net/sunrpc: v4.14-rc4 lockdep warning

Hi,

I have run into the lockdep warning below while running v4.14-rc3/rc4 on an ARM64 defconfig Juno dev board - reporting it to check whether it is a known/genuine issue.

Please let me know if you need further debug data or need some specific tests.

Thanks,
Lorenzo

[    6.209384] ======================================================
[    6.215569] WARNING: possible circular locking dependency detected
[    6.221755] 4.14.0-rc4 #54 Not tainted
[    6.225503] ------------------------------------------------------
[    6.231689] kworker/4:0H/32 is trying to acquire lock:
[    6.236830]  ((&task->u.tk_work)){+.+.}, at: [<ffff0000080e64cc>] process_one_work+0x1cc/0x3f0
[    6.245472] 
               but task is already holding lock:
[    6.251309]  ("xprtiod"){+.+.}, at: [<ffff0000080e64cc>] process_one_work+0x1cc/0x3f0
[    6.259158] 
               which lock already depends on the new lock.

[    6.267345] 
               the existing dependency chain (in reverse order) is:
[    6.274836] 
               -> #1 ("xprtiod"){+.+.}:
[    6.279903]        lock_acquire+0x6c/0xb8
[    6.283914]        flush_work+0x188/0x270
[    6.287926]        __cancel_work_timer+0x120/0x198
[    6.292720]        cancel_work_sync+0x10/0x18
[    6.297081]        xs_destroy+0x34/0x58
[    6.300917]        xprt_destroy+0x84/0x90
[    6.304927]        xprt_put+0x34/0x40
[    6.308589]        rpc_task_release_client+0x6c/0x80
[    6.313557]        rpc_release_resources_task+0x2c/0x38
[    6.318786]        __rpc_execute+0x9c/0x210
[    6.322971]        rpc_async_schedule+0x10/0x18
[    6.327504]        process_one_work+0x240/0x3f0
[    6.332036]        worker_thread+0x48/0x420
[    6.336222]        kthread+0x12c/0x158
[    6.339972]        ret_from_fork+0x10/0x18
[    6.344068] 
               -> #0 ((&task->u.tk_work)){+.+.}:
[    6.349920]        __lock_acquire+0x12ec/0x14a8
[    6.354451]        lock_acquire+0x6c/0xb8
[    6.358462]        process_one_work+0x22c/0x3f0
[    6.362994]        worker_thread+0x48/0x420
[    6.367180]        kthread+0x12c/0x158
[    6.370929]        ret_from_fork+0x10/0x18
[    6.375025] 
               other info that might help us debug this:

[    6.383038]  Possible unsafe locking scenario:

[    6.388962]        CPU0                    CPU1
[    6.393493]        ----                    ----
[    6.398023]   lock("xprtiod");
[    6.401080]                                lock((&task->u.tk_work));
[    6.407444]                                lock("xprtiod");
[    6.413024]   lock((&task->u.tk_work));
[    6.416863] 
                *** DEADLOCK ***

[    6.422789] 1 lock held by kworker/4:0H/32:
[    6.426972]  #0:  ("xprtiod"){+.+.}, at: [<ffff0000080e64cc>] process_one_work+0x1cc/0x3f0
[    6.435258] 
               stack backtrace:
[    6.439618] CPU: 4 PID: 32 Comm: kworker/4:0H Not tainted 4.14.0-rc4 #54
[    6.446325] Hardware name: ARM Juno development board (r2) (DT)
[    6.452252] Workqueue: xprtiod rpc_async_schedule
[    6.456959] Call trace:
[    6.459406] [<ffff000008089430>] dump_backtrace+0x0/0x3c8
[    6.464810] [<ffff00000808980c>] show_stack+0x14/0x20
[    6.469866] [<ffff000008a01a30>] dump_stack+0xb8/0xf0
[    6.474922] [<ffff0000081194ac>] print_circular_bug+0x224/0x3a0
[    6.480849] [<ffff00000811a304>] check_prev_add+0x304/0x860
[    6.486426] [<ffff00000811c8c4>] __lock_acquire+0x12ec/0x14a8
[    6.492177] [<ffff00000811d144>] lock_acquire+0x6c/0xb8
[    6.497406] [<ffff0000080e652c>] process_one_work+0x22c/0x3f0
[    6.503156] [<ffff0000080e6738>] worker_thread+0x48/0x420
[    6.508560] [<ffff0000080ed5bc>] kthread+0x12c/0x158
[    6.513528] [<ffff000008084d48>] ret_from_fork+0x10/0x18

