* [PATCH V2] RDMA/rtrs: Call {get,put}_cpu_ptr to silence a debug kernel warning
@ 2021-11-28 13:35 Guoqing Jiang
2021-11-28 18:16 ` Leon Romanovsky
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: Guoqing Jiang @ 2021-11-28 13:35 UTC (permalink / raw)
To: jinpu.wang, haris.iqbal, jgg; +Cc: linux-rdma
With preemption enabled (CONFIG_DEBUG_PREEMPT=y), the following appeared
when rnbd client tries to map remote block device.
[ 2123.221071] BUG: using smp_processor_id() in preemptible [00000000] code: bash/1733
[ 2123.221175] caller is debug_smp_processor_id+0x17/0x20
[ 2123.221214] CPU: 0 PID: 1733 Comm: bash Not tainted 5.16.0-rc1 #5
[ 2123.221218] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.14.0-0-g155821a-rebuilt.opensuse.org 04/01/2014
[ 2123.221229] Call Trace:
[ 2123.221231] <TASK>
[ 2123.221235] dump_stack_lvl+0x5d/0x78
[ 2123.221252] dump_stack+0x10/0x12
[ 2123.221257] check_preemption_disabled+0xe4/0xf0
[ 2123.221266] debug_smp_processor_id+0x17/0x20
[ 2123.221271] rtrs_clt_update_all_stats+0x3b/0x70 [rtrs_client]
[ 2123.221285] rtrs_clt_read_req+0xc3/0x380 [rtrs_client]
[ 2123.221298] ? rtrs_clt_init_req+0xe3/0x120 [rtrs_client]
[ 2123.221321] rtrs_clt_request+0x1a7/0x320 [rtrs_client]
[ 2123.221340] ? 0xffffffffc0ab1000
[ 2123.221357] send_usr_msg+0xbf/0x160 [rnbd_client]
[ 2123.221370] ? rnbd_clt_put_sess+0x60/0x60 [rnbd_client]
[ 2123.221377] ? send_usr_msg+0x160/0x160 [rnbd_client]
[ 2123.221386] ? sg_alloc_table+0x27/0xb0
[ 2123.221395] ? sg_zero_buffer+0xd0/0xd0
[ 2123.221407] send_msg_sess_info+0xe9/0x180 [rnbd_client]
[ 2123.221413] ? rnbd_clt_put_sess+0x60/0x60 [rnbd_client]
[ 2123.221429] ? blk_mq_alloc_tag_set+0x2ef/0x370
[ 2123.221447] rnbd_clt_map_device+0xba8/0xcd0 [rnbd_client]
[ 2123.221462] ? send_msg_open+0x200/0x200 [rnbd_client]
[ 2123.221479] rnbd_clt_map_device_store+0x3e5/0x620 [rnbd_client
To supress the calltrace, let's call get_cpu_ptr/put_cpu_ptr pair in
rtrs_clt_update_rdma_stats to disable preemption when accessing per-cpu
variable.
While at it, let's make the similar change in rtrs_clt_update_wc_stats.
And for rtrs_clt_inc_failover_cnt, though it was only called inside rcu
section, but it still can be preempted in case CONFIG_PREEMPT_RCU is
enabled, so change it to {get,put}_cpu_ptr pair either.
