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FreeBSD: fix panic due to tqid overflow

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The 32-bit counter eventually wraps to 0 which is a sentinel for invalid
id.

Make it 64-bit on LP64 platforms and 0-check otherwise.

Note: Linux counterpart uses id stored per queue instead of a global.
I did not check going that way is feasible with the goal being the
minimal fix doing the job.

Reported by:	YAMAMOTO Shigeru <shigeru@os-hackers.jp>
Reviewed by:	mav
Differential Revision:	https://reviews.freebsd.org/D26759
This commit is contained in:
Mateusz Guzik 2020-10-13 20:40:09 +00:00
parent 3f8d55c617
commit c3f8f86efd
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=366685
1 changed files with 32 additions and 10 deletions
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42
sys/contrib/openzfs/module/os/freebsd/spl/spl_taskq.c
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@ -67,7 +67,7 @@ static unsigned long tqenthash;
static unsigned long tqenthashlock;
static struct sx *tqenthashtbl_lock;
static uint32_t tqidnext = 1;
static taskqid_t tqidnext;
#define TQIDHASH(tqid) (&tqenthashtbl[(tqid) & tqenthash])
#define TQIDHASHLOCK(tqid) (&tqenthashtbl_lock[((tqid) & tqenthashlock)])
@ -90,7 +90,6 @@ system_taskq_init(void *arg)
M_TASKQ, M_WAITOK | M_ZERO);
for (i = 0; i < tqenthashlock + 1; i++)
sx_init_flags(&tqenthashtbl_lock[i], "tqenthash", SX_DUPOK);
tqidnext = 1;
taskq_zone = uma_zcreate("taskq_zone", sizeof (taskq_ent_t),
NULL, NULL, NULL, NULL,
UMA_ALIGN_CACHE, 0);
@ -121,6 +120,28 @@ system_taskq_fini(void *arg)
SYSUNINIT(system_taskq_fini, SI_SUB_CONFIGURE, SI_ORDER_ANY, system_taskq_fini,
NULL);
#ifdef __LP64__
static taskqid_t
__taskq_genid(void)
{
return (atomic_fetchadd_long(&tqidnext, 1) + 1);
}
#else
static taskqid_t
__taskq_genid(void)
{
taskqid_t tqid;
for (;;) {
tqid = atomic_fetchadd_int(&tqidnext, 1) + 1;
if (__predict_true(tqid != 0))
break;
}
return (tqid);
}
#endif
static taskq_ent_t *
taskq_lookup(taskqid_t tqid)
{
@ -140,8 +161,10 @@ taskq_lookup(taskqid_t tqid)
static taskqid_t
taskq_insert(taskq_ent_t *ent)
{
taskqid_t tqid = atomic_fetchadd_int(&tqidnext, 1);
taskqid_t tqid;
tqid = __taskq_genid();
VERIFY(tqid);
ent->tqent_id = tqid;
ent->tqent_registered = B_TRUE;
sx_xlock(TQIDHASHLOCK(tqid));
@ -289,7 +312,7 @@ taskq_dispatch_delay(taskq_t *tq, task_func_t func, void *arg,
uint_t flags, clock_t expire_time)
{
taskq_ent_t *task;
taskqid_t tid;
taskqid_t tqid;
clock_t timo;
int mflag;
@ -310,13 +333,13 @@ taskq_dispatch_delay(taskq_t *tq, task_func_t func, void *arg,
task->tqent_type = TIMEOUT_TASK;
task->tqent_cancelled = B_FALSE;
refcount_init(&task->tqent_rc, 1);
tid = taskq_insert(task);
tqid = taskq_insert(task);
TIMEOUT_TASK_INIT(tq->tq_queue, &task->tqent_timeout_task, 0,
taskq_run, task);
taskqueue_enqueue_timeout(tq->tq_queue, &task->tqent_timeout_task,
timo);
return (tid);
return (tqid);
}
taskqid_t
@ -324,7 +347,7 @@ taskq_dispatch(taskq_t *tq, task_func_t func, void *arg, uint_t flags)
{
taskq_ent_t *task;
int mflag, prio;
taskqid_t tid;
taskqid_t tqid;
if ((flags & (TQ_SLEEP | TQ_NOQUEUE)) == TQ_SLEEP)
mflag = M_WAITOK;
@ -344,11 +367,10 @@ taskq_dispatch(taskq_t *tq, task_func_t func, void *arg, uint_t flags)
task->tqent_arg = arg;
task->tqent_cancelled = B_FALSE;
task->tqent_type = NORMAL_TASK;
tid = taskq_insert(task);
tqid = taskq_insert(task);
TASK_INIT(&task->tqent_task, prio, taskq_run, task);
taskqueue_enqueue(tq->tq_queue, &task->tqent_task);
VERIFY(tid);
return (tid);
return (tqid);
}
static void