Re: [net-next] bpf: avoid hashtab deadlock with try_lock

[Tonghao Zhang <xiangxia.m.yue@gmail.com>]

On Thu, Nov 24, 2022 at 10:13 PM Hou Tao <houtao1@huawei.com> wrote:
>
> Hi,
>
> On 11/24/2022 8:57 PM, Tonghao Zhang wrote:
> > On Tue, Nov 22, 2022 at 12:06 PM Hou Tao <houtao1@huawei.com> wrote:
> >> Hi,
> >>
> >> On 11/22/2022 12:01 PM, Hou Tao wrote:
> >>> Hi,
> >>>
> >>> On 11/22/2022 11:12 AM, Tonghao Zhang wrote:
> >>>> .
> >>>>
> >>>> On Tue, Nov 22, 2022 at 9:16 AM Hou Tao <houtao1@huawei.com> wrote:
> >>>>> Hi,
> >>>>>
> >>>>> On 11/21/2022 6:05 PM, xiangxia.m.yue@gmail.com wrote:
> >>>>>> From: Tonghao Zhang <xiangxia.m.yue@gmail.com>
> >>>>>>
> >>>>>> The commit 20b6cc34ea74 ("bpf: Avoid hashtab deadlock with map_locked"),
> >>>>>> try to fix deadlock, but in some case, the deadlock occurs:
> >>>>>>
> >>>>>> * CPUn in task context with K1, and taking lock.
> >>>>>> * CPUn interrupted by NMI context, with K2.
> >>>>>> * They are using the same bucket, but different map_locked.
> >>>>> It is possible when n_buckets is less than HASHTAB_MAP_LOCK_COUNT (e.g.,
> >>>>> n_bucket=4). If using hash & min(HASHTAB_MAP_LOCK_MASK, n_bucket - 1) as the
> >>>>> index of map_locked, I think the deadlock will be gone.
> >>>> Yes, but for saving memory, HASHTAB_MAP_LOCK_MASK should not be too
> >>>> large(now this value is 8-1).
> >>>> if user define n_bucket ,e.g 8192, the part of bucket only are
> >>>> selected via hash & min(HASHTAB_MAP_LOCK_MASK, n_bucket - 1).
> >> I don't mean to extend map_locked. Using hash & min(HASHTAB_MAP_LOCK_MASK,
> >> n_bucket - 1) as index of map_locked  can guarantee the same map_locked will be
> >> used if different update processes are using the same bucket lock.
> > Thanks, I got it. but I tried it using the hash = hash &
> > min(HASHTAB_MAP_LOCK_MASK, htab->n_buckets -1) in
> > htab_lock_bucket/htab_unlock_bucket.
> > But the warning occur again.
> Does the deadlock happen ? Or just get the warning from lockdep. Maybe it is
> just a false alarm from lockdep. I will check tomorrow. Could you share the
> steps on how to reproduce the problem, specially the size of the hash table ?
Hi
only a warning from lockdep.
1. the kernel .config
#
# Debug Oops, Lockups and Hangs
#
CONFIG_PANIC_ON_OOPS=y
CONFIG_PANIC_ON_OOPS_VALUE=1
CONFIG_PANIC_TIMEOUT=0
CONFIG_LOCKUP_DETECTOR=y
CONFIG_SOFTLOCKUP_DETECTOR=y
# CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC is not set
CONFIG_HARDLOCKUP_DETECTOR_PERF=y
CONFIG_HARDLOCKUP_CHECK_TIMESTAMP=y
CONFIG_HARDLOCKUP_DETECTOR=y
CONFIG_BOOTPARAM_HARDLOCKUP_PANIC=y
CONFIG_DETECT_HUNG_TASK=y
CONFIG_DEFAULT_HUNG_TASK_TIMEOUT=120
# CONFIG_BOOTPARAM_HUNG_TASK_PANIC is not set
# CONFIG_WQ_WATCHDOG is not set
# CONFIG_TEST_LOCKUP is not set
# end of Debug Oops, Lockups and Hangs