Signed-off-by: Guoqing Jiang <guoqing.jiang@linux.dev>
---
V2: also make the change in rtrs_clt_update_wc_stats and rtrs_clt_inc_failover_cnt
drivers/infiniband/ulp/rtrs/rtrs-clt-stats.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt-stats.c b/drivers/infiniband/ulp/rtrs/rtrs-clt-stats.c
index f7e459fe68be..76e4352fe3f6 100644
--- a/drivers/infiniband/ulp/rtrs/rtrs-clt-stats.c
+++ b/drivers/infiniband/ulp/rtrs/rtrs-clt-stats.c
@@ -19,7 +19,7 @@ void rtrs_clt_update_wc_stats(struct rtrs_clt_con *con)
int cpu;
cpu = raw_smp_processor_id();
- s = this_cpu_ptr(stats->pcpu_stats);
+ s = get_cpu_ptr(stats->pcpu_stats);
if (con->cpu != cpu) {
s->cpu_migr.to++;
@@ -27,14 +27,16 @@ void rtrs_clt_update_wc_stats(struct rtrs_clt_con *con)
s = per_cpu_ptr(stats->pcpu_stats, con->cpu);
atomic_inc(&s->cpu_migr.from);
}
+ put_cpu_ptr(stats->pcpu_stats);
}
void rtrs_clt_inc_failover_cnt(struct rtrs_clt_stats *stats)
{
struct rtrs_clt_stats_pcpu *s;
- s = this_cpu_ptr(stats->pcpu_stats);
+ s = get_cpu_ptr(stats->pcpu_stats);
s->rdma.failover_cnt++;
+ put_cpu_ptr(stats->pcpu_stats);
}
int rtrs_clt_stats_migration_from_cnt_to_str(struct rtrs_clt_stats *stats, char *buf)
@@ -169,9 +171,10 @@ static inline void rtrs_clt_update_rdma_stats(struct rtrs_clt_stats *stats,
{
struct rtrs_clt_stats_pcpu *s;
- s = this_cpu_ptr(stats->pcpu_stats);
+ s = get_cpu_ptr(stats->pcpu_stats);
s->rdma.dir[d].cnt++;
s->rdma.dir[d].size_total += size;
+ put_cpu_ptr(stats->pcpu_stats);
}
void rtrs_clt_update_all_stats(struct rtrs_clt_io_req *req, int dir)
--
2.31.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH V2] RDMA/rtrs: Call {get,put}_cpu_ptr to silence a debug kernel warning
2021-11-28 13:35 [PATCH V2] RDMA/rtrs: Call {get,put}_cpu_ptr to silence a debug kernel warning Guoqing Jiang
@ 2021-11-28 18:16 ` Leon Romanovsky
2021-11-29 15:08 ` Jason Gunthorpe
2021-11-30 10:40 ` Christoph Lameter
2 siblings, 0 replies; 6+ messages in thread
From: Leon Romanovsky @ 2021-11-28 18:16 UTC (permalink / raw)
To: Guoqing Jiang; +Cc: jinpu.wang, haris.iqbal, jgg, linux-rdma
On Sun, Nov 28, 2021 at 09:35:01PM +0800, Guoqing Jiang wrote:
> With preemption enabled (CONFIG_DEBUG_PREEMPT=y), the following appeared
> when rnbd client tries to map remote block device.
>
> [ 2123.221071] BUG: using smp_processor_id() in preemptible [00000000] code: bash/1733
> [ 2123.221175] caller is debug_smp_processor_id+0x17/0x20
> [ 2123.221214] CPU: 0 PID: 1733 Comm: bash Not tainted 5.16.0-rc1 #5
> [ 2123.221218] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.14.0-0-g155821a-rebuilt.opensuse.org 04/01/2014
> [ 2123.221229] Call Trace:
> [ 2123.221231] <TASK>
> [ 2123.221235] dump_stack_lvl+0x5d/0x78
> [ 2123.221252] dump_stack+0x10/0x12
> [ 2123.221257] check_preemption_disabled+0xe4/0xf0
> [ 2123.221266] debug_smp_processor_id+0x17/0x20
> [ 2123.221271] rtrs_clt_update_all_stats+0x3b/0x70 [rtrs_client]
> [ 2123.221285] rtrs_clt_read_req+0xc3/0x380 [rtrs_client]
> [ 2123.221298] ? rtrs_clt_init_req+0xe3/0x120 [rtrs_client]
> [ 2123.221321] rtrs_clt_request+0x1a7/0x320 [rtrs_client]
> [ 2123.221340] ? 0xffffffffc0ab1000
> [ 2123.221357] send_usr_msg+0xbf/0x160 [rnbd_client]
> [ 2123.221370] ? rnbd_clt_put_sess+0x60/0x60 [rnbd_client]
> [ 2123.221377] ? send_usr_msg+0x160/0x160 [rnbd_client]
> [ 2123.221386] ? sg_alloc_table+0x27/0xb0
> [ 2123.221395] ? sg_zero_buffer+0xd0/0xd0
> [ 2123.221407] send_msg_sess_info+0xe9/0x180 [rnbd_client]
> [ 2123.221413] ? rnbd_clt_put_sess+0x60/0x60 [rnbd_client]
> [ 2123.221429] ? blk_mq_alloc_tag_set+0x2ef/0x370
> [ 2123.221447] rnbd_clt_map_device+0xba8/0xcd0 [rnbd_client]
> [ 2123.221462] ? send_msg_open+0x200/0x200 [rnbd_client]
> [ 2123.221479] rnbd_clt_map_device_store+0x3e5/0x620 [rnbd_client
>
> To supress the calltrace, let's call get_cpu_ptr/put_cpu_ptr pair in
> rtrs_clt_update_rdma_stats to disable preemption when accessing per-cpu
> variable.
