* [PATCH bpf] xdp: Handle device unregister for devmap_hash map type
@ 2019-10-16 13:28 Toke Høiland-Jørgensen
2019-10-16 16:24 ` Martin Lau
` (2 more replies)
0 siblings, 3 replies; 10+ messages in thread
From: Toke Høiland-Jørgensen @ 2019-10-16 13:28 UTC (permalink / raw)
To: daniel, ast; +Cc: Toke Høiland-Jørgensen, bpf, netdev, Tetsuo Handa
It seems I forgot to add handling of devmap_hash type maps to the device
unregister hook for devmaps. This omission causes devices to not be
properly released, which causes hangs.
Fix this by adding the missing handler.
Fixes: 6f9d451ab1a3 ("xdp: Add devmap_hash map type for looking up devices by hashed index")
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
---
kernel/bpf/devmap.c | 34 ++++++++++++++++++++++++++++++++++
1 file changed, 34 insertions(+)
diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index d27f3b60ff6d..deb9416341e9 100644
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -719,6 +719,35 @@ const struct bpf_map_ops dev_map_hash_ops = {
.map_check_btf = map_check_no_btf,
};
+static void dev_map_hash_remove_netdev(struct bpf_dtab *dtab,
+ struct net_device *netdev)
+{
+ int i;
+
+ for (i = 0; i < dtab->n_buckets; i++) {
+ struct bpf_dtab_netdev *dev, *odev;
+ struct hlist_head *head;
+
+ head = dev_map_index_hash(dtab, i);
+ dev = hlist_entry_safe(rcu_dereference_raw(hlist_first_rcu(head)),
+ struct bpf_dtab_netdev,
+ index_hlist);
+
+ while (dev) {
+ odev = (netdev == dev->dev) ? dev : NULL;
+ dev = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(&dev->index_hlist)),
+ struct bpf_dtab_netdev,
+ index_hlist);
+
+ if (odev) {
+ hlist_del_rcu(&odev->index_hlist);
+ call_rcu(&odev->rcu,
+ __dev_map_entry_free);
+ }
+ }
+ }
+}
+
static int dev_map_notification(struct notifier_block *notifier,
ulong event, void *ptr)
{
@@ -735,6 +764,11 @@ static int dev_map_notification(struct notifier_block *notifier,
*/
rcu_read_lock();
list_for_each_entry_rcu(dtab, &dev_map_list, list) {
+ if (dtab->map.map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
+ dev_map_hash_remove_netdev(dtab, netdev);
+ continue;
+ }
+
for (i = 0; i < dtab->map.max_entries; i++) {
struct bpf_dtab_netdev *dev, *odev;
--
2.23.0
^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [PATCH bpf] xdp: Handle device unregister for devmap_hash map type
2019-10-16 13:28 [PATCH bpf] xdp: Handle device unregister for devmap_hash map type Toke Høiland-Jørgensen
@ 2019-10-16 16:24 ` Martin Lau
2019-10-17 10:27 ` Toke Høiland-Jørgensen
2019-10-16 20:09 ` Tetsuo Handa
2019-10-17 19:17 ` Andrii Nakryiko
2 siblings, 1 reply; 10+ messages in thread
From: Martin Lau @ 2019-10-16 16:24 UTC (permalink / raw)
To: Toke Høiland-Jørgensen
Cc: daniel, Alexei Starovoitov, bpf, netdev, Tetsuo Handa
On Wed, Oct 16, 2019 at 03:28:02PM +0200, Toke Høiland-Jørgensen wrote:
> It seems I forgot to add handling of devmap_hash type maps to the device
> unregister hook for devmaps. This omission causes devices to not be
> properly released, which causes hangs.
>
> Fix this by adding the missing handler.