2. bpf.c, the map size is 2.
struct {
__uint(type, BPF_MAP_TYPE_HASH);
__uint(max_entries, 2);
__uint(key_size, sizeof(unsigned int));
__uint(value_size, sizeof(unsigned int));
} map1 SEC(".maps");

static int bpf_update_data()
{
unsigned int val = 1, key = 0;

return bpf_map_update_elem(&map1, &key, &val, BPF_ANY);
}

SEC("kprobe/ip_rcv")
int bpf_prog1(struct pt_regs *regs)
{
bpf_update_data();
return 0;
}

SEC("tracepoint/nmi/nmi_handler")
int bpf_prog2(struct pt_regs *regs)
{
bpf_update_data();
return 0;
}

char _license[] SEC("license") = "GPL";
unsigned int _version SEC("version") = LINUX_VERSION_CODE;

3. bpf loader.
#include "kprobe-example.skel.h"

#include <unistd.h>
#include <errno.h>

#include <bpf/bpf.h>

int main()
{
struct kprobe_example *skel;
int map_fd, prog_fd;
int i;
int err = 0;

skel = kprobe_example__open_and_load();
if (!skel)
return -1;

err = kprobe_example__attach(skel);
if (err)
goto cleanup;

/* all libbpf APIs are usable */
prog_fd = bpf_program__fd(skel->progs.bpf_prog1);
map_fd = bpf_map__fd(skel->maps.map1);

printf("map_fd: %d\n", map_fd);

unsigned int val = 0, key = 0;

while (1) {
bpf_map_delete_elem(map_fd, &key);
bpf_map_update_elem(map_fd, &key, &val, BPF_ANY);
}

