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Remove support for FUTEX_REQUEUE operation.

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Glibc does not use this operation since 2.3.3 version (Jun 2004),
as it is racy and replaced by FUTEX_CMP_REQUEUE operation.
Glibc versions prior to 2.3.3 fall back to FUTEX_WAKE when
FUTEX_REQUEUE returned EINVAL.

Any application directly using FUTEX_REQUEUE without return
value checking are definitely broken.

Limit quantity of messages per process about unsupported
operation.

Approved by:	kib (mentor)
MFC after:	1 month
This commit is contained in:
dchagin 2009-04-19 13:48:42 +00:00
parent 367054e0a3
commit ada9604fd2
3 changed files with 20 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
sys/compat/linux/linux_emul.c
View File

@ -86,6 +86,7 @@ linux_proc_init(struct thread *td, pid_t child, int flags)
em = malloc(sizeof *em, M_LINUX, M_WAITOK | M_ZERO);
em->pid = child;
em->pdeath_signal = 0;
em->used_requeue = 0;
em->robust_futexes = NULL;
if (flags & LINUX_CLONE_THREAD) {
/* handled later in the code */

1
sys/compat/linux/linux_emul.h
View File

@ -51,6 +51,7 @@ struct linux_emuldata {
struct linux_emuldata_shared *shared;
int pdeath_signal; /* parent death signal */
int used_requeue; /* uses deprecated futex op */
struct linux_robust_list_head *robust_futexes;

31
sys/compat/linux/linux_futex.c
View File

@ -114,6 +114,7 @@ linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args)
struct timeval tv = {0, 0};
struct futex *f2;
int op_ret;
struct linux_emuldata *em;
#ifdef DEBUG
if (ldebug(sys_futex))
@ -262,19 +263,6 @@ linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args)
FUTEX_SYSTEM_UNLOCK;
break;
case LINUX_FUTEX_REQUEUE:
FUTEX_SYSTEM_LOCK;
f = futex_get(args->uaddr, FUTEX_UNLOCKED);
newf = futex_get(args->uaddr2, FUTEX_UNLOCKED);
td->td_retval[0] = futex_wake(f, args->val, newf,
(int)(unsigned long)args->timeout);
futex_put(f);
futex_put(newf);
FUTEX_SYSTEM_UNLOCK;
break;
case LINUX_FUTEX_WAKE_OP:
FUTEX_SYSTEM_LOCK;
#ifdef DEBUG
@ -342,6 +330,23 @@ linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args)
/* not yet implemented */
return (ENOSYS);
case LINUX_FUTEX_REQUEUE:
/*
* Glibc does not use this operation since Jun 2004 (2.3.3),
* as it is racy and replaced by FUTEX_CMP_REQUEUE operation.
* Glibc versions prior to 2.3.3 fall back to FUTEX_WAKE when
* FUTEX_REQUEUE returned EINVAL.
*/
em = em_find(td->td_proc, EMUL_DONTLOCK);
if (em->used_requeue == 0) {
printf("linux(%s (%d)) sys_futex: "
"unsupported futex_requeue op\n",
td->td_proc->p_comm, td->td_proc->p_pid);
em->used_requeue = 1;
}
return (EINVAL);
default:
printf("linux_sys_futex: unknown op %d\n",
args->op);