T24gTW9uLCAyMDE3LTEwLTA5IGF0IDE5OjE3ICswMTAwLCBMb3JlbnpvIFBpZXJhbGlzaSB3cm90 ZToNCj4gSGksDQo+IA0KPiBJIGhhdmUgcnVuIGludG8gdGhlIGxvY2tkZXAgd2FybmluZyBiZWxv dyB3aGlsZSBydW5uaW5nIHY0LjE0LXJjMy9yYzQNCj4gb24gYW4gQVJNNjQgZGVmY29uZmlnIEp1 bm8gZGV2IGJvYXJkIC0gcmVwb3J0aW5nIGl0IHRvIGNoZWNrIHdoZXRoZXINCj4gaXQgaXMgYSBr bm93bi9nZW51aW5lIGlzc3VlLg0KPiANCj4gUGxlYXNlIGxldCBtZSBrbm93IGlmIHlvdSBuZWVk IGZ1cnRoZXIgZGVidWcgZGF0YSBvciBuZWVkIHNvbWUNCj4gc3BlY2lmaWMgdGVzdHMuDQo+IA0K PiBUaGFua3MsDQo+IExvcmVuem8NCj4gDQo+IFsgICAgNi4yMDkzODRdID09PT09PT09PT09PT09 PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PQ0KPiBbICAgIDYuMjE1NTY5 XSBXQVJOSU5HOiBwb3NzaWJsZSBjaXJjdWxhciBsb2NraW5nIGRlcGVuZGVuY3kgZGV0ZWN0ZWQN Cj4gWyAgICA2LjIyMTc1NV0gNC4xNC4wLXJjNCAjNTQgTm90IHRhaW50ZWQNCj4gWyAgICA2LjIy NTUwM10gLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0t LS0tDQo+IFsgICAgNi4yMzE2ODldIGt3b3JrZXIvNDowSC8zMiBpcyB0cnlpbmcgdG8gYWNxdWly ZSBsb2NrOg0KPiBbICAgIDYuMjM2ODMwXSAgKCgmdGFzay0+dS50a193b3JrKSl7Ky4rLn0sIGF0 OiBbPGZmZmYwMDAwMDgwZTY0Y2M+XQ0KPiBwcm9jZXNzX29uZV93b3JrKzB4MWNjLzB4M2YwDQo+ IFsgICAgNi4yNDU0NzJdIA0KPiAgICAgICAgICAgICAgICBidXQgdGFzayBpcyBhbHJlYWR5IGhv bGRpbmcgbG9jazoNCj4gWyAgICA2LjI1MTMwOV0gICgieHBydGlvZCIpeysuKy59LCBhdDogWzxm ZmZmMDAwMDA4MGU2NGNjPl0NCj4gcHJvY2Vzc19vbmVfd29yaysweDFjYy8weDNmMA0KPiBbICAg IDYuMjU5MTU4XSANCj4gICAgICAgICAgICAgICAgd2hpY2ggbG9jayBhbHJlYWR5IGRlcGVuZHMg b24gdGhlIG5ldyBsb2NrLg0KPiANCj4gWyAgICA2LjI2NzM0NV0gDQo+ICAgICAgICAgICAgICAg IHRoZSBleGlzdGluZyBkZXBlbmRlbmN5IGNoYWluIChpbiByZXZlcnNlIG9yZGVyKSBpczoNCj4g WyAgICA2LjI3NDgzNl0gDQo+ICAgICAgICAgICAgICAgIC0+ICMxICgieHBydGlvZCIpeysuKy59 Og0KPiBbICAgIDYuMjc5OTAzXSAgICAgICAgbG9ja19hY3F1aXJlKzB4NmMvMHhiOA0KPiBbICAg IDYuMjgzOTE0XSAgICAgICAgZmx1c2hfd29yaysweDE4OC8weDI3MA0KPiBbICAgIDYuMjg3OTI2 XSAgICAgICAgX19jYW5jZWxfd29ya190aW1lcisweDEyMC8weDE5OA0KPiBbICAgIDYuMjkyNzIw XSAgICAgICAgY2FuY2VsX3dvcmtfc3luYysweDEwLzB4MTgNCj4gWyAgICA2LjI5NzA4MV0gICAg