cleanup:
kprobe_example__destroy(skel);
return err;
}

4. run the bpf loader and perf record for nmi interrupts.  the warming occurs

> >   > > SNIP
> >>>>>> diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
> >>>>>> index 22855d6ff6d3..429acd97c869 100644
> >>>>>> --- a/kernel/bpf/hashtab.c
> >>>>>> +++ b/kernel/bpf/hashtab.c
> >>>>>> @@ -80,9 +80,6 @@ struct bucket {
> >>>>>>       raw_spinlock_t raw_lock;
> >>>>>>  };
> >>>>>>
> >>>>>> -#define HASHTAB_MAP_LOCK_COUNT 8
> >>>>>> -#define HASHTAB_MAP_LOCK_MASK (HASHTAB_MAP_LOCK_COUNT - 1)
> >>>>>> -
> >>>>>>  struct bpf_htab {
> >>>>>>       struct bpf_map map;
> >>>>>>       struct bpf_mem_alloc ma;
> >>>>>> @@ -104,7 +101,6 @@ struct bpf_htab {
> >>>>>>       u32 elem_size;  /* size of each element in bytes */
> >>>>>>       u32 hashrnd;
> >>>>>>       struct lock_class_key lockdep_key;
> >>>>>> -     int __percpu *map_locked[HASHTAB_MAP_LOCK_COUNT];
> >>>>>>  };
> >>>>>>
> >>>>>>  /* each htab element is struct htab_elem + key + value */
> >>>>>> @@ -146,35 +142,26 @@ static void htab_init_buckets(struct bpf_htab *htab)
> >>>>>>       }
> >>>>>>  }
> >>>>>>
> >>>>>> -static inline int htab_lock_bucket(const struct bpf_htab *htab,
> >>>>>> -                                struct bucket *b, u32 hash,
> >>>>>> +static inline int htab_lock_bucket(struct bucket *b,
> >>>>>>                                  unsigned long *pflags)
> >>>>>>  {
> >>>>>>       unsigned long flags;
> >>>>>>
> >>>>>> -     hash = hash & HASHTAB_MAP_LOCK_MASK;
> >>>>>> -
> >>>>>> -     preempt_disable();
> >>>>>> -     if (unlikely(__this_cpu_inc_return(*(htab->map_locked[hash])) != 1)) {
> >>>>>> -             __this_cpu_dec(*(htab->map_locked[hash]));
> >>>>>> -             preempt_enable();
> >>>>>> -             return -EBUSY;
> >>>>>> +     if (in_nmi()) {
> >>>>>> +             if (!raw_spin_trylock_irqsave(&b->raw_lock, flags))
> >>>>>> +                     return -EBUSY;
> >>>>>> +     } else {
> >>>>>> +             raw_spin_lock_irqsave(&b->raw_lock, flags);
> >>>>>>       }
> >>>>>>
> >>>>>> -     raw_spin_lock_irqsave(&b->raw_lock, flags);
> >>>>>>       *pflags = flags;
> >>>>>> -
> >>>>>>       return 0;
> >>>>>>  }
> >>>>> map_locked is also used to prevent the re-entrance of htab_lock_bucket() on the
> >>>>> same CPU, so only check in_nmi() is not enough.
> >>>> NMI, IRQ, and preempt may interrupt the task context.
> >>>> In htab_lock_bucket, raw_spin_lock_irqsave disable the preempt and
> >>>> irq. so only NMI may interrupt the codes, right ?
> >>> The re-entrance here means the nesting of bpf programs as show below:
> >>>
> >>> bpf_prog A
> >>> update map X
> >>>     htab_lock_bucket
> >>>         raw_spin_lock_irqsave()
> >>>     lookup_elem_raw()
> >>>         // bpf prog B is attached on lookup_elem_raw()
> > I am confused, bpf_prog A disables preempt and irq with
> > raw_spin_lock_irqsave. Why bpf prog B run here?
> Because program B (e.g., fentry program) has been attached on lookup_elem_raw(),
> calling lookup_elem_raw() will call the fentry program first. I had written a
> test case for the similar scenario in bpf selftests. The path of the test case
> is tools/testing/selftests/bpf/prog_tests/htab_update.c, you can use ./test_prog
> -t htab_update/reenter_update to run the test case.
> >>>         bpf prog B
> >>>             update map X again and update the element
> >>>                 htab_lock_bucket()
> >>>                     // dead-lock
> >>>                     raw_spinlock_irqsave()
> >>> .
> >>>
> >>>>>> -static inline void htab_unlock_bucket(const struct bpf_htab *htab,
> >>>>>> -                                   struct bucket *b, u32 hash,
> >>>>>> +static inline void htab_unlock_bucket(struct bucket *b,
> >>>>>>                                     unsigned long flags)
> >>>>>>  {
> >>>>>> -     hash = hash & HASHTAB_MAP_LOCK_MASK;
> >>>>>>       raw_spin_unlock_irqrestore(&b->raw_lock, flags);
> >>>>>> -     __this_cpu_dec(*(htab->map_locked[hash]));
> >>>>>> -     preempt_enable();
