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| author | Hou Tao <houtao1@huawei.com> | 2022-09-01 14:19:35 +0800 |
|---|---|---|
| committer | Martin KaFai Lau <martin.lau@kernel.org> | 2022-09-01 12:16:12 -0700 |
| commit | 197827a05e13808c60f52632e9887eede63f1c16 (patch) | |
| tree | 3557bd01bd7498389f9e04d93a03fcb9d44b6ba8 /kernel/async.c | |
| parent | c9ae8c966f05c85c5928c8f1790b13b71cc5ccd5 (diff) | |
| download | linux-197827a05e13808c60f52632e9887eede63f1c16.tar.gz | |
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/async.c')
0 files changed, 0 insertions, 0 deletions