>
> While at it, let's make the similar change in rtrs_clt_update_wc_stats.
> And for rtrs_clt_inc_failover_cnt, though it was only called inside rcu
> section, but it still can be preempted in case CONFIG_PREEMPT_RCU is
> enabled, so change it to {get,put}_cpu_ptr pair either.
>
> Signed-off-by: Guoqing Jiang <guoqing.jiang@linux.dev>
> ---
> V2: also make the change in rtrs_clt_update_wc_stats and rtrs_clt_inc_failover_cnt
>
> drivers/infiniband/ulp/rtrs/rtrs-clt-stats.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
>
Thanks,
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH V2] RDMA/rtrs: Call {get,put}_cpu_ptr to silence a debug kernel warning
2021-11-28 13:35 [PATCH V2] RDMA/rtrs: Call {get,put}_cpu_ptr to silence a debug kernel warning Guoqing Jiang
2021-11-28 18:16 ` Leon Romanovsky
@ 2021-11-29 15:08 ` Jason Gunthorpe
2021-11-30 10:40 ` Christoph Lameter
2 siblings, 0 replies; 6+ messages in thread
From: Jason Gunthorpe @ 2021-11-29 15:08 UTC (permalink / raw)
To: Guoqing Jiang; +Cc: jinpu.wang, haris.iqbal, linux-rdma
On Sun, Nov 28, 2021 at 09:35:01PM +0800, Guoqing Jiang wrote:
> With preemption enabled (CONFIG_DEBUG_PREEMPT=y), the following appeared
> when rnbd client tries to map remote block device.
>
> [ 2123.221071] BUG: using smp_processor_id() in preemptible [00000000] code: bash/1733
> [ 2123.221175] caller is debug_smp_processor_id+0x17/0x20
> [ 2123.221214] CPU: 0 PID: 1733 Comm: bash Not tainted 5.16.0-rc1 #5
> [ 2123.221218] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.14.0-0-g155821a-rebuilt.opensuse.org 04/01/2014
> [ 2123.221229] Call Trace:
> [ 2123.221231] <TASK>
> [ 2123.221235] dump_stack_lvl+0x5d/0x78
> [ 2123.221252] dump_stack+0x10/0x12
> [ 2123.221257] check_preemption_disabled+0xe4/0xf0
> [ 2123.221266] debug_smp_processor_id+0x17/0x20
> [ 2123.221271] rtrs_clt_update_all_stats+0x3b/0x70 [rtrs_client]
> [ 2123.221285] rtrs_clt_read_req+0xc3/0x380 [rtrs_client]
> [ 2123.221298] ? rtrs_clt_init_req+0xe3/0x120 [rtrs_client]
> [ 2123.221321] rtrs_clt_request+0x1a7/0x320 [rtrs_client]
> [ 2123.221340] ? 0xffffffffc0ab1000
> [ 2123.221357] send_usr_msg+0xbf/0x160 [rnbd_client]
> [ 2123.221370] ? rnbd_clt_put_sess+0x60/0x60 [rnbd_client]
> [ 2123.221377] ? send_usr_msg+0x160/0x160 [rnbd_client]
> [ 2123.221386] ? sg_alloc_table+0x27/0xb0
> [ 2123.221395] ? sg_zero_buffer+0xd0/0xd0
> [ 2123.221407] send_msg_sess_info+0xe9/0x180 [rnbd_client]
> [ 2123.221413] ? rnbd_clt_put_sess+0x60/0x60 [rnbd_client]
> [ 2123.221429] ? blk_mq_alloc_tag_set+0x2ef/0x370
> [ 2123.221447] rnbd_clt_map_device+0xba8/0xcd0 [rnbd_client]
> [ 2123.221462] ? send_msg_open+0x200/0x200 [rnbd_client]
> [ 2123.221479] rnbd_clt_map_device_store+0x3e5/0x620 [rnbd_client
>
> To supress the calltrace, let's call get_cpu_ptr/put_cpu_ptr pair in
> rtrs_clt_update_rdma_stats to disable preemption when accessing per-cpu
> variable.
>
> While at it, let's make the similar change in rtrs_clt_update_wc_stats.
> And for rtrs_clt_inc_failover_cnt, though it was only called inside rcu
> section, but it still can be preempted in case CONFIG_PREEMPT_RCU is
> enabled, so change it to {get,put}_cpu_ptr pair either.
>
> Signed-off-by: Guoqing Jiang <guoqing.jiang@linux.dev>
> Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
> ---
> V2: also make the change in rtrs_clt_update_wc_stats and rtrs_clt_inc_failover_cnt
>
> drivers/infiniband/ulp/rtrs/rtrs-clt-stats.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
Applied to for-rc, thanks
Jason
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH V2] RDMA/rtrs: Call {get,put}_cpu_ptr to silence a debug kernel warning
2021-11-28 13:35 [PATCH V2] RDMA/rtrs: Call {get,put}_cpu_ptr to silence a debug kernel warning Guoqing Jiang
2021-11-28 18:16 ` Leon Romanovsky
2021-11-29 15:08 ` Jason Gunthorpe
@ 2021-11-30 10:40 ` Christoph Lameter
2021-11-30 11:03 ` Jinpu Wang
2 siblings, 1 reply; 6+ messages in thread
From: Christoph Lameter @ 2021-11-30 10:40 UTC (permalink / raw)
To: Guoqing Jiang; +Cc: jinpu.wang, haris.iqbal, jgg, linux-rdma
On Sun, 28 Nov 2021, Guoqing Jiang wrote:
> int cpu;
>
> cpu = raw_smp_processor_id();
> - s = this_cpu_ptr(stats->pcpu_stats);
> + s = get_cpu_ptr(stats->pcpu_stats);
> if (con->cpu != cpu) {
> s->cpu_migr.to++;
>
> @@ -27,14 +27,16 @@ void rtrs_clt_update_wc_stats(struct rtrs_clt_con *con)
> s = per_cpu_ptr(stats->pcpu_stats, con->cpu);
> atomic_inc(&s->cpu_migr.from);
> }
> + put_cpu_ptr(stats->pcpu_stats);
> }
>
> void rtrs_clt_inc_failover_cnt(struct rtrs_clt_stats *stats)
> {
> struct rtrs_clt_stats_pcpu *s;
>
> - s = this_cpu_ptr(stats->pcpu_stats);
> + s = get_cpu_ptr(stats->pcpu_stats);
> s->rdma.failover_cnt++;
> + put_cpu_ptr(stats->pcpu_stats);
This is equivalent to
this_cpu_inc(stats->pcpu_stats.rdma.failover_cnt);
Which will also reduce the segment to a single cpu instruction.
> }
>
> int rtrs_clt_stats_migration_from_cnt_to_str(struct rtrs_clt_stats *stats, char *buf)
> @@ -169,9 +171,10 @@ static inline void rtrs_clt_update_rdma_stats(struct rtrs_clt_stats *stats,
> {
> struct rtrs_clt_stats_pcpu *s;
>
> - s = this_cpu_ptr(stats->pcpu_stats);
> + s = get_cpu_ptr(stats->pcpu_stats);
> s->rdma.dir[d].cnt++;
> s->rdma.dir[d].size_total += size;
> + put_cpu_ptr(stats->pcpu_stats);
> }
Ditto
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH V2] RDMA/rtrs: Call {get,put}_cpu_ptr to silence a debug kernel warning
2021-11-30 10:40 ` Christoph Lameter
@ 2021-11-30 11:03 ` Jinpu Wang
2021-12-01 8:51 ` Guoqing Jiang
0 siblings, 1 reply; 6+ messages in thread
From: Jinpu Wang @ 2021-11-30 11:03 UTC (permalink / raw)
To: Christoph Lameter; +Cc: Guoqing Jiang, haris.iqbal, jgg, linux-rdma
On Tue, Nov 30, 2021 at 11:40 AM Christoph Lameter <cl@gentwo.org> wrote:
>
> On Sun, 28 Nov 2021, Guoqing Jiang wrote:
>
> > int cpu;
> >
> > cpu = raw_smp_processor_id();
> > - s = this_cpu_ptr(stats->pcpu_stats);
> > + s = get_cpu_ptr(stats->pcpu_stats);
> > if (con->cpu != cpu) {
> > s->cpu_migr.to++;
> >
> > @@ -27,14 +27,16 @@ void rtrs_clt_update_wc_stats(struct rtrs_clt_con *con)
> > s = per_cpu_ptr(stats->pcpu_stats, con->cpu);
> > atomic_inc(&s->cpu_migr.from);
> > }
> > + put_cpu_ptr(stats->pcpu_stats);
> > }
> >
> > void rtrs_clt_inc_failover_cnt(struct rtrs_clt_stats *stats)
> > {
> > struct rtrs_clt_stats_pcpu *s;
> >
> > - s = this_cpu_ptr(stats->pcpu_stats);
> > + s = get_cpu_ptr(stats->pcpu_stats);
> > s->rdma.failover_cnt++;
> > + put_cpu_ptr(stats->pcpu_stats);
>
> This is equivalent to
>
> this_cpu_inc(stats->pcpu_stats.rdma.failover_cnt);
>
> Which will also reduce the segment to a single cpu instruction.