ICAgIHhzX2Rlc3Ryb3krMHgzNC8weDU4DQo+IFsgICAgNi4zMDA5MTddICAgICAgICB4cHJ0X2Rl c3Ryb3krMHg4NC8weDkwDQo+IFsgICAgNi4zMDQ5MjddICAgICAgICB4cHJ0X3B1dCsweDM0LzB4 NDANCj4gWyAgICA2LjMwODU4OV0gICAgICAgIHJwY190YXNrX3JlbGVhc2VfY2xpZW50KzB4NmMv MHg4MA0KPiBbICAgIDYuMzEzNTU3XSAgICAgICAgcnBjX3JlbGVhc2VfcmVzb3VyY2VzX3Rhc2sr MHgyYy8weDM4DQo+IFsgICAgNi4zMTg3ODZdICAgICAgICBfX3JwY19leGVjdXRlKzB4OWMvMHgy MTANCj4gWyAgICA2LjMyMjk3MV0gICAgICAgIHJwY19hc3luY19zY2hlZHVsZSsweDEwLzB4MTgN Cj4gWyAgICA2LjMyNzUwNF0gICAgICAgIHByb2Nlc3Nfb25lX3dvcmsrMHgyNDAvMHgzZjANCj4g WyAgICA2LjMzMjAzNl0gICAgICAgIHdvcmtlcl90aHJlYWQrMHg0OC8weDQyMA0KPiBbICAgIDYu MzM2MjIyXSAgICAgICAga3RocmVhZCsweDEyYy8weDE1OA0KPiBbICAgIDYuMzM5OTcyXSAgICAg ICAgcmV0X2Zyb21fZm9yaysweDEwLzB4MTgNCj4gWyAgICA2LjM0NDA2OF0gDQo+ICAgICAgICAg ICAgICAgIC0+ICMwICgoJnRhc2stPnUudGtfd29yaykpeysuKy59Og0KPiBbICAgIDYuMzQ5OTIw XSAgICAgICAgX19sb2NrX2FjcXVpcmUrMHgxMmVjLzB4MTRhOA0KPiBbICAgIDYuMzU0NDUxXSAg ICAgICAgbG9ja19hY3F1aXJlKzB4NmMvMHhiOA0KPiBbICAgIDYuMzU4NDYyXSAgICAgICAgcHJv Y2Vzc19vbmVfd29yaysweDIyYy8weDNmMA0KPiBbICAgIDYuMzYyOTk0XSAgICAgICAgd29ya2Vy X3RocmVhZCsweDQ4LzB4NDIwDQo+IFsgICAgNi4zNjcxODBdICAgICAgICBrdGhyZWFkKzB4MTJj LzB4MTU4DQo+IFsgICAgNi4zNzA5MjldICAgICAgICByZXRfZnJvbV9mb3JrKzB4MTAvMHgxOA0K PiBbICAgIDYuMzc1MDI1XSANCj4gICAgICAgICAgICAgICAgb3RoZXIgaW5mbyB0aGF0IG1pZ2h0 IGhlbHAgdXMgZGVidWcgdGhpczoNCj4gDQo+IFsgICAgNi4zODMwMzhdICBQb3NzaWJsZSB1bnNh ZmUgbG9ja2luZyBzY2VuYXJpbzoNCj4gDQo+IFsgICAgNi4zODg5NjJdICAgICAgICBDUFUwICAg ICAgICAgICAgICAgICAgICBDUFUxDQo+IFsgICAgNi4zOTM0OTNdICAgICAgICAtLS0tICAgICAg ICAgICAgICAgICAgICAtLS0tDQo+IFsgICAgNi4zOTgwMjNdICAgbG9jaygieHBydGlvZCIpOw0K PiBbICAgIDYuNDAxMDgwXSAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgbG9jaygoJnRh c2stDQo+ID51LnRrX3dvcmspKTsNCj4gWyAgICA2LjQwNzQ0NF0gICAgICAgICAgICAgICAgICAg ICAgICAgICAgICAgIGxvY2soInhwcnRpb2QiKTsNCj4gWyAgICA2LjQxMzAyNF0gICBsb2NrKCgm