files changed, 13 insertions(+), 1 deletion(-) > > diff --git a/sysdeps/mach/hurd/i386/tls.h b/sysdeps/mach/hurd/i386/tls.h > index ee7b8004..0ac8917a 100644 > --- a/sysdeps/mach/hurd/i386/tls.h > +++ b/sysdeps/mach/hurd/i386/tls.h > @@ -141,12 +141,15 @@ _hurd_tls_init (tcbhead_t *tcb) > HURD_TLS_DESC_DECL (desc, tcb); > thread_t self = __mach_thread_self (); > bool success = true; > + extern mach_port_t __hurd_reply_port0; > > /* This field is used by TLS accesses to get our "thread pointer" > from the TLS point of view. */ > tcb->tcb = tcb; > /* We always at least start the sigthread anyway. */ > tcb->multiple_threads = 1; > + /* Take over the reply port we've been using. */ > + tcb->reply_port = __hurd_reply_port0; > > /* Get the first available selector. */ > int sel = -1; > @@ -172,6 +175,8 @@ _hurd_tls_init (tcbhead_t *tcb) > > /* Now install the new selector. */ > asm volatile ("mov %w0, %%gs" :: "q" (sel)); > + /* This port is now owned by the TCB. */ > + __hurd_reply_port0 = MACH_PORT_NULL; > > out: > __mach_port_deallocate (__mach_task_self (), self); > diff --git a/sysdeps/mach/hurd/x86_64/tls.h b/sysdeps/mach/hurd/x86_64/tls.h > index da504d9c..2b7135f6 100644 > --- a/sysdeps/mach/hurd/x86_64/tls.h > +++ b/sysdeps/mach/hurd/x86_64/tls.h > @@ -177,13 +177,20 @@ _hurd_tls_init (tcbhead_t *tcb) > { > error_t err; > thread_t self = __mach_thread_self (); > + extern mach_port_t __hurd_reply_port0; > > /* We always at least start the sigthread anyway. */ > tcb->multiple_threads = 1; > + /* Take over the reply port we've been using. */ > + tcb->reply_port = __hurd_reply_port0; > > err = _hurd_tls_new (self, tcb); > if (err == 0) > - __libc_tls_initialized = 1; > + { > + __libc_tls_initialized = 1; > + /* This port is now owned by the TCB. */ > + __hurd_reply_port0 = MACH_PORT_NULL; > + } > __mach_port_deallocate (__mach_task_self (), self); > return err == 0; > } > -- > 2.39.2 >
diff --git a/sysdeps/mach/hurd/i386/tls.h b/sysdeps/mach/hurd/i386/tls.h index ee7b8004..0ac8917a 100644 --- a/sysdeps/mach/hurd/i386/tls.h +++ b/sysdeps/mach/hurd/i386/tls.h @@ -141,12 +141,15 @@ _hurd_tls_init (tcbhead_t *tcb) HURD_TLS_DESC_DECL (desc, tcb); thread_t self = __mach_thread_self (); bool success = true; + extern mach_port_t __hurd_reply_port0; /* This field is used by TLS accesses to get our "thread pointer" from the TLS point of view. */ tcb->tcb = tcb; /* We always at least start the sigthread anyway. */ tcb->multiple_threads = 1; + /* Take over the reply port we've been using. */ + tcb->reply_port = __hurd_reply_port0; /* Get the first available selector. */ int sel = -1; @@ -172,6 +175,8 @@ _hurd_tls_init (tcbhead_t *tcb) /* Now install the new selector. */ asm volatile ("mov %w0, %%gs" :: "q" (sel)); + /* This port is now owned by the TCB. */ + __hurd_reply_port0 = MACH_PORT_NULL; out: __mach_port_deallocate (__mach_task_self (), self); diff --git a/sysdeps/mach/hurd/x86_64/tls.h b/sysdeps/mach/hurd/x86_64/tls.h index da504d9c..2b7135f6 100644 --- a/sysdeps/mach/hurd/x86_64/tls.h +++ b/sysdeps/mach/hurd/x86_64/tls.h @@ -177,13 +177,20 @@ _hurd_tls_init (tcbhead_t *tcb) { error_t err; thread_t self = __mach_thread_self (); + extern mach_port_t __hurd_reply_port0; /* We always at least start the sigthread anyway. */ tcb->multiple_threads = 1; + /* Take over the reply port we've been using. */ + tcb->reply_port = __hurd_reply_port0; err = _hurd_tls_new (self, tcb); if (err == 0) - __libc_tls_initialized = 1; + { + __libc_tls_initialized = 1; + /* This port is now owned by the TCB. */ + __hurd_reply_port0 = MACH_PORT_NULL; + } __mach_port_deallocate (__mach_task_self (), self); return err == 0; }
Previously, once we set up TLS, we would implicitly switch from using __hurd_reply_port0 to reply_port inside the TCB, leaving the former unused. But we never deallocated it, so it got leaked. Instead, migrate the port into the new TCB's reply_port slot. This avoids both the port leak and an extra syscall to create a new reply port for the TCB. Signed-off-by: Sergey Bugaev <bugaevc@gmail.com> --- sysdeps/mach/hurd/i386/tls.h | 5 +++++ sysdeps/mach/hurd/x86_64/tls.h | 9 ++++++++- 2 files changed, 13 insertions(+), 1 deletion(-)