diff options
| author | Josh Poimboeuf <jpoimboe@kernel.org> | 2023-03-13 16:33:46 -0700 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2023-03-22 17:09:28 +0100 |
| commit | e92606fa172f63a26054885b9715be86c643229d (patch) | |
| tree | 022048ed36c664375b89742636a99c64df88f0e2 | |
| parent | 41abdba9374734b743019fc1cc05e3225c82ba6b (diff) | |
livepatch: Convert stack entries array to percpu
The entries array in klp_check_stack() is static local because it's too
big to be reasonably allocated on the stack. Serialized access is
enforced by the klp_mutex.
In preparation for calling klp_check_stack() without the mutex (from
cond_resched), convert it to a percpu variable.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20230313233346.kayh4t2lpicjkpsv@treble
| -rw-r--r-- | kernel/livepatch/transition.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c index f1b25ec581e0..135fc73e2e5d 100644 --- a/kernel/livepatch/transition.c +++ b/kernel/livepatch/transition.c @@ -14,6 +14,8 @@ #include "transition.h" #define MAX_STACK_ENTRIES 100 +DEFINE_PER_CPU(unsigned long[MAX_STACK_ENTRIES], klp_stack_entries); + #define STACK_ERR_BUF_SIZE 128 #define SIGNALS_TIMEOUT 15 @@ -240,12 +242,15 @@ static int klp_check_stack_func(struct klp_func *func, unsigned long *entries, */ static int klp_check_stack(struct task_struct *task, const char **oldname) { - static unsigned long entries[MAX_STACK_ENTRIES]; + unsigned long *entries = this_cpu_ptr(klp_stack_entries); struct klp_object *obj; struct klp_func *func; int ret, nr_entries; - ret = stack_trace_save_tsk_reliable(task, entries, ARRAY_SIZE(entries)); + /* Protect 'klp_stack_entries' */ + lockdep_assert_preemption_disabled(); + + ret = stack_trace_save_tsk_reliable(task, entries, MAX_STACK_ENTRIES); if (ret < 0) return -EINVAL; nr_entries = ret; |