dGFzay0+dS50a193b3JrKSk7DQo+IFsgICAgNi40MTY4NjNdIA0KPiAgICAgICAgICAgICAgICAg KioqIERFQURMT0NLICoqKg0KPiANCj4gWyAgICA2LjQyMjc4OV0gMSBsb2NrIGhlbGQgYnkga3dv cmtlci80OjBILzMyOg0KPiBbICAgIDYuNDI2OTcyXSAgIzA6ICAoInhwcnRpb2QiKXsrLisufSwg YXQ6IFs8ZmZmZjAwMDAwODBlNjRjYz5dDQo+IHByb2Nlc3Nfb25lX3dvcmsrMHgxY2MvMHgzZjAN Cj4gWyAgICA2LjQzNTI1OF0gDQo+ICAgICAgICAgICAgICAgIHN0YWNrIGJhY2t0cmFjZToNCj4g WyAgICA2LjQzOTYxOF0gQ1BVOiA0IFBJRDogMzIgQ29tbToga3dvcmtlci80OjBIIE5vdCB0YWlu dGVkIDQuMTQuMC0NCj4gcmM0ICM1NA0KPiBbICAgIDYuNDQ2MzI1XSBIYXJkd2FyZSBuYW1lOiBB Uk0gSnVubyBkZXZlbG9wbWVudCBib2FyZCAocjIpIChEVCkNCj4gWyAgICA2LjQ1MjI1Ml0gV29y a3F1ZXVlOiB4cHJ0aW9kIHJwY19hc3luY19zY2hlZHVsZQ0KPiBbICAgIDYuNDU2OTU5XSBDYWxs IHRyYWNlOg0KPiBbICAgIDYuNDU5NDA2XSBbPGZmZmYwMDAwMDgwODk0MzA+XSBkdW1wX2JhY2t0 cmFjZSsweDAvMHgzYzgNCj4gWyAgICA2LjQ2NDgxMF0gWzxmZmZmMDAwMDA4MDg5ODBjPl0gc2hv d19zdGFjaysweDE0LzB4MjANCj4gWyAgICA2LjQ2OTg2Nl0gWzxmZmZmMDAwMDA4YTAxYTMwPl0g ZHVtcF9zdGFjaysweGI4LzB4ZjANCj4gWyAgICA2LjQ3NDkyMl0gWzxmZmZmMDAwMDA4MTE5NGFj Pl0gcHJpbnRfY2lyY3VsYXJfYnVnKzB4MjI0LzB4M2EwDQo+IFsgICAgNi40ODA4NDldIFs8ZmZm ZjAwMDAwODExYTMwND5dIGNoZWNrX3ByZXZfYWRkKzB4MzA0LzB4ODYwDQo+IFsgICAgNi40ODY0 MjZdIFs8ZmZmZjAwMDAwODExYzhjND5dIF9fbG9ja19hY3F1aXJlKzB4MTJlYy8weDE0YTgNCj4g WyAgICA2LjQ5MjE3N10gWzxmZmZmMDAwMDA4MTFkMTQ0Pl0gbG9ja19hY3F1aXJlKzB4NmMvMHhi OA0KPiBbICAgIDYuNDk3NDA2XSBbPGZmZmYwMDAwMDgwZTY1MmM+XSBwcm9jZXNzX29uZV93b3Jr KzB4MjJjLzB4M2YwDQo+IFsgICAgNi41MDMxNTZdIFs8ZmZmZjAwMDAwODBlNjczOD5dIHdvcmtl cl90aHJlYWQrMHg0OC8weDQyMA0KPiBbICAgIDYuNTA4NTYwXSBbPGZmZmYwMDAwMDgwZWQ1YmM+ XSBrdGhyZWFkKzB4MTJjLzB4MTU4DQo+IFsgICAgNi41MTM1MjhdIFs8ZmZmZjAwMDAwODA4NGQ0 OD5dIHJldF9mcm9tX2ZvcmsrMHgxMC8weDE4DQo+IA0KDQpBZGRpbmcgVGVqdW4gYW5kIExhaSwg c2luY2UgdGhpcyBsb29rcyBsaWtlIGEgd29ya3F1ZXVlIGxvY2tpbmcgaXNzdWUuDQoNCkNoZWVy cw0KICBUcm9uZA0KDQotLSANClRyb25kIE15a2xlYnVzdA0KTGludXggTkZTIGNsaWVudCBtYWlu dGFpbmVyLCBQcmltYXJ5RGF0YQ0KdHJvbmQubXlrbGVidXN0QHByaW1hcnlkYXRhLmNvbQ0K

