summaryrefslogtreecommitdiff
path: root/kernel/livepatch
diff options
context:
space:
mode:
authorJosh Poimboeuf <jpoimboe@kernel.org>2023-03-13 16:33:46 -0700
committerPeter Zijlstra <peterz@infradead.org>2023-03-22 17:09:28 +0100
commite92606fa172f63a26054885b9715be86c643229d (patch)
tree022048ed36c664375b89742636a99c64df88f0e2 /kernel/livepatch
parent41abdba9374734b743019fc1cc05e3225c82ba6b (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
Diffstat (limited to 'kernel/livepatch')
-rw-r--r--kernel/livepatch/transition.c9
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;