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| author | Zhengmian Hu <huzhengmian@gmail.com> | 2026-01-19 19:03:07 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-02-26 14:59:42 -0800 |
| commit | 80c334acc6d0bee8605a358a33e69b4aea1ffb92 (patch) | |
| tree | 8e37c77233d8baabacf681cb4c840b737f16d19d /tools/perf/scripts/python/stackcollapse.py | |
| parent | 4610d536ff097adf470b3e52bb1eba96068bd501 (diff) | |
apparmor: avoid per-cpu hold underflow in aa_get_buffer
[ Upstream commit 640cf2f09575c9dc344b3f7be2498d31e3923ead ]
When aa_get_buffer() pulls from the per-cpu list it unconditionally
decrements cache->hold. If hold reaches 0 while count is still non-zero,
the unsigned decrement wraps to UINT_MAX. This keeps hold non-zero for a
very long time, so aa_put_buffer() never returns buffers to the global
list, which can starve other CPUs and force repeated kmalloc(aa_g_path_max)
allocations.
Guard the decrement so hold never underflows.
Fixes: ea9bae12d028 ("apparmor: cache buffers on percpu list if there is lock contention")
Signed-off-by: Zhengmian Hu <huzhengmian@gmail.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'tools/perf/scripts/python/stackcollapse.py')
0 files changed, 0 insertions, 0 deletions