>
> Fixes: 6f9d451ab1a3 ("xdp: Add devmap_hash map type for looking up devices by hashed index")
> Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
> ---
> kernel/bpf/devmap.c | 34 ++++++++++++++++++++++++++++++++++
> 1 file changed, 34 insertions(+)
>
> diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
> index d27f3b60ff6d..deb9416341e9 100644
> --- a/kernel/bpf/devmap.c
> +++ b/kernel/bpf/devmap.c
> @@ -719,6 +719,35 @@ const struct bpf_map_ops dev_map_hash_ops = {
> .map_check_btf = map_check_no_btf,
> };
>
> +static void dev_map_hash_remove_netdev(struct bpf_dtab *dtab,
> + struct net_device *netdev)
> +{
> + int i;
> +
> + for (i = 0; i < dtab->n_buckets; i++) {
> + struct bpf_dtab_netdev *dev, *odev;
> + struct hlist_head *head;
> +
> + head = dev_map_index_hash(dtab, i);
> + dev = hlist_entry_safe(rcu_dereference_raw(hlist_first_rcu(head)),
> + struct bpf_dtab_netdev,
> + index_hlist);
> +
> + while (dev) {
> + odev = (netdev == dev->dev) ? dev : NULL;
> + dev = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(&dev->index_hlist)),
> + struct bpf_dtab_netdev,
> + index_hlist);
> +
> + if (odev) {
> + hlist_del_rcu(&odev->index_hlist);
Would it race with the dev_map_hash's update/delete side?
> + call_rcu(&odev->rcu,
> + __dev_map_entry_free);
> + }
> + }
> + }
> +}
> +
> static int dev_map_notification(struct notifier_block *notifier,
> ulong event, void *ptr)
> {
> @@ -735,6 +764,11 @@ static int dev_map_notification(struct notifier_block *notifier,
> */
> rcu_read_lock();
> list_for_each_entry_rcu(dtab, &dev_map_list, list) {
> + if (dtab->map.map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
> + dev_map_hash_remove_netdev(dtab, netdev);
> + continue;
> + }
> +
> for (i = 0; i < dtab->map.max_entries; i++) {
> struct bpf_dtab_netdev *dev, *odev;
>
> --
> 2.23.0
>
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH bpf] xdp: Handle device unregister for devmap_hash map type
2019-10-16 13:28 [PATCH bpf] xdp: Handle device unregister for devmap_hash map type Toke Høiland-Jørgensen
2019-10-16 16:24 ` Martin Lau
@ 2019-10-16 20:09 ` Tetsuo Handa
2019-10-17 10:28 ` Toke Høiland-Jørgensen
2019-10-17 19:17 ` Andrii Nakryiko
2 siblings, 1 reply; 10+ messages in thread
From: Tetsuo Handa @ 2019-10-16 20:09 UTC (permalink / raw)
To: Toke Høiland-Jørgensen; +Cc: daniel, ast, bpf, netdev
On 2019/10/16 22:28, Toke Høiland-Jørgensen wrote:
> It seems I forgot to add handling of devmap_hash type maps to the device
> unregister hook for devmaps. This omission causes devices to not be
> properly released, which causes hangs.
>
> Fix this by adding the missing handler.
>
> Fixes: 6f9d451ab1a3 ("xdp: Add devmap_hash map type for looking up devices by hashed index")
> Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Well, regarding 6f9d451ab1a3, I think that we want explicit "(u64)" cast
@@ -97,6 +123,14 @@ static int dev_map_init_map(struct bpf_dtab *dtab, union bpf_attr *attr)
cost = (u64) dtab->map.max_entries * sizeof(struct bpf_dtab_netdev *);
cost += sizeof(struct list_head) * num_possible_cpus();
+ if (attr->map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
+ dtab->n_buckets = roundup_pow_of_two(dtab->map.max_entries);
+
+ if (!dtab->n_buckets) /* Overflow check */
+ return -EINVAL;
+ cost += sizeof(struct hlist_head) * dtab->n_buckets;
^here
+ }
+
/* if map size is larger than memlock limit, reject it */
err = bpf_map_charge_init(&dtab->map.memory, cost);
if (err)
like "(u64) dtab->map.max_entries * sizeof(struct bpf_dtab_netdev *)" does.
Otherwise, on 32bits build, "sizeof(struct hlist_head) * dtab->n_buckets" can become 0.
