Date: Tue, 13 Oct 2020 14:15:19 +0200 From: Mateusz Guzik <mjguzik@gmail.com> To: YAMAMOTO Shigeru <shigeru@os-hackers.jp> Cc: freebsd-current@freebsd.org Subject: Re: zfs panic when 'make buildworld buildkernel' Message-ID: <CAGudoHFVyX1w%2BdhWnxEKVKwpPC_AG6fAOnLiwO3%2BDyi_7oWqMw@mail.gmail.com> In-Reply-To: <CAGudoHG_RPB2C3pC3iRb=E1FdHjKL6drHz9qGbFzirTm8HeLng@mail.gmail.com> References: <20201013.202148.2154404302288800973.shigeru@os-hackers.jp> <CAGudoHG_RPB2C3pC3iRb=E1FdHjKL6drHz9qGbFzirTm8HeLng@mail.gmail.com>
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On 10/13/20, Mateusz Guzik <mjguzik@gmail.com> wrote:
> On 10/13/20, YAMAMOTO Shigeru <shigeru@os-hackers.jp> wrote:
>>
>> Hi,
>>
>> I try to 'make buildworld buildkernel' at full ZFS environment.
>> But I can't finished buildworld/buildkernel without panic.
>> Anyone have same trouble?
>>
>> uname -a:
>> ```
>> FreeBSD jenkins-02.current.os-hackers.jp 13.0-CURRENT FreeBSD
>> 13.0-CURRENT
>> #0 r366657: Tue Oct 13 13:07:15 JST 2020
>> root@jenkins-02.current.os-hackers.jp:/usr/obj/usr/src/amd64.amd64/sys/GENERIC
>> amd64
>> ```
>>
>> panic message:
>> ```
>> login: panic: VERIFY(tid) failed
>>
>> cpuid = 2
>> time = 1602582381
>> KDB: stack backtrace:
>> db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame
>> 0xfffffe002abaa9f0
>> vpanic() at vpanic+0x182/frame 0xfffffe002abaaa40
>> spl_panic() at spl_panic+0x3a/frame 0xfffffe002abaaaa0
>> taskq_dispatch() at taskq_dispatch+0xe8/frame 0xfffffe002abaaae0
>> arc_prune_async() at arc_prune_async+0x3f/frame 0xfffffe002abaab00
>> arc_evict_cb() at arc_evict_cb+0x1f6/frame 0xfffffe002abaab60
>> zthr_procedure() at zthr_procedure+0x8f/frame 0xfffffe002abaabb0
>> fork_exit() at fork_exit+0x80/frame 0xfffffe002abaabf0
>> fork_trampoline() at fork_trampoline+0xe/frame 0xfffffe002abaabf0
>> --- trap 0, rip = 0, rsp = 0, rbp = 0 ---
>> KDB: enter: panic
>> [ thread pid 19 tid 100070 ]
>> Stopped at kdb_enter+0x37: movq $0,0x10b0116(%rip)
>> db>
>> ```
>>
>
> The issue is pretty apparent:
>
> taskqid_t tqid = atomic_fetchadd_int(&tqidnext, 1);
>
> this eventually wraps to 0 and then you get the crash.
>
> Probably the thing to do is ot bump it to 64 bit and 0-check on other
> platforms.
>
This should do it for the time being:
diff --git a/sys/contrib/openzfs/module/os/freebsd/spl/spl_taskq.c
b/sys/contrib/openzfs/module/os/freebsd/spl/spl_taskq.c
index 1050816cd968..a8e53aba3915 100644
--- a/sys/contrib/openzfs/module/os/freebsd/spl/spl_taskq.c
+++ b/sys/contrib/openzfs/module/os/freebsd/spl/spl_taskq.c
@@ -67,7 +67,7 @@ static unsigned long tqenthash;
static unsigned long tqenthashlock;
static struct sx *tqenthashtbl_lock;
-static uint32_t tqidnext = 1;
+static uint32_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);
@@ -137,10 +136,23 @@ taskq_lookup(taskqid_t tqid)
return (ent);
}
+static taskqid_t
+__taskq_nextgen(void)
+{
+ taskqid_t tqid;
+
+ for (;;) {
+ tqid = atomic_fetchadd_int(&tqidnext, 1) + 1;
+ if (__predict_true(tqid != 0))
+ break;
+ }
+ return (tqid);
+}
+
static taskqid_t
taskq_insert(taskq_ent_t *ent)
{
- taskqid_t tqid = atomic_fetchadd_int(&tqidnext, 1);
+ taskqid_t tqid = __taskq_nextgen();
ent->tqent_id = tqid;
ent->tqent_registered = B_TRUE;
@@ -345,9 +357,9 @@ taskq_dispatch(taskq_t *tq, task_func_t func, void
*arg, uint_t flags)
task->tqent_cancelled = B_FALSE;
task->tqent_type = NORMAL_TASK;
tid = taskq_insert(task);
+ VERIFY(tid);
TASK_INIT(&task->tqent_task, prio, taskq_run, task);
taskqueue_enqueue(tq->tq_queue, &task->tqent_task);
- VERIFY(tid);
return (tid);
}
--
Mateusz Guzik <mjguzik gmail.com>
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