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| author | Yonghong Song <yonghong.song@linux.dev> | 2024-11-14 22:03:54 -0800 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2024-11-15 08:11:53 -0800 |
| commit | 4ff04abf9d5bc33d33c7a799887517619188b068 (patch) | |
| tree | 42539150acc9cbd6cfed90736706532f04f3fbe3 /kernel/bpf | |
| parent | ab4dc30c5322fc46d0db938d1c0bdd56d7adcea1 (diff) | |
| download | lwn-4ff04abf9d5bc33d33c7a799887517619188b068.tar.gz lwn-4ff04abf9d5bc33d33c7a799887517619188b068.zip | |
bpf: Add necessary migrate_disable to range_tree.
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: b795379757eb ("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>
Diffstat (limited to 'kernel/bpf')
| -rw-r--r-- | kernel/bpf/range_tree.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/kernel/bpf/range_tree.c b/kernel/bpf/range_tree.c index f7915ab0a6d3..5bdf9aadca3a 100644 --- a/kernel/bpf/range_tree.c +++ b/kernel/bpf/range_tree.c @@ -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(); } } |