> >>>>>>  }
> >>>>>>
> >>>>>>  static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node);
> >>>>>> @@ -467,7 +454,7 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
> >>>>>>       bool percpu_lru = (attr->map_flags & BPF_F_NO_COMMON_LRU);
> >>>>>>       bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC);
> >>>>>>       struct bpf_htab *htab;
> >>>>>> -     int err, i;
> >>>>>> +     int err;
> >>>>>>
> >>>>>>       htab = bpf_map_area_alloc(sizeof(*htab), NUMA_NO_NODE);
> >>>>>>       if (!htab)
> >>>>>> @@ -513,15 +500,6 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
> >>>>>>       if (!htab->buckets)
> >>>>>>               goto free_htab;
> >>>>>>
> >>>>>> -     for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++) {
> >>>>>> -             htab->map_locked[i] = bpf_map_alloc_percpu(&htab->map,
> >>>>>> -                                                        sizeof(int),
> >>>>>> -                                                        sizeof(int),
> >>>>>> -                                                        GFP_USER);
> >>>>>> -             if (!htab->map_locked[i])
> >>>>>> -                     goto free_map_locked;
> >>>>>> -     }
> >>>>>> -
> >>>>>>       if (htab->map.map_flags & BPF_F_ZERO_SEED)
> >>>>>>               htab->hashrnd = 0;
> >>>>>>       else
> >>>>>> @@ -549,13 +527,13 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
> >>>>>>       if (htab->use_percpu_counter) {
> >>>>>>               err = percpu_counter_init(&htab->pcount, 0, GFP_KERNEL);
> >>>>>>               if (err)
> >>>>>> -                     goto free_map_locked;
> >>>>>> +                     goto free_buckets;
> >>>>>>       }
> >>>>>>
> >>>>>>       if (prealloc) {
> >>>>>>               err = prealloc_init(htab);
> >>>>>>               if (err)
> >>>>>> -                     goto free_map_locked;
> >>>>>> +                     goto free_buckets;
> >>>>>>
> >>>>>>               if (!percpu && !lru) {
> >>>>>>                       /* lru itself can remove the least used element, so
> >>>>>> @@ -568,12 +546,12 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
> >>>>>>       } else {
> >>>>>>               err = bpf_mem_alloc_init(&htab->ma, htab->elem_size, false);
> >>>>>>               if (err)
> >>>>>> -                     goto free_map_locked;
> >>>>>> +                     goto free_buckets;
> >>>>>>               if (percpu) {
> >>>>>>                       err = bpf_mem_alloc_init(&htab->pcpu_ma,
> >>>>>>                                                round_up(htab->map.value_size, 8), true);
> >>>>>>                       if (err)
> >>>>>> -                             goto free_map_locked;
> >>>>>> +                             goto free_buckets;
> >>>>>>               }
> >>>>>>       }
> >>>>>>
> >>>>>> @@ -581,11 +559,10 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
> >>>>>>
> >>>>>>  free_prealloc:
> >>>>>>       prealloc_destroy(htab);
> >>>>>> -free_map_locked:
> >>>>>> +free_buckets:
> >>>>>>       if (htab->use_percpu_counter)
> >>>>>>               percpu_counter_destroy(&htab->pcount);
> >>>>>> -     for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++)
> >>>>>> -             free_percpu(htab->map_locked[i]);
> >>>>>> +
> >>>>>>       bpf_map_area_free(htab->buckets);
> >>>>>>       bpf_mem_alloc_destroy(&htab->pcpu_ma);
> >>>>>>       bpf_mem_alloc_destroy(&htab->ma);
> >>>>>> @@ -782,7 +759,7 @@ static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node)
> >>>>>>       b = __select_bucket(htab, tgt_l->hash);
> >>>>>>       head = &b->head;
> >>>>>>
> >>>>>> -     ret = htab_lock_bucket(htab, b, tgt_l->hash, &flags);
> >>>>>> +     ret = htab_lock_bucket(b, &flags);
> >>>>>>       if (ret)
> >>>>>>               return false;
> >>>>>>
> >>>>>> @@ -793,7 +770,7 @@ static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node)
> >>>>>>                       break;
> >>>>>>               }
> >>>>>>
> >>>>>> -     htab_unlock_bucket(htab, b, tgt_l->hash, flags);
