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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 1/19/26 16:03, Zhengmian Hu wrote: > 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. > > Signed-off-by: Zhengmian Hu thanks, Acked-by: John Johansen I have pulled this into apparmor-next > --- > security/apparmor/lsm.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c > index 9b6c2f157..a6c884ba6 100644 > --- a/security/apparmor/lsm.c > +++ b/security/apparmor/lsm.c > @@ -1868,7 +1868,8 @@ char *aa_get_buffer(bool in_atomic) > if (!list_empty(&cache->head)) { > aa_buf = list_first_entry(&cache->head, union aa_buffer, list); > list_del(&aa_buf->list); > - cache->hold--; > + if (cache->hold) > + cache->hold--; > cache->count--; > put_cpu_ptr(&aa_local_buffers); > return &aa_buf->buffer[0];