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bpf: Add necessary migrate_disable to range_tree.

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When running bpf selftest (./test_progs -j), the following warnings
showed up:

  $ ./test_progs -t arena_atomics
  ...
  BUG: using smp_processor_id() in preemptible [00000000] code: kworker/u19:0/12501
  caller is bpf_mem_free+0x128/0x330
  ...
  Call Trace:
   <TASK>
   dump_stack_lvl
   check_preemption_disabled
   bpf_mem_free
   range_tree_destroy
   arena_map_free
   bpf_map_free_deferred
   process_scheduled_works
   ...

For selftests arena_htab and arena_list, similar smp_process_id() BUGs are
dumped, and the following are two stack trace:

   <TASK>
   dump_stack_lvl
   check_preemption_disabled
   bpf_mem_alloc
   range_tree_set
   arena_map_alloc
   map_create
   ...

   <TASK>
   dump_stack_lvl
   check_preemption_disabled
   bpf_mem_alloc
   range_tree_clear
   arena_vm_fault
   do_pte_missing
   handle_mm_fault
   do_user_addr_fault
   ...

Add migrate_{disable,enable}() around related bpf_mem_{alloc,free}()
calls to fix the issue.

Fixes: b795379757 ("bpf: Introduce range_tree data structure and use it in bpf arena")
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20241115060354.2832495-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Yonghong Song 2024-11-14 22:03:54 -08:00 committed by Alexei Starovoitov
parent ab4dc30c53
commit 4ff04abf9d
1 changed files with 10 additions and 0 deletions
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10
kernel/bpf/range_tree.c
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@ -150,7 +150,9 @@ int range_tree_clear(struct range_tree *rt, u32 start, u32 len)
range_it_insert(rn, rt);
/* Add a range */
migrate_disable();
new_rn = bpf_mem_alloc(&bpf_global_ma, sizeof(struct range_node));
migrate_enable();
if (!new_rn)
return -ENOMEM;
new_rn->rn_start = last + 1;
@ -170,7 +172,9 @@ int range_tree_clear(struct range_tree *rt, u32 start, u32 len)
} else {
/* in the middle of the clearing range */
range_it_remove(rn, rt);
migrate_disable();
bpf_mem_free(&bpf_global_ma, rn);
migrate_enable();
}
}
return 0;
@ -223,7 +227,9 @@ int range_tree_set(struct range_tree *rt, u32 start, u32 len)
range_it_remove(right, rt);
left->rn_last = right->rn_last;
range_it_insert(left, rt);
migrate_disable();
bpf_mem_free(&bpf_global_ma, right);
migrate_enable();
} else if (left) {
/* Combine with the left range */
range_it_remove(left, rt);
@ -235,7 +241,9 @@ int range_tree_set(struct range_tree *rt, u32 start, u32 len)
right->rn_start = start;
range_it_insert(right, rt);
} else {
migrate_disable();
left = bpf_mem_alloc(&bpf_global_ma, sizeof(struct range_node));
migrate_enable();
if (!left)
return -ENOMEM;
left->rn_start = start;
@ -251,7 +259,9 @@ void range_tree_destroy(struct range_tree *rt)
while ((rn = range_it_iter_first(rt, 0, -1U))) {
range_it_remove(rn, rt);
migrate_disable();
bpf_mem_free(&bpf_global_ma, rn);
migrate_enable();
}
}