> >>>>>> +     htab_unlock_bucket(b, flags);
> >>>>>>
> >>>>>>       return l == tgt_l;
> >>>>>>  }
> >>>>>> @@ -1107,7 +1084,7 @@ static int htab_map_update_elem(struct bpf_map *map, void *key, void *value,
> >>>>>>                */
> >>>>>>       }
> >>>>>>
> >>>>>> -     ret = htab_lock_bucket(htab, b, hash, &flags);
> >>>>>> +     ret = htab_lock_bucket(b, &flags);
> >>>>>>       if (ret)
> >>>>>>               return ret;
> >>>>>>
> >>>>>> @@ -1152,7 +1129,7 @@ static int htab_map_update_elem(struct bpf_map *map, void *key, void *value,
> >>>>>>       }
> >>>>>>       ret = 0;
> >>>>>>  err:
> >>>>>> -     htab_unlock_bucket(htab, b, hash, flags);
> >>>>>> +     htab_unlock_bucket(b, flags);
> >>>>>>       return ret;
> >>>>>>  }
> >>>>>>
> >>>>>> @@ -1198,7 +1175,7 @@ static int htab_lru_map_update_elem(struct bpf_map *map, void *key, void *value,
> >>>>>>       copy_map_value(&htab->map,
> >>>>>>                      l_new->key + round_up(map->key_size, 8), value);
> >>>>>>
> >>>>>> -     ret = htab_lock_bucket(htab, b, hash, &flags);
> >>>>>> +     ret = htab_lock_bucket(b, &flags);
> >>>>>>       if (ret)
> >>>>>>               return ret;
> >>>>>>
> >>>>>> @@ -1219,7 +1196,7 @@ static int htab_lru_map_update_elem(struct bpf_map *map, void *key, void *value,
> >>>>>>       ret = 0;
> >>>>>>
> >>>>>>  err:
> >>>>>> -     htab_unlock_bucket(htab, b, hash, flags);
> >>>>>> +     htab_unlock_bucket(b, flags);
> >>>>>>
> >>>>>>       if (ret)
> >>>>>>               htab_lru_push_free(htab, l_new);
> >>>>>> @@ -1255,7 +1232,7 @@ static int __htab_percpu_map_update_elem(struct bpf_map *map, void *key,
> >>>>>>       b = __select_bucket(htab, hash);
> >>>>>>       head = &b->head;
> >>>>>>
> >>>>>> -     ret = htab_lock_bucket(htab, b, hash, &flags);
> >>>>>> +     ret = htab_lock_bucket(b, &flags);
> >>>>>>       if (ret)
> >>>>>>               return ret;
> >>>>>>
> >>>>>> @@ -1280,7 +1257,7 @@ static int __htab_percpu_map_update_elem(struct bpf_map *map, void *key,
> >>>>>>       }
> >>>>>>       ret = 0;
> >>>>>>  err:
> >>>>>> -     htab_unlock_bucket(htab, b, hash, flags);
> >>>>>> +     htab_unlock_bucket(b, flags);
> >>>>>>       return ret;
> >>>>>>  }
> >>>>>>
> >>>>>> @@ -1321,7 +1298,7 @@ static int __htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
> >>>>>>                       return -ENOMEM;
> >>>>>>       }
> >>>>>>
> >>>>>> -     ret = htab_lock_bucket(htab, b, hash, &flags);
> >>>>>> +     ret = htab_lock_bucket(b, &flags);
> >>>>>>       if (ret)
> >>>>>>               return ret;
> >>>>>>
> >>>>>> @@ -1345,7 +1322,7 @@ static int __htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
> >>>>>>       }
> >>>>>>       ret = 0;
> >>>>>>  err:
> >>>>>> -     htab_unlock_bucket(htab, b, hash, flags);
> >>>>>> +     htab_unlock_bucket(b, flags);
> >>>>>>       if (l_new)
> >>>>>>               bpf_lru_push_free(&htab->lru, &l_new->lru_node);
> >>>>>>       return ret;
> >>>>>> @@ -1384,7 +1361,7 @@ static int htab_map_delete_elem(struct bpf_map *map, void *key)
> >>>>>>       b = __select_bucket(htab, hash);
> >>>>>>       head = &b->head;
> >>>>>>
> >>>>>> -     ret = htab_lock_bucket(htab, b, hash, &flags);
> >>>>>> +     ret = htab_lock_bucket(b, &flags);
> >>>>>>       if (ret)
> >>>>>>               return ret;
> >>>>>>
> >>>>>> @@ -1397,7 +1374,7 @@ static int htab_map_delete_elem(struct bpf_map *map, void *key)
> >>>>>>               ret = -ENOENT;
> >>>>>>       }
> >>>>>>
> >>>>>> -     htab_unlock_bucket(htab, b, hash, flags);
> >>>>>> +     htab_unlock_bucket(b, flags);
> >>>>>>       return ret;
> >>>>>>  }
> >>>>>>
> >>>>>> @@ -1420,7 +1397,7 @@ static int htab_lru_map_delete_elem(struct bpf_map *map, void *key)
> >>>>>>       b = __select_bucket(htab, hash);
> >>>>>>       head = &b->head;
> >>>>>>
> >>>>>> -     ret = htab_lock_bucket(htab, b, hash, &flags);
> >>>>>> +     ret = htab_lock_bucket(b, &flags);
> >>>>>>       if (ret)
> >>>>>>               return ret;
> >>>>>>
> >>>>>> @@ -1431,7 +1408,7 @@ static int htab_lru_map_delete_elem(struct bpf_map *map, void *key)