Hello, Trond.

..

It looks a bit cryptic but it's warning against the following case.

1. Memory pressure is high and rescuer kicks in for the xprtiod workqueue. There are no other kworkers serving the workqueue.

2. The rescuer runs the xptr_destroy path and ends up calling cancel_work_sync() on a work item which is queued on xprtiod.

3. The work item is pending on the same workqueue and assuming that memory pressure doesn't let off (let's say reclaim is trying to kick off nfs pages), the only way it can get executed is by the rescuer which is waiting for the work item - an A-B-A deadlock.

Thanks.

tejun

T24gVHVlLCAyMDE3LTEwLTEwIGF0IDA3OjAzIC0wNzAwLCB0akBrZXJuZWwub3JnIHdyb3RlOg0K PiBIZWxsbywgVHJvbmQuDQo+IA0KPiBPbiBNb24sIE9jdCAwOSwgMjAxNyBhdCAwNjozMjoxM1BN ICswMDAwLCBUcm9uZCBNeWtsZWJ1c3Qgd3JvdGU6DQo+ID4gT24gTW9uLCAyMDE3LTEwLTA5IGF0 IDE5OjE3ICswMTAwLCBMb3JlbnpvIFBpZXJhbGlzaSB3cm90ZToNCj4gPiA+IEkgaGF2ZSBydW4g aW50byB0aGUgbG9ja2RlcCB3YXJuaW5nIGJlbG93IHdoaWxlIHJ1bm5pbmcgdjQuMTQtDQo+ID4g PiByYzMvcmM0DQo+ID4gPiBvbiBhbiBBUk02NCBkZWZjb25maWcgSnVubyBkZXYgYm9hcmQgLSBy ZXBvcnRpbmcgaXQgdG8gY2hlY2sNCj4gPiA+IHdoZXRoZXINCj4gPiA+IGl0IGlzIGEga25vd24v Z2VudWluZSBpc3N1ZS4NCj4gPiA+IA0KPiA+ID4gUGxlYXNlIGxldCBtZSBrbm93IGlmIHlvdSBu ZWVkIGZ1cnRoZXIgZGVidWcgZGF0YSBvciBuZWVkIHNvbWUNCj4gPiA+IHNwZWNpZmljIHRlc3Rz Lg0KPiA+ID4gDQo+ID4gPiBbICAgIDYuMjA5Mzg0XQ0KPiA+ID4gPT09PT09PT09PT09PT09PT09 PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09DQo+ID4gPiBbICAgIDYuMjE1NTY5 XSBXQVJOSU5HOiBwb3NzaWJsZSBjaXJjdWxhciBsb2NraW5nIGRlcGVuZGVuY3kNCj4gPiA+IGRl dGVjdGVkDQo+ID4gPiBbICAgIDYuMjIxNzU1XSA0LjE0LjAtcmM0ICM1NCBOb3QgdGFpbnRlZA0K PiA+ID4gWyAgICA2LjIyNTUwM10gLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0t LS0tLS0tLS0tLS0tLS0NCj4gPiA+IC0tLS0NCj4gPiA+IFsgICAgNi4yMzE2ODldIGt3b3JrZXIv NDowSC8zMiBpcyB0cnlpbmcgdG8gYWNxdWlyZSBsb2NrOg0KPiA+ID4gWyAgICA2LjIzNjgzMF0g ICgoJnRhc2stPnUudGtfd29yaykpeysuKy59LCBhdDoNCj4gPiA+IFs8ZmZmZjAwMDAwODBlNjRj Yz5dDQo+ID4gPiBwcm9jZXNzX29uZV93b3JrKzB4MWNjLzB4M2YwDQo+ID4gPiBbICAgIDYuMjQ1 NDcyXSANCj4gPiA+ICAgICAgICAgICAgICAgIGJ1dCB0YXNrIGlzIGFscmVhZHkgaG9sZGluZyBs