Thanks for your suggestion, Christoph.
As the patch is already applied, I will send a new patch as suggested.
>
> > }
> >
> > int rtrs_clt_stats_migration_from_cnt_to_str(struct rtrs_clt_stats *stats, char *buf)
> > @@ -169,9 +171,10 @@ static inline void rtrs_clt_update_rdma_stats(struct rtrs_clt_stats *stats,
> > {
> > struct rtrs_clt_stats_pcpu *s;
> >
> > - s = this_cpu_ptr(stats->pcpu_stats);
> > + s = get_cpu_ptr(stats->pcpu_stats);
> > s->rdma.dir[d].cnt++;
> > s->rdma.dir[d].size_total += size;
> > + put_cpu_ptr(stats->pcpu_stats);
> > }
>
> Ditto
>
Regards!
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH V2] RDMA/rtrs: Call {get,put}_cpu_ptr to silence a debug kernel warning
2021-11-30 11:03 ` Jinpu Wang
@ 2021-12-01 8:51 ` Guoqing Jiang
0 siblings, 0 replies; 6+ messages in thread
From: Guoqing Jiang @ 2021-12-01 8:51 UTC (permalink / raw)
To: Jinpu Wang, Christoph Lameter; +Cc: haris.iqbal, jgg, linux-rdma
On 11/30/21 7:03 PM, Jinpu Wang wrote:
> On Tue, Nov 30, 2021 at 11:40 AM Christoph Lameter<cl@gentwo.org> wrote:
>> On Sun, 28 Nov 2021, Guoqing Jiang wrote:
>>
>>> int cpu;
>>>
>>> cpu = raw_smp_processor_id();
>>> - s = this_cpu_ptr(stats->pcpu_stats);
>>> + s = get_cpu_ptr(stats->pcpu_stats);
>>> if (con->cpu != cpu) {
>>> s->cpu_migr.to++;
>>>
>>> @@ -27,14 +27,16 @@ void rtrs_clt_update_wc_stats(struct rtrs_clt_con *con)
>>> s = per_cpu_ptr(stats->pcpu_stats, con->cpu);
>>> atomic_inc(&s->cpu_migr.from);
>>> }
>>> + put_cpu_ptr(stats->pcpu_stats);
>>> }
>>>
>>> void rtrs_clt_inc_failover_cnt(struct rtrs_clt_stats *stats)
>>> {
>>> struct rtrs_clt_stats_pcpu *s;
>>>
>>> - s = this_cpu_ptr(stats->pcpu_stats);
>>> + s = get_cpu_ptr(stats->pcpu_stats);
>>> s->rdma.failover_cnt++;
>>> + put_cpu_ptr(stats->pcpu_stats);
>> This is equivalent to
>>
>> this_cpu_inc(stats->pcpu_stats.rdma.failover_cnt);
>>
>> Which will also reduce the segment to a single cpu instruction.
> Thanks for your suggestion, Christoph.
Good suggestion!
> As the patch is already applied, I will send a new patch as suggested.
Thanks for it.
Cheers,
Guoqing
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-12-01 8:52 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2021-11-28 13:35 [PATCH V2] RDMA/rtrs: Call {get,put}_cpu_ptr to silence a debug kernel warning Guoqing Jiang
2021-11-28 18:16 ` Leon Romanovsky
2021-11-29 15:08 ` Jason Gunthorpe
2021-11-30 10:40 ` Christoph Lameter
2021-11-30 11:03 ` Jinpu Wang
2021-12-01 8:51 ` Guoqing Jiang
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