----------
#include <stdio.h>
#include <linux/types.h>
int main(int argc, char *argv[])
{
volatile __u32 i = 4294967296ULL / sizeof(unsigned long *);
volatile __u64 cost = sizeof(unsigned long *) * i;
printf("cost=%llu\n", (unsigned long long) cost);
return 0;
}
----------
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH bpf] xdp: Handle device unregister for devmap_hash map type
2019-10-16 16:24 ` Martin Lau
@ 2019-10-17 10:27 ` Toke Høiland-Jørgensen
0 siblings, 0 replies; 10+ messages in thread
From: Toke Høiland-Jørgensen @ 2019-10-17 10:27 UTC (permalink / raw)
To: Martin Lau; +Cc: daniel, Alexei Starovoitov, bpf, netdev, Tetsuo Handa
Martin Lau <kafai@fb.com> writes:
> On Wed, Oct 16, 2019 at 03:28:02PM +0200, Toke Høiland-Jørgensen wrote:
>> It seems I forgot to add handling of devmap_hash type maps to the device
>> unregister hook for devmaps. This omission causes devices to not be
>> properly released, which causes hangs.
>>
>> Fix this by adding the missing handler.
>>
>> Fixes: 6f9d451ab1a3 ("xdp: Add devmap_hash map type for looking up devices by hashed index")
>> Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
>> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
>> ---
>> kernel/bpf/devmap.c | 34 ++++++++++++++++++++++++++++++++++
>> 1 file changed, 34 insertions(+)
>>
>> diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
>> index d27f3b60ff6d..deb9416341e9 100644
>> --- a/kernel/bpf/devmap.c
>> +++ b/kernel/bpf/devmap.c
>> @@ -719,6 +719,35 @@ const struct bpf_map_ops dev_map_hash_ops = {
>> .map_check_btf = map_check_no_btf,
>> };
>>
>> +static void dev_map_hash_remove_netdev(struct bpf_dtab *dtab,
>> + struct net_device *netdev)
>> +{
>> + int i;
>> +
>> + for (i = 0; i < dtab->n_buckets; i++) {
>> + struct bpf_dtab_netdev *dev, *odev;
>> + struct hlist_head *head;
>> +
>> + head = dev_map_index_hash(dtab, i);
>> + dev = hlist_entry_safe(rcu_dereference_raw(hlist_first_rcu(head)),
>> + struct bpf_dtab_netdev,
>> + index_hlist);
>> +
>> + while (dev) {
>> + odev = (netdev == dev->dev) ? dev : NULL;
>> + dev = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(&dev->index_hlist)),
>> + struct bpf_dtab_netdev,
>> + index_hlist);
>> +
>> + if (odev) {
>> + hlist_del_rcu(&odev->index_hlist);
> Would it race with the dev_map_hash's update/delete side?
Oh, right, seems I forgot to grab the lock; will send a v2!
-Toke
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH bpf] xdp: Handle device unregister for devmap_hash map type
2019-10-16 20:09 ` Tetsuo Handa
@ 2019-10-17 10:28 ` Toke Høiland-Jørgensen
2019-10-17 15:23 ` Alexei Starovoitov
0 siblings, 1 reply; 10+ messages in thread
From: Toke Høiland-Jørgensen @ 2019-10-17 10:28 UTC (permalink / raw)
To: Tetsuo Handa; +Cc: daniel, ast, bpf, netdev
Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> writes:
> On 2019/10/16 22:28, Toke Høiland-Jørgensen wrote:
>> It seems I forgot to add handling of devmap_hash type maps to the device
>> unregister hook for devmaps. This omission causes devices to not be
>> properly released, which causes hangs.
>>
>> Fix this by adding the missing handler.
>>
>> Fixes: 6f9d451ab1a3 ("xdp: Add devmap_hash map type for looking up devices by hashed index")
>> Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
>> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
>
> Well, regarding 6f9d451ab1a3, I think that we want explicit "(u64)" cast
>
> @@ -97,6 +123,14 @@ static int dev_map_init_map(struct bpf_dtab *dtab, union bpf_attr *attr)
> cost = (u64) dtab->map.max_entries * sizeof(struct bpf_dtab_netdev *);
> cost += sizeof(struct list_head) * num_possible_cpus();
>
> + if (attr->map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
> + dtab->n_buckets = roundup_pow_of_two(dtab->map.max_entries);
> +
> + if (!dtab->n_buckets) /* Overflow check */
> + return -EINVAL;
> + cost += sizeof(struct hlist_head) * dtab->n_buckets;
>
> ^here
>
> + }
> +
> /* if map size is larger than memlock limit, reject it */
> err = bpf_map_charge_init(&dtab->map.memory, cost);
> if (err)
>
> like "(u64) dtab->map.max_entries * sizeof(struct bpf_dtab_netdev *)" does.
> Otherwise, on 32bits build, "sizeof(struct hlist_head) * dtab->n_buckets" can become 0.
Oh, right. I kinda assumed the compiler would be smart enough to figure
that out based on the type of the LHS; will send a separate fix for this.
-Toke
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH bpf] xdp: Handle device unregister for devmap_hash map type
2019-10-17 10:28 ` Toke Høiland-Jørgensen
@ 2019-10-17 15:23 ` Alexei Starovoitov
2019-10-17 15:40 ` Toke Høiland-Jørgensen
0 siblings, 1 reply; 10+ messages in thread
From: Alexei Starovoitov @ 2019-10-17 15:23 UTC (permalink / raw)
To: Toke Høiland-Jørgensen, Tetsuo Handa; +Cc: daniel, bpf, netdev
On 10/17/19 3:28 AM, Toke Høiland-Jørgensen wrote:
> Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> writes:
>
>> On 2019/10/16 22:28, Toke Høiland-Jørgensen wrote:
>>> It seems I forgot to add handling of devmap_hash type maps to the device
>>> unregister hook for devmaps. This omission causes devices to not be
>>> properly released, which causes hangs.
>>>
>>> Fix this by adding the missing handler.
>>>
>>> Fixes: 6f9d451ab1a3 ("xdp: Add devmap_hash map type for looking up devices by hashed index")
>>> Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
>>> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
>>
>> Well, regarding 6f9d451ab1a3, I think that we want explicit "(u64)" cast
>>
>> @@ -97,6 +123,14 @@ static int dev_map_init_map(struct bpf_dtab *dtab, union bpf_attr *attr)
>> cost = (u64) dtab->map.max_entries * sizeof(struct bpf_dtab_netdev *);
>> cost += sizeof(struct list_head) * num_possible_cpus();
>>
>> + if (attr->map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
>> + dtab->n_buckets = roundup_pow_of_two(dtab->map.max_entries);
>> +
>> + if (!dtab->n_buckets) /* Overflow check */
>> + return -EINVAL;
>> + cost += sizeof(struct hlist_head) * dtab->n_buckets;
>>
>> ^here
>>
>> + }
>> +
>> /* if map size is larger than memlock limit, reject it */
>> err = bpf_map_charge_init(&dtab->map.memory, cost);
>> if (err)
>>
>> like "(u64) dtab->map.max_entries * sizeof(struct bpf_dtab_netdev *)" does.
>> Otherwise, on 32bits build, "sizeof(struct hlist_head) * dtab->n_buckets" can become 0.
>
> Oh, right. I kinda assumed the compiler would be smart enough to figure
> that out based on the type of the LHS; will send a separate fix for this.
compiler smart enough?! you must be kidding.
It's a C standard. Compiler has to do 32 bit multiply because n_buckets
is u32 and sizeof is 32 bit in 32bit arches as Tetsuo explained.
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH bpf] xdp: Handle device unregister for devmap_hash map type
2019-10-17 15:23 ` Alexei Starovoitov
@ 2019-10-17 15:40 ` Toke Høiland-Jørgensen
0 siblings, 0 replies; 10+ messages in thread
From: Toke Høiland-Jørgensen @ 2019-10-17 15:40 UTC (permalink / raw)
To: Alexei Starovoitov, Tetsuo Handa; +Cc: daniel, bpf, netdev
Alexei Starovoitov <ast@fb.com> writes:
> On 10/17/19 3:28 AM, Toke Høiland-Jørgensen wrote:
>> Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> writes:
>>
>>> On 2019/10/16 22:28, Toke Høiland-Jørgensen wrote:
>>>> It seems I forgot to add handling of devmap_hash type maps to the device
>>>> unregister hook for devmaps. This omission causes devices to not be
>>>> properly released, which causes hangs.
>>>>
>>>> Fix this by adding the missing handler.
>>>>
>>>> Fixes: 6f9d451ab1a3 ("xdp: Add devmap_hash map type for looking up devices by hashed index")
>>>> Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
>>>> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
>>>
>>> Well, regarding 6f9d451ab1a3, I think that we want explicit "(u64)" cast
>>>
>>> @@ -97,6 +123,14 @@ static int dev_map_init_map(struct bpf_dtab *dtab, union bpf_attr *attr)
>>> cost = (u64) dtab->map.max_entries * sizeof(struct bpf_dtab_netdev *);
>>> cost += sizeof(struct list_head) * num_possible_cpus();
>>>
>>> + if (attr->map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
>>> + dtab->n_buckets = roundup_pow_of_two(dtab->map.max_entries);
>>> +
>>> + if (!dtab->n_buckets) /* Overflow check */
>>> + return -EINVAL;
>>> + cost += sizeof(struct hlist_head) * dtab->n_buckets;
>>>
>>> ^here
>>>
>>> + }
>>> +
>>> /* if map size is larger than memlock limit, reject it */
>>> err = bpf_map_charge_init(&dtab->map.memory, cost);
>>> if (err)
>>>
>>> like "(u64) dtab->map.max_entries * sizeof(struct bpf_dtab_netdev *)" does.
>>> Otherwise, on 32bits build, "sizeof(struct hlist_head) * dtab->n_buckets" can become 0.
>>
>> Oh, right. I kinda assumed the compiler would be smart enough to figure
>> that out based on the type of the LHS; will send a separate fix for this.
>
> compiler smart enough?! you must be kidding.
> It's a C standard. Compiler has to do 32 bit multiply because n_buckets
> is u32 and sizeof is 32 bit in 32bit arches as Tetsuo explained.
Sure, I can see that now that Tetsuo pointed it out (thanks for that,
BTW!).
I'm just saying that since it's being assigned to a u64, the fact that
the calculation is not automatically promoted to 64-bit is somewhat
unintuitive (to me), regardless of whether it's in the standard or not.
-Toke
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH bpf] xdp: Handle device unregister for devmap_hash map type
2019-10-16 13:28 [PATCH bpf] xdp: Handle device unregister for devmap_hash map type Toke Høiland-Jørgensen
2019-10-16 16:24 ` Martin Lau
2019-10-16 20:09 ` Tetsuo Handa
@ 2019-10-17 19:17 ` Andrii Nakryiko
2019-10-18 10:31 ` Toke Høiland-Jørgensen
2 siblings, 1 reply; 10+ messages in thread
From: Andrii Nakryiko @ 2019-10-17 19:17 UTC (permalink / raw)
To: Toke Høiland-Jørgensen
Cc: Daniel Borkmann, Alexei Starovoitov, bpf, Networking, Tetsuo Handa
On Wed, Oct 16, 2019 at 9:07 AM Toke Høiland-Jørgensen <toke@redhat.com> wrote:
>
> It seems I forgot to add handling of devmap_hash type maps to the device
> unregister hook for devmaps. This omission causes devices to not be
> properly released, which causes hangs.
>
> Fix this by adding the missing handler.
>
> Fixes: 6f9d451ab1a3 ("xdp: Add devmap_hash map type for looking up devices by hashed index")
> Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
> ---
> kernel/bpf/devmap.c | 34 ++++++++++++++++++++++++++++++++++
> 1 file changed, 34 insertions(+)
>
[...]
> +
> + while (dev) {
> + odev = (netdev == dev->dev) ? dev : NULL;
> + dev = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(&dev->index_hlist)),
Please run scripts/checkpatch.pl, this looks like a rather long line.
> + struct bpf_dtab_netdev,
> + index_hlist);
[...]
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH bpf] xdp: Handle device unregister for devmap_hash map type
2019-10-17 19:17 ` Andrii Nakryiko
@ 2019-10-18 10:31 ` Toke Høiland-Jørgensen
2019-10-18 16:28 ` Andrii Nakryiko
0 siblings, 1 reply; 10+ messages in thread
From: Toke Høiland-Jørgensen @ 2019-10-18 10:31 UTC (permalink / raw)
To: Andrii Nakryiko
Cc: Daniel Borkmann, Alexei Starovoitov, bpf, Networking, Tetsuo Handa
Andrii Nakryiko <andrii.nakryiko@gmail.com> writes:
> On Wed, Oct 16, 2019 at 9:07 AM Toke Høiland-Jørgensen <toke@redhat.com> wrote:
>>
>> It seems I forgot to add handling of devmap_hash type maps to the device
>> unregister hook for devmaps. This omission causes devices to not be
>> properly released, which causes hangs.
>>
>> Fix this by adding the missing handler.
>>
>> Fixes: 6f9d451ab1a3 ("xdp: Add devmap_hash map type for looking up devices by hashed index")
>> Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
>> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
>> ---
>> kernel/bpf/devmap.c | 34 ++++++++++++++++++++++++++++++++++
>> 1 file changed, 34 insertions(+)
>>
>
> [...]
>
>> +
>> + while (dev) {
>> + odev = (netdev == dev->dev) ? dev : NULL;
>> + dev = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(&dev->index_hlist)),
>
> Please run scripts/checkpatch.pl, this looks like a rather long line.
That was a deliberate departure from the usual line length, actually. I
don't think it helps readability to split that into three lines just to
adhere to a strict line length requirement...
-Toke
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH bpf] xdp: Handle device unregister for devmap_hash map type
2019-10-18 10:31 ` Toke Høiland-Jørgensen
@ 2019-10-18 16:28 ` Andrii Nakryiko
0 siblings, 0 replies; 10+ messages in thread
From: Andrii Nakryiko @ 2019-10-18 16:28 UTC (permalink / raw)
To: Toke Høiland-Jørgensen
Cc: Daniel Borkmann, Alexei Starovoitov, bpf, Networking, Tetsuo Handa
On Fri, Oct 18, 2019 at 3:31 AM Toke Høiland-Jørgensen <toke@redhat.com> wrote:
>
> Andrii Nakryiko <andrii.nakryiko@gmail.com> writes:
>
> > On Wed, Oct 16, 2019 at 9:07 AM Toke Høiland-Jørgensen <toke@redhat.com> wrote:
> >>
> >> It seems I forgot to add handling of devmap_hash type maps to the device
> >> unregister hook for devmaps. This omission causes devices to not be
> >> properly released, which causes hangs.
> >>
> >> Fix this by adding the missing handler.
> >>
> >> Fixes: 6f9d451ab1a3 ("xdp: Add devmap_hash map type for looking up devices by hashed index")
> >> Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> >> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
> >> ---
> >> kernel/bpf/devmap.c | 34 ++++++++++++++++++++++++++++++++++
> >> 1 file changed, 34 insertions(+)
> >>
> >
> > [...]
> >
> >> +
> >> + while (dev) {
> >> + odev = (netdev == dev->dev) ? dev : NULL;
> >> + dev = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(&dev->index_hlist)),
> >
> > Please run scripts/checkpatch.pl, this looks like a rather long line.
>
> That was a deliberate departure from the usual line length, actually. I
> don't think it helps readability to split that into three lines just to
> adhere to a strict line length requirement...
Wouldn't local variable make it even more readable?
>
> -Toke
>
^ permalink raw reply [flat|nested] 10+ messages in thread
end of thread, other threads:[~2019-10-18 16:28 UTC | newest]
Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-10-16 13:28 [PATCH bpf] xdp: Handle device unregister for devmap_hash map type Toke Høiland-Jørgensen
2019-10-16 16:24 ` Martin Lau
2019-10-17 10:27 ` Toke Høiland-Jørgensen
2019-10-16 20:09 ` Tetsuo Handa
2019-10-17 10:28 ` Toke Høiland-Jørgensen
2019-10-17 15:23 ` Alexei Starovoitov
2019-10-17 15:40 ` Toke Høiland-Jørgensen
2019-10-17 19:17 ` Andrii Nakryiko
2019-10-18 10:31 ` Toke Høiland-Jørgensen
2019-10-18 16:28 ` Andrii Nakryiko
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