b2NrOg0KPiA+ID4gWyAgICA2LjI1MTMwOV0gICgieHBydGlvZCIpeysuKy59LCBhdDogWzxmZmZm MDAwMDA4MGU2NGNjPl0NCj4gPiA+IHByb2Nlc3Nfb25lX3dvcmsrMHgxY2MvMHgzZjANCj4gPiA+ IFsgICAgNi4yNTkxNThdIA0KPiA+ID4gICAgICAgICAgICAgICAgd2hpY2ggbG9jayBhbHJlYWR5 IGRlcGVuZHMgb24gdGhlIG5ldyBsb2NrLg0KPiA+ID4gDQo+ID4gPiBbICAgIDYuMjY3MzQ1XSAN Cj4gPiA+ICAgICAgICAgICAgICAgIHRoZSBleGlzdGluZyBkZXBlbmRlbmN5IGNoYWluIChpbiBy ZXZlcnNlIG9yZGVyKQ0KPiA+ID4gaXM6DQo+IA0KPiAuLg0KPiA+IEFkZGluZyBUZWp1biBhbmQg TGFpLCBzaW5jZSB0aGlzIGxvb2tzIGxpa2UgYSB3b3JrcXVldWUgbG9ja2luZw0KPiA+IGlzc3Vl Lg0KPiANCj4gSXQgbG9va3MgYSBiaXQgY3J5cHRpYyBidXQgaXQncyB3YXJuaW5nIGFnYWluc3Qg dGhlIGZvbGxvd2luZyBjYXNlLg0KPiANCj4gMS4gTWVtb3J5IHByZXNzdXJlIGlzIGhpZ2ggYW5k IHJlc2N1ZXIga2lja3MgaW4gZm9yIHRoZSB4cHJ0aW9kDQo+ICAgIHdvcmtxdWV1ZS4gIFRoZXJl IGFyZSBubyBvdGhlciBrd29ya2VycyBzZXJ2aW5nIHRoZSB3b3JrcXVldWUuDQo+IA0KPiAyLiBU aGUgcmVzY3VlciBydW5zIHRoZSB4cHRyX2Rlc3Ryb3kgcGF0aCBhbmQgZW5kcyB1cCBjYWxsaW5n DQo+ICAgIGNhbmNlbF93b3JrX3N5bmMoKSBvbiBhIHdvcmsgaXRlbSB3aGljaCBpcyBxdWV1ZWQg b24geHBydGlvZC4NCj4gDQo+IDMuIFRoZSB3b3JrIGl0ZW0gaXMgcGVuZGluZyBvbiB0aGUgc2Ft ZSB3b3JrcXVldWUgYW5kIGFzc3VtaW5nIHRoYXQNCj4gICAgbWVtb3J5IHByZXNzdXJlIGRvZXNu J3QgbGV0IG9mZiAobGV0J3Mgc2F5IHJlY2xhaW0gaXMgdHJ5aW5nIHRvDQo+ICAgIGtpY2sgb2Zm IG5mcyBwYWdlcyksIHRoZSBvbmx5IHdheSBpdCBjYW4gZ2V0IGV4ZWN1dGVkIGlzIGJ5IHRoZQ0K PiAgICByZXNjdWVyIHdoaWNoIGlzIHdhaXRpbmcgZm9yIHRoZSB3b3JrIGl0ZW0gLSBhbiBBLUIt QSBkZWFkbG9jay4NCj4gDQoNCkhpIFRlanVuLA0KDQpUaGFua3MgZm9yIHRoZSBleHBsYW5hdGlv bi4gV2hhdCBJJ20gbm90IHJlYWxseSB1bmRlcnN0YW5kaW5nIGhlcmUNCnRob3VnaCwgaXMgaG93 IHRoZSB3b3JrIGl0ZW0gY291bGQgYmUgcXVldWVkIGF0IGFsbC4gV2UgaGF2ZSBhDQp3YWl0X29u X2JpdF9sb2NrKCkgaW4geHBydF9kZXN0cm95KCkgdGhhdCBzaG91bGQgbWVhbiB0aGUgeHBydC0N Cj50YXNrX2NsZWFudXAgd29yayBpdGVtIGhhcyBjb21wbGV0ZWQgcnVubmluZywgYW5kIHRoYXQg aXQgY2Fubm90IGJlDQpyZXF1ZXVlZC4NCg0KSXMgdGhlcmUgYSBwb3NzaWJpbGl0eSB0aGF0IHRo ZSBmbHVzaF9xdWV1ZSgpIG1pZ2h0IGJlIHRyaWdnZXJlZA0KZGVzcGl0ZSB0aGUgd29yayBpdGVt IG5vdCBiZWluZyBxdWV1ZWQ/DQoNCi0tIA0KVHJvbmQgTXlrbGVidXN0DQpMaW51eCBORlMgY2xp ZW50IG1haW50YWluZXIsIFByaW1hcnlEYXRhDQp0cm9uZC5teWtsZWJ1c3RAcHJpbWFyeWRhdGEu Y29tDQo=