> >>>>>>       else
> >>>>>>               ret = -ENOENT;
> >>>>>>
> >>>>>> -     htab_unlock_bucket(htab, b, hash, flags);
> >>>>>> +     htab_unlock_bucket(b, flags);
> >>>>>>       if (l)
> >>>>>>               htab_lru_push_free(htab, l);
> >>>>>>       return ret;
> >>>>>> @@ -1494,7 +1471,6 @@ static void htab_map_free_timers(struct bpf_map *map)
> >>>>>>  static void htab_map_free(struct bpf_map *map)
> >>>>>>  {
> >>>>>>       struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
> >>>>>> -     int i;
> >>>>>>
> >>>>>>       /* bpf_free_used_maps() or close(map_fd) will trigger this map_free callback.
> >>>>>>        * bpf_free_used_maps() is called after bpf prog is no longer executing.
> >>>>>> @@ -1517,10 +1493,10 @@ static void htab_map_free(struct bpf_map *map)
> >>>>>>       bpf_map_area_free(htab->buckets);
> >>>>>>       bpf_mem_alloc_destroy(&htab->pcpu_ma);
> >>>>>>       bpf_mem_alloc_destroy(&htab->ma);
> >>>>>> +
> >>>>>>       if (htab->use_percpu_counter)
> >>>>>>               percpu_counter_destroy(&htab->pcount);
> >>>>>> -     for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++)
> >>>>>> -             free_percpu(htab->map_locked[i]);
> >>>>>> +
> >>>>>>       lockdep_unregister_key(&htab->lockdep_key);
> >>>>>>       bpf_map_area_free(htab);
> >>>>>>  }
> >>>>>> @@ -1564,7 +1540,7 @@ static int __htab_map_lookup_and_delete_elem(struct bpf_map *map, void *key,
> >>>>>>       b = __select_bucket(htab, hash);
> >>>>>>       head = &b->head;
> >>>>>>
> >>>>>> -     ret = htab_lock_bucket(htab, b, hash, &bflags);
> >>>>>> +     ret = htab_lock_bucket(b, &bflags);
> >>>>>>       if (ret)
> >>>>>>               return ret;
> >>>>>>
> >>>>>> @@ -1602,7 +1578,7 @@ static int __htab_map_lookup_and_delete_elem(struct bpf_map *map, void *key,
> >>>>>>                       free_htab_elem(htab, l);
> >>>>>>       }
> >>>>>>
> >>>>>> -     htab_unlock_bucket(htab, b, hash, bflags);
> >>>>>> +     htab_unlock_bucket(b, bflags);
> >>>>>>
> >>>>>>       if (is_lru_map && l)
> >>>>>>               htab_lru_push_free(htab, l);
> >>>>>> @@ -1720,7 +1696,7 @@ __htab_map_lookup_and_delete_batch(struct bpf_map *map,
> >>>>>>       head = &b->head;
> >>>>>>       /* do not grab the lock unless need it (bucket_cnt > 0). */
> >>>>>>       if (locked) {
> >>>>>> -             ret = htab_lock_bucket(htab, b, batch, &flags);
> >>>>>> +             ret = htab_lock_bucket(b, &flags);
> >>>>>>               if (ret) {
> >>>>>>                       rcu_read_unlock();
> >>>>>>                       bpf_enable_instrumentation();
> >>>>>> @@ -1743,7 +1719,7 @@ __htab_map_lookup_and_delete_batch(struct bpf_map *map,
> >>>>>>               /* Note that since bucket_cnt > 0 here, it is implicit
> >>>>>>                * that the locked was grabbed, so release it.
> >>>>>>                */
> >>>>>> -             htab_unlock_bucket(htab, b, batch, flags);
> >>>>>> +             htab_unlock_bucket(b, flags);
> >>>>>>               rcu_read_unlock();
> >>>>>>               bpf_enable_instrumentation();
> >>>>>>               goto after_loop;
> >>>>>> @@ -1754,7 +1730,7 @@ __htab_map_lookup_and_delete_batch(struct bpf_map *map,
> >>>>>>               /* Note that since bucket_cnt > 0 here, it is implicit
> >>>>>>                * that the locked was grabbed, so release it.
> >>>>>>                */
> >>>>>> -             htab_unlock_bucket(htab, b, batch, flags);
> >>>>>> +             htab_unlock_bucket(b, flags);
> >>>>>>               rcu_read_unlock();
> >>>>>>               bpf_enable_instrumentation();
> >>>>>>               kvfree(keys);
> >>>>>> @@ -1815,7 +1791,7 @@ __htab_map_lookup_and_delete_batch(struct bpf_map *map,
> >>>>>>               dst_val += value_size;
> >>>>>>       }
> >>>>>>
> >>>>>> -     htab_unlock_bucket(htab, b, batch, flags);
> >>>>>> +     htab_unlock_bucket(b, flags);
> >>>>>>       locked = false;
> >>>>>>
> >>>>>>       while (node_to_free) {
> >>> .
> >
>


-- 
Best regards, Tonghao