diff options
| author | Hou Tao <houtao1@huawei.com> | 2022-09-01 09:19:35 +0300 |
|---|---|---|
| committer | Martin KaFai Lau <martin.lau@kernel.org> | 2022-09-01 22:16:12 +0300 |
| commit | 197827a05e13808c60f52632e9887eede63f1c16 (patch) | |
| tree | 3557bd01bd7498389f9e04d93a03fcb9d44b6ba8 /kernel/bpf/bpf_local_storage.c | |
| parent | c9ae8c966f05c85c5928c8f1790b13b71cc5ccd5 (diff) | |
| download | linux-197827a05e13808c60f52632e9887eede63f1c16.tar.xz | |
bpf: Use this_cpu_{inc|dec|inc_return} for bpf_task_storage_busy
Now migrate_disable() does not disable preemption and under some
architectures (e.g. arm64) __this_cpu_{inc|dec|inc_return} are neither
preemption-safe nor IRQ-safe, so for fully preemptible kernel concurrent
lookups or updates on the same task local storage and on the same CPU
may make bpf_task_storage_busy be imbalanced, and
bpf_task_storage_trylock() on the specific cpu will always fail.
Fixing it by using this_cpu_{inc|dec|inc_return} when manipulating
bpf_task_storage_busy.
Fixes: bc235cdb423a ("bpf: Prevent deadlock from recursive bpf_task_storage_[get|delete]")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/r/20220901061938.3789460-2-houtao@huaweicloud.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Diffstat (limited to 'kernel/bpf/bpf_local_storage.c')
| -rw-r--r-- | kernel/bpf/bpf_local_storage.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c index 4ee2e7286c23..802fc15b0d73 100644 --- a/kernel/bpf/bpf_local_storage.c +++ b/kernel/bpf/bpf_local_storage.c @@ -555,11 +555,11 @@ void bpf_local_storage_map_free(struct bpf_local_storage_map *smap, struct bpf_local_storage_elem, map_node))) { if (busy_counter) { migrate_disable(); - __this_cpu_inc(*busy_counter); + this_cpu_inc(*busy_counter); } bpf_selem_unlink(selem, false); if (busy_counter) { - __this_cpu_dec(*busy_counter); + this_cpu_dec(*busy_counter); migrate_enable(); } cond_resched_rcu(); |