Hello,

Yeah, for sure. The lockdep annotations don't distinguish those cases and assume the worst case.

Thanks.

tejun

T24gVHVlLCAyMDE3LTEwLTEwIGF0IDEwOjE5IC0wNzAwLCB0akBrZXJuZWwub3JnIHdyb3RlOg0K PiBIZWxsbywNCj4gDQo+IE9uIFR1ZSwgT2N0IDEwLCAyMDE3IGF0IDA0OjQ4OjU3UE0gKzAwMDAs IFRyb25kIE15a2xlYnVzdCB3cm90ZToNCj4gPiBUaGFua3MgZm9yIHRoZSBleHBsYW5hdGlvbi4g V2hhdCBJJ20gbm90IHJlYWxseSB1bmRlcnN0YW5kaW5nIGhlcmUNCj4gPiB0aG91Z2gsIGlzIGhv dyB0aGUgd29yayBpdGVtIGNvdWxkIGJlIHF1ZXVlZCBhdCBhbGwuIFdlIGhhdmUgYQ0KPiA+IHdh aXRfb25fYml0X2xvY2soKSBpbiB4cHJ0X2Rlc3Ryb3koKSB0aGF0IHNob3VsZCBtZWFuIHRoZSB4 cHJ0LQ0KPiA+ID4gdGFza19jbGVhbnVwIHdvcmsgaXRlbSBoYXMgY29tcGxldGVkIHJ1bm5pbmcs IGFuZCB0aGF0IGl0IGNhbm5vdA0KPiA+ID4gYmUNCj4gPiANCj4gPiByZXF1ZXVlZC4NCj4gPiAN Cj4gPiBJcyB0aGVyZSBhIHBvc3NpYmlsaXR5IHRoYXQgdGhlIGZsdXNoX3F1ZXVlKCkgbWlnaHQg YmUgdHJpZ2dlcmVkDQo+ID4gZGVzcGl0ZSB0aGUgd29yayBpdGVtIG5vdCBiZWluZyBxdWV1ZWQ/ DQo+IA0KPiBZZWFoLCBmb3Igc3VyZS4gIFRoZSBsb2NrZGVwIGFubm90YXRpb25zIGRvbid0IGRp c3Rpbmd1aXNoIHRob3NlDQo+IGNhc2VzIGFuZCBhc3N1bWUgdGhlIHdvcnN0IGNhc2UuDQo+IA0K DQpPSy4gTGV0J3MganVzdCByZW1vdmUgdGhhdCBjYWxsIHRvIGNhbmNlbF93b3JrX3N5bmMoKSB0 aGVuLiBBcyBJIHNhaWQsDQppdCBzaG91bGQgYmUgcmVkdW5kYW50IGR1ZSB0byB0aGUgd2FpdF9v bl9iaXRfbG9jaygpLg0KDQotLSANClRyb25kIE15a2xlYnVzdA0KTGludXggTkZTIGNsaWVudCBt YWludGFpbmVyLCBQcmltYXJ5RGF0YQ0KdHJvbmQubXlrbGVidXN0QHByaW1hcnlkYXRhLmNvbQ0K

Hi Trond,

is there a patch available for this issue? I'm running into with 4.14-rc5 on my ARM64 board.

thanks, Jan

2017-10-11 19:49 GMT+02:00 Trond Myklebust <[email protected]>: